STIMULATORY AND TOXIC EFFECTS OF ACID, PENTACHLOROPHENOL OR ZINC ON THE MINERALIZATION OF ACETATE IN ACID OR CALCAREOUS SOILS AND SUBSOILS

The toxic effects of pollutants on the soil microflora was studied as part of a research program aimed at the setting of soil quality standa rds. The effects of pentachlorophenol, zinc or hydrochloric acid on th e mineralization of 1 mu g/L [C-14] acetate to (CO2)-C-14 was Studied in an acid surface soil an acid subsoil, an calcareous surface soil an d a calcareous subsoil. The chalky surface soil was most sensitive for pentachlorophenol (PCP) which caused a marked stimulation of the (CO2 )-C-14 production at low doses. The chalky subsurface soil was most se nsitive for zinc. The chalky soil and subsoil neutralized added HCl mo re rapidly and showed a stronger sorption of zinc compared with the ac idic soils. Nevertheless these soils showed a much higher sensitivity for acid, zinc and also for pentachlorophenol. The microflora of the a cid surface soil were relatively resistant to acid, PCP or zinc. This resistant microflora showed a relatively low acetate mineralization ra te.