 BackResearch Article ScienceAsia 12 (1986): 225-238 |doi: 10.2306/scienceasia1513-1874.1986.12.225
ORGANOCHLORINE PESTICIDE RESIDUES IN THE LOWER CHAO PHRAYA RIVER AND KLONGS ALONG THE RIVER AT BANGKOK METROPOLITAN AREA, 1982-1984
SUKEO ONODERA* AND MONTHIP SRIRATANA TABUCANONABSTRACT: Organochlorine pesticides were ubiquitously found in the lower Chao Phraya River and klongs along the river at Bangkok metropolitan area. . These pesticides such as
BHCs, Heptachlor, Aldrin, Dieldrin and DDTs had the highest frequencies of
occurrence in water and sediment samples collected from the river and klongs. The arithmetric averages of these pesticide residues in the river water on April and October 1984 were 0.233 and 0.100 Environmental Quality Standard Division, Office of. National Environment Board, (ONEB), Rama 6 Rd., Bangkok 10400, Thailand. Received 18 October 1985
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g/l, respectively. In particular, the concentrations of a
-BHC, Aldrin, and Dieldrin in the river water in dry season were found to be 3-10 times higher than those values measured. in rainy season. The distancial distribution of these pesticides in the river water was strongly influenced by tidal effect and flow rate of the river in the low pari of the Chao Phraya River. For example, the tested compounds were highly concentrated in the river water from the river mouth to 30 km upstreams, while, the compounds were highly accumulated in the river sediment from 30 to 60 km up the river, when the survey was conducted on September 1984. In addition, these pesticide residues in the river sediment were 200-350 times higher than those found in the river water.
