Acute Toxicity of water‐borne dimethylnitrosamine (DMN) to Fundulus heteroclitus (L.)

Abstract

Acute (120 h) toxicity of the water-borne carcinogen, dirnethylnitrosamine (DMN) to adult Fundulus hereroclitus (L.) at 20" C and 20*2%, salinity in natural seawater was determined. The LC-50 values were 8300 mg/l at 24 h, 5500 mg/l at 48 h, 4700 mg/l at 72 h, 3300 mg/l at 96 h and 2700 mg/l at 120 h.Gross lesions consisted of peritoneal and cephalic ecchymoses. Microscopic lesions included necrosis and sloughing of the gastrointestinal mucosa, haemorrhage and necrosis of the liver, and necrosis of taste buds, with severity and incidence being a function of DMN concentration. Acute pathological effects of DMN on Fundulus hetermlitus conformed closely to those reported in other species exposed to this compound by respiratory, oral or parenteral route. DMN concentrations used in this experiment greatly exceeded those expected to be found under natural conditions, and this report is intended both to improve our understanding of DMN-induced pathology in marine fishes and to provide further evidence of the consistency of acute lesions induced by DMN, regardless of test organism or mode of exposure.