THE ASSESSMENT OF EPISODIC METAL POLLUTION .1. USES AND LIMITATIONS OF TISSUE CONTAMINANT ANALYSIS IN RAINBOW-TROUT (ONCORHYNCHUS-MYKISS) AFTER SHORT WATERBORNE EXPOSURE TO CADMIUM OR COPPER

Rainbow trout were exposed to 8 h episodes of either Cd (0.1 or 0.2 mg/L) or Cu (0.1 or 0.6 mg/L) at pH 7. Gill, liver, mucus, blood, skin, muscle, and body remainder were examined for metal content during and after exposure. Accumulation of Cd occurred mostly in the gill, liver, mucus, and muscle, with the gill supporting 21-36% of the body burden. Copper appeared primarily in the gill, liver and mucus, with the gill supporting 4-40% of the body burden. After exposure, rapid clearance of toxicant from the gill and mucus occur-red within 16 h, while contamination in the liver increased, resulting in the liver supporting 11-14% or 58-61% of the Cd or Cu body burdens respectively 24 h after exposure. The time of sampling after exposure as well as choice of organs and control data are important aspects of post-exposure analysis. In the absence of control data, exposure status may be derived from the ratio of contaminants in the gill/liver and the distribution of the body burden.