In Nagano Prefecture, the sudden death of many wild birds became appearent in 1997. In order to investigate the cause, the authors developed a simultaneous analytical method using GC/MS. The method was applied to investigate the reason of sudden wild bird death in 3 cases that happened in 1998. Therefore, the every cause was cleared as following. 1) In the case of Komagane City, seeds of buckwheat were found in the residues of their stomachs, and the buckwheat was subjected to analyses. A high concentration of highly toxic insecticide, Methomyl, was detected. The authors presumed that was the cause of birds' death. 2) In the case of Saku City, some flesh, probably from apples was found in the birds' stomachs. The result of flesh analysis was the highly toxic insecticide, EPN, detected in a high concentration. The authors assumed that was the cause of death. 3) In the case of Asashina Village, fish, shrimp, rice, among others were found in the birds' stomachs. The result of their analysis was the highly toxic insecticide, Benfuracarb, detected in a high concentration. The authors assumed that was the cause of death.

A method by GC/MS has been established for the determination of Etoxazole in agricaltural products. Etoxazole was decomposed by acid contained in citrus fruits, but this decomposition could be prevented by addition of sodium acetate solution and extraction above pH 4. In the present method, the Etoxazole in agricultural products was extracted with acetone above pH 4, concentrated, and reextracted with n-hexane. After partition with acetonitrile followed by chromatographic clean-up with Florisil, the sample was subjected to GC/MS. The present method is excellent in sensitivity and has a detection limit of 0.002 micro g/g, and thus is about 10 times as sensitive as that of GC-NPD. The recovery by the present method is over 85% except for tea, the C.V. of recovery is less than 8%, and the method is applicable to actual samples.

The Transition of organochlorine pesticide residues la raw milk produced in Nagano prefecture during the period of 197O-1977, were investigated. alpha, beta, gamma and delta-BHC, pp'-DDT, pp'-DDE and pp'-DDD, dieldrin were found to be present in raw milk. The following substances were not detected; op'-DDT, aldrin, endrin, heptachlor and heptachlor epoxide. It was observed that the contamination of raw milk by organochlorine pesticides showed a decrease by about 90% in BHC residues for a period of eight years.

A method by GC/MS has been established for the determination of Pyrimidifen in agricaltural products. The Pyrimidifen in agricultural products is extracted with acetone, concentrated, and extracted with n-hexane. The solution is cleaned up with a Florisil column and subjected to a determination by GC/MS using p-terphenyl-d14 as the internal standard. This method is featured by the recovery over 80 % with its C .V. below 8 % and the detection limit 1 micro g/kg. This method, excellent in sensitivity and selectivity, is useful as a rutine analytical method for agricultural products.