After the Second World War, pesticide residue problems have arisen in Japan as a result of the extensive use of organosynthetic pesticides, especially persistent pesticides such as organomercury fungicides and organochlorine insecticides. The successive problems encountered can be summarized according to the following chronological order.
1) Mercury contamination of rice grains, 2) Contamination of cow milk with BHC isomers,
3) Contamination of vegetables with dieldrin residues in soil, 4) Contamination of waterways
with organochlorine insecticides, and 5) Pesticide effects on fish and shellfish.