Impact of granular insecticides application on fish in rice field
2000
Wantana Srirataanasak | Wipa Thangnipol | Pinya Chamraskul | Orapin Watanesk
Results showed that carbofuran (Furadan 3 percent G) at the application rates of 4 and 8 kg per rai were found highly toxic to both P. sutchi and O. niloticus. percentage of fish mortality in carbofuran plots have statistically significant different compared to fipronil (Tempo 0.2 percent), cartap/isoprocarp (Padan/Mipcin 3 percent/3 percent G) and control plots. Moreover, the rate at 8 kg per rai of carbofuran had significantly higher mortality than those using 4 kg per rai. In contrast, the two rates of fipronil, cartap/isoprocarp and the control plots did not show statistically significant different mortality in the both fish. While the mortality percentage did not also significantly different after fish stocking in 1, 3, 5 and 7 days thereafter. Acute toxicity of the insecticides was confirmed. It was found that carbofuran reduced ChE level in the both fish brain within one day after direct exposure but eventually increased in 5 to 7 days thereafter. Also cartap, it has a toxic effect on the ChE level in one day. In the other hand, fipronil found slightly effect to the ChE level of the both fish. Pesticide residues in paddy water and soil sediment were detected. It was found that carbofuran were present in the water ranged from 0.30 to 0.01 and 0.60 to 0.01 ppm at the rates of 4 and 8 kg per rai, Respectively, while the residues in soil sediment were 0.20 to 0.02 ppm. Plots applied with 4 and 8 kg per rai of fipronil, its residues in water ranged from 0.01 to 0 and 0.03 to 0 ppm, respectively, and ranged from 0.1 to 0 ppm in soil sediment in both rates. However, the amounts of carbofuran and fipronil residues detected in water and soil sediment were less. These may have quick degradation.
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