Tetrachloroethylene

Toxicity to soil microorganisms

Description of key information

The NOEC for respiration rate in loam soil is ≤ 0.1 mg/kg soil ww.

Key value for chemical safety assessment

Long-term EC10 or NOEC for soil microorganisms:

0.11 mg/kg soil dw

Additional information

Vonk et al. (1986) studied the effect of tetrachloroethylene on micro-organisms responsible for soil respiration, ammonification and nitrification. A NOEC of <2,000 mg/kg (wet weight) was determined for soil respiration in both loam and humic sand and NOECs of < 40 mg/kg (wet weight) and ≤ 0.1 mg/kg (wet weight) determined for nitrification with humic sand and loam soil, respectively. Kanazawa and Filip (1987) studied the effect of tetrachloroethylene on soil biomass and microbial counts. Very little effect on the population of soil fungi was observed at 0.1 mg/kg and 1 mg/kg levels, although at 10 mg/kg the growth of soil fungi was inhibited. Both copiotrophic and oligotrophic aerobic soil bacteria were inhibited at 10 mg/kg after 3 days, this was followed by an increase in the populations up to 28 days. The organic matter content of the soil was reported as 1.44%. The effect of tetrachloroethylene on the dehydrogenase activity of soil micro-organisms was studied by Danneburg (1993). Two concentrations were tested: 0.5 and 5 mg/kg (dry weight). Initially an increase (42-62%) in dehydrogenase activity was found. This was followed by a decrease (11-18%) after 14 days and an increase (6-13%) after 28 days in dehydrogenase activity. The data show no consistent effect and therefore the study is considered not valid.