Residue studies on aldrin and dieldrin in soils, water, and crawfish from rice fields having insecticide contamination.

Abstract

Studies were conducted on aldrin and dieldrin residue in soil, water, and crawfish ( Procambarus clarrkii (Girard)) from rice paddies. Samples of a Midland silt loam soil taken on the drill row from plots planted with rice seed (100 pounds per acre) treated with 0.25 pounds aldrin per 100 pounds of seed showed residues of both aldrin dieldrin. Samples taken 1 month after planting had of aldrin in samples taken on the drill row and 2.5 inches from it, but none in samples taken 5 inches from the drill row. At later sampling times no difference noted in aldrin residue at either the 2.5 or the 5 inches sites in check or treated plots. A preexisting dieldrin residue of 300–500 parts per billion (ppb) was found in all plots. No measurable difference in dieldrin levels was found at any site caused by conversion of aldrin to residues decreased at slower rates under these flooded conditions than have been reported for soils exposed to air. Pesticide residues in water from paddies planted with rice seed (100 pounds per acre) treated with aldrin at rates of 0.25 and 0.5 pounds per 100 pounds of seed showed a positive correlation with treatment rate in drill planted but not with water-planted seed. Dieldrin residues dues averaged 0.18 ppb for water-planted rice and 0.28 ppb for drill-planted rice. The dieldrin residues are attributed to a 1.1 ppb aldrin and 850 ppb dieldrin residue present in soils prior to planting. Crawfish reared in paddies planted with treated or non-treated seed and on soil containing up to 200 ppb aldrin and 500 ppb dieldrin were found to contain residues of aldrin, dieldrin, and DDE (I, 1-dichloro-2,2-bis ( P -chlorophenyl) ethylene).