United States
Environmental Protection
Agency
Office of Water
4601
EPA811-F-95-002e-T
October 1995
National Primary Drinking
Water Regulations
Mercury
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-* 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 soRpnoN 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.
DRINKING WATER STANDARDS
MCLG: 0.002 mg/L
Met: 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
trial 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
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 Ibs. of mercury were produced in the
U.S. in 1986.
Electrical products such as dry-cell batteries, fluores-
cent 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 (1 2%), and dental
preparations (3%). Lesser quantities are used in indus-
Tpxic RELEASE INVENTORY -
RELEASES TO WATER AND LAND: 19
Water
TOTALS (in pounds) 6,971
Top Six States
TN 164
LA 431
DE 117
OH . 29
A A A A f*f\
AL . 1,462
WV 1 657
T'» V 1 f*'*' *
Major Industries
Chemical, allied products 12,269
Electric lamps 0
Paper mills 2,500
87^T01993
Land
60.877
29,161
21,829
3,860
2,760
1f\f\A
,001
454
.
74,720
2,750
0
October 1995
Technical Version
Printed on Recycled Paper
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manufacture. Water borne pollution may originate in rate and membrane permeability, accelerates the rates
sewage, metal refining operations, or most notably, from of methylation and uptake, affects partitioning between
chloralkali plants. In general, industrial and domestic sediment and water, or reduces growth or reproduction of
products, such as thermometers, batteries, and electrical fish.
switches which account for & significant loss of mercury
to the environment, ultimatr.y become /olid waste in
major urban areas.
From 1987 to 1993, according to EPA's Toxic Chemi-
cal Release Inventory, mercury releases to land and
watertotalled nearly 68,000 Ifos., of which 90 percent was
to land. These releases were primarily from chemical and
allied industries. The largest releases occurred in Ten-
nessee and Louisiana. The largest direct releases to
water occurred in West Virginia and Alabama.
ENVIRONMENTAL FATE
Two characteristics, volat-ity and biotransformation,
make mercury somewhat unique as an environmental
toxicant. Its volatility accounts for atmospheric concen-
trations 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 dis-
solved 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 phos-
phate.
In the atmosphere, 50% of the volatile form is mercury
(Hg) vaporwith 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 residenca 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 inverte-
brates, 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
OTHER REGULATORY INFORMATION
MONITORING:
- FOR GROUND WATER SOURCES:
INITIAL FREQUENCY- 1 sample once every 3 years
REPEAT FREQUENCY- If no detections for 3 rounds, once every 9 years
- FOR SURFACE WATER SOURCES:
INITIAL FREQUENCY- 1 sample annually
, REPEATFREQUENCY- If 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
NlETHODNUMBERS
245.1;245.2
303F
TREATMENT
BEST AVAILABLE TECHNOLOGIES
Coagulation/Filtration*; Granular Activated Carbon; Lime softening*; Re-
verse osmosis*. •
* These treatments are recommended only if influent Hg concentrations do
not exceed 10 ug/L -
FOR ADDITIONAL INFORMATION:
A EPA can provide further regulatory and other general information:
• EPA Safe Drinking Water Hotline - 800/426-4791
* Other sources of lexicological 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
October 1995
Technical Version.
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