Human Health Effects from Cyanide, Mercury and Arsenic

Western Mining Action NetworkSeptember 29, 2007

Amy CrookCentre for Science in Public Participation

Victoria, British Columbia, Canada250 721-3627

acrook@csp2.org

How Are People Exposed to Toxic Chemicals?

• Industry discharges into air, water and food

• Major toxins discharged at mine sites are Mercury, Arsenic, Cyanide, Lead, Zinc, Cadmium, and others

• Dispersion of chemicals is global – we all live downstream

Basic Toxicology: Exposure-related Concepts

Metals:

• Persist in the environment forever

• Can bioconcentrate in our food and bodies

• Can cause damage with transient exposures

Primary Routes of Exposure

Who is most impacted from toxins?

• Those with highest exposure-workers and their families

• Those who live closest to the source • Those who fish/hunt from contaminated

areas• Those with the most vulnerability-pregnant

women, infants, children, sick and elderly• Even transient exposures can have

significant toxic impact

Child Health Exposures

• Prenatal-transplacental-developmental

windows

• Postnatal– pound per pound children

eat, drink and breath far more than adults

– prolonged gastric emptying– increased metabolic rate– increased time indoors and

on floors– breast milk (still best to

breastfeed, but breast milk now contains many contaminants)

Why don’t we know more about toxic impacts?

• Good data hard to get and large scale epidemiology studies are rare

• Can’t dose people with toxins and look at the response

• Data comes from accidents/spills- not a controlled lab setting w/good study design

• There is a long latency window between exposure and affect

Why don’t we know more about toxic impacts?

• People are exposed to a mixture of toxins, not one at a time.

• Toxicity tests are designed to measure the effects of one toxin at a time, don’t reflect reality.

• Interactive effects of toxins are important, but few studies look at chemical mixtures.

• Exposure rates are hard to measure in uncontrolled situations.

• Precautionary approach needed in estimating toxicity and allowing the discharge of toxic compounds.

An Overview of Mercury

Dry Deposition Combustion Wet Deposition

LandfillsVolcanoes

Particulates & Vapor

PesticidesFertilizers

Ground-water Flow

to Streams, lakes, vegetation, soil

Rain & Streams to Groundwater

Farming

Industry & Incinerators

Runoff

WasteWater Releases

Bioaccumulation in Fish

Volatilization

Sedimentation

MethylationHg to HgCH3

Mercury Effects of Higher Dose Prenatal

Exposure

• Mental retardation• Seizures• Cerebral palsy• Disturbances of vision, hearing, sensation• Abnormal gait• Abnormal speech• Disturbances of swallowing and sucking• Abnormal reflexes

Mercury:Declining Threshold of Harm

20001990198019700.01

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1

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100

YEAR

Level associated with harmful effectRegulatory standard (maximum safe exposure or high end exposure from allowed fish contamination)

FDA WHO

EPA

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Mercury Exposures

Advised Exposure Limit• EPA Reference Dose (“safe” upper limit) –

0.1 microgram/kilogram/day

• Equivalent consumption limit – Women: 1.5 oz. swordfish or 7 oz. tuna/week– Child: 1 oz. tuna per 20 lb. body weight/week

Environmental Concerns of Mercury

• Methylmercury bioaccumulation in fish• Elevated concentrations build up in river

reservoirs above dams • Previous mercury mining has left a legacy of

tremendous health impacts. Tl'azt'en First Nation impacts from old Teck Cominco mine at Lake Pinchi.

• Large sources of mercury come from roasters at gold mines and from active cyanide heap leaches.

Are the current standards protective?

• Thresholds of harm for As, Hg & Cn

• Is policy keeping up with the science?

• Compounded effects from multiple exposures and toxic mixtures

• Chemicals we don’t even know yet

• Cumulative impacts from other factors: nutrition, genetics, social, cultural, economic

How to assess if your community is at risk

• Attend the workshop by Sue Moodie, Lisa Sumi and Catherine Coumans Health Assessment for Mining Affected Communities Workshop, Sunday afternoon.

Questions to ask mining companies

• How much dust will be generated? Where will it go? What’s in it? Will it affect harvest areas, play areas, yards, haul roads, etc?

• Where will the waste water be discharged? What’s in it? Will it affect fish, wildlife, recreation and sacred areas?

• Where are the transportation routes for hauling ore, hazardous materials, and fuels? Are they close to homes, communities? Are the current roads capable of handling the extra traffic and weight? What are the plans to upgrade and maintain the road? Who pays for that?

• How will ore and hazardous materials spills be handled? Are the response plans and notification procedures adequate? Who pays for the clean up?

References:Toxic impacts: • Sandra Steingraber. 2001. Having Faith- An Ecologist’s Journey to

Motherhood. Perseus Publishing. Cambridge, Massachusetts. • Daniel Peplow, Robert Edmonds. The effects of mine waste

contamination at multiple levels of biological organization. Elsevier Ecological Engineering 24 (2005) 101–119.

Mercury:• Leonardo Trasande, Philip J. Landrigan, and Clyde Schechter.

Public Health and Economic Consequences of Methyl Mercury Toxicity to the Developing Brain. Environmental Health Perspectives Volume 113, Number 5, May 2005. http://www.mineralpolicy.org/mercury.cfm

• LA Times, March 17, 2005. Possible Mercury, Autism Connection Found in Study.Thomas H. Maugh II Texas researchers have found a possible link between autism and mercury in the air and water.

• Reno Gazette-jounal, April 14, 2007. Researchers at UNR to study mining waste link to mercury. Jeff DeLong.

References• Chan HM, Receveur. Environmental Pollution. 2000 Oct;110(1):1-2.

Mercury in the traditional diet of indigenous peoples in Canada. Centre for Indigenous Peoples' Nutrition and Environment, McGill University Quebec, Canada.

• Hansen JC, Gilman AP. Int J Circumpolar Health. 2005 Apr;64(2):121-36. Exposure of Arctic populations to methylmercury from consumption of marine food: an updated risk-benefit assessment. Centre for Arctic Environmental Medicine (CAM), University of Aarhus, Denmark.

• Stephen C. Jewett, Lawrence K. Duffy. Mercury in fishes of Alaska, with emphasis on subsistence species. Science Direct, STOTEN-10138; No of Pages 25. www.sciencedirect.com

• Environmental Protection Agency. Mercury Study Report to Congress: An Assessment of Exposure to Mercury in the United States. Vol IV, 1997. http://www.epa.gov/ttnuatw1/112nmerc/volume4.pdf

• Environmental Protection Agency. Mercury Update: Impact on Fish Advisories. EPA-823-F-99-016 September 1999. http://www.epa.gov/ostwater/fish/mercury.html

References• Greg Jones and Glenn Miller. October, 2005 Mercury and Modern

Gold Mining in Nevada. University of Nevada, Reno, NV• Great Basin Mine Watch, Idaho Conservation League and

Earthworks. August 2006. Three Nevada Gold Mines Grossly Under-Report Mercury Air Emissions.

Cyanide:• Agency for Toxic Substances and Disease Registry (ATSDR). 2006.

Toxicological Profile for Cyanide. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

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