Small Dose of Lead and Mercury A Small Dose of Toxicology A Small Dose of Pb or Hg An Introduction...
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Transcript of Small Dose of Lead and Mercury A Small Dose of Toxicology A Small Dose of Pb or Hg An Introduction...
Small Dose of Lead and Mercury A Small Dose of Toxicology
A Small Dose of Pb or Hg
An Introduction To The Health Effects ofLead & Mercury
A Small Dose of Toxicology Small Dose of Lead and Mercury
“Conditions that ensure that all living things have the best opportunity to reach and maintain their full genetic potential.”
Steven G. Gilbert, 1999
Environmental & Human Health
A Small Dose of Toxicology Small Dose of Lead and Mercury
“The Commons”
The Tragedy of the CommonsBy Garrett Hardin, Science, 1968
A Small Dose of Toxicology Small Dose of Lead and Mercury
Technical Solutions
“It is our considered professional judgment that
this dilemma has no technical solution.”
The Tragedy of the CommonsBy Garrett Hardin, Science, 1968
A Small Dose of Toxicology Small Dose of Lead and Mercury
Problems – Solutions?
Lead and kids Fetal alcohol syndrome Nuclear disarmament Bioterrorism Ocean Fisheries Persistent chemicals The Commons
A Small Dose of Toxicology Small Dose of Lead and Mercury
Key Words of Toxicology
Hazard + Exposure = Risk
Individual Susceptibility
Dose / Response
A Small Dose of Toxicology Small Dose of Lead and Mercury
6500 BC. - Lead discovered in Turkey, first mine.
500 BC-300 AD.- Roman lead smelting produces dangerous emissions.
100 BC. - Greek physicians give clinical description of lead poisoning.
Ancient Awareness
A Small Dose of Toxicology Small Dose of Lead and Mercury
"Lead makes the mind give way."
Ancient Awareness
GreekDioscerides - 2nd BC
A Small Dose of Toxicology Small Dose of Lead and Mercury
“If we were to judge of the interest excited by any medical subject by the number of writings to which it has given birth, we could not but regard the poisoning by lead as the most important to be known of all those that have been treated of, up to the present time.”
Historical Awareness
Orfila, 1817
A Small Dose of Toxicology Small Dose of Lead and Mercury
Public Health Service - L. Sullivan, 1991
“Lead Poisoning remains the most common and societal devastating environmental disease of young children.”
L. Sullivan, 1991
A Small Dose of Toxicology Small Dose of Lead and Mercury
Lead Based Paint
1887 - US medical authorities diagnose childhood lead poisoning
1904 - Child lead poisoning linked to lead-based paints
1909 - France, Belgium and Austria ban white-lead interior paint
1914- Pediatric lead-paint poisoning death from eating crib paint is described
1921 - National Lead Company admits lead is a poison
1922 - League of Nations bans white-lead interior paint; US declines to adopt
1943- Report concludes eating lead paint chips causes physical and neurological disorders, behavior, learning and intelligence problems in children
1971- Lead-Based Paint Poisoning Prevention Act passed
A Small Dose of Toxicology Small Dose of Lead and Mercury
Lead In Gasoline
1854 - Tetraethyl lead discovered by German chemist
1921 - Midgley discovers that tetraethyl lead curbs engine knock
1922 - Public Health Service warns of dangers of lead production, leaded fuel
1923 - Leaded gasoline goes on sale in selected markets
1936 - 90 percent of gasoline sold in US contains Ethyl
1972 - EPA gives notice of proposed phase out of lead in gasoline.
1986 - Primary phase out of leaded gas in US completed
1994 - Study shows that US blood-lead levels declined by 78 percent from 1978 to 1991
2000 - European Union bans leaded gasoline
A Small Dose of Toxicology Small Dose of Lead and Mercury
Investigator Date Blood Findings
Dioscerides 2nd BC 100 "Lead makes the mind give way."
B. Franklin 1763 100 "Dry gripes"
A.J. Tuner 1894 80 Childhood plumbism
R. Byers 1943 80 Long-term sequelae
CDC 1973 40 Undue lead exposure
CDC 1975 30 Undue lead exposure
CDC 1985 25 Undue lead exposure
WHO 1986 20 Undue lead exposure
EPA 1986 15 Undue lead exposure
Fulton et al. 1987 15 IQ Deficits
Hansen et al. 1987 15 IQ Deficits
CDC 1990 10 Undue lead exposure
History Of Lead Toxicology
A Small Dose of Toxicology Small Dose of Lead and Mercury
Agency Blood Lead Levels
40
30
25
20
15
10
0
5
10
15
20
25
30
35
40
Blo
od
Lea
d (
ug
/dl)
CDC1973
CDC1975
CDC1985
WHO1986
EPA1986
CDC1990
Agency and Year
Acceptable Childhood Blood Lead Levels
A Small Dose of Toxicology Small Dose of Lead and Mercury
Health Effects
• Encephalopathy• Colic• Frank Anemia• Hemoglobin Synthesis• Peripheral Neuropathies• Infertility (MEN)• Systolic Blood Pressure (MEN)• Nerve Conduction Velocity• Erythrocyte Protoporphyrin• DEVELOPMENTAL TOXICITY• IQ, Memory, Learning• Growth
A Small Dose of Toxicology Small Dose of Lead and Mercury
Common Lead Uses
Lead acetate (Pb (C2H3 O2)2· 3H2O) • White, crystalline substance• Sugar of lead has a sweet taste• Paint
Lead tetraethyl (Pb(C2H 5)4)• antiknock compound added to gasoline • significant contributor to air pollution
A Small Dose of Toxicology Small Dose of Lead and Mercury
Sources Of Lead
• Lead Paint• Dust, Soil• Water• Industry• Hobbies• Traditional Ethnic Remedies
A Small Dose of Toxicology Small Dose of Lead and Mercury
California, 1998Lead poisoning in furniture workers
and their families Father 46 µg/dL
18-month-old child BLL 26 µg/dL
4-month-old daughter BLL 24 µg/dLtwo refinishers BLLs of 29 and 54 µg/dL,
the four carpenters BLLs of 46, 46, 47, and 56 µg/dL.
Take Home Lead Exposure
MMWR - April 06, 2001 / 50(13);246-8
A Small Dose of Toxicology Small Dose of Lead and Mercury
Herculaneum, MissouriDoe Run – Lead smelter
160,000 tons of lead per year
One of the largest lead smelters in US
Past over 800 tons of lead released into the
environment as part of the smelting process.
Reduced to 81 tons in 2001
Target is 34 tons in 2002.
Lead Contaminated Town
NY Times, Jan 19, 2002
A Small Dose of Toxicology Small Dose of Lead and Mercury
1990 – lead removed from Gasoline
Between 1976 and 1994, the mean blood
lead concentration in children dropped
from 13.7 mcg/dL to 3.2 mcg/dL
One of the major public health
triumphs of the 20th century
Lead Out of Gasoline
A Small Dose of Toxicology Small Dose of Lead and Mercury
Lead - Absorption
Orally Consumed Lead Absorbed In Place of Calcium
CHILDREN – 30-50% OF LEADADULTS – 5-10% OF LEAD
Increased During Pregnancy
A Small Dose of Toxicology Small Dose of Lead and Mercury
Lead - Nutrition
NUTRITIONAL DEFICIENCIES INCREASE ABSORPTION
(high fat diets, iron, calcium) VITAMIN D (from sun) INCREASES
A Small Dose of Toxicology Small Dose of Lead and Mercury
• 25 DAYS -- BLOOD• 40 DAYS -- SOFT TISSUE • 20 YEARS -- BONE
Half-life Of Lead
A Small Dose of Toxicology Small Dose of Lead and Mercury
Children Vulnerability
CHILDREN are more vulnerable exposure than ADULTS
Size Consume More Food
Inhale More AirDeveloping Nervous SystemIncreased need for Calcium
A Small Dose of Toxicology Small Dose of Lead and Mercury
150
10
20
30
40
50
100
Death
EncephalopathyNephropathy
Frank Anemia
Colic
Hemoglobin Synthesis
Vitamin D Metabolism
Encephalopathy
Frank Anemia
Decreased Longevity
Hemoglobin Synthesis
Nephropathy
Peripheral NeuropathiesInfertility (MEN)
Systolic Blood Pressure (MEN)Hearing Acuity
Erythrocyte Protoporphyrin(Women)
Hypertension (?)
Nerve Conduction Velocity
Erythrocyte ProtoporphyrinVitamin D Metabolism(?)
DEVELOPMENTAL TOXICITYIQ
HEARINGGROWTH
Transplacental Transfer
Blood Lead(ug Pb/dl)
- Low birth weight- Miscarriages, Stillbirth- Premature birth
CHILDREN ADULTS
A Small Dose of Toxicology Small Dose of Lead and Mercury
WOMEN• lead crosses the placenta • low infant birth weight• retarded mental development• miscarriages• premature birth• stillbirth
MEN• decreased sex drive• impotence• sterility• altered sperm-birth defects
Reproductive Effects Of Lead
A Small Dose of Toxicology Small Dose of Lead and Mercury
-- LONG TERM PROBLEMS --
• LOW GRADES •
• ABSENTEEISM •
• READING DISABILITY •
• HIGH SCHOOL DROP OUT •
Childhood Lead Exposure
A Small Dose of Toxicology Small Dose of Lead and Mercury
• Increased risk of not graduating from high school (rr 4.8)
• Poorer reading scores• Increased evidence of depression• Higher rate of hard drug use• Increased risk for attention deficit
disorder • Increased risk for antisocial behavior
Academic & Social Costs Of Lead Exposure
A Small Dose of Toxicology Small Dose of Lead and Mercury
16% of all American children
Children with blood leads above 15 UG/DL
7% of economically favored white children
55% of African American children in poverty
source: The nature and extent of lead poisoning in children in the US: a report to Congress - ATSDR
Children Affected
A Small Dose of Toxicology Small Dose of Lead and Mercury
Mechanisms Of Lead Toxicity
• Lead-Calcium Interactions• Lead-Protein Interactions• Lead-Dopamine Systems
Interactions• Lead-Opioid Systems Interactions
A Small Dose of Toxicology Small Dose of Lead and Mercury
• EDTA, Bal, Succimer
• EDTA In Use For 48 Years
• Little Knowledge Of Benefits Or
Hazards Of These Drugs
• The Treatment Is Removing The
Source Of Lead
Lead Chelating
A Small Dose of Toxicology Small Dose of Lead and Mercury
Lead In Ethnic Remedies
Remedy Use Lead Content
Azarcon (Mexico)
Digestive problems
76-86%
Greta (Mexico)
Digestive problems
4-90%
Surma (India)
Cosmetic to improve eye sight
23-26%
Tibet Improve slow development
1-3%
A Small Dose of Toxicology Small Dose of Lead and Mercury
California Suing Major Retailers Over Lead in Jewelry Allegations
California is suing 13 major retailers alleging they broke state law by not warning customers that some of their jewelry contains lead. Private lawsuits containing similar allegations have been filed against a further 11 retailers.
Named in the state's suit were Macy's, Target, Wal-Mart, Kmart, J.C. Penney, Mervyn's, Nordstrom, Ross, Sears, Express, Claire's, Toys "R" Us and Burlington Coat Factory, along with some of their affiliates and parent companies, according to The San Jose Mercury News. (June 24, 2004)
Lead in Jewelry
A Small Dose of Toxicology Small Dose of Lead and Mercury
Lead in Jewelry
http://www.leadinspector.com/
A Small Dose of Toxicology Small Dose of Lead and Mercury
Test siblings
Find the source
Reduce risky behaviors
Education about the hazards
Education about nutrition
Why Screen For Lead Exposure
A Small Dose of Toxicology Small Dose of Lead and Mercury
Environmental Pollutants and Disease in American Children: Estimates of
Morbidity, and Costs for Lead Poisoning, Asthma, Cancer, and Developmental
Disabilities, by Landrigan, P. et al. EHP, 110, July 2002, 721-728.
Cost of Childhood Lead
Assumptions in calculating costs
• All lead is harmful and from environment
• Blood lead of children age 5 – 2.7 ug/dl (CDC)
• 5-year old boys (1,960,200) and girls (1,869,800)
• 1 ug/dl of lead = 0.25 IQ point reduction
• Cost – boys $27.8 and girls $15.6 Billion
Total Costs $43.4 Billion
A Small Dose of Toxicology Small Dose of Lead and Mercury
Agency Blood Lead Levels
40
30
25
20
15
10
0
5
10
15
20
25
30
35
40
Blo
od
Lea
d (
ug
/dl)
CDC1973
CDC1975
CDC1985
WHO1986
EPA1986
CDC1990
Agency and Year
Acceptable Childhood Blood Lead Levels
A Small Dose of Toxicology Small Dose of Lead and Mercury
Water Quality at Seattle Public Schoolshttp://www.seattleschools.org/area/facilities/WaterQuality/
water_quality_update_nov5.htm
Lead entering schools < 1 ppb
Max found 1600 ppb
EPA standard for schools 20 ppb
Lead in Water – Seattle Schools
A Small Dose of Toxicology Small Dose of Lead and Mercury
“What are the legal limits regarding lead
and drinking water?
Lead and copper are regulated by a
treatment technique that requires systems
to control the corrosiveness of their water.
If more than 10% of tap water samples
exceed the action level of 15 parts per
billion, water systems must take additional
steps to reduce corrosivity.” EPA - http://www.epa.gov/safewater/lead/leadfacts.html#concerned
Lead in Water - regulation
Small Dose of Lead and Mercury A Small Dose of Toxicology
Truth and Lead
“How long a useful truth may be known and exist,
befort it is generally receiv’d and practis’d on”
Benjamin Franklin
A Small Dose of Toxicology Small Dose of Lead and Mercury
Hg - Inorganic & Organic
Hg
CH3
Inorganic – Quick Silver
Hg
Organic – Methyl Mercury
A Small Dose of Toxicology Small Dose of Lead and Mercury
Hg Facts & Uses
• Quicksilver• 13.6 times the weight of water• Evaporates at room temperature• Bacteria change to Methylmercury• Amalgam• Many Industrial uses
(thermometers, chemical reactions, gold mining)
A Small Dose of Toxicology Small Dose of Lead and Mercury
• Alchemy• Medicine - cure syphilis?• Egyptian tomb -1500 BC
Ancient Awareness
A Small Dose of Toxicology Small Dose of Lead and Mercury
Greek God Mercury
“For then she bare a son, of many shifts, blandly cunning, a robber, a cattle driver, a bringer of dreams, a
watcher by night, a thief at the gates, one who was soon to show forth
wonderful deeds among the deathless gods...”
Description of the birth of the Greek God Mercury
A Small Dose of Toxicology Small Dose of Lead and Mercury
Occupational ExposureGold mining.
Hatters in the felt industry.
Historical Events
A Small Dose of Toxicology Small Dose of Lead and Mercury Polluting with HG
Discharge in Minamata Bay
A Small Dose of Toxicology Small Dose of Lead and Mercury
Outbreaks of MeHg Poisoning
Place Year CasesMinamata 1953-60 1000
Nigata 1964-65 646
Guatemala 1963-65 45
Ghana 1967 144
Pakistan 1969 100
Iraq 1956 100
Iraq 1960 1,002
Iraq 1971 40,000
On-going 2001 ???
A Small Dose of Toxicology Small Dose of Lead and Mercury
Inorganic - elemental mercury vapor Hg0
Inorganic - elemental mercury vapor Hg0
Biotransformation
Organic - Methylmercury - CH3Hg+
Bioaccumulation
Mercury to Methyl Mercury
A Small Dose of Toxicology Small Dose of Lead and Mercury
Mercury Release
50-75% mercury of released in the environment related to human activities
A Small Dose of Toxicology Small Dose of Lead and Mercury
Ambient WaterSediments
Edible Fish
Inorganic Mercury
Methyl-Mercury
Methyl-MercuryIn Humans
Biomethylation
Bioaccumulation
Exposure
Discharge
Biotransformation of Mercury
A Small Dose of Toxicology Small Dose of Lead and Mercury
• Natural Degassing of the earth• Combustion of fossil fuel• Industrial Discharges and Wastes• Incineration & Crematories• Dental amalgams
Hg0 Hg2+ CH3Hg+
Environmental Sources of Mercury
A Small Dose of Toxicology Small Dose of Lead and Mercury
• Blindness - Deafness• Cerebral Palsy - Seizures• Abnormal reflexes & muscle tone• Retarded motor development• Visual and Auditory Deficits• Delayed motor development• Altered DRH performance
Neurobehavioral Effects
A Small Dose of Toxicology Small Dose of Lead and Mercury
• Decrease in Brain Size• Cell loss• Disorganization of cells• Cell migration failures
Effects On The Brain
A Small Dose of Toxicology Small Dose of Lead and Mercury
MONKEY - 25 µg/kg - LOAELRAT - 10 µg/kg - LOAELRAT - 50 µg/kg - replicated
Animal - Risk Assessment
A Small Dose of Toxicology Small Dose of Lead and Mercury
2.5 µg/kg - NOAEL (animals) 0.25 µg/kg - Human 0.025 µg/kg - Sensitive populations
Animal - Risk Assessment
(the rule of dividing by 10)
A Small Dose of Toxicology Small Dose of Lead and Mercury
• 10-20 ppm hair - LOAEL •• 40-80 ppb blood - LOAEL •
• 0.645 µg/kg •• 0.06 µg/kg - RfD •
Human - Risk Assessment
A Small Dose of Toxicology Small Dose of Lead and Mercury
Mercury Fishing Advisories
In 2000, 41 States have over 2000 fish consumption advisories
An increase form 27 in 1993 Pregnant women, nursing
mothers, women who intend to have children, and children under 15
A Small Dose of Toxicology Small Dose of Lead and Mercury
• Reduce environmental release
• Restrict global production and sale
• Advise women of child bearing age
• Research mechanisms of action
• Assess neurodegenerative effects
Recommendations
A Small Dose of Toxicology Small Dose of Lead and Mercury
MeHg Consumption Limits
US EPA – 0.1 ug/kg-day
US FDA – 1 ppm (mg/kg) in tuna
A Small Dose of Toxicology Small Dose of Lead and Mercury
Limit the amount of canned tuna you
eat, based on your bodyweight. Guidelines are: Women of childbearing age should limit the amount
of canned tuna they eat to about one can per week (six ounces.) A
woman who weighs less than 135 pounds should eat less than one
can of tuna per week. Children under six should eat less than one
half a can of tuna (three ounces) per week. Specific weekly limits for
children under six range from one ounce for a twenty pound child,
to three ounces for a child weighing about sixty pounds.
WA State Advisory
http://www.doh.wa.gov/fish/FishAdvMercury.htm
A Small Dose of Toxicology Small Dose of Lead and Mercury
WA State Mercury Chemical Action Plan• Reduce Hg in fish
• Reduce Hg release into the environment
• 4-5 tons of Hg released in WA
• Educating consumers about Hg in home
WA State Hg CAP
http://www.ecy.wa.gov/biblio/0303001.html
http://www.ecy.wa.gov/programs/eap/pbt/mercuryplan.html
A Small Dose of Toxicology Small Dose of Lead and Mercury
U.S. EPA Produced
“First-Ever Rule to Reduce Mercury
Emissions from Power Plants”
• Last 15 years no drop in Hg emissions
from power plants
• Is Cap and Trade appropriate for a
demonstrated neurotoxic compound?
Hg CAP and Trade
A Small Dose of Toxicology Small Dose of Lead and Mercury
Mercury A Global Issue
Mercury distribution and exposure is a global problem
A Small Dose of Toxicology Small Dose of Lead and Mercury
Precautionary Principle
"When an activity raises threats of harm to the environment or human health, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically."
- Wingspread Statement on the Precautionary Principle, Jan. 1998
A Small Dose of Toxicology Small Dose of Lead and Mercury
Alice’s Adventures
“Everything’s got a moral, if you can only find it”
Lewis Carroll in Alice’s Adventures in Wonderland
A Small Dose of Toxicology Small Dose of Lead and Mercury
• Children have a right to a safe, fair and healthy environment
• Ethical Responsibility to share and use of knowledge
• Duty to promote health and well being of children
• Thoughtful public health advocate
Knowledge - Responsibility
Small Dose of Lead and Mercury A Small Dose of Toxicology
Additional Information - Pb
Web Sites U.S. EPA
http://www.epa.gov/opptintr/lead/index.html
CDC Childhood Lead Poisoning Prevention Program http://www.cdc.gov/nceh/lead/lead.htm
“A Small Dose of Toxicology” – A Small Dose of Lead – http://www.asmalldoseof.org/toxicology/lead.htm
Small Dose of Lead and Mercury A Small Dose of Toxicology
Additional Information - Hg
Web Sites World Health Organization - global
prospective on mercury health effects. http://www.who.int/water_sanitation_health/GDWQ/Chemicals/mercuryfull.htm
US EPA - Main site on Mercury. http://www.epa.gov/mercury/
The Mercury Policy Project (MPP). - works to raise awareness about the threat of mercury contamination - http://www.mercurypolicy.org/
www.asmalldoseof.org
A Small Dose of Toxicology Small Dose of Lead and Mercury
Authorship Information
For Additional Information ContactSteven G. Gilbert, PhD, DABT
E-mail: [email protected]: www.asmalldoseof.org
This presentation is supplement to “A Small Dose of Toxicology”