| The development of methods for the quantitative assessment of the health risk associated with the exposure to hazardous organic chemicals in drinking water is an ongoing effort of many federal and state environmental departments. Such estimates are based on the quantitation of individual organic compounds. The approach considered in this research is the determination of the genotoxic effect of organic extracts of drinking water samples using the Ames Salmonella bioassay. Contaminants in drinking water samples are present at nanogram/L to microgram/L levels. While these levels can not cause acute effects, exposure to such levels over a lifetime may have a detrimental impact on human health.; A 2 L/hr and a 10 L/hr continuous liquid-liquid extractor (CLLE) were optimized to extract organic material from water into dichloromethane in a reproducible manner. The CLLE collected time based composites as a stand alone unit sampling raw and finished drinking water sources. The extractor isolated mutagenic substances from raw and finished drinking water, and instrumental analysis was able to identify compounds at the part per trillion level in the drinking water. The 10 L/hr CLLE had a sufficient flow rate to evaluate temporal and spacial variability of organic compounds in potable water. This research has explored the use of conventional capillary GC, GC/MS, multidimensional gas chromatography, microbore HPLC, and LC/MS, for analysis of the CLLE extracts.; The CLLE extracts showed Ames activity which ranged from 40 to 645 revertants per liter of finished water. The detected mutagenic activity is a direct result of the chlorine disinfection process used in water treatment. The two tester strains, TA100 and TA98, indicate that the majority of the mutagenic activity was due to base pair insertion mutagens.; Order of magnitude decreases in detection levels for organic compounds by GC/MS are achieved when comparing the CLLE method to USEPA method 625. HPLC analysis of the CLLE extracts isolated four discrete fractions. The testing of each fraction for mutagenic activity is possible due to the milligram quantities of residue isolated by CLLE. Several nonionic surfactants and plasticizers were identified by LC/MS. |
