Comparison of gas chromatography and immunoassay methods in measuring the distribution of dieldrin in rainbow trout tissues

Studies have been conducted to determine the distribution of dieldrin in va rious tissues of rainbow trout when exposed to several dieldrin concentrati ons. Medium sized fish with an average weight and length of 195.4 +/- 30.5 g and 25.7 +/- 1.4 cm, respectively, were placed in groups of 6 in 300 L ta nks containing purified and aerated water and maintained at 10 degreesC. Fo llowing an acclimatization period of 10 days, each group of fish was expose d to one of four dieldrin concentrations ranging from 50 to 80 ppb. After 2 4 hours, the fish were taken out of the tanks and sacrificed. The brain, gi lls, liver, muscles and skin were collected from each fish. Dieldrin was ex tracted from each tissue using SPE techniques and analyzed by both gas chro matography (GC) and enzyme linked immunosorbent assay (ELISA). Results of a nalyses by the two techniques were highly correlated. The results also show ed that liver and skin tissues had the highest level of dieldrin residues. In comparing the means of the six fish samples, it was found that liver or skin contained about 1.5-fold the level in brain, about 4.0 fold the level in muscles and about 6.5 fold the level in gills. Immunoassay proved to be as reliable an analytical tool as gas chromatography in this case.