AN EVALUATION OF THE PREVENTIVE AND CONTROL …
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MASTER’S THESIS 2003:069 CIV Sindiswa Eunice Tanda An Evaluation of the Preventive and Control Measures for Lead Dust Exposure in One of the South African Foundries MASTER OF SCIENCE PROGRAMME M.Sc. Programme in Industrial Ergonomics Department of Human Work Sciences Division of Industrial Ergonomics 2003:069 CIV • ISSN: 1402 - 1617 • ISRN: LTU - EX - - 03/69 - - SE
Transcript of AN EVALUATION OF THE PREVENTIVE AND CONTROL …
MASTER’S THESIS
2003:069 CIV
Sindiswa Eunice Tanda
An Evaluation of the Preventive andControl Measures for Lead Dust Exposure
in One of the South African Foundries
MASTER OF SCIENCE PROGRAMMEM.Sc. Programme in Industrial Ergonomics
Department of Human Work SciencesDivision of Industrial Ergonomics
2003:069 CIV • ISSN: 1402 - 1617 • ISRN: LTU - EX - - 03/69 - - SE
AN EVALUATION OF THE PREVENTIVE AND
CONTROL MEASURES FOR LEAD DUST EXPOSURE
IN ONE OF THE SOUTH AFRICAN FOUNDRIES
By
Sindiswa Eunice Tanda
For
Partial fulfilment of the
Master of Science in Ergonomics
Industrial Ergonomics
Department of Human Work Sciences
Luleå University of Technology
Supervisor
Moses Shaba
15 February, 2003
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TABLE OF CONTENTS
A. Abstract .........................................................................................................................7
B. Preface ...........................................................................................................................9
C. Abbreviations ...............................................................................................................10
D. Definitions of terms .....................................................................................................11
1. INTRODUCTION .......................................................................................................12
2. RELEVANCE OF STUDY .........................................................................................15
2.1 Objectives ....................................................................................................................15
2.2 Beneficiaries of the study ............................................................................................16
2.3 Hypothesis ...................................................................................................................16
3. LITERATURE REVIEW ............................................................................................17
3.1 Prevalence of occupational lead exposure ...................................................................17
3.1.1 Correlation between airborne lead levels ...............................................................18
3.1.2 Sources of lead exposures in industries .................................................................20
3.2 Effects of occupational lead overexposure ..................................................................21
3.2.1 Effects of lead on renal function ............................................................................24
3.2.2 Effects of lead on hearing systems ........................................................................26
3.2.3 Effects of lead on blood pressure ...........................................................................26
3.3 Physical effects of lead in industry ..............................................................................28
3.4 Studies of lead exposure for lead acid battery workers ...............................................28
3.5 Measurement of lead dust ............................................................................................32
3.6 Lead emission control measures ..................................................................................33
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3.6.1 Containment ...........................................................................................................34
3.6.2 Engineering controls............................. .................................................................34
3.6.2.1 Local exhaust ventilation........................................................................................35
3.6.2.2 General ventilation .................................................................................................35
3.6.2.3 Personal protective equipment ...............................................................................36
3.7 Ergonomical aspects of the work environment ............................................................37
4. EVALUATION OF THE PREVENTIVE AND CONTROL MEASURES FOR LEAD
EXPOSURE .................................................................................................................39
4.1 Methodology ................................................................................................................39
4.1.1 Study design ...........................................................................................................40
4.1.2 Independent variables ............................................................................................41
4.1.3 Dependent variables ...............................................................................................41
4.1.4 Subjects...................................................................................................................41
4.1.5 Limitations .............................................................................................................41
4.1.6 Data analysis ..........................................................................................................42
4.2 Results ..........................................................................................................................43
4.2.1 Description of lead production processes ..............................................................43
4.2.1.1 Detailed lead production process ...........................................................................45
4.2.2 Assessment of lead exposure during the recycling process ...................................48
4.2.3 Assessment of the preventive and control measures .............................................48
4.2.3.1 Safety programmes.................................................................................................48
4.2.3.2 Engineering controls ..............................................................................................49
4.2.3.2.1 Education and training .....................................................................................50
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4.2.3.3 Environmental monitoring .....................................................................................50
4.2.3.3.1 Air monitoring .................................................................................................51
4.2.3.3.2 Personal and static air sampling .......................................................................51
4.2.3.3.3 Stack monitoring...............................................................................................52
4.2.3.3.4 Ground water monitoring .................................................................................52
4.2.4 Personal protective equipment ...............................................................................54
4.2.5 Staff medical surveillance ......................................................................................55
4.2.5.1 Blood lead levels for the foundry workers .............................................................56
4.2.5.2 Comparison of lead blood levels against work experience ....................................57
4.2.5.3 Stratification of lead blood levels according to departments ................................61
4.2.6 Questionnaire and interviews .................................................................................62
4.2.6.1 Analysis of categorical variables ...........................................................................62
4.2.6.2 Perceptions about the work environment ...............................................................64
4.2.6.3 Health risks ............................................................................................................66
4.2.7 Analysis of physical measurements of airborne lead levels ..................................67
4.2.7.1 Maintenance area ...................................................................................................67
4.2.7.2 Change-room area ..................................................................................................69
4.2.7.3 Foreman offices .....................................................................................................71
4.2.7.4 Managers offices ....................................................................................................72
4.2.7.5 Yard area ................................................................................................................74
4.2.7.6 Smelters and refinery areas ....................................................................................75
4.3 Discussion ....................................................................................................................78
4.4 Conclusion ...................................................................................................................87
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4.5 Recommendations ........................................................................................................88
4.5.1 Engineering controls ..............................................................................................88
4.5.2 Personal protective equipment ...............................................................................89
4.5.3 Work organisation ..................................................................................................89
4.5.4 Housekeeping .........................................................................................................90
4.5.5 Personal hygiene ....................................................................................................90
5. ACKNOWLEDGEMENTS .........................................................................................91
6. REFERENCES ............................................................................................................92
7. APPENDICES ...........................................................................................................101
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LIST OF TABLES
Table 1: Range of health problems associated with various blood levels modified from
SHARP Programme (1994).
Table 2: Schedule for the air lead monitoring programme in 2002
Table 3: Blood lead levels for the foundry workers (2000 – 2002)
Table 4: The age group of the interviewed workers
Table 5: Duration of employment in the current positions
Table 6: Interview responses on workers’ perception of their work environment
Table 7: Summary of the reported illnesses linked with lead poisoning
Table 8: Summary of air lead results from the maintenance department
Table 9: Summary for lead air data in the change-room area
Table 10: Summary of air lead data in the foremen offices
Table 11: Air lead data from the managers’ offices
Table 12: Air lead data for the yard area
Table 13: Summary of air lead levels in the smelter and refinery areas
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LIST OF FIGURES
Figure 1: Mixed scrap lead recycled in this foundry
Figure 2: Finished product of the lead-recycling foundry
Figure 3: Summary of the foundry operation process
Figure 4: Some of the PPE used in the foundry
Figure 5: Blood lead levels of foundry workers
Figure 6: Blood levels vs work experience in the year 2000
Figure 7: Blood lead levels vs work experience in the year 2001
Figure 8: Blood lead levels vs work experience in 2002
Figure 9: Blood lead levels stratified according to departments for the year 2002
Figure 10: Lead in air levels in the maintenance area from January 2001 until September
2002
Figure 11: Air lead levels in the change rooms and canteen from January 2001 until
September 2002
Figure 12: Air lead levels in the foremen offices from January 2001 until September 2002
Figure 13: Air lead levels in the production managers’ offices from January 2001 until
September 2002
Figure 14: Lead in air levels in the yard area from December 2000 until September 2002
Figure 15: Air lead levels in the smelter and refinery area from January 2001 until
September 2002
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A. ABSTRACT
Foundry workers are exposed to numerous health hazards (WHO, 1999). However, there
are preventive and control measures available for dust hazards, which are stipulated by the
Occupational Health and Safety Act, 1993 (Act no. 85 of 1993). In particular, lead
exposure poses workers to illnesses. The aim of this study was to investigate the
effectiveness of the preventive and control measures of lead dust exposure implemented
in one of the South African foundries. The foundry recycles lead-acid batteries hence the
need to conduct a study in this workplace.
The contemporaneous data was gathered through the method of interviews with the
technical director and two environmental officers. Subjective information from the
workers was obtained by use of the questionnaire. Other information was obtained from
the walkthrough evaluation of the plant. For retrospective data (from the year 2000 until
2002), records for air monitoring and blood samples for lead was obtained from the
company. Other information was obtained from the company throughout the research
through correspondence with relevant stakeholders.
From this study it was found that the foundry implements the most effective preventive
and control measures for lead exposure. The measures that are implemented include
engineering and administrative controls, education and training, medical examinations and
air monitoring. It was reported that the engineering controls are implemented as the first
priority in controlling lead exposure in this foundry. Baghouses are the best engineering
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control measure that the environmental officers recommended. However, in areas such as
the battery breaking and smelting there were very high air and blood lead levels. These
high levels could be attributed to either improper maintenance of the engineering controls
or a lack of supervision or monitoring for regular use of PPE in designated areas.
From this study it was concluded and recommended that the foundry should consider an
effective maintenance programme for all control measures implemented in the foundry.
There should also be a clear policy regarding use of PPE. It is also recommended that the
management should allow workers to rotate and have autonomy in their work.
Housekeeping and personal hygiene should also be strictly enforced.
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B. PREFACE
The document contains information of the preventive and control measures for lead dust
exposure that are used in one of the South African foundries. It investigates the techniques
used by the management to protect workers from lead dust inhalation. The information is
obtained from the foundry’s records and from the workers themselves.
It was a great pleasure for me to be engaged in such an interesting project. It gave me an
insight of what is really happening in the industries. It had given me an urge for doing
more ergonomics case studies in order to improve the health of workers at their
workplaces. Furthermore, this creates awareness to the management, the workers and the
public about the health hazards that people are exposed to in the workplaces.
I hope everyone would benefit from it as I did when I was writing it.
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C. ABBREVIATIONS
Approved Inspection Authority (AIA)
Biological Exposure Index (BEI)
Haemoglobin (Hb)
Health and Safety Executive (HSE)
Local Exhaust Ventilation (LEV)
Maximum Exposure Limit (MEL)
Occupational Exposure Standard (OES)
Personal Protective Equipment (PPE)
Serum creatinine (SC)
South African Bureau of Standards (SABS)
Threshold Limit Value (TLV)
Uric acid (UA)
Urinary delta-aminolevulinic acid (ALAU)
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D. DEFINITION OF TERMS
1. Air Monitoring – The planning and carrying out of a measurement programme and
the recording of the results thereof.
2. Approved Lead Authority – An approved inspection authority for the monitoring of
lead concentrations in the air or analysis of blood lead or urinary lead concentrations.
3. Exposed – Exposed to lead while at the workplace.
4. Exposure – Exposure to lead while at the workplace.
5. Health and Safety Standard – Health and Safety Standards that have been
incorporated into the lead regulations under the Occupational Health and Safety Act,
1993 (Act No. 85 of 1993).
6. Lead – Lead, lead alloys and lead compounds that can be absorbed in anyway by any
person.
7. Occupational Exposure Limit for Lead – An exposure limit of 0.15 mg lead per
cubic meter of air, measured in accordance with a Health and Safety Standard.
8. Respiratory Protective Equipment – A device which is worn over at least the mouth
and nose to prevent the inhalation of air that is not safe and which furthermore
conforms to a standard approved by the Minister.
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1. INTRODUCTION
There are a number of occupational hazards in all workplaces worldwide due to a lack of
inadequate prevention and control measures (World Health Organisation (WHO), 1999).
Work is indispensable for the individual, society and for the development of nations.
Significant human suffering related to occupation is unacceptable and often results in
appreciable financial loss due to the burden on health and social security systems, which
impacts negatively on production and associated environmental costs (Goelzer, 1996).
Occupational diseases share many common characteristics with infectious diseases (Wu,
et. al. 1995). The prevention of occupational hazards is far more effective and less costly
when considered during the early stages, i.e. planning stage of any work process and
workplace controlling the preventive measures already in place. However, hazards can be
minimized by replacing the hazardous substance with a non-hazardous or by using these
substances without the exposure to workers. If this does not work or completely prevent
the exposure, then the emission of the substance to the air should be prevented or
minimized. As the last resort, use of personal protective equipment (PPE) including
respirator protective equipment (RPE) to the people exposed is necessary (WHO, 1999).
In order for controls to be effective, continuous supervision and maintenance is necessary.
The workplace control measures should be integrated with other measures such as control
of emissions to the atmosphere and waterways and waste disposal so that all these
measures work together. Moreover, control of exposure to dust should be a key priority to
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the top management and workers should continually get feedback from the management.
Incentive systems for supervisors and workers should be designed to encourage safe
procedures and not concern primarily to the productivity (WHO, 1999). Generally, more
resources are placed into dealing with the consequences of harmful occupational exposure
rather than prevention of such consequences (Newsletter of International Occupational
Hygiene Association, 2000).
It has been shown that there is under-reporting of occupational diseases (Mendes, 1978).
However, studies in different countries have shown reduction in the prevalence of
occupational respiratory diseases, as the result of the introduction of dust control measures
(Lee 1997), but the application of these measures is still not effective. For example,
silicosis has been known for centuries, but exposure to dusts containing free crystalline
silica still remains uncontrolled in many workplaces worldwide in both developing and
developed countries (Page, et. al. 1997). Another hazard that has not been properly
controlled is inorganic lead.
Lead is a naturally occurring soft, bluish-gray metal found in small amounts throughout
the environment. It has been used almost since the beginning of civilization. Lead can
combine with several substances to form numerous lead compounds (Safety and Health
Assessment for Research Programme (SHARP), 1999). About 40 percent of lead is used
as a metal, 25 percent in alloys and 35 percent in chemical compounds. Lead oxides are
used in the plates of electric batteries and accumulators and in other substances (Stellman
and Osinsky, 1997).
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Lead levels have increased enormously from the ancient times (Flegal and Smith, 1995).
The magnitude of increase has resulted in adverse health effects (Budd et. al, 1998). There
are many sources of lead exposure. These include dust, air, drinking water, food and
contaminated soil. Airborne lead enters the body when one breathes or swallows lead
particles or dust when lead has settled (Fact Sheet Library, 2002).
Lead is popular about its toxicity. In lead smelting industries, the main hazard is the lead
dust produced during the crushing and dry grinding operations and lead fumes and lead
oxide encountered in sintering, blast-furnace reduction and refining (Stellman and
Osinsky, 1997).
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2. RELEVANCE OF THE STUDY
In developing countries, lead-acid battery factories are one of the heaviest consumers of
lead (Araujo, et. al. 1999). Clinical lead poisoning is one of the most important
occupational diseases. However, reported cases have been reduced through the medical
and engineering prevention. It is therefore evident that the exposure levels in workplaces
that use lead are at acceptable ranges (Stellman and Osinsky, 1997). In South Africa, new
Lead Regulations have been compiled and were released in February 2002. These
regulations were amended from the Occupational Health and Safety Act, 1993. More
improvement in reporting cases of lead poisoning is expected in South African industries.
This study is therefore aimed at investigating such expected outcomes in one of the South
African foundries that recycles batteries as the major process of this industry.
2.1 Objectives
The main objectives of this study are to:
i. Identify the existing preventive and control measures in the selected foundry.
ii. Analyse the implementation of the preventive and control measures
iii. Make ergonomic recommendations that could improve the quality and
effectiveness of these measures.
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2.2 Beneficiaries of the study
The primary target beneficiaries are foundry workers who are exposed to lead dust near
the source of dust generation, and those who get exposure through disposal of dust to
distal sections of the plant. The families and the company as the whole would also benefit,
since the ill health of workers would influence the turnover of the company. Moreover,
people working in the companies situated near the foundry including the nearby
communities would also benefit from this study from environmental exposure.
2.3 Hypothesis
There are effective control and preventive measures for airborne lead dust in the selected
foundry.
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3. LITERATURE REVIEW
The purpose of this literature review is to obtain more information about the prevalence of
occupational lead exposure in industries, determine the effects of occupational lead over-
exposure and to review studies that have been done worldwide to investigate the problems
of over-exposure to lead.
3.1 Prevalence of occupational lead exposure in industries
Common workplaces which are likely to produce dust include mining, quarrying,
tunneling, construction and processes which separate solid material, foundries and other
metallurgical processes, any processes using abrasive blasting, glass and ceramic
manufacturing, handling of powdered chemicals, agricultural work and food processing
(WHO, 1999).
Lead is processed at foundries that cast molten metals into objects of desired shapes. The
essences of foundry processes are the melting and casting of metals. Basic foundry
operations include preparing sand for molds, cores, pattern making, mold and core
making, placing cores in mold cavities, melting alloys, pouring molten metal into mold
cavities, separating molds from castings and grinding irregularities from castings (i.e.
finishing) (Andjelkovich, et. al. 1990). The casting of iron, steel, light metals such as
aluminium and heavy metals such as copper and zinc are made in units that may be
independent or part of a production line (Pollution Prevention and Abatement Handbook,
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1998). Secondary aluminium melting is mainly performed in sand, die and static die-
casting foundries (Westberg et. al. 2001).
Regarding the economic contribution of the foundries to the country, it has been shown
that in the USA, the foundry industry currently produces 11 million tons of metal products
per year with a shipment value of $19 billion. Furthermore, about 200 000 people are
employed in more than 3 000 foundries in the USA, and these foundries make huge
profits. However, it has been a concern that these foundries employ less people than they
can (www.wmrc.uiuc.edu/manuals/primmetals/chapter3.htm). This is supported by the
studies done by Burgess (1995), which found that in the USA, the number of employees
in the foundries declined after 1991.
3.1.1 Correlation between airborne lead levels and blood lead levels
Idiebele (1994) conducted a study to investigate the possibility of the correlation between
lead in air and lead in blood. Idiebele found a positive correlation between these two
variables. However, Idiebele suggested a further investigation into the prediction of lead
in blood by monitoring lead in air. This was further supported by the study performed by
Park and Paik (2002) who also concluded that the measurement of lead in air may not be
adequate to reflect a worker’s exposure to lead particles with diverse characteristics.
These authors recommend that both respirable lead particles as well as lead in air be
measured. Ulenbelt, et. al. (1991) performed a study in a secondary smelter where data on
exposure to lead were collected by systematic observation of hygienic behaviour, a
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questionnaire, personal sampling of lead dust and ambient air and determination of lead in
blood. The results of that particular study were consistent with those that were obtained by
Idiebele in 1994 and Park and Paik in 2002, which revealed that a positive relation
between lead in air and lead in blood exists. These authors suspected that the confounding
factors could be the percentage of time of exposure and air stream helmet that were worn,
the amount of spitting, and frequency of cigarette smoking at the workplace. The two
former factors contribute to the reduction in lead in blood, whereas the latter contributes
to the higher lead in blood. Furthermore, a positive relation between the level of education
and the level of lead in blood was obtained. These authors concluded that the hygienic
behaviour is a major factor that modifies the relation between lead air and lead in blood in
several groups of workers.
Bashir et.al. (1995), investigated whether there is correlation between lead in blood
exposure and anaemia. These authors concluded that chronic lead exposure causes
normocytic normochromicanaemia and showed dose response relationship between lead
levels and severity of anaemia. In contrary to this, Froom et. al. (1999) found that blood
samples obtained from 94 workers in lead-acid battery plant in Israel between 1980 and
1993 exceeded 60 µg/dl in 14 % of the blood samples. They found no correlation between
haemoglobin and blood lead levels. These authors suggested that, a diagnosis of anaemia
in a person with blood lead levels up to 80 µg/dl should be considered to be due to lead
toxicity only after other causes for anemia are phased out. In Brazil, a cross sectional
study to evaluate the validity of the Brazilian biological exposure limits applied to lead
blood was conducted by Cordeiro, et. al. (1996). The results showed that the lead workers
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suffered from loss of memory, mood and motor coordination disorders. They also found
that there was a significant difference between this group and the control (P = 0.02).
Similar study conducted by Barth et. al. (2002) showed that there are significant
correlations between current exposure and cognitive deficits. However, they found no
correlation between cumulative exposure measures and cognitive parameters. These
authors were able to show that blood lead levels below 70 µg/dl reduce neuro-behavioural
abilities, in particular, the visio-spatial abilities and executive functions referring to the
prefrontal cortex. They concluded that the Brazilian biological exposure limits of 60 µg/dl
should be revised.
Lai et. al. (1997) found that improvements of hygienic practice was more effective at
lowering blood lead levels than reducing ambient lead level. Therefore, these authors
concluded that hygienic practice may be the preferential way to reduce lead exposure,
especially in developing countries as compared to the engineering controls.
3.1.2 Sources of lead exposures in industries
Common industrial processes which are likely to produce lead dust include mining,
quarrying, tunneling, construction, processes which separate solid material, foundries and
other metallurgical processes using abrasive blasting, glass and ceramic manufacturing,
handling of powdered chemicals, agricultural work and food processing (WHO, 1999).
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3.2 Effects of occupational lead over-exposure
The major route of lead exposure is oral ingestion. Inorganic lead is not metabolized. It is
directly absorbed, distributed and excreted. The rate of absorption depends on the
chemical and physical form and the physiological characteristics of the exposed person
such as, age and nutritional status. When lead reaches the blood, it is distributed primarily
among the three compartments blood; soft tissue such as kidney, bone marrow, liver and
brain; and in the mineralizing tissue such as bones and teeth. Absorption via the gastro-
intestinal tract proceeding ingestion is highly dependent on the presence of the levels of
calcium, iron, fats and proteins (U.S. Dept. of Labour, 1996). Exposure to excessive levels
of lead can cause brain damage, damage to kidneys, impair hearing, cause vomiting,
headaches, appetite loss and cause learning and behavioural problems, increase blood
pressure, cause digestive problems, nerve disorders, sleep problems etc. (Fact Sheet
Library, 2002).
Almost all inhaled lead is absorbed into the body, whereas only from 20 – 70 % of
ingested lead is absorbed (Agency for Toxic Substances and Disease Registry (ATSDR),
2002). Workers in the lead smelting, refining and manufacturing industries experience the
highest and most prolonged occupational exposures to lead (ATSDR, 2002). The major
exposure pathways for workers are inhalation and ingestion of lead-bearing dust and
fumes. It is also vitally important to note that occupational exposures can also result in
secondary exposure for workers’ families if workers bring home lead-contaminated dust
on their skin, clothes or shoes. ATSDR (1992) recommended that workers should prevent
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these secondary exposures by showering and or changing clothes before returning home.
Moreover, people living near battery recycling centres or other industrial lead sources
may be exposed to lead and chemicals that contain lead.
Overexposure to lead is the most common problem found in industry that results in
workplace illness. Occupational Safety and Health Administration (OSHA) has therefore
set a 5-year strategic plan to reduce the average severity of lead exposure of employee
blood lead levels by 15 % in selected workplaces.
Too much lead in ones body can damage the brain, nerves, kidneys or blood cells. Lead
can also affect the reproductive system in both men and women. However, most people
with lead poisoning do not feel sick or poisoned. In spite of the healthy feeling, high lead
levels may still seriously affect health. The longer the high levels exist in the blood, the
greater the risk of health problems and the damage may be irreversible (SHARP
Programme, 1994). Ranges of health problems associated with various blood lead levels
are presented in table 1.
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Table 1: Range of health problems associated with various blood lead levels modified
from SHARP Programme, (1994).
Lead Levels in the Blood
(µg/dl)
Severity of Health
Problems
Effects of Exposure
0 - 15 Typical level for adults Average adult blood lead levels in US.
15 - 20 Symptomless Fetal effects in pregnant women.
20 - 55 Symptomless lead
damage. Lead starts to
build up at +20 µg/dl
• Decreased blood production
• Male infertility, nerve damage
• Decreasing hearing, increased blood
pressure
55 - 80 Serious health damage
may happen
Anaemia, kidney failure and reduced
neuro-behavioural abilities.
80 - 110 Severe health damage
that may occur quickly
and be permanent
Brain damage (Encelophalopathy)
Chronic occupational exposure to lead is related to low urate excretion and a high
incidence of gout in lead workers (Lin et. al. 2002). Lead induced oxidative stress
contributes to the pathogenesis of lead poisoning for disrupting the delicate pro-oxidant-
antioxidant balance that exists within mammalian cells (Hsu and Guo, 2002). Moreover,
bone lead levels are higher in men who work in blue collar occupations even if they have
not worked in primary lead exposed occupations. This effect is even greater in non-white
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blue-collar workers and suggests an interaction between occupational exposures and race
with respect to cumulative exposure to lead (Elmarsafawy et. al. 2002).
3.2.1 Effects of lead on renal function
An increase in blood lead levels above 22.4 µg/dl follows an increase in urinary delta-
aminolevulinic acid (ALAU) and rise markedly above 35.5 µg/dl. In contrary, ALAU
level decreases with a concomitant rise in blood lead level lower than 20 µg/dl (Makino,
et. al. 2000). Pinto de Almeida et. al. (1989) assessed Brazilian lead workers and found
that renal dysfunction of workers from Lead exposed group was statistically associated
with duration of employment at the smelter and with age. They also reported that the
levels of lead and zinc in blood and ALAU did not affect the renal function.
Ehrlich et. al. (1998) investigated South African battery workers for the association
between inorganic lead exposure, blood pressure and renal function. The mean blood lead
levels was 53.4 µg/dl and the mean exposure duration was 11.6 years (range 0.5 to 44.5
years). The mean historical blood lead levels on 246 of 382 workers was 57.3 µg/dl. After
adjustment for age and other confounding parameters, it was found that an exposure-
response relation between lead and renal dysfunction across the range from less than 40
µg/dl up to greater than 70 µg/dl blood lead levels existed. This was found with
conventional measures of short and long term lead exposure and of renal function. These
authors believe that their finding probably reflected a higher cumulative renal burden of
lead exposure among industrial workers in South Africa.
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Wang et. al. (2002) investigated the correlation between blood lead levels and renal
function indices of blood-urea nitrogen (BUN), serum creatinine (SC) and uric acid (UA)
among lead battery workers who were exposed to lead. These authors reported that blood
lead levels higher than 60 µg/dl had increasing chances of inducing adverse renal effects.
Similarly, in studies conducted in Korea by Lee (1982), a dose-response relationship
between blood lead levels and ALAU was obtained. Lee, suggested that a lead blood level
below 50 – 60 µg/dl is a proper practical limit of biological monitoring for lead workers.
At a given lead blood concentration, the ALAU of lead workers increased with an
increase in the duration of exposure. Lee explained this as the chronic effect of lead on
haem precursors. Lilis et. al. (1979) conducted two clinical field studies of secondary lead
smelter workers. These researchers assessed BUN and creatinine levels with respect to
duration of lead exposure. These studies done by Lilis et. al. (1979) indicated that a
sizeable and significant decrement in kidney function in the secondary lead smelter
workers studied was found to be lead-induced. Moreover, the outcome of these studies
showed that the decrement of kidney function is age dependent.
Omae, et. al. (1990) conducted a cross-sectional study on 165 male lead exposed workers
to clarify the quantitative relationship between less severe exposure to lead and its effects
on renal function. The mean blood lead concentration was 36.5 µg/dl. The duration of
lead exposure was 0.1 to 26.3 years. Renal function indices of these workers from 1972 to
1984 were not different from those of remaining lead-exposed workers whose lead
exposure duration were 10 years or less. These authors concluded that long-term and less
severe exposure to lead up to 70 µg/dl of blood lead levels might not cause adverse effects
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on renal glomerular function and proximal tubular function. Furthermore, Lim et. al.
(2001) looked at the renal dysfunction of workers exposed to lead. These authors found
that there is a positive correlation between the overall lead exposure and renal
dysfunction. The renal parameters were significantly higher among those subjects with at
least one case of blood lead levels above 60 µg/dl.
3.2.2 Lead exposure on hearing systems
Wu et. al. (2000) conducted a study to investigate the effects of lead and noise exposures
on hearing ability. These authors found a significant correlation between a high, long-term
lead exposure index (defined by duration of employment and ambient lead concentration)
and decreased hearing ability. They also reported that lead via different systems may
damage hearing ability and in some cases may cause severe and irreversible damage.
However, neither noise exposure alone nor the interaction between noise exposure level
and short or long-term lead exposure was correlated significantly with hearing ability.
These authors then concluded that measures should be taken against lead exposure for
preservation of workers’ hearing ability.
3.2.3 Lead exposure on male fertility
Coste et.al. (1991) conducted a cohort study in a French battery factory between 1977 –
1982 to explore the relationship between occupational exposure to lead and fertility.
Findings of this study were that lead exposure at any level of absorption did not appear
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significantly associated with a reduction in fertility after controlling confounding factors
such as age, French origin, educational level, number of children at start of the period of
work, cigarette smoking and exposure to heat.
Studies of the association between occupational lead exposure with semen quality and
infertility among male workers have produced conflicting results. Robins, et. al. (1997)
studied workers from a South African lead-acid battery factory. The results obtained were
that lead in semen ranged from 1 to 87 µg/dl. There was a significant correlation between
an increased percentage of sperm with abnormal morphology and higher measures of
current blood lead, cumulative blood lead and duration of exposure. However, there were
no associations of sperm density or sperm count with any of the lead-exposed
measurements. The only valid outcome of that study was the relatively high range of
current blood lead levels and high prevalence of abnormalities in semen quality.
3.2.4 Lead exposure and blood pressure
Wu, et. al. (1996) assessed the relationship between occupational lead exposure and
elevated blood pressure with consideration of a possible confounding effect of noise
exposure. It should be noted that studies done by these authors showed no relation or
correlation between lead exposure and blood pressure. Gerr, et. al. (2002) in their study
that investigated the association between bone lead concentration and blood pressure
among young adults concluded that substantial lead exposure during childhood can
increase blood pressure during young adulthood. Pinto de Almeida et. al. (1989)
28
compared a group of 52 workers of a primary lead smelter located in North-East Brazil to
a reference group of 44 group of workers from a paper mill. It was found from the
exposed group that 32.7 percent had a greater SC level and these workers also had high
mean serum UA levels. These researchers found a strong association between
hypertension and renal dysfunction in the lead workers.
3.3 Physical effects of lead in industry
Lead powder poses a higher risk to cause fire than the solid because of its greater contact
area with air with resultant higher ignition characteristics. Lead dust cloud has similar risk
hazards like gas in causing fire. Accumulations of lead dust should be removed regularly
by techniques, which do not generate a dust cloud such as damp sweeping or vacuum
cleaning. Also, the electrical equipment in areas where flammable solids and powders are
handled or occur must be designed and maintained to the appropriate flameproof standard
(Ridley and Channing, 1999). Airborne flammable lead dust in sufficient concentrations
can explode posing danger of accidents. The combustible lead dust on the ground may
become airborne which may increase and propagate an explosion initiated by flammable
gas ignition. This occurs in all oxidisable dusts (WHO, 1999).
3.4 Studies of lead exposure for lead acid battery workers
Chao, et. al. (2002) reported that in Taiwan there were several reports about elevated
blood lead levels in lead battery workers. These authors visited all registered lead acid
29
battery plants in Taiwan and collected their health examination records. The average
blood lead concentration was found to be 37.1 µg/dl and 37 % of blood lead levels were
more than 40 µg/dl, the action level set by the Department of Health, Taiwan. From the
results of this study it was suggested that analysis should be performed each year to
monitor the effectiveness of occupational hygiene in the workplace of lead battery plants.
Earlier studies conducted by Chuang et. al. (1999) from1991 to 1997 in Taiwan have
shown that blood lead concentrations of workers in lead battery factories are more than
four times higher than those of the general population. During the first five years of the
study blood lead levels decreased significantly and the personal habits most closely
related to blood lead concentrations were smoking at work sites (P < 0.001) and eating at
work sites (P = 0.069). The risk ratio for workers with both these habits exceeding the
action level was 2.93 and the 95 percent confidence intervals (C.I.) were between 1.27
and 6.77. Moreover, differences in job titles also accounted for this variance. These
authors suggested an improvement in engineering controls for reduction of lead in these
workers.
Kononen (1991) conducted a study in lead acid storage battery workers and found that the
greatest absolute and percentage increases above baseline blood lead levels occurred
during the first three months of continuous exposure. The blood lead levels increased by
99 percent and the peak average blood lead levels were reached during the second quarter
of exposure for battery workers (27.3 µg/dl). However, the trend for quarterly doses were
not statistically significantly different and there was no exposure-related trend. In The
Phillipines, the medical examination of workers exposed to lead was conducted as part of
30
the activity of the Occupational Safety and Health Centre Project. The outcome of the
research was that there were high blood lead levels in the lead smelter and in the storage
battery manufacturer. The working group in these industries was old and the duration of
employment was long as compared to other industries that were researched. These two
companies had the highest exposure to lead hence the blood lead levels were higher
(Makino, et. al. 1994).
Jakubowski et. al. (1998) conducted a study to evaluate the effectiveness of the directive
from the Minister of Health and Social Welfare, Poland in 1996 stating that the blood lead
levels determinations in employees occupationally exposed to lead were compulsory. The
result of that study indicated that exposure to lead continues to be a serious problem in
Polish industry. Lead in blood concentrations exceeded the Polish biological exposure
index (BEI) value of 50 µg/dl for men. These results clearly showed the need to improve
on compliance of industries to ministerial ordinance.
Studies done by Suplido and Ong, (2000) in the small-scale battery recyclers showed that
the mean Lead in blood level was significantly high in battery workers (54.23 µg/dl).
Among the battery workers, 94 % had blood lead levels above the WHO permissible
exposure limit of 40 µg/dl for males and 30 µg/dl for females. It is important to note that,
children who live in the immediate vicinity of battery shops also had significantly higher
mean lead in blood levels (49.88 µg/dl).
31
Matte et. al. (1989) assessed lead exposure in lead acid battery industry in Jamaica. They
reported that engineering controls and respiratory protection were observed to be
inadequate in the industries studied. Workers with blood lead levels above 60 µg/dl
tended to have higher prevalence of most symptoms of lead toxicity than did workers with
lower blood lead levels. Although this finding was not statistically significant, it should be
noted that the finding of this research was in accordance with studies of battery workers in
other developing countries such as China and Iraq. In Taiwan, the Ministry of Health
developed an obligatory surveillance system for blood lead. This assisted in upgrading
the occupational disease control to the stage of specific prevention and health promotion
(Wu, et. al. 1995).
Hodgkins et. al. (1991) investigated a relationship between air lead levels and blood lead
levels in 132 lead acid battery workers in two plants. These workers were followed for 30
months between 1983 and1985. Their frequent air lead exposures and lead in blood were
determined. These plants converted to more modern technologies around 1978 with
associated reductions in mean lead in air exposures from greater than 100 µg/dl to less
than 30 µg/dl. There were however variations influenced by the seniority of the job
category, age, ethnicity, gender and smoking habits. Nuwayhid et. al. (2001) reported that
the non-occupational environmental exposure to lead is mainly caused by smoking and
exposure to leaded gasoline. The study by Nuwayhid et. al. (2001) revealed that
occupational exposure to lead was prevalent among a wide spectrum of Lebanese
workers. Another study conducted in Alabama among battery reclamation workers and
the workers’ family members showed that fourteen out of fifteen workers had blood lead
32
levels greater than 50 µg/dl. This increased significantly over a period of 2 years. Twelve
of the sixteen employees’ children had blood levels more than 10 µg/dl, and three children
had blood lead levels greater than 40 µg/dl (Gittleman, et. al. 1994).
3.5 Measurement of lead dust
A quantitative evaluation of airborne lead dust requires instruments with high precision
and which will select the correct size range for the hazard concerned. It is advisable to
collect either the inhalable fraction ± 30 µm or the respirable fraction (i.e. the particles
that are likely to reach the gas-exchange region of the lungs) (WHO, 1999).
The determination of airborne dust concentrations involves air sampling and further
analysis of the collected dust sample. This is achieved by conducting chemical,
gravimetrical or microscopical analysis. Sampling for exposure assessment is usually
done by attaching a personal sampler to the worker. This device consists of a pump (air
mover) and a sampling head located in the breathing zone. The sampling head has a filter
holder with a filter where the dust sample is collected, preceded by the pre-collector to
separate the fraction of interest. Sampling heads are designed to collect either the
inhalable or respirable fraction of the airborne dust. From this data, an average worker's
exposure during part of a shift can be estimated (WHO, 1999).
Other measurements may give information about the origin of the dust or the period(s)
during the working shift whereby dust is emitted. These measurements are based on fast-
33
response and direct-reading instruments. Simpler qualitative means such as forward light
scattering (dust lamp) techniques to illuminate the dust or smoke tubes to trace air
movement may be sufficient. There are also systems that combine video imaging with
dust concentration measurements, to allow the visualisation of how exposure changes as
workers perform their tasks, such as exhaust ventilation or wet methods. Quantitative
evaluations are done to assess worker's exposure in relation to an adopted standard to
determine the need for control measures and assess the effectiveness of control strategies
(WHO, 1999).
3.6 Lead emmision control measures
Emission control can be described as the tool for measuring the specific dust production
(i.e. the transmission rate per production unit per unit time). The introduction of this
control enabled the control of a machine, tool or operation with regard to its emission and
setting up of standard permissible emission from different types of machines. The
permissible emission values set should ensure that the exposure for a worker does not
exceeded the emission threshold limit value (Gerhardsson, 2002).
Baghouse air emission control systems are one of the most frequently used technologies
for controlling air emissions in foundries. The system works by pumping air into the
baghouse, where particulates accumulate on a fabric filter. This system is efficient for
particles between 0.1 and 0.3 µm in diameter (Shen, 1995).
34
3.6.1 Containment
Indoor air quality focuses on the nature and concentration of air pollutants inside
enclosures that can adversely affect comfort, performance and health. Since the energy
crisis in the early 1970’s, which resulted in reduction in the design standard for
mechanical ventilation rates, there has been a growing awareness of the impact of indoor
air quality on comfort, health and performance (Hedge, 2001).
Containment involves placing a barrier between the substance and the people. When the
substance is contained and enclosed, it is necessary to have a ventilation system that keeps
the enclosure under negative pressure to avoid any leakage or air emission of the
substance in and out of the enclosure. The design of the enclosure has to enable good
maintenance and cleaning of the system without causing high exposure. It is acceptable to
partially enclose a process by having an opening at the front of an enclosure for
maintenance. The worker's breathing zone should not be between the contaminant source
and the enclosure (WHO, 1999).
3.6.2 Engineering controls
The design of engineering and administrative controls should also ensure that hazardous
substances are not dispersed to the general environment. Air cleaning devices must be
incorporated in the ventilation system to prevent re-circulation to the workplace. The
control of disposal of toxic dusts should also be done to minimise exposure (WHO, 1999).
35
3.6.3.1 Local Exhaust Ventilation
Local exhaust ventilation (LEV) is the removal of airborne contaminants close to their
source of generation or release before they can spread or reach the worker's breathing
zone (WHO, 1999). LEV is intended to control mechanically the emission of
contaminants such as dust and fumes that are given off during the manufacturing process.
Normally, this is done as close to the point of emission as possible using a stream of air to
remove the airborne particulate matter and transport it to where it can be safely collected
for ultimate disposal. The physical layout and setting of LEV equipment is critical for it to
work effectively and comparatively minor alterations can affect its performance. It is
therefore important that LEV equipment should be properly designed, manufactured,
installed, operated and maintained (Ridley and Channing, 1999). Also it is necessary to
ensure that the airflow is sufficient and its direction of flow is appropriate (i.e. away from
the workers’ breathing zone). The velocity of air being drawn towards the hood opening
rapidly decreases with the distance from the opening. Bearing in mind that a minimum air
velocity is required to ensure the capture of an airborne contaminant, the hood should be
kept clean up to the point of dust generation (WHO, 1999).
3.6.3.2 General Ventilation
General ventilation is usually desirable to control the temperature and humidity of the
environment or a properly designed system that can act as a back-up control of exposure
to airborne substances by diluting the airborne contaminants (WHO, 1999).
36
Ventilation must be designed by a specially trained professional in such a way that
movement of personnel or the opening of doors and windows do not obstruct the system.
If the system has only one fan from a multi-hood system, this may pose a problem. It is
easy to accidentally design a ductwork system that is ineffective (high resistance to flow).
Also, the ductwork design should allow easy cleaning and the abrasive effect of dust.
Managers should ensure a continuous inspection and maintenance programme for
ventilation systems to be effective. They should also involve workers about the use and
maintenance of the system (WHO, 1999).
Where an assessment has identified an exposure level above the occupational exposure
standard (OES) or maximum exposure limit (MEL) for the substance, then under a
hierarchy of preferred controls, LEV equipment must be installed wherever practicable as
opposed to providing personal protective equipment (PPE). These are the means for
reducing the employee’s exposure. Such equipment must be properly used by the operator
and visually inspected for obvious defects. Further, the employer must ensure that the
equipment is maintained and the legal inspections are carried out. In addition, this
inspection should be synchronized with work environment monitoring by air sampling to
ensure that the plant is continuing to operate effectively (Ridley and Channing, 1999).
3.6.3 Personal Protective Equipment
OSHA requires the use of PPE to reduce employee’s exposures to hazards as the last
resort when engineering and administrative controls have failed in reducing the exposures
37
to acceptable levels. However, if PPE is to be used, a PPE programme should be
initialized and maintained. The programme should include identification and evaluation of
hazards in the workplace, selecting of an appropriate PPE to be used, maintenance of PPE
and its use evaluated. Also, employees should be trained on how the PPE is used (OSHA,
2002).
Other types of air emission control systems may be used including wet scrubbers,
absorption and adsorption systems, combustion and electrostatic precipitation. All
systems generally produce a solid waste from the air emission and release the cleaned air
(Primary Metals Paper, 2002).
3.7 Ergonomical aspects of the work environment
Ergonomics is the science of fitting the work environment and job activities with the
capabilities, dimensions and needs of people. Ergonomics deals with the physical work
environment, tools and technology design, workstation design, job demands,
physiological and biomechanical loading on the body. Its goal is to increase the degree of
fit among the employees and the environment in which they work, their tools and their job
demands (Smith, 1997).
Workplace design is concerned with a variety of physical conditions within the work
environment that can be objectively observed or recorded and modified through
architectural, interior design and site planning interventions. The relationship between
38
worksite design, or occupational health includes physical arrangement of employees’
immediate work area and ambient environmental qualities of the work area. The physical
work environment extends from the core of an employee’s desk or workstation to the
physical enclosure or imaginary boundary surrounding his/her workspace. Several
features of the immediate work area have been found to influence the employees’ well
being (Stokols, 1997).
39
4. EVALUATION OF THE PREVENTIVE AND CONTROL MEASURES FOR
LEAD EXPOSURE
The selected foundry operates as a secondary lead smelter in the Gauteng region in South
Africa. The foundry has three plants that run for 24 hours and five people man each plant.
It comprises of 200 employees per day of which, 150 are permanently employed. The
foundry has three, 8-hour shifts. It should be noted that the workers do the same type of
jobs and there is no job rotation. The workers only change their tasks when they get a
promotion or get ill in that particular workstation and the cause is occupational. All
departments have their safety representatives, who are appointed by the workers. Also,
there are supervisors for each department appointed by the management. The supervisors
are the ones who mandate or draw daily schedules for their departments.
This industry welcomes visitors from all sectors. The visitors are supplied with PPE such
as safety boots, facemask, helmet and goggles before they are taken for a tour inside the
plant.
4.1 Methodology
The different methods that were used in conducting this study are discussed below:
40
4.1.1 Study Design
The study was designed by using the Logic Framework Approach (LFA). LFA is a tool
that helps the researcher to identify the important parameters of the study. These
parameters include the problem or the question that needs to be addressed by the study,
the objectives of the study, the effects of the problems and possible solutions to the
problem. Furthermore, LFA helps in the determination of the short and long term goals of
the research and how to achieve those goals. Also, the obstacles that the research might
encounter and how the researcher would overcome them. Hence this approach was chosen
for the design of the study. The LFA for this study is presented in Appendix A.
This study was conducted in a lead acid battery-recycling foundry to evaluate the
preventive and control measures for lead dust exposure that are implemented in this
foundry. The study was conducted by doing a walkthrough evaluation of the factory. The
evaluation entailed conducting informal interviews with the technical director and two
environmental officers and by administering structured questionnaires to the workers. The
questionnaires were answered in the presence of a researcher. The questionnaire is
presented in Appendix B. The presence of the researcher during the answering of the
questionnaire was to interpret the questions that the respondents could not understand.
Also, aided in speeding the collection of responses from the workers and the researcher
was able to ensure that the questions were all answered.
41
Retrospective data from the year 2000 until 2002 (i.e. records of the levels of lead in
blood and lead in air) were obtained from the factory occupational nurse and the chemist.
4.1.2 Independent Variables
The independent variables were age and work experience.
4.1.3 Dependent Variables
The dependent variables were blood lead levels, lead in air levels and occupational
illnesses.
4.1.4 Subjects
Subjects were randomly selected from each department. This depended on the availability
of the workers and their willingness to participate in the study after they were assured
about the confidentiality of their interviews and how the study would benefit them.
4.1.5 Limitations
• Time
42
The study was conducted during normal production processes. Therefore, the time to
interview the workers and time to answer the questionnaire was limited so that production
was not interrupted.
• Language
The questionnaire was available in English only, unfortunately most of the workers were
unable to fully understand English, which necessitated interpreting the questionnaire and
giving explanation about the purpose of the study by the interviewer.
4.1.6 Data Analysis
Results were analysed using Microsoft Excel. The means, standard deviation (S.D.),
standard error of the mean (S.E.M.) and the significance level using the z-test were
calculated using this software. For analysis of the categorical variables such as personal
information, perception of workers about their work environment and health risks, were
converted to parametric variables. Furthermore, z-test was performed to calculate the
probability of rejecting the null hypothesis. A probability-value (p-value) of less than 5
percent was used as the level of significance and the 95 % confidence intervals were also
calculated. To determine the distribution of the data, test for skewness was performed.
Duration of employment in the current job and the lead in blood levels were analysed and
a simple linear regression done. The correlation coefficient (r2), which lies between 0 and
1, was used as a measure of how well the data fits into a straight line.
43
4.2 Results
All employees who work inside the factory are males, therefore the sample was biased in
terms of gender aspect. There was only one female who was interviewed. This worker
was working at the canteen, as a contractor. In all, there were 23 interviews that were
conducted. One interview was with the technical director of the factory to obtain
background information about the company. Two out of the 23 interviewees were with the
environmental officers to obtain information about preventive and control measures and
the company policy regarding environmental health. Supervisors and workers from all
departments answered the structured questionnaires.
The sequence in which the results are presented starts with the description of the process
of lead production. This is followed by the assessment of lead exposure during the
recycling process, assessment of the preventive and control measures, data about the staff
medical surveillance, questionnaire and interview data and finally analyses of physical
measurements of airborne lead levels.
4.2.1 Description of the Lead Production Process
The industry where this study was conducted recycles spent lead acid batteries and lead
residues. The raw material for lead production is shown in figure 1.
44
Figure 1: Mixed scrap lead recycled in this foundry
The description of the production processes was obtained during the interview with the
technical director and during the walkthrough. It was reported that the batteries were
crushed in an MA Breaker and the plastic (polypropylene) fraction was recycled on the
site. The acid is neutralized prior to disposal via the municipal sewer. All contaminated
material, which cannot be recycled, was sent for safe disposal. It is also noteworthy that
this foundry complies with ISO 14001 since the year 2000.
It was reported that the lead material was smelted in rotary furnaces. There are four
furnaces but production is generally carried out on the two 20 ton furnaces with the 10 ton
partially utilized as a back-up or to meet increased demand. The bullion is refined or
alloyed in a series of kettles viz, two 90 tons, seven 70 tons and one 15 tons kettles. The
finished product is cast as 30 kg lead ingots according to customer specifications.
Finished product is shown in figure 2.
Figure 2: Finished product of the lead-recycling foundry
45
It was also reported that twenty to fourty thousand tons of lead are produced annually and
the annual consumption of gas is 190 000 GJ, oxygen 8000 mt, and diesel 160 000 l. The
maximum demand for electricity is reported to be 1500 KVA, which is determined by a
30 minute peak demand. There are no standby generators, but emergency lighting is
provided in strategic locations.
4.2.1.1 Detailed lead production process
The components of the car battery are 60 % lead, 40 % sulphuric acid (10 % solution) and
polypropylene as the plastic case of the battery. The first step in the production process is
the flotation process, whereby the battery is crushed to separate its three components.
The process begins by pre- mixing of lead with charcoal, iron, soda ash and borax. Pre-
mixing is followed by the smelting process, which involves separation of lead from slag.
Slag is disposed and the remaining lead is transferred to a holding pot, whereby refining
with compounds such as sulphur, soda ash, nitric acid, calcium and sodium is done. The
46
refined lead is then transferred to the marketer pots for alloying. Finally, the alloys are
cast.
In the case of polypropylene, it is recycled in the polypropylene plant to form new battery
cases, car bumpers, chairs, etc. In the polypropylene plant, the separated polypropylene is
melted at 280 0C, dried, crushed into small pieces, washed, dried and packaged into a
desired product. Figure 3 shows the summary of the process.
47
Effluent Waste
SafeDisposal
Recyclers
Safe Disposal
Figure 3: Summary of the foundry operation process
Raw Material Receipts
Dross Plate Residues Concentrates
Whole Batteries Crushed
Acid
Rubber / Separators
Paste Metallics Plastic
Rotary Furnace Smelting Fume Fluxes
• Coal • Salt • Soda Ash • Cast Iron
Heat • Sasol Gas • Oxygen
Refinery Drosses
Lead Bullion Slag
Refining and
Alloying
Refined Soft Lead
Cable Lead
Calcium Alloys
(Ca/Sn/Al)
Antmontial Lead Alloys
48
4.2.2 Assessment of lead exposure during the recycling process
From the results of the walkthrough, the processes of recovering lead from the battery (i.e.
battery crushing and the smelting process) were found to be the most generators of dust.
During the smelting process, lead paste is mixed with lead sulphide, lead oxide, coal,
sodium sulphide, cast iron and salts in the rotary furnace. These compounds are heated at
temperatures around 950oC. This results in high production of fumes and lead dust. Fumes
and dust are thus released into the work environment.
4.2.3 Assessment of the preventive and control measures
The preventive and control measures were assessed during the walkthrough. Data
regarding these measures was obtained from the technical director and the chemist of the
foundry.
4.2.3.1 Safety Programmes
It was established from the interviews and during the walkthrough that the company
provides induction programmes for new employees. Once a month, there are safety
meetings that are held for safety representatives with the directors of the foundry.
Furthermore, twice a month, a Health and Safety Executive (HSE) workgroup holds a
meeting. It was reported that all the safety representatives are trained and elected by other
workers. In addition to the safety representatives, there are first aiders, and fire fighters,
49
who are also trained. The company compiles the ISO 14001 inspection reports, which are
kept at the foundry. Furthermore, the company undergoes internal and external audits,
which are done by environmental health experts.
4.2.3.2 Engineering Controls
The engineering controls that are used in this foundry include air conditioners, which have
disposable filters, wet methods and baghouses. Baghouses are used at many facilities to
prevent particles created by industrial processes from entering the air. In concept,
baghouses work like vacuum cleaners. Particulates in an airstream are filtered out on the
surfaces of the bags housed inside the unit. In this foundry baghouses are regarded as the
best engineering control measures.
The filters that are used in the air conditioners are inspected once a week in the areas with
low lead exposure and three times a week in highly exposed areas. The primary filters are
washed 10 –12 times before being disposed as toxic waste whereas the secondary filters
are washed 36 times before disposal. In the case of air conditioners, it is mentioned that
disposable filters are used which the South African Bureau of Standards (SABS) tests.
These filters are said to have 97 % efficiency and they are specific for lead particles.
Lead is removed by using lime solution of pH 7 – 8 since lead dissolves in higher pH.
Lime reacts with sulphuric acid to form water.
50
4.2.3.2.1 Education and Training
The company complies with the lead regulations. The regulations are specific to industries
exposed to lead. Lead regulations include information about monitoring of lead
concentrations in the air or analysis of blood lead or urinary lead concentrations.
Moreover, it includes information and training of workers who are exposed or may be
exposed to lead.
The regulations require that education and training of employees must be done for all
employees after appointment into the industry. Furthermore, education and training of
employees about their duties and the hazards that they are exposed to in their workplace is
required. Air monitoring, biological monitoring, medical surveillance are also done as
stipulated in the lead regulations. Records of all the processes done in the foundry for
inspection by the enforcers of the legislation are also kept.
4.2.3.3 Environmental monitoring
Environmental monitoring includes air monitoring, personal and static air sampling, stack
monitoring and ground water monitoring.
51
4.2.3.3.1 Air Monitoring
A wet method is used for lead air monitoring. The monitoring method is conducted
according to the SABS Method 1664 – 1990: A wet method of lead air monitoring.
An environmental health expert or professional environmental officer, that is an Approved
Inspection Authority (AIA) by the Dept. of Labour does air monitoring once a year. An
occupational exposure limit (OEL) of 0.15 mg/cm3 according to Lead Regulations for
Hazardous Chemical Substances, 1995 is used as a guideline. It should be noted that the
Lead Regulations are written specifically for work environments that have lead as the
hazard.
4.2.3.3.2 Personal and static air sampling
For personal and static air samplers, Gil-Air Personal Air Sampler is used. This sampler is
used for internal air measurements. Measurements are taken for the entire work shift of 8
hours and the average exposure is determined. According to regulations of the selected
foundry, these measurements are done once a month. Atomic absorption spectroscopy
(AAS) is used to determine lead particles in the air, where the samples were collected.
52
4.2.3.3.3 Stack monitoring
The stack that the foundry covers is a 1 000 m2 area and is monitored two times a year.
The stack monitoring includes measurement of lead sulphide and particulate. Air
monitoring in areas with low lead exposure is done twice a year similar to the stack
monitoring. These areas include the laundry and canteen. For areas that are in the range of
the ‘action level’ (0.07 mg/cm3), according to this company, air monitoring is done four
times a year and above the threshold limit value (TLV) it is done once a month.
According to the legislation however, the areas exposed to lead that is below the ‘action
level’ should be monitored once a year.
4.2.3.3.4 Ground water monitoring
Ground water monitoring is done using Piezometers. Effluent discharge is also monitored.
This includes monitoring of pH, lead, zinc and other chemicals.
A detailed schedule of the environmental monitoring programme for all locations is
presented in table 2. The chemist reported the schedule for the lead air monitoring. The
records of the air monitoring were presented to the researcher. It was reported that the
schedule of lead air monitoring records the minimum times of measurements that should
be taken. According to the chemist of the foundry, the measurements could be done more
than the stipulated times in the schedules. It is also important to note that all lead exposure
zones are demarcated and enforcement of use of PPE in such areas is practiced.
53
Table 2: Schedule for the air lead monitoring programme in 2002.
LOCATION JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Samples below Action Level
Laundry Canteen
Monthly Change Room
Weekly Change Room
Security Clinic
Sample Prep. Lab Passage
Lab Admin. Balance Room
Smelter Foreman Weigh Bridge
Plinthin Front of Laundry
Final Product Loading
Polyprop Polyprop Car
Park
Tefo’s Office Action Level
Samples
New Workshop Electrical Workshop
Old Workshop Mechanical Workshop
Posion Cage Battery Breaker Samples Above
TLV
Baghouse Smelter
Downstairs
Hot Metal Transfer
Casting Diesel Pump Bullet Pump
Stacks East Stack West Stack
54
4.2.4 Personal protective equipment
It was reported that the company spends between ten thousand and fifteen thousand South
African Rand on PPE. Also, there is a personal preference on the PPE used by employees.
However, it was reported that engineering controls are the first priority in protection of
workers against lead dust exposure. The required PPE ensemble comprises of the
disposable facemask, air-stream helmet, safety hat, goggles, ear muffs, gloves, safety
boots and an overall coat. It was reported and observed during the walkthrough that the
disposable facemasks are utilised by workers who work in areas, which are believed to
have low lead dust exposure. On the other hand, air-stream helmets are used in high lead
exposure zones. Figure 4 shows some of the PPE used by the workers at the foundry.
Figure 4: Some of the PPE used in the foundry
4.2.5 Staff medical surveillance
55
The occupational health nurse reported that the factory doctor does a pre-placement
medical examination for all new employees and contractors. Furthermore, new employees
undergo an induction programme before they start working so that they are aware of the
dangers of lead, why blood lead levels need to be tested and why they will be required to
wear PPE when performing their tasks. The medical examination involves taking blood
samples for lead tests before workers start working. Also audiometric tests are done. The
blood lead levels is monitored for the first three months so that quick absorbers of lead are
identified during the early stages of their employment. Employers are not allowed to have
blood lead levels of more than 30 µg/dl in the first three months of employment. If so,
further steps are taken which include consideration of the placement of the worker in a
more suitable workstation or dismissal of the worker if the levels do not drop down to
acceptable levels.
Every three months, all employees’ lead in blood levels are tested regardless of their
results before employment. Employees with lead in blood more than 40 µg/dl are tested
monthly as it is the goal of the company to reduce all lead in blood levels to below 40
µg/dl by the year 2003.
4.2.5.1 Blood lead levels for the foundry workers
56
Figure 5: Blood lead levels of foundry workers
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
50.00
Date (months)
Blo
od le
ad le
vels
(ug/
dl)
2000 39.57 40.12 46.70 45.19 45.19 42.59 41.46 40.79 39.81 39.33 43.41 43.42342001 36.3996 36.5891 36.1832 38.396 37.4343 37.3 34.4021 34.4021 34.3298 33.2024 33.1548 31.57142002 27.79 27.66 27.69 30.28 29.77 28.93 31.98 31.62 29.14 34.57 34.59 34.2857
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
The mean blood lead levels of foundry workers from the year 2000 up to 2002 during
each month is presented in figure 5.
It was found that the levels of lead in blood were quite high in the year 2000 (above the
limit, 40 µg/dl) and gradually decreased from the year 2001 until 2002. It is interesting to
note that in 2000 and 2002 there was a steady increase in the lead in blood levels from the
month of October.
4.2.5.2 Comparison of blood lead levels against work experience
57
The mean blood lead levels of foundry workers and the duration of employment from the
year 2000 up to 2002 are presented in table 3.
Table 3: Blood lead levels for the foundry workers (2000 – 2002) 2000 2001 2002
Duration (years) Mean S.D. SEM Mean S.D. S.E.M Mean S.D. SEM 0.5 24.14 0.00 0.00 31.37 14.38 10.42 26.49 7.71 6.09 1 40.99 7.37 5.79 29.25 11.33 9.40 27.17 9.57 7.69 2 39.32 10.87 8.14 33.11 8.41 6.64 35.64 8.54 6.09 3 43.47 8.84 6.77 31.06 9.75 7.63 30.18 6.65 4.82 4 41.40 8.16 6.00 33.65 8.78 6.82 28.86 8.35 6.38 5 35.71 8.87 7.12 35.00 4.48 3.45 29.64 9.57 7.17 6 39.43 13.07 10.43 32.67 7.07 5.67 30.30 10.65 9.05 7 45.36 8.11 5.68 31.78 12.23 10.19 30.15 5.93 3.79 8 43.34 10.99 9.17 39.06 9.33 7.35 28.86 11.92 9.18 9 30.25 0.00 0.00 41.80 9.01 6.63 29.71 8.00 5.14
10 45.29 3.58 3.14 20.50 0.00 0.00 36.52 10.12 7.40 11 44.88 5.25 3.81 37.88 5.55 4.34 17.00 0.00 0.00 12 36.22 9.52 7.10 41.79 7.57 5.25 35.15 6.51 4.60 13 58.92 0.00 0.00 34.77 10.95 9.31 32.36 3.45 2.46 14 34.95 2.82 2.02 48.17 0.00 0.00 28.63 7.25 5.13 15 41.86 8.13 5.43 29.92 2.95 2.09 47.92 0.00 0.00 16 43.63 3.60 2.55 39.28 10.24 7.13 29.50 0.00 0.00 17 59.67 0.00 0.00 35.90 4.38 3.10 35.17 0.00 0.00 18 - - - 53.67 0.00 0.00 27.83 0.00 0.00 19 52.13 6.43 4.55 - - - 51.00 0.00 0.00 20 - - - 27.33 0.00 0.00 - - - 21 48.17 0.00 0.00 - - - 33.08 0.00 0.00 22 - - - 38.75 0.00 0.00 - - - 23 - - - - - - 31.83 0.00 0.00 24 - - - - - - - - - 25 44.89 5.85 4.48 - - - - - - 26 47.67 0.00 0.00 38.25 6.28 4.83 - - - 27 50.75 0.00 0.00 37.92 0.00 0.00 34.75 0.00 0.00 28 39.71 9.96 7.04 41.83 0.00 0.00 38.08 0.00 0.00 29 - - - 35.33 8.96 6.34 36.42 0.00 0.00 30 - - - - - - 31.00 0.00 0.00 31 - - - - - - - - - 32 - - - - - - - - - 33 34.58 0.00 0.00 - - - - - - 34 - - - 27.33 0.00 0.00 - - - 35 54.00 0.00 0.00 - - - - - - 36 - - - 50.56 0.00 0.00 - - -
(-) represents that data was not available
58
Figure 6: Blood lead levels vs Work experience in the year 2000
R2 = 0.2001
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
Work experience (yrs)
Blo
od le
ad le
vels
(ug/
dl)
PbB 24.14 40.99 39.32 43.47 35.71 39.43 45.36 43.34 30.25 45.29 44.88 36.22 34.95 41.86 43.63 59.67 52.13 48.17 44.89 47.67 39.71 34.58 54.00
0.5 1 2 3 5 6 7 8 9 10 11 12 14 15 16 17 19 21 25 26 28 33 35
A correlation between lead in blood and the duration at the same company was also done
using a linear regression analysis. For the year 2000, r2 was found to be 0.200. In 2001, r2
was 0.127 and in 2002, r2 was 0.143. This shows that there is a very small degree of linear
relationship between lead in blood and work duration. However, there is an insignificant
increment in the lead in blood levels as the work duration increases. This is shown in
figure 6, 7 and 8.
59
Figure 7: Blood lead levels vs Work experience in the year 2001
R2 = 0.1271
0
10
20
30
40
50
60
Work experience (yrs)
Blo
od le
ad le
vels
(ug/
dl)
PbB 31.35 29.25 31.06 33.65 35 32.67 39.06 41.8 20.5 41.79 34.77 48.17 29.92 35.9 53.67 27.33 38.25 37.92 41.83 35.34 50.56
0.5 1 3 4 5 6 8 9 10 12 13 14 15 17 18 20 26 27 28 29 36
60
Figure 8: Blood lead levels vs Work experience in 2002
R2 = 0.1433
0.00
10.00
20.00
30.00
40.00
50.00
60.00
Work experience (yrs)
Blo
od le
ad le
vels
(ug/
dl)
PbB 26.49 27.17 35.64 30.18 29.64 30.35 30.15 28.86 29.71 36.52 17.00 35.15 28.63 47.92 29.50 35.17 27.83 51.00 33.08 31.83 38.08 36.42 31.000.5 1 2 3 5 6 7 8 9 10 11 12 14 15 16 17 18 19 21 23 28 29 30
61
Figure 9: Blood lead levels stratified according to departments for the year 2002
R2 = 0.9525
0
5
10
15
20
25
30
35
40
Department
Blo
od le
ad le
vels
(ug/
dl)
PbB 11.92 14.5 17.98 19.92 24.57 24.58 26.5 27.54 28.84 29.65 29.88 31.34 36 37.21
Clinic Engineering Technical Welfare Stores Ref/Castin
gWeighbrid
ge Cleaners Contractor Polyprop Lab Smelting Art Battery Breaking
4.2.5.3 Stratification of blood lead levels according to departments
For the 2002 data, blood lead levels were stratified according to departments as shown in
figure 9.
62
It was found that the department with the least blood lead was the clinic and the
department with the highest blood levels was the battery-breaking department. However,
blood lead levels for clinic workers were also below the legal limit.
4.2.6 Questionnaire and Interviews
Supervisors and workers from all departments answered structured questionnaire
(presented in Appendix B). Informal interviews were conducted with the technical
director and two environmental officers.
4.2.6.1 Analysis of categorical variables
Categorical variables included the age of workers, duration of employment in the current
position, the percentage of workers who have changed positions while working for the
same industry and the duration of employment in previous jobs. The results for the
workers’ age groups are presented in table 4.
Table 4: The age group of the interviewed workers.
Age Group (years) Workers interviewed 25 - 35 9 36 – 55 11 56 -60 0
It was found that the majority of interviewed workers are young adults of ages between 36
and 55 years. It should however be noted that no workers were above the age of 55 years.
The duration of employment in the same position ranged from 3 months up to 24 years.
63
This was in contrary to the data obtained from the staff medical surveillance where
duration of employment was up to 36 years. It could be explained by the fact that workers
were not all interviewed.
It was further found that the duration of employment in the same position ranged from 3
months up to 24 years. Fifty percent of the interviewed workers had been working in the
same position since their recruitment whilst fifty percent of the workers have changed
positions that they were placed in when they first joined the company. Table 5 shows the
data for employment duration.
Table 5: Duration of employment in the current positions Employment duration
(years) No. of workers working in the same
positions 0.6 1 1 2
1.5 0 2 5 3 1 6 1 8 3 9 1 10 1 11 1 14 1 15 1 16 1 24 1
According to the interviews, the main reason for workers changing their positions was due
to promotion. It is interesting to note that only one worker had changed a position because
64
of heat and high exposure to lead. This worker was previously working at the smelting
department and changed to polypropylene department.
4.2.6.2 Perception about the work environment
Seventy five percent (15 workers) perceived their work environment to be dusty. The data
about the workers responses to their perception of their work environment is summarised
in table 6.
Table 6: Interview responses on workers’ perception of their work environment. Visibility of the dust Workers interviewed Walls and machinery 2
Walls, machinery and PPE 7 PPE and smell 1
Walls, PPE and smell 5 None 5
Two interviewees further explained that they know about the dustiness of their workplace
from objective measurement reports.
Interestingly, one worker who said that he did not think that the work environment is
dusty, reported that the material that is used to recover lead is the major source of dust.
Four workers who perceived the work environment to be dusty believe that the source of
dust is the vehicles. Whereas, eleven workers reported that the source of dust are the
chemicals that are used in the plant from premixing, charging, battery breaking, loading of
material, ventilators, refinery and smoking furnaces.
65
Four workers reported that they protect themselves from inhaling the dust by using simple
disposable mask. It should be noted that, two of these workers work in the laboratory. Out
of the nine workers who perceived their work environment to be dusty reported that they
use both the simple disposable mask and special respirators. Two workers reported that
they only use special respirators. These workers work in the smelting and in the battery
breaking sections.
Out of 15 workers who perceived their work environment to be dusty, only one worker
thinks that the company is not doing much to protect the workers from dust inhalation. It
is important to note that 14 workers think that the company is doing a lot to protect the
workers from inhalation of dust. These workers mentioned that the company provides
training, PPE, engineering controls such as sprinklers, road sweepers, pressurisation
system, ventilators and extractor fans. On the question of the main source of dust before
the implementation of control measures, it was reported that the extractors were the main
cause of dust. Dust was also high in the premixing and in the receiving areas. All the
workers interviewed during this study reported that they wear PPE when performing their
tasks, except when they are in the canteen. It was however found during the walkthrough
that not all the workers wore all the required PPE.
Fourteen workers think that their workplace is clean. All workers interviewed reported
that their workplace is cleaned once a shift. Fifty percent of the workers reported that the
contractors do the housekeeping whereas the other fifty percent reported that the operators
themselves do the housekeeping.
66
4.2.6.3 Health Risks
Nine workers interviewed during this study reported that they have never suffered from
illnesses that are known to be commonly linked with lead poisoning. A summary of the
illnesses reported by 11 workers is presented in table 7.
Table 7: Summary of reported illnesses linked with lead poisoning Subjects Headache Stomachache Memory
loss Nausea Kidney
problems Weak joints
Chest pains
1 - - - - - 2 - - - 3 - - - - 4 - - - 5 - - - - 6 - - - - - - 7 - - - - - - 8 - - - - - - 9 - - - - -
10 - - - - 11 - - - - -
(-) None reported about the specific illness
Five of the workers who indicated that they have suffered from stomachaches reported to
have visited the factory clinic due to their illnesses and were given sick leave days. These
workers do not know whether the cause of their illnesses was a result of occupational
exposure to lead. One worker who reported to suffer from kidney problems had visited the
clinic due to the illness. This worker was given the sick leave days. The worker did not
know the cause of the illness. Three of the workers who had headaches had been absent
from work due to this illness. These workers suspect that the cause of the headaches was
heat from work.
67
Fourteen workers reported that they are worried about their health in this foundry because
they know about the hazards of lead poisoning. However, three workers were uncertain
about their health while working in this industry.
Only three workers seem to be confident about the preventive measures taken by the
company towards their health. Seven workers reported that they are smokers and thirteen
workers reported that they are non-smokers. On average, the interviewed smokers smoke
five cigarettes per day.
4.2.6 Analysis of physical measurements of airborne lead levels
Records for physical measurements from the year 2000 up to 2002 were obtained from the
foundry. These records included all the areas within the foundry that were measured
during the stipulated years. Analysis of the data from all the departments showed an
asymmetric distribution of positive skewness. This shows that the data lie on the positive
side of the mean values. Furthermore, it is interpreted that the data follows a normal
distribution.
4.2.6.1 Maintenance department
The airborne lead levels in the maintenance area from January 2001 up to September 2002
is shown in figure 10. Summary of the analyses of the results is presented in table 8.
68
Figure 10 : Lead in air levels in the maintenance area from January 2001 until September 2002
-0.050
0.000
0.050
0.100
0.150
0.200
0.250
0.300
Date (Months)
Air
lead
leve
ls (u
g/dl
)
OLD WORKSHOP 0.035 0.049 0.081 0.010 0.101 0.000 0.02 0.032 0 0.124 0.08 0.2 0.221 0.071NEW WORKSHOP 0.043 0.029 0.006 0.025 0.026 0.010 0.054 0.188 0.08 0.211 0.087 0.058 0.096MECH. WORKSHOP 0.091 0.029 0.113 0.010 0.025 0.170 0.030 0.107 0.033 0.049 0.035 0.019 0.048 0.037ELEC. WORKSHOP 0.016 0.038 0.022 0.029 0.051 0.012 0.038 0.093 0.084 0.064 0.017 0.007 0.046 0.008TEFO'S OFFICE 0.024 0.082 0.006 0.086 0.020 0.020 0.017 0.018 0 0.006 0.018 0.02 0.01 0.008LEGAL LIMIT 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.15 0.15 0.15 0.15 0.15 0.15 0.15
1-Jan 1-Feb 1-Apr 1-May 1-Jul 1-Aug Oct-01
Nov-01
Jan-02
Mar-02
Apr-02
Jun-02 Jul-02 2-Sep
Table 8: Summary of lead in air results from the maintenance department Area Skewness Mean
(µg/dl) S.D. SEM Z -Test 95 % C.I.
[min; max] Old workshop 1.098 0.093 0.067 0.051 -1.727 [0.065;0.120] New workshop 1.596 0.064 0.051 0.036 -2.660 [0.043;0.085] Mech. Workshop 1.244 0.060 0.045 0.036 -2.789 [0.042;0.079] Elec. Workshop 0.462 0.044 0.027 0.022 -3.348 [0.033;0.055] Tefo’s Office 0.855 0.034 0.028 0.024 -3.653 [0.023;0.046] Legal limit 1.083 0.150 0.000 0.000 0.000 [0.150;0.150] The mean lead air values (± S.E.M.) range from 0.034 µg/dl (± 0.024) up to 0.093 µg/dl
(± 0.051). These values correspond to Tefo’s office and the old workshop respectively.
However, it should be noted that from October until July 2002, the air lead levels in the
old workshop were above the legal limit. The new workshop air lead levels were also
above the legal limit in November 2001 and March 2002. Nevertherless, their mean
69
values were below the legal limit. The 95 % confidence interval shows that the given
results in comparison with the legal limit of 0.15 µg/dl are all statistically significant.
Furthermore, a p-value of less than 5 % from the z-test results confirms that probability
that this difference occurred by chance, i. e. randomly. The results from the z-test show
that all the areas measured are significantly different from the legal limit except for the
old workshop which is more than -1.96 (a value that determines whether to accept or
reject the null hypothesis). However, it is interesting to note that these values are all below
the legal limit value of 0.15 µg/dl, which could mean that the company’s preventive
measures are effective.
4.2.6.2 Change-room area
The airborne lead levels in the change-room area from January 2001 up to September
2002 is shown in figure 11. Summary of the analyses of the results is presented in table 9.
70
Figure 11: Air lead levels in the change rooms and canteen from January 2001 until Septermber 2002
-0.0200.0000.0200.0400.0600.0800.1000.1200.1400.160
Date (Months)
Air
lead
leve
ls (u
g/dl
)
LAUNDRY 0.048 0.010 0.028 0.018 0.029 0.026 0.01 0.021 0 0.007 0.034 0.013 0.028 0.008CANTEEN 0.010 0.010 0.014 0.010 0.017 0.013 0.01 0 0 0.007 0.037 0.004 0.015 0.002MONTHLY Ch. Room 0.010 0.021 0.000 0.024 0.019 0.026 0 0 0 0.007 0.039 0 0.015WEEK Ch. Room 0.010 0.017 0.022 0.032 0.043 0.039 0.01 0.037 0 0.007 0.034 0.01 0.02 0.003SECURITY 0.048 0.000 0.050 0.000 0.011 0.061 0.01 0.062 0 0.007 0.055 0.024 0.021 0.002LEGAL LIMIT 0.15 0.15 0.15 0.15 0.150 0.150 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15
1-Jan 1-Feb 1-Apr 1-May 1-Jul 1-Aug Oct-01
Nov-01
Jan-02
Mar-02
Apr-02
Jun-02 Jul-02 2-Sep
Table 9: A summary for lead in air data in the change-room area
Area Skewness Mean
(µg/dl)
S.D. SEM Z -Test 95 % C.I.
[min; max]
Laundry 0.993 0.021 0.012 0.010 -4.026 [0.016;0.026]
Canteen 1.321 0.013 0.009 0.006 -4.276 [0.009;0.017]
Monthly change- room 0.119 0.015 0.010 0.009 -4.205 [0.011;0.020]
Week change-room 0.348 0.018 0.016 0.013 -4.103 [0.012;0.025]
Security 0.477 0.025 0.022 0.019 -3.883 [0.016;0.034]
Legal limit 1.083 0.150 0.000 0.000 0.000 [0.150;0.150]
The mean air lead values (± S.E.M.) range from 0.013 µg/dl (± 0.002) up to 0.025 µg/dl
(± 0.019). These values correspond to the canteen and the laundry respectively. The 95 %
71
Figure 12: Air lead levels in the foremen offices from January 2001 until September 2002
-0.020
0.000
0.020
0.040
0.060
0.080
0.100
0.120
0.140
0.160
0.180
Date (Months)
Air
lead
leve
ls (u
g/dl
)
REFINERY FOREMAN 0.034 0.133 0.139 0.045 0.055 0.012 0.029 0.01 0.03 0.02 0 0.023 0.023 0.026 0.087 0.032 0.03SMELTER FOREMAN 0.033 0.115 0.166 0.036 0.037 0.024 0.047 0.046 0.109 0.02 0.064 0 0.018 0.019 0.061 0.038 0.072DISPATCH FOREMAN 0.017 0.019 0.007 0.026 0.010 0.012 0.01 0.018 0.02 0.02 0.024 0.001 0.018 0.015 0.028 0.051 0.06YARD FOREMAN 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0LEGAL LIMIT 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.15
1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct Nov-01
Jan-02
Feb-02
Mar-02
Apr-02
May-02 2-Sep
confidence interval shows that the given results are different in comparison with the legal
limit of 0.15 µg/dl are all statistically significant. Furthermore, a z-test showed that all the
results are statistically significant when compared to the legal limit. However, it is
interesting to note that these values are all below the legal limit value of 0.15 µg/dl.
4.2.6.3 Foremen offices
The airborne lead levels in the foremen offices from January 2001 up to September 2002
is shown in figure 12. Summary of the analyses of the results is presented in table 10.
72
Table 10: Summary for air lead data in the foremen offices Area Skewness Mean
(µg/dl) S.D. SEM Z -Test 95 % C.I.
[min; max] Refinery 1.716 0.046 0.040 0.003 -3.036 [0.028;0.063] Smelting 1.537 0.057 0.041 0.008 -2.712 [0.038;0.075] Dispatch 1.598 0.021 0.015 0.003 -3.750 [0.014;0.028] Legal limit 1.099 0.150 0.000 0.000 0.000 [0.012;0.025]
The mean air lead values (± S.E.M.) range from 0.021 µg/dl (± 0.003) up to 0.057 µg/dl
(± 0.008). These values correspond to the dispatch and smelting foremen offices
respectively. However, in March 2001, the smelter foreman office was above the legal
limit. This was dramatically decreased thereafter. The 95 % confidence interval shows
that the given results are different in comparison with the legal limit of 0.15 µg/dl are all
statistically significant. Furthermore, a z-test showed that all the results are statistically
significant when compared to the legal limit. However, it is interesting to note that these
mean values are all below the legal limit value of 0.15 µg/dl as the other areas above.
4.2.6.4 Managers offices
The airborne lead levels in the managers’ offices from January 2001 up to September
2002 is shown in figure 13. Summary of the analyses of the results is presented in table
11.
73
Figure 13: Air lead levels in the production managers's offices from January 2001 until September 2002
-0.05
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Date (months)
Air
lead
leve
ls (u
g/dl
)
Smel. Mng 0.069 0.163 0.404 0.043 0.018 0.012 0.047 0.017 0.020 0.058 0.007 0 0.021 0.038 0.013 0.06Ref. Mng 0.045 0.119 0.144 0.039 0.025 0.012 0.016 0.018 0.030 0.036 0.007 0 0.019 0.072 0.014 0.066LEGAL LIMIT 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.15
1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug Oct-01
Nov-01
Jan-02
Feb-02
Mar-02
Apr-02
May-02 2-Sep
Table 11: Air lead data from the managers’ offices
Area Skewness Mean
(µg/dl)
S.D. SEM Z -Test 95 % C.I.
[min; max]
Smelting 3.175 0.064 0.098 0.055 -2.275 [0.019;0.110]
Refinery 1.316 0.047 0.041 0.032 -2.855 [0.028;0.066]
Legal limit 1.099 0.150 0.000 0.000 0.000 [0.15;0.15]
The mean air lead values (± S.E.M.) range from 0.047 µg/dl (± 0.032) up to 0.064 µg/dl
(± 0.055). The data is from the refinery and smelting manager’s office respectively. In
March 20001 there was rise in the smelter manager’s office. A drop in the air lead levels
74
Figure 14: Lead in air levels in the yard area from December 2000 until September 2002
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Date (Months)
Air
lead
leve
ls (u
g/dl
)
WEIGH BRIDGE 0.01 0.02 0.020 0.064 0.010 0.160 0.000 0.041 0.010 0.013 0.008 0 0.006 0.12 0.008 0.012 0.012 0.011BATTERY BREAKER 0.034 0.068 0.019 0.043 0.109 0.102 0 0.311 0.04 0.039 0.055 0.134 0.208 0.071 0.04 0.088 0.33 0.163Plinth in laundry 0.014 0.021 0.026 0.007 0.010 0.087 0.101 0.137 0.03 0.037 0 0.052 0.025 0.063 0.02 0.082 0.104 0.02BAGHOUSES 0.022 0.207 0.107 0.186 0.010 0.412 0.057 0.384 0.09 0.647 0.054 0 0.199 0.575 0.371 0.126 0.126 0.27POLY PROP 0.024 0.01 0.007 0.030 0.010 0.059 0.088 0.020 0.050 0.006 0.069 0.04 0.006 0.066 0.034 0.041 0.051 0.17CAR PARK(polyprop) 0.01 0.071 0.020 0.000 0.010 0.080 0.000 0.045 0.020 0.039 0 0 0.018 0.042 0.013 0.024 0.025 0.016Final product loading 0.086 0.037 0.049 0.070 0.030 0.041 0.118 0.103 0.030 0.064 0.033 0.015 0.056 0.092 0.077 0.219 0.219 0.026LEGAL LIMIT 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15
Dec-00 1-Feb 1-Mar 1-Apr 1-May 1-Jul 1-Aug Sep-
01Oct-01
Nov-01
Jan-02
Feb-02
Mar-02
Apr-02
Jun-02 Jul-02 Aug-
02 2-Sep
in this office followed this. The 95 % confidence interval does not include zero, therefore
the p-value is less than 5 %. Both offices have air lead levels less than 0.15 µg/dl and the
difference is statistically significant.
4.2.6.5 Yard area
The airborne lead levels in the yard area from December 2000 up to September 2002 is
shown in figure 14. Summary of the analyses of the results is presented in table 12
75
Table 12:Air lead data for the yard area Area Skewness Mean
(µg/dl) S.D. SEM Z -Test 95 % C.I.
[min; max] Weigh-bridge 2.261 0.033 0.043 0.030 -3.602 [0.015;0.050] Battery Breaking 1.412 0.112 0.089 0.067 -1.085 [0.075;0.149] Plinth in Laundry 1.007 0.045 0.040 0.033 -3.216 [0.028;0.061] Baghouses 1.133 0.209 0.187 0.148 1.322 [0.131;0.287] Polypropylene 1.749 0.045 0.040 0.029 -3.215 [0.029;0.062] Car park (polyprop) 1.391 0.027 0.022 0.016 -3.809 [0.018;0.036] Final Product Loading 1.390 0.080 0.061 0.046 -2.088 [0.055;0.106] Legal Limit 1.083 0.150 0.000 0.000 0.000 [0.150;0.150] The mean lead in air values (± S.E.M.) range from 0.027 µg/dl (± 0.016) up to 0.209 µg/dl
(± 0.148). The data from the car park, an area near the polypropylene area and the other
data is from the bag-houses area, respectively. It is interesting to note that all areas except
for the baghouses and battery breaking areas were statistically different from the legal
limit and the difference is significant. Also, the measurements from the other areas are
below the legal limit. In contrary, there is no chance that the physical measurements from
the baghouses are statistically significant from the legal limit. This is shown from the z-
test. Furthermore, the results are higher than the stipulated 0.15 µg/dl from lead
regulations. However, for the battery breaking, the physical measurements are below the
legal limit but they are not statistically different from the legal limit.
4.2.6.6 Smelter and refinery area
The airborne lead levels in the yard area from January 2001 up to September 2002 is
shown in figure 15. Summary of the analyses of the results is presented in table 13.
76
Figure 15: Air lead levels in the smelter/refinery area from January 2001 until September 2002
-1
0
1
2
3
4
5
Date (Months)
Air
lead
leve
ls (u
g/dl
)
Smel D/STAIS 0.734 0.471 1.53 0.421 0.731 1.163 0.239 0.190 0.697 0.370 0.814 0 0.385 2.27 0.78 1.52HOT METAL 1.211 0.534 0.435 0.601 0.389 0.986 0.930 0.240 0 1.895 0.157 1.002 1.932 0.548 0.373 0.38REFINERY 0.78 1.276 0.232 1.223 1.197 2.045 0.721 1.220 0.213 0.312 0.807 0.358 0.542 2.35 1.07 1.32CASTING 0.125 0.154 0.039 0.065 0.794 0.794 0.175 0.175 0.072 0.057 0.183 0.124 0.214 0.475 0.12 0.31DIESEL PUMP 0.137 0.125 0.211 0.236 0.095 0.095 0.667 0.667 0.662 0.206 0.556 0.054 0.331 0 0.22 0.26LEGAL LIMIT 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.15 0.15 0.15
1-Jan 1-Feb 1-Apr 1-May 1-Jun 1-Jul Sep-01
Oct-01
Nov-01
Jan-02
Mar-02
Apr-02
May-02
Jun-02
Aug-02 2-Sep
Table 13: Summary of air lead levels in the Smelter/Refinery area
Area Skewness Mean
(µg/dl)
S.D. SEM Z -Test 95 % C.I.
[min; max]
Smelting 0.728 0.942 0.587 0.484 7.330 [0.740;1.144]
Hot Metal 2.758 0.991 1.044 0.651 5.900 [0.554;1.427]
Refinery 0.599 1.014 0.584 0.468 8.245 [0.770;1.258]
Casting 1.634 0.268 0.275 0.208 2.165 [0.153;0.383]
Diesel Pump 3.572 0.427 0.667 0.375 3.217 [0.148;0.706]
Legal Limit 1.083 0.150 0.000 0.000 0.000 [0.150;0.150]
The mean lead in air values (± S.E.M.) range from 0.268 µg/dl (± 0.208) up to 1.014 µg/dl
(± 0.468). The areas with the lowest and highest range are casting and refinery
77
respectively. The difference between the legal limit and the physical measurements done
on these areas is statistically significant. However, the measurements done are all above
the legal limit, which indicates much concern for these areas.
78
4.3 Discussion
Physical surroundings, job demands and technological factors, improper design of the
work environment and job activities can cause adverse employee perceptions,
psychosocial stress and health problems (Smith and Saifort, 1989 & Cooper and Marshal,
1976). Clinical lead poisoning has always been one of the most important occupational
diseases and occurs in many occupations. Hence in November 1980, in the USA, OSHA
issued the Final Standard on Occupational Exposure to Lead. In addition, in November
1980 a comprehensive Approved Code of Practice was issued in the United Kingdom
regarding the control of lead at work (Stellman and Osinsky, 1997).
From the results of the walkthrough evaluation and interviews held with the workers of
this foundry, most workers were found to be middle aged (36-55 years). It was also found
that work experience ranges from 3 months up to 24 years. It can therefore be concluded
that the workers do stay in the company for a long time. This was also evidenced by the
fact that results from lead in blood showed a work experience range of 6 months up to 36
years since the year 2000. This was impressive. One of the reasons why workers remain in
the company could be the incentives that they get such as promotions, good salaries, job
contentment, comfortability etc. However, due to high unemployment rates in South
Africa it might be possible that the workers do not have a choice but to work in that
company.
79
The results of the questionnaire showed that 75 % of the workers perceive their workplace
to be dusty and 93 % of the workers think that management is doing its best to prevent
dust inhalation or ingestion. These workers mentioned that the company provides training,
PPE, engineering controls such as sprinklers, road sweepers, ventilators and extractor fans
for controlling the dust. During the walkthrough evaluation, the above mentioned
preventive and control measures were also observed to be present. Despite all the control
measures that the foundry implements, it was observed during the walkthrough evaluation
and was also mentioned by some of the respondents that their workplace is dusty. Also,
the extractor fans were seen as the most generators of dust, according to responses of the
workers and the environmental officers. It can be suggested that this could be the
maintenance problem because extractor fans are supposed to reduce dust, not vice versa.
Safety and health measures should be considered first to prevent the inhalation of lead.
Secondly, effective maintenance procedures for the control measures should be
considered to prevent it from being ingested. This is mostly achieved by substitution of
lead with a less toxic substance (Stellman and Osinsky, 1997). In this study it is obvious
that this option is not feasible because the lead is the raw material of this foundry.
Workers and environmental officers reported that lead dust might be avoided by
implementing engineering controls such as water sprays to prevent dust formation.
Results of this study showed that engineering controls are used as the first priority in
controlling lead exposure in this foundry. The engineering controls that are used include
air conditioners that are fitted with disposable filters, pressurisation system, wet methods
80
and baghouses. Workers and environmental officers reported baghouses to be the best
engineering control measure. This is interesting because the results of the objective
measurements showed that baghouses were one of the areas with the highest air lead
levels. This can be explained by the fact that baghouses are efficient in extracting lead
dust from the air hence the high levels of lead in the baghouses. Furthermore, it was
reported by one of the environmental officers that the company is always trying to
improve on the engineering controls implemented in this foundry. It was mentioned that a
new mist sprayer was installed in the refinery area and that it was working effectively. In
contrary, the results of air monitoring from the year 2001 until 2002 showed that the
refinery had the highest air lead levels.
Stellman and Osinsky (1997) also noted that workers who are exposed to lead should be
provided with PPE that should be washed or renewed regularly. According to OSHA,
1993, Lead Regulation of 2001, it is stated that:
1. ‘Employers should ensure that the relevant PPE is capable of keeping the exposure at
or below the OEL for the type of lead used in the industry,
2. The relevant equipment is correctly selected and properly used, training on how to use
the PPE is provided,
3. The equipment is kept in good condition and efficient working order
4. Employer issues no personal protective equipment that has already been used by
another person, unless the relevant protection equipment is properly decontaminated
and where appropriate sterilised’.
81
During this study it was observed that the company has no clear policy regarding the use
of PPE. In some areas, it was observed that the workers were performing their tasks
without using appropriate PPE. In contrary to this observation, all respondents reported
that all workers wear PPE when performing their tasks except when they go to the
canteen because the canteen is classified as one of the ‘below the limit’ areas for lead
exposure in this foundry. The results of both the blood lead levels for workers from the
canteen and the results from measurements of the levels of lead in air show that the
canteen has the lowest lead levels. This area was one of those areas that had air lead
levels with the acceptable limits.
Therefore, this foundry complied with the ILO (1996) which states that all companies
should provide drinking facilities, eating areas and rest rooms to ensure good
performance and well being.
Regarding decontamination and sterilisation, the results obtained from the study were that
the foundry has a contracting laundry system where PPE is sterilised and decontaminated.
Also, workers have exclusive PPE to avoid a case whereby a worker uses another
person’s PPE. As a result it was reported that the workers selected PPE depending on
their preferences with regards to size and comfortability. The Ergonomic Checkpoints
prepared by ILO in collaboration with the International Ergonomics Association (1996),
also recommends that a well fitting and easy-to-maintain PPE when risks cannot be
eliminated by other means should be chosen.
82
During the walkthrough it was found that not all areas were clean and most of the
workers interviewed were working in some of the areas which were not clean. It was
surprising that the majority of workers reported that they think their workplace is clean.
Furthermore, confusing reports came about the issue of the responsibility of who does the
housekeeping. This aspect would require further investigation in order to identify who
should be held accountable for the inefficient housekeeping.
In the lead smelting, the main hazards are the lead dust produced during the crushing and
dry grinding operations and lead fumes encountered in sintering, blast furnace reduction
and refining. In this study it has been found that most lead exposure occurs during the
smelting step from the furnaces, which is in accordance with the literature by Stellman
and Osinsky (1997). The technical director of the plant also reported that most of lead
exposure occurs during the smelting process. These results were further supported by
results from physical measurements, which showed that highest lead exposure was from
the smelting and refinery areas where all sections in this area were above the legal limit
of 0.15 µg/dl. Furthermore, air lead levels in baghouses were also above the legal limit.
This could be explained by the fact that baghouses are one of the control measures for
lead exposure where lead from the surrounding air is extracted and kept in the baghouses.
However, results from questionnaire assessment about work environment it was indicated
that the majority of the workers think that the premixing, charging, battery breaking,
loading of material, ventilators, refinery and smoking furnaces are the major sources of
dust.
83
Records of blood lead levels for the year 2002 showed that the battery breaking area had
the highest blood lead levels (37.21µg/dl), followed by the smelting area which had blood
lead levels of 31.34 µg/dl. These two areas were the ones with the highest air lead levels.
It should be noted that, Park and Paik (2002) and Idiebele (1994) suggested that air lead
measurements should not be used solely as the prediction of blood lead levels inspite of
the positive correlation between the two variables which is in accordance with the results
from the present study. The smelting area was also the area where the worker reported
that he was forced to change into a different workstation because of heat and lead
exposure.
It was the company’s goal to reduce blood lead to below 40 µg/dl, which is the highest
blood lead level limit set by the OSHA Standard. It can be reported that the foundry has
reached their goal as almost all lead in blood were below 40 µg/dl. Except for two
workers who have 15 and 19 years of work experience in that foundry. However, Roscoe,
et. al. (2002) reported that the majority of workplace related U.S. Dept. of Health and
Human Services recommends that all adults’ lead in blood should be below 25 µg/dl.
However, a study done by Haber and Maier (2002) on the transparency of OEL
documentation showed that OEL documentation should adhere to good risk
characterisation principles and should identify methodology, calculations, uncertainties
and overall confidence into the OEL derivation. These authors also suggest that each
company should have a uniform way of deriving OEL’s.
84
It should be noted that the areas which had lead levels above the ‘action level’ of 0.07
µg/dl were found to be the battery breaking area, baghouses, final product loading area,
the old workshop (which forms part of the maintenance department), the smelting and
refinery areas. However, areas, which were recorded to have lead levels below the ‘action
level’, included the laundry, canteen, change rooms, clinic, final product loading area,
weigh-bridge, polypropylene and offices. From the results, the battery breaking area had
exceeded the lead exposure limit. In this foundry, the old workshop is regarded as the area
within the ‘action level’ range. Therefore, classification of areas according to lead
exposure levels needs to be re-evaluated.
Results of the study showed that the majority of workers had some of the common
symptoms of lead poisoning. According to Roscoe, et. al. (2002), the elevated blood lead
levels in adults can damage the cardiovascular, central nervous, reproductive,
hematological and renal system. However, since the symptoms of lead poisoning are
chronic and are only observable after some years of lead exposure, it was difficult to
associate the reported symptoms with occupational lead exposure. These symptoms
included headaches, stomachaches and memory loss. Nevertheless, workers reported that
they are very concerned about their health whilst working in this foundry. This somehow
strengthens the possibility of reported symptoms to originate from occupational lead
exposure.
Workers who were interviewed mentioned that they were educated about smoking and its
effects on ones health. Workers also reported that they know about the association
85
between smoking and lead exposure. It is important to note that more than 50 % of
workers reported that they do not smoke.
Workers reported that they work a 40-hour shift per week that is recommended by the
ILO. However, none of the workers complained about the work organisation. In the case
of autonomy in the workplace, it seemed to be very limited. Ganster (1997) reports that,
autonomy and job control, are concepts that have a long history in the study of work and
health. Autonomy can be defined as the extent to which workers can exercise discretion in
how they perform their work. It is most closely related to theories that are concerned with
the challenge of designing work so that it is intrinsically motivating, satisfying and
conducive to physical and mental well being. Whereas, job control on the other hand
means the way the ability of the employer influences what exactly happens in the work
environment and this is determined by the worker’s personal goal. This is related to the
predictability of the demands anticipated by the worker (Ganster, 1997). It is therefore a
concern that these workers do not have such control over their work. However, the
workers did not complain about this factor, it is possible that the reason is partly because
they are not aware about their rights of having autonomy in their job. It is also possible
that they are happy with the schedules that they are given by the management.
The workers reported that they get a written schedule from the supervisors, which gives
workers no sense of authority over their work as mentioned above. Moreover, it was
observed and reported that workers do monotonous work. This prevents workers from
gaining more skills and that may lead to de-motivation, reduced performance and that
86
would eventually results in low production. It was interesting to note that workers
reported that they change workstations through promotion. Others reported that they
change workstations due to high exposures to environmental hazards in their work areas.
This was not a completely satisfactory preventive measure instead of improving the work
environment of the worker, they change the worker to a different workstation. This was
surprising because this means that the next worker that is assigned to work in the ‘non-fit’
environment would also be exposed to the same hazard.
87
4.4 Conclusion
The selected foundry implements the most effective preventive and control measures for
reducing lead exposure to their employees. These measures include the engineering
control, education and training, medical examinations and air monitoring. The
effectiveness of the preventive and control measures was shown from the results of the
medical and physical measurement records. This was also confirmed by the responses of
subjects obtained from the questionnaire. However, there are work areas in the foundry
where the airborne lead levels were very high and the subjects’ blood levels were also
very high. Furthermore, the selection and use of PPE and RPE in this foundry is not
strictly enforced.
It is interesting to note that the foundry has a long-term plan of developing a new smelter
layout with the new ventilation system, which could help to protect workers from lead
over-exposure.
88
4.5 Recommendations
From the results obtained from this study, a list of ergonomics recommendations are
provided and categorised in terms of engineering controls, PPE, work organisation,
housekeeping and personal hygiene.
4.5.1 Engineering controls
• Local ventilation system – It is recommended that the foundry should
install local ventilation. It was reported that there is only general
ventilation in the foundry for prevention of lead exposure. Based on Ridley
and Channing (1999), it is recommended that the main elements of the
LEV equipment should comprise of:
(i) Captor Hood
(ii) Exhaust Ducting
(iii) Extraction Fan
(iv) Filter or Collecting Bags
(v) Parts of the machinery such as integral machine casting or guarding which has
a dual purpose of controlling and venting emissions form the process to the
atmosphere
(vi) Vacuum cleaners when permanently connected to exhaust system and fitted
portable tools
89
(vii) Shaft or flue from a furnace or oven
• Physical Enclosures - It is also recommended that the sources of lead dust
should be enclosed.
• Increased volume of wet methods - It is recommended that the quantity of
water sprays be increased to prevent the formation of dust and that could
also prevent lead from being airborne.
• The control measures in the battery breaking area and old workshop should
be re-assessed because of high air lead levels.
• Effective maintenance programme for all control measures implemented in
the foundry should be seriously enforced.
4.5.2 Personal protective equipment
• The company should have a clear policy regarding PPE and ensure that all
workers wear the required PPE.
• There should be regular supervision for the proper use of PPE. In
accordance to ILO (1996) clear instructions and proper adaptation trial and
training should be given to the workers.
4.5.3 Work Organisation
• Job rotation - It is recommended that workers should do job rotation.
Monotonous tasks and a lack of variety makes work to be boring, therefore
90
frequent changes in tasks are a necessity. Job rotation will help to improve
worker motivation, satisfaction, comfortability and knowledge.
• Autonomy - Workers should be involved in the planning of day-to-day
work schedules. The management should not decide for the workers
because the workers are the ones who are actually doing the work.
4.5.4 Housekeeping
• It is recommended that clear assignment of responsibilities regarding the day-to-day
cleaning of the work areas and general housekeeping be considered.
• General housekeeping needs to be done at least after each shift because the workplace
is reported to be dusty.
4.5.5 Personal hygiene
• It is recommended that workers should take responsibility of ensuring that they wash
their hands after using the toilet and before each meal to prevent workers from
ingesting lead.
• Ensure that work clothes are left in the laundry or in the appropriate storage areas.
• Take a shower before they leave the workplace so that lead does not spread to the
workers’ families.
91
5. ACKNOWLEDGEMENTS
First and foremost, I would like to thank God for all the strength He has given me to
complete this project. Secondly, my supervisor, Mr M. Shaba for all the time and effort he
has put in assisting me with this project. Thirdly, the department of the Occupational
Medicine at the National Centre for Occupational Health, in particular Mrs B. Nyantumbu
for all the assistance she has given me.
I would also like to thank the staff members of the foundry where the study was
conducted for their enthusiasm and willingness in helping me whenever I needed
information for my project. All my family and friends, Mrs S.S. Madide in particular for
all the support she has given me for the whole duration of the course. Lastly but not least,
I thank my husband, Luzuko. I wouldn't have achieved this without his love and support.
92
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10
1
7. A
PPE
ND
ICE
S
APP
EN
DIX
A: L
OG
ICA
L F
RA
ME
WO
RK
APP
RO
AC
H (L
FA)
1. P
RO
BLE
M T
REE
Staf
f tur
nove
r in
crea
sed
Com
pany
has
bad
repu
tatio
n
Inad
equa
te
vent
ilatio
n sy
stem
s
Man
agem
ent/e
mpl
oyer
s ig
nora
nt a
bout
wor
ker’
s he
alth
and
safe
ty
Envi
ronm
enta
l m
onito
ring
inad
equa
te
Prev
entiv
e /C
ontr
ol m
easu
res f
or
lead
dus
t exp
osur
e in
effe
ctiv
e
Empl
oyee
s suf
fer f
rom
lead
poi
soni
ng
Sick
leav
es in
crea
sed
Empl
oyee
s ret
ire a
t an
early
age
Inap
prop
riate
re
spira
tors
/ PP
Es
Com
pany
’s p
rodu
ctio
n de
crea
sed
Com
pany
has
eco
nom
ic p
robl
ems
Poor
ly
desi
gned
w
orks
tatio
ns
Lack
of
know
ledg
e
Wor
kers
no
t aw
are
of th
e pr
oble
m
Poor
ly
mai
ntai
ned
Lack
of s
uper
visi
on
for i
ts u
se
10
2
2. O
BJE
CTI
VE
TREE
Red
uced
staf
f tu
rnov
er
Econ
omy
of c
ompa
ny im
prov
es
Wor
kers
wel
l inf
orm
ed a
bout
le
ad d
ust a
nd
prev
entiv
e/co
ntro
l mea
sure
s
Man
agem
ent
esta
blis
hes e
ffec
tive
safe
ty a
nd h
ealth
pr
o gra
m
Envi
ronm
enta
l m
onito
ring
adeq
uate
Prev
entiv
e/C
ontro
l mea
sure
s for
lead
du
st e
xpos
ure
effe
ctiv
e Empl
oyee
s’ w
ell b
eing
impr
oves
Sick
leav
es re
duce
d
Com
pany
’s
prod
uctio
n in
crea
sed
Ade
quat
e ve
ntila
tion
syst
em
App
ropr
iate
re
spira
tors
/PPE
Prop
erly
m
aint
aine
d R
egul
ar
supe
rvis
ion
for u
se
103
THE ELEMENTS OF THE PROJECT MATRIX (PM)
Goal: Exposure to high levels of lead dust in South African industries eradicated
Indicators > 90 % decrease of reported lead poisoning cases by year 2010.
Assumptions: Workers from industries producing lead dust do not suffer from lead poisoning any more.
Purpose: Existing preventive/control measures for lead dust exposure in one of the South African foundries evaluated
Indicators: Records for environmental surveillance from 1998 - 2002 analyzed.
Assumptions: The company has up-to date records
Outputs: • Employees knowledgeable
about lead dust as a hazard, its effects on their health and how to protect themselves from lead dust inhalation.
• Employees use RPE/PPE appropriately
• Supervision for use of RPE/ PPE done on a regular basis
• RPE /PPE and engineering equipment maintained and serviced according to specifications
Indicators: • More than 70 % response
from subjects obtained by February 2003
• Availability of PPE /RPE and ventilation systems
• Their maintenance/service records for 3 months.
Assumptions: The company requires more ergonomic interventions to be conducted for further improvement of the company’s production
Activities: • Abstract information
from records about environmental monitoring (‘98 – 2002)
• Walkthrough and talk-through
• Conduct interviews with management and workers
• Make ergonomic recommendations
Inputs: • Records • Safety representatives
or supervisors • Workers • Finance (stationery,
computer, transport)
Assumptions: Management and workers will co-operate fully until completion of the project.
104
APPENDIX B:
STRUCTURED INTERVIEW FOR FOUNDRY WORKERS The aim of this questionnaire is to gather information regarding (i) Your job background, (ii) Your perception of the work environment, (iii) Your perceived health risks and (v) Work practices. It would be highly appreciated if you can take a few minutes to answer the following questions as it would assist the researcher in understanding the problems you encounter in your work in order to make ergonomic recommendations. All answers will be treated confidentially and your anonymity will be maintained throughout the research.
I. PERSONAL INFORMATION
25-35 (yrs) 36-55 (yrs) 56-60 (yrs) 1.1 Age (yrs) 1.2 Description of your current job 1.3 Duration in Current Job (months) 1.4 Description of your previous job before joining the current job 1.5 Duration in Previous Job (months)
II. PERCEPTION ABOUT WORK ENVIRONMENT
2.1 Is your work area dusty? YES NO (If YES, answer questions 2.2 to 2.10 below. If NO, answer questions 2.4 to 2.10) 2.2 How do you know that it is dusty? Visible on the walls and machinery/equipment Dust on protective clothing Smell dust in the air 2.3 What is the main cause of the dust? 2.4 How do you protect yourself from inhaling the dust? Simple disposable mask
105
Special respirator None 2.5 How does your organization control the dust? 2.6 Where was the main source of dust before the organization implemented the control measures?
2.7 Do any workers wear respirators or masks when performing work?
2.8 Do you think your workplace is clean? 2.9 How often is your workplace cleaned? 2.10 Who cleans your workplace?
III. HEALTH RISKS
3.1 Have you ever suffered from the following illness? Chest pain Chest tightness Coughing Shortness of breadth Lessened capacity to do physical work Fever Others, please specify, 3.2 Did you visit a doctor/clinic due to this illness? 3.3 Which illness indicated above prevented you from coming to work? 3.4 How long were you absent from work due to the illness? 3.5 Were you hospitalized due to this illness? 3.6 When were you ill? Last month/week
106
6 Months ago Over a year 3.7 What do you think was the cause of the illness? 3.8 What do you think could be done to prevent you from getting this illness? 3.9 Are you worried about your health working here? 3.10 Do you smoke? YES NO If yes, 3.11 How many cigarettes do you smoke per day?
IV. WORK PRACTICES
4.1 How many hours do you work per day? 4.2 How long are your breaks? 4.3 Did you get training for the job you are currently doing? 4.4 Are you involved in planning day-to-day activities?
……………THANK YOU FOR YOUR CO-OPERATION……………..
