V.E. Narke, S.R. Bhonglae, S.N. Shegar4 and U.V. Khisti
Abstract
Chlorpyrifos 50% EC was found to be hazardous when evaluated with a terrestrial test system, i.e., in earthworms and honey bees. In earthworms, at concentrations 40, 64, 102.4, 163.8, and 262.1 mg/kg (dry weight of artificial soil) on day 14, 0/40, 0/40, 4/40, 9/40, 16/40, and 40/40 cumulative mortality was observed when treated with 0, 40, 64, 102.4, 163.8 and 262.1 mg/kg (dry weight of artificial soil) respectively. Behavioural or pathological signs were observed such as dullness in the worms treated with 64, 102.4, 163.8, and 262.1 mg/kg (dry weight of artificial soil) on day 7. The LC50 of Chlorpyrifos 50% EC for earthworms observed for a period of 14 days was found to be 240.443 mg/kg (dry weight of artificial soil) with lower confidence limits of 155.014 mg/kg (dry weight of artificial soil) and the upper confidence limits of 372.951 mg/kg (dry weight of artificial soil). The Chlorpyrifos 50% EC is classified under ââ¬ÅCategory 3ââ¬Â as per the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) (Mariyadas et al., 2018; Nöel, 2015). When the bees were exposed to Chlorpyrifos 50% EC at 0.1, 0.2, 0.4, and 0.8 üg a.i./bee mortalities were observed at 0.2 üg, 0.4, and 0.8 üg a.i./bee concentration at 4h and 24 h. The signs of intoxication were observed 4th h onwards. The signs observed were lethargy, and dullness till 48 h. The LD50 of Chlorpyrifos 50% EC in Honey bees by oral route for a period of 24 h was found to be 0.400 üg a.i./bee with confidence limits of 0.263 üg a.i./bee to 0.609 üg a.i./bee.