title: Effects of chlorpyrifos ethyl on acetylcholinesterase activity in climbing perch cultured in rice fields in the Mekong Delta, Vietnam.
abstract: Climbing perch is commonly harvested in rice fields and associated wetlands in the Mekong Delta. Despite its importance in providing food and income to local households, there is little information how this fish species is affected by the high use of pesticides in rice farming. Organophosphate insecticides, such as chlorpyrifos ethyl, which are highly toxic to aquatic organisms, are commonly used in the Mekong Delta. This study shows that the brain acetylcholinesterase (AChE) activity in climbing perch fingerlings cultured in rice fields, was significantly inhibited by a single application of chlorpyrifos ethyl, at doses commonly applied by rice farmers (0.32-0.64 kg/ha). The water concentration of chlorpyrifos ethyl decreased below the detection level within 3 days, but the inhibition of brain AChE activity remained for more than 12 days. In addition, the chlorpyrifos ethyl treatments had a significant impact on the survival and growth rates of climbing perch fingerlings, which were proportional to the exposure levels. The results indicate that the high use of pesticides among rice farmers in the Mekong Delta could have a negative impact on aquatic organisms and fish yields, with implications for the aquatic biodiversity, local people's livelihoods and the aquaculture industry in the Mekong Delta.
authors.affiliation: Faculty of Fishery, Nong Lam University, Block 6, Linh Trung Ward, Thu Duc District, HCM city, Vietnam; Department of Physical Geography, Stockholm University, SE-106 91 Stockholm, Sweden. Electronic address: tam@ecology.su.se.
authors.forename: Tam Thanh
authors.initials: TT
authors.lastname: Nguyen
authors.affiliation: Department of Physical Geography, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Berg
authors.affiliation: Faculty of Fishery, Nong Lam University, Block 6, Linh Trung Ward, Thu Duc District, HCM city, Vietnam.
authors.forename: Hang Thi Thuy
authors.initials: HT
authors.lastname: Nguyen
authors.affiliation: College of Environment and Natural Resources, Can Tho University, 3/2 Street, Can Tho city, Vietnam.
authors.forename: Cong Van
authors.initials: CV
authors.lastname: Nguyen
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000383:Agriculture; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000201:enzymology; D004390:Chlorpyrifos / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D012275:Oryza; D010471:Perches; D010575:Pesticides / Q000633:toxicity; D014744:Vietnam
chemical_list: D007306:Insecticides; D010575:Pesticides; D000110:Acetylcholinesterase; D004390:Chlorpyrifos
keywords: Acetylcholinesterase; Chlorpyrifos ethyl; Climbing perch; Mekong Delta; Pesticides; Rice farming