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Behaviour of an alginate-kaolin based controlled-release formulation of the herbicide thiobencarb in simulated ecosystems

1994; Wiley; Volume: 42; Issue: 4 Linguagem: Inglês

10.1002/ps.2780420403

1096-9063

Jianying Gan, Manzoor Hussain, Nasir M. Rathor,

Pharmaceutical and Antibiotic Environmental Impacts

Abstract An alginate‐kaolin based controlled‐release formulation of the herbicide thiobencarb, TCR‐1, was prepared. The distribution, bioaccumulation and persistence of thiobencarb from this formulation were compared to those from a commercial granular formulation, 10 G, in flooded paddy soil under controlled conditions and in simulated aquatic systems and rice paddy/fish systems under greenhouse conditions. Persistence of the total residues and thiobencarb parent increased significantly in the soil treated with TCR‐1, and at the end of a 49‐day incubation 32.5% of the applied herbicide was recovered as the parent from the soil treated with TCR‐1, compared to only 15.2% from the soil treated with 10 G. Slower release into water and less accumulation in fish tissues were found in the simulated aquatic system treated with TCR‐1. A lower concentration was detected in the paddy water in the simulated rice paddy/fish system treated with TCR‐1 over the duration of a 66‐day greenhouse experiment. Fish and rice plants accumulated less residues from the system treated with TCR‐1 than from that with commercial formulation 10 G. The overall results indicated that the persistence of thiobencarb in the controlled‐release formulation was prolonged in water and soil, and the potential impact on non‐target components such as rice plants and fish was concurrently reduced.