Mutagenicity of chlorinated products from soil humic substances.

Soil humic substances were chlorinated in solution, extracted with ether and subjected to mutagenicity assay. Mutagenicity was detected using Salmonella typhimurium TA 100, with or without S9 mix; mutagenic activity was found to be less with added S9 mix. Ether extracts were analyzed by gas chromatography-mass spectrometry (GC-MS) and various chlorinated and non-chlorinated compounds were detected, e.g. chlorinated esters, acetones and carboxylic acids, as well as non-chlorinated aromatics. The mutagenicity of the major chlorination products was examined. Chloral and 1,1,1,3,3-pentachloro-2-propanone (pentachloroacetone) were found to be mutagenic, and 1,1-dichloro-2-propanone (1,1-dichloroacetone) was a possible mutagen. The yields of these mutagens increased with an increase in chlorine concentration.