EFFECT OF PENTACHLOROPHENOL ON SELECTED SOIL ENZYME ACTIVITIES IN A CHILEAN ANDISOL

Abstract

aBstract The activities of laccase, Mn-peroxidase, phosphatase and dehydrogenase were studied in a Chilean Andisol (Temuco Serie) contaminated with pentachlorophenol (PCP). Experiments were conducted on the top of 0–20 cm soil, adding different concentrations of PCP (0.41, 4.1 and 41 mg kg -1 ). Enzymatic activities and residual concentrations of PCP were evaluated in soil incubated at 25 ± 1 oC for 112 days. Enzyme activities of PCP-treated soil varied according to the PCP concentration added. For instance, an inhibitory effect on Mn-peroxidase activity was not observed during incubation at the three levels of PCP, whereas acid phosphatase activity was only affected by the 0.41 mg kg -1 PCP treatment. By contrast, laccase and dehydrogenase activities were negatively affected by the smallest concentration of PCP. After seven days of incubation, no residual PCP was measured in the soil with 0.41 and 4.1 mg kg -1 PCP. By contrast, with 41 mg kg -1 PCP the amount of phenol in soil decreased gradually and disappeared only after 42 days of incubation. The overall results indicate that PCP concentrations influence some enzymatic activities.