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