Chlorpyrifos is a widely used organosphosphate insecticide in India. Residue of the insecticide is frequently detected in trace to moderate concentration in food grains and in surface water of different freshwater ecosystems of the country. In this study, 96 h LC of the technical grade (94% a.i.) and commercial formulation (20% EC) of chlorpyrifos to freshwater fish Oreochromis niloticus were determined as 90.0 and 42.0 µg/L based on 2 h actual concentration of chlorpyrifos in water. About 96 h exposure to sublethal concentrations (0, 12.0 and 25.0 μg/L) of the commercial formulation (20% EC) of chlorpyrifos reduced the level of hepatic glycogen, activities of alkaline phosphatase, acetylcholinesterase, and catalase in liver and elevated the level of plasma glucose and activities of hepatic acid phosphatase, aspartate aminotransferase, and alanine aminotransferase in O. niloticus. About 28-day exposure to these sub-lethal concentrations caused anemia in fish, while 90 days exposure reduced growth of the fish and carcass concentration of crude protein and crude lipid as compared to control. It was concluded from this study that commercial formulation of chlorpyrifos (20% EC) was highly toxic to O. niloticus. Exposure to sub-lethal concentrations of the insecticide could induce oxidative stress and anemia resulting in reduced growth of the fish.

Bioassays were conducted with technical grade and commercial formulation of cypermethrin using freshwater fish Oreochromis niloticus as the test fish. The technical grade cypermethrin contained 92% active ingredient (a.i.) and the commercial formulation was an emulsified concentrate (EC) containing 10% a.i. (10% EC). Based on the actual concentration in water (2 h), the commercial formulation was found to be more acutely toxic to O. niloticus (96-h LC 50 = 4.85 lg/L) than the technical grade cypermethrin (96-h LC 50 = 9.74 lg/L). Exposure to sub-lethal concentrations (1.25, 2.5 lg/L) of commercial cypermethrin for 96 h produced stress on the fish, which was evident from the reduction of hepatic glycogen, reduction in the activities of alkaline phosphatase, acetylcholinesterase and catalase in liver and elevation of plasma glucose level and activities of hepatic acid phosphatase, aspartate aminotransferase and alanine aminotransferase. Exposure to these concentrations of cypermethrin for 14-28 days produced anaemia in fish. Long-term exposure (90 days) of the fish to these concentrations reduced the growth and deposition of protein and lipid in the body of fish as compared to control.It is concluded from this study that even minute concentration (1.25 lg/L) of cypermethrin (10% EC) in water can produce stress on fish. Long term exposure to such concentration of cypermethrin may also affect growth of the fish.

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The Gangetic plain of India is one of the most intensively farmed lands in the world. This study examined the species composition of the herpetofaunal community in Haripal, Hooghly, West Bengal, India, located within the Gangetic Delta’s plain of eastern India. A total of 32 species (10 amphibians, 22 reptiles) belonging to 23 genera (7 amphibian, 16 reptile), 13 families (4 amphibian, 9 reptile), and two orders (1 amphibian, 1 reptile) were recorded. Among the amphibians, the highest number of species (5) was recorded in the family Dicroglossidae, while the Colubridae family was represented by a maximum of 7 species among the reptiles. All of the recorded species except Varanus flavescens (Hardwicke and Gray, 1827) are listed as Least Concern (LC) in the IUCN Red List. Varanus flavescens has been declared as Endangered (EN). Among the recorded species, one species is included in Schedule I, 6 species in Schedule II, and 13 species are listed in Schedule IV of the Indian Wildlife (Protection) Act, 1972. This report provides baseline data on herpetofaunal community composition in the Haripal block for the first time. The study area is rich in herpetofaunal diversity. This study also emphasises the necessity of holistic conservation strategies in the study area and the demand for additional studies to explore the country’s biodiversity beyond the protected areas.

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