Technical Factsheet on: MERCURY
List of Contaminants
As part of the Drinking Water and Health pages, this fact sheet is part of a larger publication:
National Primary Drinking Water Regulations
Drinking Water Standards
MCLG: 0.002 mg/L
MCL: 0.002 mg/L
HAL(child): none
Health Effects Summary
Acute: EPA has found mercury to potentially cause kidney damage from short-term exposures at levels
above the MCL. No Health Advisories have been established for short-term exposures.
Chronic: Mercury has the potential to cause kidney damage from long-term exposure at levels above the
MCL.
Cancer: There is inadequate evidence to state whether or not mercury has the potential to cause cancer
from lifetime exposures in drinking water.
Usage Patterns
Nearly 8 million lbs. of mercury were produced in the U.S. in 1986.
Electrical products such as dry-cell batteries, fluorescent light bulbs, switches, and other control
equipment account for 50% of mercury used. Mercury is also used in substantial quantities in electrolytic
preparation of chlorine and caustic soda (chlor-alkali industry, mercury cell process; 25%), paint
manufacture (12%), and dental preparations (3%). Lesser quantities are used in industrial catalyst
manufacture (2%), pesticides manufacture (1%), general laboratory use (1%), and pharmaceuticals
(0.1%).
Release Patterns
A joint FAO/WHO expert committee on Food Additives in 1972 quotes the major source of mercury as the
natural degassing of the earth's crust in the range of 25,000-150,000 ton of Hg/yr. Twenty thousand tons
of mercury are also released into the environment each year by human activities such as combustion of
fossil fuels and other industrial release. Anthropogenic sources of airborne mercury (Hg) may arise from
the operation of metal smelters or cement manufacture. Water borne pollution may originate in sewage,
metal refining operations, or most notably, from chloralkali plants. In general, industrial and domestic
products, such as thermometers, batteries, and electrical switches which account for a significant loss of
mercury to the environment, ultimately become solid waste in major urban areas.
From 1987 to 1993, according to EPA's Toxic Chemical Release Inventory, mercury releases to land and
watertotalled nearly 68,000 lbs., of which 90 percent was to land. These releases were primarily from
chemical and allied industries. The largest releases occurred in Tennessee and Louisiana. The largest
direct releases to water occurred in West Virginia and Alabama.
Environmental Fate

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Two characteristics, volatility and biotransformation, make mercury somewhat unique as an
environmental toxicant. Its volatility accounts for atmospheric concentrations up to 4 times the level of
contaminated soils in an area. Inorganic forms of mercury (Hg) can be converted to organic forms by
microbial action in the biosphere.
In aquatic systems, mercury appears to bind to dissolved matter or fine particulates, while the transport of
mercury bound to dust particles in the atmosphere or bed sediment particles in rivers and lakes is
generally less substantial. The conversion, in aquatic environments, of inorganic mercury compounds to
methyl mercury implies that recycling of mercury from sediment to water to air and back could be a rapid
process. In a study of mercury elimination from wastewater, 47% of added mercury was removed in
presence of a Pseudomonas strain. Uptake of mercury was severely inhibited by sodium chloride, sodium
sulfate, and mono- and dibasic potassium phosphate.
In the atmosphere, 50% of the volatile form is mercury (Hg) vapor with sizeable portion of remainder
being Hg(ll) and methylmercury, 25 to 50% of Hg in water is organic. Hg in the environment is deposited
and revolatilized many times, with a residence time in the atmosphere of at least a few days. In the
volatile phase it can be transported hundreds of kilometers.
Bioconcentration factors of 63,000 for freshwater fish, 10,000 for salt water fish, 100,000 for marine
invertebrates, and 1000 for freshwater and marine plants have been found. As the tissue concentration
approaches steady-state, net accumulation rate is slowed either by a reduction in uptake rate, possibly
due to inhibition of membrane transport, or by an increase in depuration rate, possibly because of a
saturation of storage sites, or both. Acidification of a body of water might also increase mercury residues
in fish even if no new input of mercury occurs, possibly because lower pH increases ventilation rate and
membrane permeability, accelerates the rates of methylation and uptake, affects partitioning between
sediment and water, or reduces growth or reproduction offish.
Chemical/Physical Properties
CAS Number: 7439-97-6
Color/ Form/Odor: Silver-white, heavy, mobile, liquid metal. Solid mercury is tin-white. Odorless
M.P.: -38.87 C B.P.: 356.7 C
Vapor Pressure: 2x10-3 mm Hg at 25 C
Density/Spec. Grav.: 13.5 at 25 C
Solubility: 0.06 g/L of water at 25 C; Slightly soluble in water
Soil sorption coefficient: N/A
Odor/Taste Thresholds: N/A
Bioconcentration Factor: Bioconcentration factors of 63,000 for freshwater and 10,000 for salt water
fishes. BCFs of 100,000 for invertebrates.
Henry's Law Coefficient: N/A; volatilization from water and soil is significant
Synonyms/Ores: Liquid silver, Quicksilver, Hydragyrum, Colloidial mercury. Important commercial ore is
cinnabar, but also found in limestone, calcareous shales, sandstone, serpentine, chert andesite and
others.

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Other Regulatory Information
Monitoring:
- For Ground Water Sources:
Initial Frequency-1 sample once every 3 years
Repeat Frequency-lf no detections for 3 rounds, once every 9 years
- For Surface Water Sources:
Initial Frequency-1 sample annually
Repeat Frequency-lf no detections for 3 rounds, once every 9 years
- Triggers - If detect at > 0.002 mg/L, sample quarterly.
Analysis
Reference Source
EPA 600/4-79-020
Standard Methods
Method Number
245.1; 245.2
303F
Treatment/Best Available Technologies: Coagulation/Filtration*; Granular Activated Carbon; Lime
softening*; Reverse osmosis*
* These treatments are recommended only if influent Hg concentrations do not exceed 10 ug/L
Toxic Release Inventory - Releases to Water and Land, 1987 to 1993 (in pounds):

Water

TOTALS
6,971

Top Six States


TN
164
29,161
LA
431
21,829
DE
117
3,860
OH
29
2,760
AL
1,462
4,001
WV
1,657
454
Industries*
74,720
2,750
0
Chemical, allied products	12,269
Electric lamps	0
Paper mills	2,500
For Additional Information:
EPA can provide further regulatory and other general information:
EPA Safe Drinking Water Hotline - 800/426-4791
Other sources of toxicological and environmental fate data include:
Toxic Substance Control Act Information Line - 202/554-1404
Toxics Release Inventory, National Library of Medicine - 301/496-6531
Agency for Toxic Substances and Disease Registry - 404/639-6000 National Pesticide Hotline - 800/858-
7378

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