Development of a Simplified Chlorinated Hydrocarbon Screening Technique for Water and Sediment

摘要

The development of a simple screening technique for chlorinated hydrocarbons in water and sediment was undertaken. Extraction and concentration techniques were used as an alternative to the present costly and time consuming methods. Water samples spiked with known amounts of six chlorinated hydrocarbons were passed through Sep-Paks, a Waters Assocs. C-18 disposable column, and the adsorbed compounds eluted with methanol. The methanol extract was analyzed directly by furnace evaporation and decomposition into a microcoulometer cell and reported as total organic halide (TOX). Recoveries were variable and were a function of the Sep-Pak loading, concentration and volume of samples and type of chlorinated hydrocarbon. Chlorinated phenols exhibited the best recoveries (100%) and volatile compounds the worst (20%). The technique offers promise as a qualitative screening procedure for natural waters. Dried sediment were spiked with known amounts of the same six chlorinated hydrocarbons, extracted with hexane and analyzed for TOX using furnace microcoulometry. Sediments run directly without the extraction step exhibited interferences from naturally occurring sulfur compounds and inorganic chlorides. The extraction step affords an additionally opportunity for a 100-fold concentration. Recoveries ranged from 100% (PCB and chlorophenols) to 20-30% (Tetrachloroethylene and chloroform) for volatile compounds. The lower recoveries may never be encountered in field samples since volatiles may have already been evaporated from the sediment or soil.