Uptake of hexachlorobenzene (HCB) from feed by rainbow trout (Salmo gairdneri)

Determination of the dietary absorption efficiency of hexachlorobenzene with the channel catfish (Ictalurus punctatus)

This study was designed to experimentally measure the assimilation efficiency of hexachlorobenzene (HCB) in a warm-water, benthic-feeding fish species, the channel catfish (Ictalurus punctatus). Catfish were exposed to (14)C-radiolabeled HCB in catfish food over a 28-day exposure period, followed by a 14-day clearance period. Over the experimental period, the total (14)C residues were measured in fish tissue and a simple two-box kinetic model was applied to the data to simulate uptake and clearance dynamics. No detectable metabolism of HCB by catfish was found. A two-box kinetic model effectively modeled the uptake and clearance of (14)C-HCB in catfish, with a calculated assimilation efficiency of the chemical into the whole catfish of 67% (growth corrected). The growth-corrected pseudo first-order elimination half-life of (14)C-HCB from whole catfish was determined to be 29 days (k(2)=0.024 day(-1)).

Extraction and clean-up procedures for measuring chlorobenzenes in sediments and fish by capillary gas chromatography

A soxhlet extraction technique for recovering chlorobenzenes from sediments and fish is described. The extract is concentrated by evaporation, cleaned up with florisil (sediments) or a combination of alumina, silica gel, florisil and acidified silica gel (fish) before quantitation by capillary gas chromatography with an electron capture detector. Recoveries for all chlorobenzenes are greater than 80%. Detection limits of the technique are approximately 0.05 ng/g (ppb) for penta- and hexachlorobenzene, approximately 0.2 ppb for the tetrachlorobenzenes, approximately 0.4 ppb for the trichlorobenzenes, approximately 5 ppb for the dichlorobenzenes, and approximately 1500 ppb for monochlorobenzene.