7088

• UCREFRP Catalog Number: 7088
• Author: Eisler, R.
• Title: Mercury Hazards to Fish, Wildlife, and Invertebrates
• USFW Year: 1987.
• USFW - Doc Type: A Synoptic Review.
• Copyright Material: NO

SUMMARY
Available literature on the ecological and toxicological aspects of
mercury (Hg) in the environment, with special reference to fish and wildlife
resources, is reviewed and summarized. Subdivisions include sources, chemical
properties, background concentrations, acute and chronic toxicity, sublethal
effects, and proposed criteria to protect sensitive resources.
Mercury has been used by man for at least 2,300 years, most recently as a
fungicide in agriculture, in the manufacture of chlorine and sodium hydroxide,
as a slime control agent in the pulp and paper industry, in the production of
plastics and electrical apparatus, and in mining and smelting operations.
Mercury burdens in some environmental compartments are estimated to have
increased up to 5X precultural levels, primarily as a result of man's
activities. The construction of artificial reservoirs, for example, which
releases Hg from flooded soils, has contributed to the observed elevation of
Hg concentrations in fish tissues from these localities. Elevated levels of
Hg in living organisms in Hg-contaminated areas may persist for as long as 100
years after the source of pollution has been discontinued. One major
consequence of increased mercury use, coupled with careless waste disposal
practices, has been a sharp increase in the number of epidemics of fatal
mercury poisonings in humans, wildlife, and aquatic organisms.
Most authorities agree on six points: (1) mercury and its compounds have
no known biological function, and the presence of the metal in the cells of
living organisms is undesirable and potentially hazardous; (2) forms of
mercury with relatively low toxicity can be transformed into forms of very
high toxicity, such as methylmercury, through biological and other processes;
(3) mercury can be bioconcentrated in organisms and biomagnified through food
chains; (4) mercury is a mutagen, teratogen, and carcinogen, and causes
embryocidal, cytochemical, and histopathological effects; (5) some species of
fish and wildlife contain high concentrations of Hg that are not attributable
to human activities; (6) anthropogenic use of Hg should be curtailed, as the
difference between tolerable natural background levels of Hg and harmful
effects in the environment is exceptionally small.
Concentrations of total Hg lethal to sensitive, representative, nonhuman
species range from 0.1 to 2.0 ug/l (ppb) of medium for aquatic organisms; from
2,200 to 31,000 ug/kg body weight (acute oral) and 4,000 to 40,000 ug/kg
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