PATTERNS OF SENSITIVITY TO CADMIUM AND PENTACHLOROPHENOL AMONG NEMATODE SPECIES FROM DIFFERENT TAXONOMIC AND ECOLOGICAL GROUPS

The variation of acute toxicity data among nematode species belonging to different taxonomic and ecological groups was investigated. Twelve different nematode species were extracted from the soil and directly exposed to cadmium and pentachlorophenol. LC(50)-values were estimated after 24, 48, 72, and 96 h of exposure in aqueous solutions. The species exhibited large differences in sensitivity. LC(50)-values (72 h) for pentachlorophenol ranged from 0.5 to more than 34.5 mu mol/L and for cadmium from 29 to more than 800 mu mol/L. These toxicity data could be described by a log-logistic distribution function. LC(50)-values for cadmium were not correlated with those for pentachlorophenol. Species of the subphylum Secernentia were less sensitive to pentachlorophenol than species of the subphylum Penetrantia, while no differences were observed for cadmium. In addition, no relationship was found between toxicity data and life-history strategies. Slow colonizers (K-strategists, sensu late) were not more sensitive to cadmium and pentachlorophenol than opportunistic species (r-strategists, sensu late). Nematodes appeared to be as sensitive to pentachlorophenol as other soil invertebrates. Nematodes were generally tolerant to cadmium.