Stimulatory and toxic effects of acid, pentachlorophenol or zinc on the mineralization of acetate in acid or calcareous soils and subsoils

Abstract

The toxic effects of pollutants on the soil microflora was studied as part of a research program aimed at the setting of soil quality standards. The effects of pentachlorophenol, zinc or hydrochloric acid on the mineralization of 1 μg/L [¹⁴C] acetate to ¹⁴CO₂ was studied in an acid surface soil, an acid subsoil, an calcareous surface soil and a calcareous subsoil. The chalky surface soil was most sensitive for pentachlorophenol (PCP) which caused a marked stimulation of the ¹⁴CO₂ production at low doses. The chalky subsurface soil was most sensitive for zinc. The chalky soil and subsoil neutralized added HCl more rapidly and showed a stronger sorption of zinc compared with the acidic soils. Nevertheless these soils showed a much higher sensitivity for acid, zinc and also for pentachlorophenol. The microflora of the acid surface soil were relatively resistant to acid, PCP or zinc. This resistant microflora showed a relatively low acetate mineralization rate.