Effects of trichloroethylene, tetrachloroethylene and dichloromethane on enzymatic activities in soil

Enzyme assays for β-glucosidase, β-acetylglucosaminidase, phosphatase, phosphodiesterase, and proteinase were made in soil samples incubated for two months after contamination with trichloroethylene, tetrachloroethylene, and dichloromethane. These volatile chlorinated hydrocarbons were added at doses of 10, 100, and 1000 μg per 100 g dry soil, respectively. Almost no effect was observed in soil sample contaminated with 10 μg of the chemicals when compared with control soil. When 100 μg of the volatile chlorinated hydrocarbons was added, the activity of β-glucosidase, β-acetylglucosaminidase and, in part, also of proteinase, was reduced during the first 28 days of incubation but returned to the same or slightly higher level than in the control soil after 2 months. Trichloroethylene, tetrachloroethylene, and dichloromethane at a concentration of 1000 μg per 100 g soil primarily inhibited activity of all enzymes under test. However, after two months, the enzymatic activities especially in soil samples contaminated with tetrachloroethylene and dichloromethane were found to be at the same or higher level than in the control soil.