Mercury :: coastal and rocky habitats


Key Conerns

Mercury is toxic to aquatic organisms (WHO 1989). The saltwater invertebrates which are most sensitive to mercury are oyster (Ostrea edulisi) larvae (WHO 1989), with 48h-LC50 values for inorganic mercury ranging from 0.001 to 0.0033 mg/l (Connor 1972). Acute LC50 values for other saltwater invertebrates range from 0.01 to 32 mg/l (WHO 1989).

Acute LC50 values for saltwater fish exposed to inorganic mercury ranged from 0.140 to 3.3 mg/l (Portmann and Wilson 1971; Rehwoldt et al. 1972; Klaunig et al. 1975; Eisler and Hennekey 1977; Menezes and Qusim 1983). The 96h-LC50 for lamprey (Petromyzon marinus) larvae exposed to methylmercuric chloride was 48 µg/l (Mallatt et al. 1986).

Additional Comments

Mercury normally binds to soil particles, reducing its availability to plants (WHO 1989). Plants are generally insensitive to the effects of mercury compounds. Methyl mercury is more toxic to terrestrial organisms than aryl or inorganic mercury.

Environmental limit: 

Habitat/ Ecosystem Type Critical Load/ Level Status Reliability Indication of exceedance Reference
Coastal saltwater ecosystems

0.3 ug/l

Environmental Assessment Level (Non-Statutory) quite reliable i.e. the results of some studies are comparable

Total dissolved mercury and its compounds, annual mean in coastal waters. The corresponding EQS for estuarine waters is 0.5 µg/l.



Connor, P. M. 1972 Acute toxicity of heavy metals to some marine larvae Pollution Bulletin 190-192
Eisler, R ; Hennekey, R. J. 1977 Acute toxicities of Cd2+, Cr+6, Hg2+, Ni2+ and Zn2+ to estuarine macrofauna Archives of Environmental Contamination and Toxicology 315-323
Klaunig, J ; Koepp, S ; McCormick, M 1975 Acute toxicity of a native mummichog population (Fundulus heteroclitus) to mercury Bulletin of Environmental Contamination and Toxicology 534-536
Mallatt, J ; Barron, M. G.; McDonough, C 1986 Acute toxicity of methyl mercury to the larval lamprey Petromyzon marinus Bull Environ Contam Toxicol 281-288
Menezes, M. R.; Qusim, S. Z. 1983 Determination of acute toxicity levels of mercury to the fish, Tilapia mossambica Proceedings of the Indian Academy of Sciences (Animal Sciences) 375-380
Rehwoldt, R ; Menapace, L. W.; Nerrie, B ; Alessandrello, D 1972 The effect of increased temperature upon the acute toxicity of some heavy metal ions Bulletin of Environmental Contamination and Toxicology 91-96