Seasonal and Spatial Studies on Pesticide Residues in Surface Waters of the Shinano River in Japan

TLDR

Water samples were collected weekly from early April to late August 1996 at four sites on the Shinano River and analyzed for pesticides and metabolites using GC‑MS. The survey identified 53 chemicals (22 herbicides, 15 insecticides, 11 fungicides, 5 metabolites) with concentrations ranging from 3 to 8,200 ng/L, with herbicides peaking in May–June and insecticides/fungicides in July–August, mirroring pesticide application in nearby rice fields. Keywords: GC‑MS, pesticides, river water, Shinano River.

Abstract

Water samples collected once a week from early April 1996 to the end of August 1996 from four sites on the Shinano River in Japan were analyzed for pesticides and their metabolites using a gas chromatograph−mass spectrometer. Among the total of 53 chemicals found, 22 were herbicides, 15 were insecticides, 11 were fungicides, and 5 were metabolites. The concentrations of chemicals found ranged from 3 ng/L (bromobutide) to 8200 ng/L (isoprothiolane). Herbicides were found primarily during May and June at all four sites. Insecticides and fungicides were found primarily during July and August at all four sites. The presence of pesticides in the river water correlated with the time of pesticide application to the rice fields near the river. Keywords: GC-MS; pesticides; river water; Shinano River