EFFECTS OF TEMPERATURE AND CHEMICAL FORMULATION ON THE ACUTE TOXICITYOF PENTACHLOROPHENOL TO SIMOCEPHALUS-VETULUS (SCHOEDLER, 1858) (CRUSTACEA, CLADOCERA)

The influence of temperature on the acute toxicity of a technical form ulation (86%) and pure formulation (99%) of pentachlorophenol (PCP) to less than 24-h-old Simocephalus vetulus neonates was determined with 48-h static toxicity tests. The technical grade PCP was significantly more toxic to S. vetulus than the pure PCP (P < 0.05). Sensitivity of S. vetulus to technical PCP also significantly increased with temperat ure (P < 0.05), but a significant temperature effect was not found wit h the pure PCP. The mean 48-h LC(50) values for neonates exposed to te chnical PCP were 140 and 199 mu g 1(-1) at 22 degrees C and 16 degrees C, respectively, and for those exposed to pure PCP were 262 and 304 m u g 1(-1), respectively.