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Mercury

Resources for Mercury Science and Research

On this page:

Chemical Profile; Toxicology and Health Effects

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Reference Values and Regulatory Limits

Type of mercury Type of value Value Issuing agency Source of information

Elemental mercury vapor

Acute Exposure Guideline Levels

See EPA AEGL Program: Mercury Vapor Results

EPA

EPA AEGL Program: Mercury Vapor Results

Mercuric chloride

RfD for chronic oral exposure
(no RfC for inhalation)

3 x10-4 mg/kg-day 
LOAEL : 0.317 mg/kg-day

EPA

IRIS Assessment

Mercuric chloride

carcinogenicity assessment

possible human carcinogen

EPA

IRIS Assessment

Metallic mercury

RfC for chronic inhalation
(RfD for chronic oral exposure not assessed)

3x10-4 mg/m3
LOAEL (ADJ): 0.009 mg/m3

EPA

IRIS Assessment

Metallic mercury

carcinogenicity assessment

not classifiable

EPA

IRIS Assessment

Methylmercury

RfD for chronic oral exposure
(no RfC for inhalation)

1 x10-4 mg/kg-day ; equivalent to a blood Methylmercury concentration of 5.8 micrograms per liter (?g/L)

EPA

IRIS Assessment

Mercuric chloride

Maximum Contaminant Level Goal (MCLG) and Maximum Contaminant Level (MCL) in drinking water

both the MCLG and the MCL are 0.002 mg/L (2 parts per billion [ppb])

EPA

EPA Basic Information about Mercury (inorganic) in Drinking Water page

Mercuric chloride

water bodies

recommends that the level of inorganic mercury in rivers, lakes, and streams be no more than 144 parts mercury per trillion [ppt]

EPA

ATSDR Public Health Statement on Mercury

Methylmercury

fish tissue-based water quality criteria

0.3 micrograms of mercury per gram (0.3 mg/kg) of fish as an indicator that water bodies should not have higher levels in their fish

EPA

EPA Human Health Criteria: Methylmercury Fish Tissue Criterion page

Methylmercury

seafood products sold through interstate commerce - FDA can seize shipments of these products.  Does not apply to in-state shipments or to sport fish caught recreationally

1 ppm

FDA

FDA Guidance for Industry: Action Levels for Poisonous or Deleterious Substances in Human Food and Animal Feed page

?

allowable levels in bottled water

0.002 mg/L

FDA

Code of Federal Regulations, as set forth on FDA.gov

Mercuric chloride

Minimal Risk Level: health-based screening level for chronic exposures to airborne mercury; estimate of the daily human exposure to a hazardous substance that is likely to be without appreciable risk of adverse non-cancer health effects over a specified duration of exposure.

Acute:
0.007 mg/kg/day

Intermediate:
0.002 mg/kg/day

ATSDR

ATSDR List of Minimal Risk Levels (MRLs) for Hazardous Substances

Metallic mercury

Minimal Risk Level: health-based screening level for chronic exposures to airborne mercury; estimate of the daily human exposure to a hazardous substance that is likely to be without appreciable risk of adverse non-cancer health effects over a specified duration of exposure.

Chronic:  0.0002 mg/m3

ATSDR

ATSDR List of Minimal Risk Levels (MRLs) for Hazardous Substances

Methylmercury

MRL

Chronic:  0.0003 mg/m3

ATSDR

ATSDR List of Minimal Risk Levels (MRLs) for Hazardous Substances

All

Medical Management Guideline (MMG)

N/A

ATSDR

ATSDR Medical Management Guidelines for Mercury page

Mercury compounds

workplace exposure limit/REL (health-based screening levels used to identify potentially hazardous situations due to short-term exposures to contaminants in air)

Hg Vapor: TWA 0.05 mg/m3 [skin]
Other: no more than 0.1 mg/m3 [skin]

NIOSH

NIOSH Pocket Guide to Chemical Hazards: Mercury Compounds

Mercury compounds

workplace exposure limit/PEL

no more than 0.1 mg/m3

OSHA

NIOSH Pocket Guide to Chemical Hazards: Mercury Compounds

Organo alkyl compounds

workplace exposure limit/REL (health-based screening levels used to identify potentially hazardous situations due to short-term exposures to contaminants in air)

TWA 0.01 mg/m3 ST 0.03 mg/m3 [skin]

NIOSH

NIOSH Pocket Guide to Chemical Hazards: Mercury (organo) alkyl compounds (as Hg)

Organo alkyl compounds

workplace exposure limit/PEL

TWA 0.01 mg/m, no more than 0.04 mg/m3

OSHA

NIOSH Pocket Guide to Chemical Hazards: Mercury (organo) alkyl compounds (as Hg)

Metallic and inorganic compounds

Industrial workplace PEL

0.025 mg/m3

California OSHA

Occupational Health Hazard Risk Assessment Project for California: Identification of Chemicals of Concern, Possible Risk Assessment Methods, and Examples of Health Protective Occupational Air Concentrations (2007) (PDF)

Mercury and inorganic mercury compounds

Acute, 8-hour and Chronic Reference Exposure Levels (chRELs)

Acute: 0.6 micrograms Hg/m3; 8-hour: 0.06 micrograms Hg/m3; Chronic: 0.03 micrograms Hg/m3

California EPA Office of Environmental Health Hazard Assessment (OEHHA)

OEHHA table of All OEHHA Acute, 8-hour and Chronic Reference Exposure Levels (chRELs) as of June 2014.

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Analytic and Test Methods

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Sources of Emissions and Discharges

Emissions into the Air

Discharges into Bodies of Water

  • Toxics Release Inventory (TRI) compiles TRI data submitted by regulated facilities each year and makes the data available
    • TRI Explorer: Generate reports on releases, transfers, and waste managed that can be compared across facilities, chemicals, geographic areas, industries (NAICS code) or reporting years.
    • TOXMAP: allows you to visually explore TRI data and Superfund program data.
  • Discharge Monitoring Report (DMR) Pollutant Loading Tool: learn who is discharging mercury, how much is being discharged, and where the discharges are occurring.

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Fate and Transport; Deposition

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Ecolo assessments; risks to wildlife

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Exposures

  • 2014 National-Scale Air Toxics Assessment (NATA) -- NATA gives a snapshot of outdoor air quality with respect to emissions of air toxics. It suggests the long-term risks to human health if air toxics emissions are steady over time. NATA estimates the cancer risks from breathing air toxics over many years. It also estimates noncancer health effects for some pollutants, including diesel particulate matter (PM). NATA calculates these air toxics concentrations and risks at the census tract level. NATA produces results that are useful in identifying potential patterns in emissions, concentrations and risk from air toxics nationwide and is intended as a tool to prioritize specific air toxics and sources for further study or regulation. The 2014 (most recent) assessment includes emissions, ambient concentrations, and exposure estimates for 180 of the 187 Clean Air Act air toxics, including mercury, and diesel particulate matter.
  • 1997 Mercury Study Report to Congress:
    • Volume IV, Exposure Assessment
    • Volume VII, Characterization of Human Health and Wildlife Risks
  • Biomonitoring - The biomonitoring section of the America's Children and the Environment report presents information on selected chemicals measured in the bodies of women of child-bearing age and children.
  • ATSDR Toxicological Profile for Mercury (1999): Chapter on potential for human exposure (PDF)

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Pollution prevention, emergency resposnse, waste treatment and cleanup

Pollution Prevention

Responding to Exposures

Responding to Spills/Contaminated Soils, Waste and Water

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Geospatial/mapped data

  • NLFA Fish Tissue Search - allows state and tribal fish advisory program managers to view information about fish tissue; and NLFA Technical Advisories Search - allows state and tribal fish advisory program managers to access advisories. Both searches let you sort by:
    • the geographic location of a waterbody, the species of
    • the fish, and the pollutants identified in the advisory.

      It also allows users to search the National Listing Fish Advisories (NLFA) database for fish tissue contaminant data.

    • TOXMAP: allows you to visually explore TRI and Superfund data program data.

    • Mercury Maps -- a tool that relates changes in mercury air deposition rates to changes in mercury fish tissue concentrations, on a national scale.

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