Survey of Pesticide Concentrations, Including Neonicotinoids, in the Sagami River, Its Tributaries and Tap Water

Abstract

The concentrations of emerging pesticides in the Sagami River, its tributaries and tap water in the basin were investigated throughout the year of 2014. We investigated six neonicotinoids, tebuconazole, bromacil, tefuryltrione and 2-chloro-4-mesyl-3-［（tetrahydrofurane-2-il-methoxy） methyl］benzoate （CMTBA） which is one of the products of tefuryltrione degradation. Nine pesticides were detected in river water. Imidacloprid and tefuryltrione were detected during the periods of their application to fields. Tebuconazole and bromacil, which are commonly used as herbicides in urban areas, were mainly detected in winter. We compared the concentrations of pesticides with the Predicted Environmental Concentrations （PEC） that were calculated by the Ministry of the Environment. The maximum concentrations of tebuconazole and bromacil exceeded the PEC for aquatic animals and plants. The concentrations of imidacloprid and clothianidin in tap water varied in accordance with their concentrations in the river water. CMTBAwas detected in tap water samples at concentrations almost comparable to the concentrations of tefuryltrione in river water on a mo