1 TRAINING FOR HEALTH CARE PROVIDERS Children's Health and the Environment CHEST Training Package for the Health Sector MERCURY

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TRAINING FOR HEALTH CARE PROVIDERSTRAINING FOR HEALTH CARE PROVIDERS

Children's Health and the Environment

CHEST Training Package for the Health Sector

MERCURY

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Mercury and Children's Environmental Health (DRAFT)Mercury and Children's Environmental Health (DRAFT)

LEARNING OBJECTIVESLEARNING OBJECTIVES

Health hazards associated with exposure to the 3 different species of mercury (Hg)

How to diagnose and manage mercury exposure and poisoning

Public health implications

How to prevent and reduce exposure

To understand, recognize and knowTo understand, recognize and know

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MERCURYMERCURY

Is persistent and cycles globallyIs persistent and cycles globally

Continues to be widely usedContinues to be widely used

Exposure has serious effectsExposure has serious effects

Has an impact on global fishingHas an impact on global fishing

May generate bigger problems in less-May generate bigger problems in less-developed regionsdeveloped regions

Interventions can be successfulInterventions can be successful

UNEP. Global Mercury Assessment, December 2002: www.chem.unep.ch/mercury/default.htm

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OVERVIEWOVERVIEW

Environmental origin, transport and fate

Routes of exposure

Toxicokinetics

Toxicodynamics

Target organs/systems

Treatment

Prevention

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ORIGINORIGIN

One element

3 species Elemental Inorganic Organic

Different

toxicity profiles!

pearl1.lanl.gov/periodic/default.htm

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ENVIRONMENTAL SOURCES OF EXPOSURE ENVIRONMENTAL SOURCES OF EXPOSURE

Chloralkali production Artisanal gold and

silver mining Mercury mining,

smelting and use Burning fossil fuels Waste incinerators Volcanoes

© Stephan Boese-O´Reilly 2003Goldman, Pediatrics (2001) 108:197

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- Natural background- Natural background- Volcanic- Volcanic -- Gold rushGold rush-- World War IIWorld War II-- IndustrializationIndustrialization

Hg released in the last 100 Hg released in the last 100 years: 70% man madeyears: 70% man made

http://toxics.usgs.gov/pubs/FS-051-02/

A man made problemA man made problem

Major atmospheric releases Major atmospheric releases detected in the ice coredetected in the ice core

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A LARGE ENVIRONMENTAL PROBLEMA LARGE ENVIRONMENTAL PROBLEM

In small scale gold mining areas Hg is used to extract In small scale gold mining areas Hg is used to extract gold from ore (amalgamation process)gold from ore (amalgamation process)

1 to 2 kg of Hg are used to process 1 kg of gold1 to 2 kg of Hg are used to process 1 kg of gold Most Hg is released into the environment (soil, air, Most Hg is released into the environment (soil, air,

water)water)

More than 50% workersMore than 50% workers have high levels have high levels

……and their children?and their children?

© Stephan Boese-O´Reilly 2003

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Drasch , Wiley VHC, Verlag, 2004, all data in metric tons

Continent

Stationary Combustion

Pig iron & steel production

Cement production

Waste disposal

Non-ferrous metal production

Artisanal gold mining

Sum quantified sources

Europe 186186 1010 2626 1212 1515 250250

Africa 197197 0.50.5 5.25.2 7.97.9 210210

Asia 860860 1212 8282 3333 8787 10751075

North America

105105 4.64.6 1313 6666 2525 210210

South America

2727 1.41.4 5.55.5 2525 6060

Australia &Oceania

100100 0.30.3 0.80.8 0.10.1 4.44.4 105105

Sum, quantified sources 1995

14701470 3030 130130 110110 170170 ~1900~1900

Worldwide 300-100300-100

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TRANSPORT: GLOBAL CYCLE OF MERCURYTRANSPORT: GLOBAL CYCLE OF MERCURY

Hg is emitted into Hg is emitted into the atmosphere the atmosphere and circulated and circulated globallyglobally

EPA EPA

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TRANSPORT: GLOBAL CYCLE OF MERCURYTRANSPORT: GLOBAL CYCLE OF MERCURY

EPA

Ultimately enters water bodies and depositsUltimately enters water bodies and deposits Close to source Long distance from source global pollution

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Hg in sediments converts into methyl-mercury (MeHg)

MeHg enters the aquatic food chain: fish, marine and freshwater

MeHg uptake by humans through fish consumption

Metabolic conversion and Metabolic conversion and bio-accumulation bio-accumulation through “food-chain”through “food-chain”

FATEFATE

EPA

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ELEMENTALELEMENTAL (METALLIC) MERCURY – (METALLIC) MERCURY – ""QUICKSILVER"QUICKSILVER"

Sources of exposureSources of exposure

Environmental: Volcanic explosions, rock weathering, degassing

Anthropogenic inadvertent: Combustion: fossil fuels (coal), waste incineration Industrial: gold/silver mining, chloralkali plants, batteries,

switches, fluorescent lights, thermometers, sphyngomanometers

Anthropogenic intentional: Dental amalgams Ritual and folk-medicine use

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Routes of exposureRoutes of exposure

Inhalation (volatile at room temp): 75-85% absorption Ingestion and skin: almost no absorption

Elimination Elimination Urine and Feces

ToxicityToxicity Lungs, eyes, gingival, skin Also: Central nervous system, kidneys, immune

system

ELEMENTALELEMENTAL MERCURY - QUICKSILVER MERCURY - QUICKSILVER

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Sources of ExposureSources of Exposure

Environmental None

Industrial products Vapor lamps, embalming, Photography Latex paint (pre 1990s) Disinfectants, antimicrobials Alternative medicines, cosmetics

INORGANICINORGANIC MERCURY MERCURY

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Routes of ExposureRoutes of Exposure Ingestion - 10% absorbed Skin - can be high and deadly

EliminationElimination Renal

ToxicityToxicity Primary: kidneys, gastrointestinal tract Secondary: Central nervous system

INORGANICINORGANIC MERCURY MERCURY

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Sources of ExposureSources of Exposure

Environmental conversion: Fish and shellfish (methyl-mercury)

Industrial production: Fungicides, bactericides (phenylmercury) Vaccine preservatives (thimerosal)

ORGANICORGANIC MERCURY MERCURY

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Routes of ExposureRoutes of Exposure Gastrointestinal - rapid & complete absorption Parenteral - 100% absorbed Transplacental – Bioconcentrated

EliminationElimination Feces- T1/2 45 to70 days in adults

ToxicityToxicity Primary: Central nervous system Secondary: Cardiovascular

ORGANICORGANIC MERCURY MERCURY

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MercuryMercury SourcesSources Routes of Routes of exposureexposure

EliminationElimination ToxicityToxicity

Elemental Elemental (metallic)(metallic)

Volcanoes Combustion Waste incineration

Thermometers

Amalgams

Folk remedies

Inhalation Urine and faeces

CNS

Kidney

Lungs

Skin (Acrodynia in children)

Inorganic Inorganic (mercuric (mercuric chloride)chloride)

Lamps

Photography

Disinfectants

Cosmetics

Folk medicine

Ingestion

Dermal

Urine CNS

Kidney

GI tract

Skin (Acrodynia in children)

Organic Organic (methyl; (methyl; ethyl)ethyl)

Fish

Fungicides

Preservatives

Ingestion

Parenteral

Transplacental

Faeces CNS

Cardiovascular

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MERCURY: ACRODYNIAMERCURY: ACRODYNIA

Uncommon syndrome "Pink disease":

Pain in the extremities

Pinkish discoloration and desquamation

Hypertension

Sweating

Insomnia, irritability, apathy

Considered as idiosyncratic reaction.

Schwarz,

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v. Muhlendahl

v. Muhlendahl

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Muhlendahl

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CHILD EXPOSURE IN INDUSTRIALIZED CHILD EXPOSURE IN INDUSTRIALIZED COUNTRIESCOUNTRIES

Methylmercury Methylmercury Consumption of contaminated fish & shellfish Emitted to atmosphere by electric generation Transplacental Breast milk

EthylmercuryEthylmercury Thimerosal

Elemental - vaporsElemental - vapors Ritual and folk-medicine use Amalgam (minor source)

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CHILD EXPOSURE IN DEVELOPING COUNTRIESCHILD EXPOSURE IN DEVELOPING COUNTRIES

Regional cultural usesRegional cultural uses

Eating contaminated fishEating contaminated fish

High exposure may cause overtHigh exposure may cause overt

symptomssymptoms


““Occupational” exposures from gold/silver miningOccupational” exposures from gold/silver mining

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MERCURY: TOXIC EFFECTSMERCURY: TOXIC EFFECTS

Neurotoxicity

Nephrotoxicity

Teratogenicity: MeHg is a teratogen (Minamata disease)

CVS: elevated risk of heart attack, hypertension

Carcinogenicity: MeHg is a possible human carcinogen

Mutagenesis: Hg seems not to be mutagen

Reproduction: no clear evidence of effect

Immunotoxicity: under scientific discussion

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PEDIATRIC EXPOSURE - FISHPEDIATRIC EXPOSURE - FISH

Major source of mercury burden for children in most countries

Fish may contain methyl-mercury

Children exposed By eating fish Transplacentally Via breast milk Rice field in the Philippines, irrigated with

tailing sediments containing mercury © Stephan Boese-O´Reilly 1999

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METHYLMERCURY LEVELS IN FISHMETHYLMERCURY LEVELS IN FISH

www.cfsan.fda.gov/~frf/sea-mehg.html

Ocean Fish with high levels of mercury

SpeciesSpeciesMercury concentration (PPM)Mercury concentration (PPM) N° of N° of

samplessamplesMeanMean MedianMedian MinMin MaxMax

Mackerel King

0.73 NA 0.23 1.67 213

Shark 0.99 0.83 ND 4.54 351

Swordfish 0.97 0.86 0.10 3.22 605

Tilefish 1.45 NA 0.65 3.73 60

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METHYLMERCURY LEVELS IN FISHMETHYLMERCURY LEVELS IN FISH

Drasch,, Wiley VHC Verlag, 2004: Adapted from US EPA (1997)

Typical average mercury concentration in marine fish

SpeciesSpecies mg Hg/kgmg Hg/kg SpeciesSpecies mg Hg/kgmg Hg/kg

HerringHerring 0.0130.013 Sea BassSea Bass 0.1450.145

SalmonSalmon 0.0350.035 TunaTuna 0.2060.206

MackerelMackerel 0.0810.081 HalibutHalibut 0.2500.250

PerchPerch 0.1160.116 SnapperSnapper 0.2500.250

CodCod 0.1210.121 SharkShark 1.3271.327

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METHYLMERCURY: POWERFUL METHYLMERCURY: POWERFUL NEURODEVELOPMENTAL TOXICANT NEURODEVELOPMENTAL TOXICANT

Impedes nerve cell division Impedes nerve cell division and migration and migration

Binds with microtubules Binds with microtubules required for neuronal required for neuronal developmentdevelopment

Binds to and distorts DNA & Binds to and distorts DNA & RNARNA EHP

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EFFECTS OF PRENATAL EXPOSUREEFFECTS OF PRENATAL EXPOSURE

Mental retardation Ataxia & cerebral palsy Seizures Vision & hearing loss Delayed developmental milestones Language disorders Deficits in fine motor function Visual spatial disabilities Memory problems High blood pressure low cardiac rate variability

DOSEDOSE

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CONGENITAL MINAMATA DISEASE: CONGENITAL MINAMATA DISEASE: METHYLMERCURY EXPOSURE IN PREGNANCYMETHYLMERCURY EXPOSURE IN PREGNANCY

Mothers often asymptomatic!

Microcephaly

Cerebral palsy/spasticity

Mental deficits

Malformation of ears,

heart, skeleton, eyes

Minamata Bay, Japan


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NEURODEVELOPMENTNEURODEVELOPMENT

Rice, EHP, 2000 108 (3): 511

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EXAMPLE OF EXAMPLE OF “TREMOR MERCURIALIS”“TREMOR MERCURIALIS”

Hand-writing of Hand-writing of a 9 year old girl in a 9 year old girl in monthly intervals after monthly intervals after an accidental intake of an accidental intake of mercury containing mercury containing seed preservativesseed preservatives

Boese, Paediat Prax (1993) 45: 183

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SUBCLINICAL EFFECTSSUBCLINICAL EFFECTS

Susceptibility of the fetal brain is very high

Altered neuro-psychological tests postpartum, if prenatal Hg-burden was raised by whale fish consumption (Faroe Islands study)

No effects found in a similar study (Seychelles study)

Recommendations EPA recommendation: 0,1 μg of methyl Hg/kg body

weight/day WHO recommendation: 1.6 µg/kg body weight/week

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FAROE STUDYFAROE STUDY Cohort of 1022 children born 1986-1987 Exposure to methyl-mercury from:

Pilot whale meat - episodic, and potentially high Fish consumption - continuous, but low

At age 7: neuropsychological tests At age 14: neurophysiologic tests Neuropsychological dysfunctions

Language Attention Memory

Neurophysiologic tests Delayed brainstem auditory evoked potentials Decreased autonomic heart rate variability

Attributed to pre-natal exposure

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SEYCHELLES STUDYSEYCHELLES STUDY

Cohort of 779 mother-infant pairs

Exposure from mothers with high fish consumption

At age 9: neuropsychological tests

No support for any mercury related neurodevelopmental risks due to prenatal MeHg exposure

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ANOTHER ORGANIC MERCURY: THIMEROSALANOTHER ORGANIC MERCURY: THIMEROSAL

A mercury preservative used in Eye drops, antiseptics, other pharmaceuticals Multidose vaccinations

It is metabolized to ethyl-mercury T1/2 ~7 days in babies

Crosses blood brain barrier Neurotoxic in high doses, “Safe dose” unknown

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PEDIATRIC EXPOSURE TO PEDIATRIC EXPOSURE TO THIMEROSAL IN IMMUNIZATIONSTHIMEROSAL IN IMMUNIZATIONS

Vaccine practices in the 1990s raised the body Vaccine practices in the 1990s raised the body burden of mercury for small and preterm babies*burden of mercury for small and preterm babies*

Thimerosal free vaccinations for neonates ** Thimerosal free vaccinations for neonates ** In the US, all infant vaccinations are thimerosal free since March

2001, except some influenza Still used to prevent microbial contamination of multidose vials in

some countries

No harmful effect of thimerosal proven in infants ***No harmful effect of thimerosal proven in infants ***

* Stajich, 2000, ** Ball, 2001, 2001, *** Heron, 2004

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CHILD LABOUR WITH MERCURYCHILD LABOUR WITH MERCURY

In small scale mining areas, children may work with In small scale mining areas, children may work with mercurymercury

This is Child Labour at its worst limits:This is Child Labour at its worst limits: Physically very hard and dangerous High risk of injury Major health hazard

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Hg in urine of Hg in urine of children aged 8 children aged 8 to 13, who live to 13, who live and/or work in and/or work in the areathe area

TATELU (INDONESIA) – EXPOSED CHILDRENTATELU (INDONESIA) – EXPOSED CHILDREN

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TATELU (INDONESIA) – DYSDIADOCHOKINESIATATELU (INDONESIA) – DYSDIADOCHOKINESIA

Cerebellar Cerebellar effects in effects in children aged children aged 8 to 13, who 8 to 13, who live or work live or work and live in and live in the areathe area

Children from Tatelu (Sulawesi)

0,0%

5,0%

10,0%

15,0%

20,0%

25,0%

30,0%

35,0%

40,0%

Fre

qu

ency

of

Dys

dia

do

cho

kin

esia

controlN = 31

not workingN = 22

working with HgN = 42

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SYMPTOMS AND SIGNS OF HG EXPOSURESYMPTOMS AND SIGNS OF HG EXPOSURE

Typical symptoms of Typical symptoms of chronic metallic mercury chronic metallic mercury intoxication are:intoxication are: Tremor Ataxia Coordination problems Excessive salivation Metallic taste

(© Stephan Boese-O´Reilly 1999)

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OUTCOME

EFFECTS:

Brain

Kidney

Multi-systemic

Acrodynia

SUSCEPTIBILITIES

Foetus

Newborn

Young children

ENVIRONMENTAL EXPOSURE TO HG ENVIRONMENTAL EXPOSURE TO HG HAZARDS:

IndustryFish

Folk

Medicine

Cosmetics

Spills

MEDIA: Food, Air, Soil

SETTINGSHome

School

Outdoors

ACTIVITIES: Eating, Playing, Working

(© Stephan Boese-O´Reilly 2004)

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DIAGNOSIS: HAVE A HIGH INDEX OF SUSPICION!DIAGNOSIS: HAVE A HIGH INDEX OF SUSPICION!

Careful history taking: food, activities, environment, … Clinical observation

Typical signs and symptoms

+ Increased mercury body burden

Urine Hg: inorganic exposure Blood Hg: organic exposure Hair mercury reflects long term exposure

MERCURY

INTOXICATION

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TREATMENT TREATMENT

STOP EXPOSURESTOP EXPOSURE

Chelating agents may reduce the body burden of Chelating agents may reduce the body burden of mercury and may improve some symptomsmercury and may improve some symptoms

DMPS simple to use (orally), has few side effects DMPS is effective in "mixed" and "combined" Hg exposures DMSA may have some advantages in Me-Hg poisoning

Symptomatic treatmentSymptomatic treatment

Rehabilitation Rehabilitation

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TO CHELATE OR NOT TO CHELATE?TO CHELATE OR NOT TO CHELATE?

YESYES Acute elemental Chronic elemental Acute inorganic Chronic inorganic

MAYBEMAYBE Acute organic

- Phenylmercury

- Methoxymercury

NONO Chronic low grade

methyl-Hg

- No ion to grab

- Redistributes

NEVERNEVER Oral EDTA Herbals To “cure” autism

Consult the Poisons Centre!Consult the Poisons Centre!

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POSSIBLE CONTROL MECHANISMSPOSSIBLE CONTROL MECHANISMS

UNEP, 2002

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WHAT HEALTH CARE PROVIDERS CAN DOWHAT HEALTH CARE PROVIDERS CAN DO

SECONDARY PREVENTIONSECONDARY PREVENTION Fish consumption advice

PRIMARY PREVENTIONPRIMARY PREVENTION Mercury free office and hospital Mercury free communities

Thermometer exchange Hazardous waste education Change high-risk behaviors

Folk medicines, cottage industries, …

Get politically active Request emission controls on power plants, incinerators Prevent childhood exposure to artisanal mining

NOAA Photo Gallery, Tuna

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EXAMPLE OF FISH CONSUMPTION GUIDELINESEXAMPLE OF FISH CONSUMPTION GUIDELINES

For women and young children in the USA (USEPA/FDA)For women and young children in the USA (USEPA/FDA)

1. Do not eat Shark, Swordfish, King Mackerel, or Tilefish

2. Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury

Shrimp, canned light tuna, salmon, pollock, and catfish are examples

Albacore ("white") tuna has more mercury than canned light tuna, you may eat up to 6 ounces (one average meal) per week.

3. Check local advisories. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch, but don't consume any other fish during that week.

...to your young child, serve smaller portions!

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For women and young children in developing countries, where diets are based on fish that may have high levels of Hg

WHO

Recognize neurodevelopmental problems in children::

•Determine amount, type and frequency of fish consumption and provide advise

Encourage consumption of fish low in methyl mercury, but:

•Limit intake of larger, predatory fish.•Greatly limit intake of marine mammals.•Encourage consumption of "light" or "chunk light" tuna

EXAMPLE OF FISH CONSUMPTION GUIDELINESEXAMPLE OF FISH CONSUMPTION GUIDELINES

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PRIMARY PREVENTION PRIMARY PREVENTION

In the medical domain:

Avoid the use of Hg mercury thermometers and manometers.

Indicate/promote Hg-free vaccines

Consider non-Hg amalgams

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Primary prevention at home

Avoid ritual use of quicksilver

Eliminate equipment with mercury

Avoid having children play with “quicksilver”

Dispose safely of mercury-containing products (old batteries and thermometers).


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In case of metallic mercury spill

DO NOT clean yourself if amount is greater than that contained in a thermometer: Call local health or environmental agencies.

NEVER VACUUM or use a broom

NEVER put mercury down the drain

NEVER wash mercury-contaminated items in a washing machine

NEVER walk around if your shoes might be contaminated with mercury.

Beware of contaminated clothes too.

www.epa.gov/epaoswer/hazwaste/mercury/spills.htm#cleanmercuryspills


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PRIMARY PREVENTIONPRIMARY PREVENTION

Regulatory measures

Control and reduction of Hg release into the environment

Regulation/Eradication of child labour with mercury

Environmental quality standards

Standards, actions and programs on Hg exposure

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Global Mercury Assessment (UNEP, Dec 2002)

Mercury is present throughout the environment Is persistent and cycles globally Has serious effects Interventions can be successful

Global actions are required because: Hg's global cycling increases the problem Hg has an impact on global fishing Hg may be more problematic in less-developed regions Hg is subject to significant international use and commerce

Calls for international coordinated actions

PREVENTION AND REGULATIONSPREVENTION AND REGULATIONS

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Diagnose and treatDiagnose and treat Publish, do researchPublish, do research

Sentinel cases Community-based interventions

EducateEducate Patients and families Colleagues and students

AdvocateAdvocate Role modelRole model

HEALTH AND ENVIRONMENT PROFESSIONALSHEALTH AND ENVIRONMENT PROFESSIONALSPLAY A CRITICAL ROLE:PLAY A CRITICAL ROLE:

WHO

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POINTS FOR DISCUSSIONPOINTS FOR DISCUSSION

Documents

1 TRAINING FOR HEALTH CARE PROVIDERS Children's Health and the Environment CHEST Training Package for the Health Sector MERCURY