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

Child Health


“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


“The Commons”

The Tragedy of the CommonsBy Garrett Hardin, Science, 1968


Technical Solutions

“It is our considered professional judgment that

this dilemma has no technical solution.”

The Tragedy of the CommonsBy Garrett Hardin, Science, 1968


Problems – Solutions?

Lead and kids Fetal alcohol syndrome Nuclear disarmament Bioterrorism Ocean Fisheries Persistent chemicals The Commons


Key Words of Toxicology

Hazard + Exposure = Risk

Individual Susceptibility

Dose / Response


Lead In Homes


Lead in Families


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


"Lead makes the mind give way."

Ancient Awareness

GreekDioscerides - 2nd BC


“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


Public Health Service - L. Sullivan, 1991

“Lead Poisoning remains the most common and societal devastating environmental disease of young children.”

L. Sullivan, 1991


Lead Based Paint Products


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


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


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



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


History Of Lead Toxicology


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


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


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


Sources Of Lead

• Lead Paint• Dust, Soil• Water• Industry• Hobbies• Traditional Ethnic Remedies


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


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


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


Lead - Absorption

Orally Consumed Lead Absorbed In Place of Calcium

CHILDREN – 30-50% OF LEADADULTS – 5-10% OF LEAD

Increased During Pregnancy


Lead - Nutrition

NUTRITIONAL DEFICIENCIES INCREASE ABSORPTION

(high fat diets, iron, calcium) VITAMIN D (from sun) INCREASES


• 25 DAYS -- BLOOD• 40 DAYS -- SOFT TISSUE • 20 YEARS -- BONE

Half-life Of Lead


Children Vulnerability

CHILDREN are more vulnerable exposure than ADULTS

Size Consume More Food

Inhale More AirDeveloping Nervous SystemIncreased need for Calcium


Needleman, NEJM, 1979


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


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


-- LONG TERM PROBLEMS --

• LOW GRADES •

• ABSENTEEISM •

• READING DISABILITY •

• HIGH SCHOOL DROP OUT •

Childhood Lead Exposure


• 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


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


Mechanisms Of Lead Toxicity

• Lead-Calcium Interactions• Lead-Protein Interactions• Lead-Dopamine Systems

Interactions• Lead-Opioid Systems Interactions


• 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


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%


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


Lead in Jewelry

http://www.leadinspector.com/


Test siblings

Find the source

Reduce risky behaviors

Education about the hazards

Education about nutrition

Why Screen For Lead Exposure


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


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


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


“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


Recycling Lead


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


Mercury the Metal


Methyl Mercury (MeHg)

Hg

CH3


Hg - Inorganic & Organic

Hg

CH3

Inorganic – Quick Silver

Hg

Organic – Methyl 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)


Hg – Like Water


Hg – Solid Enough to Sit On


• Alchemy• Medicine - cure syphilis?• Egyptian tomb -1500 BC

Ancient Awareness


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


Occupational ExposureGold mining.

Hatters in the felt industry.

Historical Events


Historical Awareness

A Small Dose of Toxicology Small Dose of Lead and Mercury Polluting with HG

Discharge in Minamata Bay


Fetal Effects of MeHg


Life-Long Effects of MeHg


Planting Seed with Mercury


Iraq Mothers with Bread


Iraq Infant - Effects of Mercury


Coal Fired Plants – Hg Emissions


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 ???


Inorganic - elemental mercury vapor Hg0

Inorganic - elemental mercury vapor Hg0

Biotransformation

Organic - Methylmercury - CH3Hg+

Bioaccumulation

Mercury to Methyl Mercury


Mercury Release

50-75% mercury of released in the environment related to human activities


Atmospheric Hg


Ambient WaterSediments

Edible Fish

Inorganic Mercury

Methyl-Mercury

Methyl-MercuryIn Humans

Biomethylation

Bioaccumulation

Exposure

Discharge

Biotransformation of 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


The Mercury Cycle


• Blindness - Deafness• Cerebral Palsy - Seizures• Abnormal reflexes & muscle tone• Retarded motor development• Visual and Auditory Deficits• Delayed motor development• Altered DRH performance

Neurobehavioral Effects


• Decrease in Brain Size• Cell loss• Disorganization of cells• Cell migration failures

Effects On The Brain


MONKEY - 25 µg/kg - LOAELRAT - 10 µg/kg - LOAELRAT - 50 µg/kg - replicated

Animal - Risk Assessment


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)


• 10-20 ppm hair - LOAEL •• 40-80 ppb blood - LOAEL •

• 0.645 µg/kg •• 0.06 µg/kg - RfD •

Human - Risk Assessment


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


• Reduce environmental release

• Restrict global production and sale

• Advise women of child bearing age

• Research mechanisms of action

• Assess neurodegenerative effects

Recommendations


MeHg Consumption Limits

US EPA – 0.1 ug/kg-day

US FDA – 1 ppm (mg/kg) in tuna


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


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


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


Mercury A Global Issue

Mercury distribution and exposure is a global problem


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


Alice’s Adventures

“Everything’s got a moral, if you can only find it”

Lewis Carroll in Alice’s Adventures in Wonderland


• 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


Mercury or Lead

Questions or Comments?


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


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


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”

Small Dose of Lead and Mercury A Small Dose of Toxicology A Small Dose of Pb or Hg An Introduction...

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