RESIDUAL PESTICIDES AND THEIR TOXICITY TO FRESH-WATER SHRIMP IN THE LITTORAL AND PELAGIC ZONES OF LAKE-KASUMIGAURA, JAPAN

Pesticide residues in water and their toxicity to the freshwater shrim p (Paratya compressa improvisa) were studied in a river mouth in Takah amairi Bay, Lake Kasumigaura, from April to July in 1987. Concentratio ns of fenthion, diazinon and fenobucarb in water of the littoral zone were lower than that in the pelagic zone. The maximum concentrations o f fenthion, diazinon, iprobenfos and simetryn in water were 1.9, 0.8, 6.5, and 1.1 mu g l(-1), respectively. The 4-day mortality of the fres hwater shrimp increased in lake water al Takahamairi Bay, reaching 50% at maximum in May. The mortality was probably due to residual insects ide fenthion. Copyright (C) 1996 Elsevier Science Ltd