2.1 INTRODUCTION

This chapter was provided the discussion of the past research that related to volatile organic

compound (VOC) that were measured in this study. Other than that, in this chapter also explain

the details about the BTEX emission that produced in open municipal solid waste which will

effect the environment and workers in landfill workplace. The discussion on health risk

assessment which was categorised into carcinogenic and non-carcinogenic are also provided in

this chapter. Plus, other related to the concentration of BTEX emission were also discussed in

this chapter.

2.2 MUNICIPAL SOLID WASTE (MSW)

Municipal solid waste consists of household waste, construction and demolition debris,

sanitation residue, and waste from streets. Residential and commercial complexes are the main

generator for this garbage. With rising urbanization and change in lifestyle and food habits, the

amount of municipal solid waste has been increasing rapidly and its composition changing.

(EPA, Types of solid waste, 2009). Waste filthy and unnecessary matter, in solid or liquid state

(excluding radioactive substances) Industrial waste are materials from business activities, such as

ashes, sludge, waste oil and waste plastics. While municipal waste on the other hand are waste

that not menton to be industrial waste (Foundation, 2011). Municipal Solid Waste (MSW)

consists of everyday items we use and then throw away, more commonly known as trash or

rubbish that packaging, appliances, grass clippings, paint, bottles, food scraps, newspapers,

furniture, clothing, and batteries. These trash are all generated from our homes, schools,

hospitals, and businesses. (EPA, 2012)

2.2.1 CHARACTERISITC MUNICIPAL SOLID WASTE IN MALAYSIA

Municipal waste is part of solid waste, including the following; any scrap material or other

unwanted surplus substance or rejected products arising from the application of any process.

Any substance required to be disposed of as being broken, worn out, contaminated or otherwise

spoiled; or any other material that, according to Solid Waste and Public Cleansing Management

Act 2007 [Act 672]. Other than written law, it is required by the authority to be disposed of. This

includes public solid waste, imported solid waste, household solid waste, institutional solid waste

and special solid waste such as waste from commercial, construction, industrial and controlled

activities. (Pacific, 2010)

2.1 THE AVERAGE COMPOSITION OF MUNICIPAL SOLID WASTE FROM VARIOUS

STUDIED IN MALAYSIA

The average amount of municipal solid waste (MSW) generated in Malaysia is 0.5–0.8

kg/person/day and has increased to 1.7 kg/person/day in main cities. Recently, the waste

management approach being employed is landfill, but due to rapid development and lack of

space for new landfills, incineration are the alternatives to encounter such issue in big cities in

Malaysia. A simple evaluation was conducted to establish the amount of energy that would be

recovered based on the characteristics of the MSW if it were to be incinerated. From the

characterization exercise, it is found that, food, paper and plastic are the main components of the

Malaysian MSW which made up almost 80% of the waste by weight. The average moisture

content of the MSW was about 55%, making incineration a challenging task. The calorific value

of the Malaysian MSW ranged between 1500 and 2600 kcal/kg. However, the energy potential

from an incineration plant operating based on 1500 ton of MSW/day with an average calorific

value of 2200 kcal/kg is assessed to be at 640 kW/day (Mohd Armi, 2009).

Generation of Malaysia MSW has increased more than 91% in 10 years time (Faisal Sayyid

Hamid, 2009). In 2001, estimated 5.475 million tons of solid waste generated which is about

0.81 kg/capita/day (Schnitzer, 2009) while in main cities, the figure escalated to 1.7

kg/capita/day. The highest average generation rate per capital of MSW was reported in Penang at

1.1 kg/capita/day. A report found that about 7.34 million tons of solid wastes were generated in

Penang on 2006, enough to fill up 42 buildings. (Mohd Dinie Muhaimin Samsudin, 2012) The

main waste generator is the urban population which is constitutes more than 65% of the total

population (Faisal Sayyid Hamid, 2009). In 1980, Malaysia population was 13,136,109,

increasing to 17,563,420 in 1991, 22,198,276 in 2000, and 27,565,821 in 2010 (Mohd Dinie

Muhaimin Samsudin, 2012).

Presently, the amount of solid wastes was produced in Kuantan is about 500 tons daily,

consisting of 300 tons domestic and 200 tons industrial and construction wastes. These solid

wastes will then being dumped at Jerangau Jabor Landfill, Kuantan. However, that sanitary

landfill is nearly filled up and the new cell is in the planning for construction. At the same time,

the government has planned for a gasification unit with ash melting. incineration system to be

implemented in Malaysia as an alternative to the old concept of just dumping all the waste that is

generated. (Siva Kathirvale, 2009)

MUNICIPAL WASTE GENERATION

The rate of waste generation in Malaysia is increasing, covering community activities such as

commercial, institutional, industrial and markets. It is also related to the economic level of

different sectors in the community such as squatters, low, medium and high class residential

area. The rate varies according to the type of waste generators and land use. Depending on the

economic status of the area, the per capita solid waste generation rate varies from 0.45 to 1.44

kilogram per capita per day [8]. Based on data produced by Ministry of Housing and Local

Government (MHLG) [11], the national average rate estimated for year 1991 to 1993 was about

0.711 kilogram per capita per day. This average has been increased to 0.8 kilogram per capita.

(Sakhawi, 2011) The trends of MSW generation in Malaysia have been studied since the early

1980s.

On average, the MSW generation increased 2% annually and is expected to reach 2.5–3% due to

rapid population and economic growth during the Ninth Malaysia Plan (2006–2010). Based on

the census data and Malaysia’s experience in waste study, Sekarajasekaran projected the

residential waste generated in 20 studied municipalities would increase almost 100% from 1980

to 1990 due to growing urbanisation reaching up to 40% of population. This projection is

realistic and realises in the present situation where the total MSW generation in Malaysia

increased from 5.91 million tonnes in 2001 to 6.97 million tonnes in 2005. Moreover, the

average per capita generation rate increased from 0.67 kg/capita/day in 2001 to 0.8 kg/capita/

day in 2005 and this amount is expected to increase to double digits in line with the population

growth by the year 2020. (Zamali Tarmudi, 2009)

Factor Contruting to Municipal Waste Generation

The contributing factors towards the increasing MSW generation in Malaysia are almost similar

to other developing countries. Firstly, the tremendous population growth is identified as one of

the main contributing factors, based on the ministry of housing and local government (MHLG)

annual report in 2002. According to this report, the increasing MSW generation is strongly

related with the population growth, with 13,068.97 tonnes per day recorded in 1996 as compared

to 16,247.93 tonnes per day in 2001, in line with the increase of population from 15,146,236

inhabitants to 17,136,575 inhabitants in the same period. It means, in the six years period, the

total MSW generation increased almost 20% or 3.3% annually. These phenomena clearly

indicate that the increasing in MSW generation is significantly related to the population growth

in Malaysia. As in other developing countries, Malaysia shows a sharp increase in population

from 1970 to 2005. The total population increased from 23.49 million in 2000 to 26.75 million in

2005, an increase of 13.8 % in the ten years period. It is estimated that, by year 2010, the

population will increase to around 29 million with a corresponding increase of MSW generation

in Malaysia. On a regional basis, the total population in the central region was the highest at 8.17

million in 2005 consisting of Melaka, Negeri Sembilan, Selangor and Kuala Lumpur, while

Sarawak was the lowest at 2.34 million, as seen in Table 2

Secondly, the rapid urbanisation process is another main contributing factor to generate more

MSW in all cites throughout Malaysia. The urbanisation growth in Malaysia was stated to be the

most rapid in Southeast Asia in 1980. Generally, the trend of urbanisation can be linked directly

to several federal government policies. For example, in the Ninth Malaysia Plan (2006–2010),

the government plans to expand the urban area development based on a hierarchy growth

conurbation approach which includes national, regional, intermediate and urban centres.

Moreover, the extension of five new development corridors across Malaysia, such as Iskandar

Development Region (IDR) in south Johor, Northern Corridor Economic Region (NCER)

encompassing Penang, Kedah, south of Perlis and north of Perak, East Coast Economic Region

(ECER) covering north of Mersing in Johor, Pahang, Terengganu and Kelantan. The other two

development corridors are Sabah Development Corridor (SDC) and Sarawak Corridor of

Renewable Energy (SCORE). Thus, these policies will have adirect impact to the expansion of

urban boundaries, migration of the young population from the rural areas and increasing

opportunities available in the urban areas as well as on the MSW generation increased.

Thirdly, the urban population showed a significant increase from 8.8 million or 28.7% in 1970 to

16.85 million or 63% in 2005. In 2005, the rate of urbanisation in Pulau Pinang, Wilayah

Persekutuan Labuan, Selangor and Wilayah Persekutuan Kuala Lumpur, Melaka and Johor was

higher than the national urbanisation rate (2.5%). Moreover, the trends of population growth in

selected town in Peninsular Malaysia also demonstrate the significant increase from 1980 to

2005. For example, the total population in Kajang, recorded as only 29,301 in 1980, increased to

99,914 inhabitants in 1991, which means an increase of 70,613 inhabitants or a growth of more

than 24%

annually. Thus, the mean monthly income of urban households increased from RM3103 in 1999

to RM3956 in 2004 or an increase of 27.5% during that period. This resulted in an increase of

MSW generation in the urban areas. Table 3 demonstrates the sharp increase for mean of urban

households’ income from RM1,541 in 1985 to RM3,151 in 2005 or an average 4.7 % annually in

20 years period.

Fourthly, the age structure of population in Malaysia is relatively young, the category 0 – 14

years increased to 32.6% from 8 million in 2000 to 8.72 million in 2005. It means the labour

forces age group 15–64 constitutes only 63.1% of the total population. Thus, Malaysia has

somewhat of a high dependence ratio proportion. It is highly demanding for the government to

provide schools, hospitals, housing and others services. This implies that the government will

face more challenges to provide funds for sustainable development and environmental

improvement in the near future.

Fifthly, rapid economic growth is another main contributing factor of the increasing MSW

generation. For the last two decades, Malaysia has experienced a rapid economic growth since

gaining independence from the United Kingdom in 1957 and it grew almost three times higher

than the world’s average annual economic growth rate at 2.5% per annum. Despite a financial

crisis in 1997 – 1998, the economic development before 1997 was the most impressive since

1986. The Gross Domestic Product (GDP) of the country has increased from RM57,093 millions

in 1985 to RM79,103 in 1990. The total per capita and total GDP of Malaysia from 1970 to 2006

is shown in Table 4. It can be seen that the GDP has significantly increased from RM25,233

million in 1970 to RM240,223 million in 2006, or on average, the annual growth recorded

maintained a range of 6.3% to 8.5% in the studied period.

As an impact of the rapid economic growth in Malaysia, the production structure has also seen a

significant change moving from the agriculture sectors before 1970 to industrial and service

sectors as the engine of growth. Thus, these changes of production structure will also directly

influence the composition of the solid waste disposal. For example, in 1970, the highest

composition of the solid waste generated was agricultural and services waste (including food

waste etc.). However, recently, the trends of solid waste generated completely changed to

manufacturing and services base due to the changing structure of production. Table 5 shows the

significant shifts of production structures from agriculture and mining sector, which recorded

38.6% in 1970 and only 14.5% in 2006. However, the manufacturing and services recorded a

significant increase from 57.4% in 1970 to 89.8% in 2006.

Lastly, the multi-racial society with more than 32 ethnic groups, including the bumiputeras in

Sabah and Sarawak may have also contributed to waste increase. In 2005, for instance, the ethnic

composition in the Malaysian population was bumiputera which comprised of Malay (majority in

Peninsular Malaysia), Iban and Dayak (in Sarawak), Kadazan, Bajau, and Dusun (in Sabah) etc.

(65.9%), followed by Chinese (25.3%), Indian (7.5%) and others (1.3%). The different races

have different cultures, customs and different holidays. Due to these differences of customs, for

certain period of the year the MSW generated will sharply increase because they celebrate their

festivities. For example, Malay people celebrate ‘Hari Raya Puasa’ in the month of Syawal (tenth

month of Muslim calendar) and the Chinese celebrate ‘Chinese New Year’ every year based on

the Chinese calendar, and the Indian race celebrate ‘Deepavali.’

2.2.4 solid waste management

Waste management is currently one of the key areas of public policy. Population growth in cities

usually results in corresponding increase in waste generation. Basically solid waste generation

has

always been related to the economic status of a country and the lifestyle of its population. This

turning also affects the management style of the waste generated. (Saat, 2013) Solid waste

management is a very wide topic where it involves the generation, storage, collection, transfer

and transport, processing, treatment and disposing the solid waste with the best environmental

and social consideration. Within the scope of waste management, it includes all administrative,

financial, legal, planning and engineering functions. (LUMES, 2001). There four functional

elements should be practice properly before final disposal method. The first element is the

material generate at the source. Then, the wastes were needed to separate before placing into the

containers, The second element is waste handling, separation and storage site. Collection of the

solid waste is the third element. Afterwards, the vehicles collected the waste at disposal centre

before dispose them to site disposal. In addition, figure 2.1 showed the steps involve from

dispose them to site disposal.

2.2.5 regulation of solid waste

Solid waste and Public Cleansing Management Act 2007 to minimize and prevent the wastes that

produced in daily life is new legislation by the government was established and implemented in

the year of 2007. This is to minimize and prevent the wastes that produced in daily life (Ken Hen

Chua, 2011)This is also to maintain a proper sanitation and any matters that related to it.

2.3 landfill

For many decades, all municipalities in Malaysia have practiced the open dumping and

landfilling for disposal of the MSW. Landfills still cover 60 to 90% of the served areas, and are

projected to cover more than 75% in the near future, with 80 % of the waste disposal sites having

less than two years of remaining operating life]. Thus the urgency for municipalities to secure

new landfills is priority before the existing ones exhausted. Moreover, the technical evaluation

study in 1992 also found that landfills would remain the major waste disposal system for the

nation in the near future.

Landfilling is done almost solely through this method and open dumping is being practiced and

takes place at about 50% of total landfills. The landfills sites can categorised into five types

according to the landfill stages such as, (i) open dumping sites, (ii) open tipping site, (iii) landfill

with bund and waste disposal covered with layer of suitable cover materials, (iv) landfill

equipped with pipe system for leachate recirculation and aeration, and (v) sanitary landfill. As

seen in Figure 3, there are 161 landfill sites available across Malaysia and only six landfills or

3.7% are in the

sanitary landfills category, while 77 landfills still practice open dumping and have in an adverse

impact on the environment and public health. With regards to this problem, the government has

plan to upgrade some of the existing landfill sites to sanitary landfills, build ten new sanitary

landfills and 18 transfer stations during the Ninth Malaysia Plan. These efforts are seen as further

steps taken by the government in reaching the sustainable solid waste management in Malaysia

for the short and middle term solution.

Types of landfill

A landfill or historically know as midden is a carefully engineered depression in the ground (or

built on top of the ground, resembling a football stadium) into which wastes are put by burial.

The aim is to avoid any hydraulic [water-related] connection between the wastes and the

surrounding

environment, particularly groundwater. Basically, a landfill is a bathtub in the ground; a double-

lined landfill is one bathtub inside another. Bathtubs leak two ways: out the bottom or over the

top. Although landfill is the least desirable option for solid waste disposal, a well developed

waste

management strategy must incorporate landfilling as an essential element to dispose of wastes.

There are basically three types of engineered waste disposal facilities:

1) Municipal Solid Waste (MSW) Landfills

Municipal solid waste ( MSW) landfill contain general (less toxic) wastes from sources

such as private homes, institutions, schools, and businesses without hazardous wastes.

2) Hazardous Waste Landfills

Hazardous waste landfills are disposal facilities for the more toxic chemicals and dangerous

by products. These landfills must be extremely well designed to reduce any chance of the

escape of hazardous compounds into the environment.

3)

Surface Impoundments

The surface impoundments are facilities that deal with liquid waste disposal. Many of the

design procedures used for MSW landfills are also applicable to hazardous waste landfills

and surface impoundments.

Aprt from that, due to operating landfill site, Ministry of Housing and Local Government

(MHLG) classified landfills into 4 levels whch are level 1 for controlled tipping, Level 2 for

sanitary landfill with a leachate recirculation system and Level 4 for sanitary landfill with a

lachate treatment system. Therefore the characterisitic of landfill site using these levels can be

seen also in table 2.5

Landfill Gas Monitoring and Management

When waste decomposes over time, gaseous products will be generated. During the first stage of

degradation which is aerobic degradation, oxygen will be consumed and carbon dioxide will be

formed.These gases can pose potential hazards such as explosion, asphyxiation, offsite gas

migration as so on. A routine gas monitoring is essential to control the gases movement,

especially the methane gas. The methane gas is odourless and highly combustible thus a proper

gas venting and treatment facility should be installed to avoid potential hazard. If the energy

recovery technique is available, methane gas should be processed to produce bio-fuel.

Leachate Management

Leachate is a liquid consisting of moisture generated from landfill during the waste degradation

process. When leachate is produced and moving inside the landfill, it picks up soluble heavy

metals and acids from the waste. Leachate has high content of iron, chlorides, organic nitrogen,

phosphate and sulphate (Preez and Pieterse, 1998). If the leachate that produced during the

degradation process is not collected and treated, it will contaminate the nearby water resources.

Other than to equip with the leachate collection and treatment facilities, ground water monitoring

should be done from time to time to ensure that the leachate does not percolate through the

liners. The nutrients that contain in the leachate can be recovered by irrigating the weak leachate

to the woodland or grassland.

2.4 Volatile Oraganic compound

Volatile organic compounds (VOCs) are emitted as gases from certain solids or liquids. VOCs

include a variety of chemicals, some of which may have short- and long-term adverse health

effects. Concentrations of many VOCs are consistently higher indoors (up to ten times higher)

than outdoors. VOCs are emitted by a wide array of products numbering in the thousands.VOC

present at vapour stage at 20°C which is less than 760 Torr (101.3kPa) and greater than 1 Torr

(0.13kPa). This VOC has been classified by EPA as hexane, benzene, toluene, xylene,

ethylbnzene, 1,3-butadiene and others are hazardous pollutants in the environment. (EPA, 2008)

2.4.1 Source of volatile organic compound

Major sources of VOC concentration are emphasise by (Ying Liu, 2007) in distribution of fuel,

fossil fuel combustion, domestic heating and electrical generation, solvent us and also waste

treatment plants.They also stated that mobile sources have higher concentration to expose than

point sources which is stimulating the interaction between the VOCs and surface environment.

According to Environment Canada, the sources and percentage amounts of man-made volatile

organic compounds generated in Alberta in 1985, were:

(1) Transportation - 45.0%

(2) Petroleum and petrochemical industry - 26.0%

(3) Solvents, coatings and miscellaneous sources - 19.0%

(4) Fuel marketing (gasoline transfers from refinery to bulk stations, bulk stations to gas stations,

gas stations to wehicles) - 6.0%

(5) Electrical power generation - 0.3%

(6) All other - 3.7%

(Envromental Canada, 2006)

VOCs can move easily through the environment. If improperly discarded onto the ground, these

chemicals can travel downward through the soil and eventually end up in the groundwater.

VOCs are not usually found in drinking water that comes from a surface water source, such as a

lake, reservoir, or stream, because they tend to evaporate from the water into the air. (Snauch,

2007)

Most of the global annual VOC emission

is from biogenic sources but biomass burning, fossil fuel combustion and industrial activities

dominate in some regions. Each of these major sources can be further categorized, e.g., biogenic

sources include plant chloroplasts, plant specialized tissues, microbes, and animals. The

processes for removing VOC from the atmosphere include VOC surface deposition, VOC

deposition to particles, and surface deposition after oxidation to CO or CO (Guenther, 2007)

Types of Volatile Organic Compound

There are many type of VOCs concentration that emit in the air. Based on…. They said that the

vocs is including alkanes nd alkenes, cycloalkenes and cycloalkenes, aromatic, cyclic aromatic,

poycyclic aromatic, hydrocarbons and derivatives, aldehydes, alcohols, ketones, esters,

organohalogens, and organosulphur compounds. In the environment, the most profound VOC are

acetic acidm acetone, benzene, ethylbenzene, butanol, butanone, decane, dodecane, ethyl acetate,

benzene dervatives, hexane, limonene, methylsulfides, naphthalene, penetenes, pinenes, propyl

benzenes, styrene, tetrachloroethene, toluene, undecane, and xylene.

However, this study, is imited to BTEX concentrations whc are benzene, toluene, ethylbenzene,

and xylene. BTEX compound are an mportant group of aromatic VOC because of their role in

tropospheric chemistry. Besides that, they also expose most risk to the human health. According

to ….. the most compound of vocs foun din the landfill gas are benzene, toluene, ethylbenzene

and xylenes. These are compound known as hazardous pollutants

2.4.2.1 benzene

Human exposure to benzene has been associated with a range of acute and long-term adverse

health effects and diseases, including cancer and aplastic anaemia. Exposure can occur

occupationally and domestically as a result of the ubiquitous use of benzene-containing

petroleum products, including motor fuels and solvents. Active and passive exposure to tobacco

smoke is also a significant source of exposure. Benzene is highly volatile, and exposure occurs

mostly through inhalation.1–3.Public health actions are needed to reduce the exposure of both

workers and the general population to benzene. (Organisation, 2010)

Benzene is a clear, colorless, flammable liquid with a gasoline-like odor that can volatilize to

vapors in air (EPA U. , 2006)Benzene is highly volatile, and most exposure is through inhalation.

Benzene is degraded rapidly in the upper atmosphere. Because of its solubility in water, a minor

amount may be removed by rain to contaminate surface waters and soil. However, it is not

persistent in surface water or soil, either volatilizing back to air or being degraded by bacteria.

2.4.2.2 ethyl benzene

Ethylbenzene is a colorless liquid found in a number of products including gasoline and paints.

Breathing very high levels can cause dizziness and throat and eye irritation. Breathing lower

levels has resulted in hearing effects and kidney damage in animals. Exposure to high levels of

ethylbenzene in air for short periods can cause eye and throat irritation. Exposure to higher levels

can result in dizziness. Irreversible damage to the inner ear and hearing has been observed in

animals exposed to relatively low concentrations of ethylbenzene for several days to weeks.

Exposure to relatively low concentrations of ethylbenzene in air for several months to years

causes kidney damage in animals. On top of that, Agency for toxic substance and disease

registry (ATSDR) state that etylbenzene found in water is near landfill, waste sites or

underground fuel storage tank which is leaking. (ATSDR, 2007)

2.4.3.2 Toluene

EPA has found toluene to potentially cause the following health effects from acute exposures at

levels above the MCL: low oral toxicity to central nervous system, may cause fatigue, nausea,

weakness, confusion. Toluene may affect the nervous system. Low to moderate levles can cause

tiredness, confusion, weakness, drunkentype actions, memory loss, nausea, loss of appetite, and

hearing and color vision loss. These symptoms usually disappear when exposure is stopped.

Inhaling High levels of toluene in a short time can make you feel light-headed, dizzy, or sleepy.

It can also cause unconsciousness, and even death. (ATSDR, Toulene, 2001)

Toluene is released into the atmosphere principally from the volatilization of petroleum fuels and

toluene based solvents and thinners and from motor vehicle exhaust. Considerable emissions are

from: its discharge into waterways or spills on land during the storage, transport and disposal of

fuels and oils; from its production from petroleum and coal; as a by-product from styrene

production, and from its use as a chemical intermediate. (EPA, Toulene Characteristic in

Solvent, 2005)

Xylene

Xyeln is a colourless and it is easily to catch the fire. Actually, there are there categorise of

xylene whch are me-xylene, ortho-xylene, and para-xylene (m-, o- and p-xylene). These different

categories are refered to each isomer. Xylene naturally occurs in petroleum and coal tar.It has

various of usage in rubber, printing, leather, paint, cleaning agent, and many more. Fact is,

xylene can evaporate from water and soil through air. (ATSDR, Toxicological Profile for

Xylene, 2005)

2.5 EFFECT OF BTEX

2.5.1 health

After exposure to BTEX, several factors determine whether harmful health effects will occur, as 

well as the type and 

severity of such health effects. These factors include the amount of BTEX to which you are expo

sed and the length of  time 

of the exposure, as well as which BTEX compound you were exposed to. Of the four BTEX com

pounds, benzene 

is the most toxic. Most toxicity data is available for airborne exposure to BTEX, as this is the mo

st common route of  exposure to these volatile compounds. (Frederic Leusch, 2010)

2.5.2 Water

The U.S. EPA has established permissible levels for chemical contaminants in drinking water

supplied by public water systems. These levels are called Maximum Contaminant Levels

(MCLs). To derive these MCLs, the US EPA uses a number of conservative assumptions,

thereby ensuring adequate protection of the public .

Toxicity testing for BTEX compounds have also been conducted on aquatic organisms. Typicall

y water concentrations in excess of 1 mg/L are required to produce acute toxic effects in organis

ms such as algae, daphnids and fish. Due to low background concentrations of these chemicals in 

water, rapid 

volatilization and degradation processes and their low to moderate toxicity, the overall risk to the 

aquatic environment is therefore considered low. It should be noted, however, that higher concen

trations of these chemicals can occur in water at contaminated sites (Frederic Leusch, 2010)

2.5.3 Air Pollution

The National Environment Protection (Air Toxics) Measure (Air Toxics NEPM) provides a fram

ework for monitoring, assessing and reporting on ambient levels of five air toxics that includes b

enzene, toluene and xylene to assist in the future development of national air quality standards fo

r these pollutants. The Air Toxics NEPM uses the term 'monitoring investigation levels' for air to

xics. If these levels are exceeded then further investigation may be 

appropriate, but exceedance does not indicate that adverse health effects will occur and the goal i

s to gather ufficient data nationally to facilitate development of standards. (Frederic Leusch,

2010)

Health risk assement

According to risk assement is the one of the fastestmethod which is need to evaluat the impact

of the hazards on hman health and also need to determine the levl of treatment whch are tend to

solve the environmental problem that occur in daily life. State that in order to estimate human

health risk, the pollutants that produce are classified as carcinogenic and non –carcinogenic.

Based on , normally, long term measurement areeded to evealuate the human health riskm but

the measurement on carbonyl or btex concentration can done n short period of time. Apart from

that, although the concentration of btex emission need to identified to determine the individual

exposure to air pollution, but the individual exossure can determined depend on their work

activity ehich I reat with the environment

Carcinogenic

Caricinogenic is the compound that harmful to human health. Based on …. Formaldehyde,

acetaldehyde and benzene are suspected to classify as carcinogenic compunds. World Health

Organization estimated that when benzene are mix at the environment, even I ug/m3 of benzene

expose to human life it will lead to 6 cases of leukemia disease for 1000000 in habitants…..

Besides that, benzene and 1,3-butadienes were classified as human carcinogens agents by

international agency for research on cncer….. apart from that, hellen also state that benzene is n

important compound din the urban atmosphere and it is considered to be genetic carcinogenic

agents to human. Therefore, ertan state that cancer risk for benzene is calculated based on the

following equation

Where,

I= daily intak (mg kg day)

CPF= carcinogenic potency factor. It is basically the slope of dose respone curve at low exposure

and it is expresses as the inverse value of daily intake therefore according to US EPA, integrated

risk information system, CPF estimatd as 0.029. the maximum acceptable risk range I between

106 and 104

Non carcinogenic

In contrast internatonal agency for research n cancer has been classified ethyl benzene toluene

and xylenes as non-carcinogenic agents. Beside that, based on juana ethyl benze, stryenem and

naphtlene are not classified as carcinogenic agents by international agency for tesearch on

cancer. But it has only possibility carcinogenic to humans, Apart from that based, non

carcinogenic rsk is characterized in terms of hazard ration. Therefore the calculation is based n

the following equation

Where,

RfD= reference dose which is level o daily intake of a particular substance that not contain

adverse health effect

Therefore, according to US EPA, IRIS 2009 RfD value for TEX whc is toluene ethylbenzen and

tolune is estimated to be as 1.43, 0.29, an 0.029 mgkg day

The risk can be negligible if HR is less than or equal to 1.0

Moreover ertan also state that, to calculate the daiy intak, it base on the equation

Where

C=contaminant

CF= conversion factor

IR= inhalation

Ef= exposurefrequency

Ed=exposure durarion

Bw=bodyd weight

At= averaging tim