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The joint toxicity effects of Chlorpyrifos ethyl and Fenobucarb to Climbing perch (Anabas testudineus) from rice fields in the Mekong Delta, Vietnam
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi. Nong Lam University, Vietnam.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi.
2018 (Engelska)Ingår i: Environmental Science and Pollution Research, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 25, nr 4, s. 13226-13234Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Organophosphates (e.g. chlorpyrifos ethyl) and carbamates (e.g. fenobucarb), are commonly used to control a wide range of pests in rice fields of the Mekong Delta in Vietnam. This study assesses the combined effect of chlorpyrifos ethyl (CPF) and fenobucarb (F) on the brain acetylcholinesterase (AChE) activity in climbing perch fingerlings from rice fields in the Mekong Delta. It also investigates if Pyridine-2-aldoxime methiodide (2-PAM) can be used to re-activate cholinesterase that has been blocked by CPF and F. Three days after spraying, the water concentrations of both insecticides decreased quickly below the detection levels. However the brain AChE activity in fish was inhibited for more than seven days. The results indicate a quicker but less prolonged inhibition of the brain AChE activity by the mixture than by only CPF. The inhibition levels were above 70% only during the first 48 hours, which could explain why all fish survived. 2-PAM resulted in a significant re-activation of the cholinesterase blocked by a combination of CPF and F, and it is proposed that the re-activation by 2-PAM could provide a way to assess the AChE inhibition level in organisms, when no unexposed individuals are available as controls. The results indicate that current use of CPF and F in rice farming in the Mekong Delta is likely to cause negative effects on non-target organisms. Many of these effects may be sub-lethal, and there is a need to develop relevant bio-markers, that are relevant, cheap and easy to apply under tropical conditions in developing countries.

Ort, förlag, år, upplaga, sidor
2018. Vol. 25, nr 4, s. 13226-13234
Nyckelord [en]
Anabas testudineus, Chlorpyrifos ethyl, Fenobucarb, Mixture, Acetylcholinesterase, Mekong Delta
Nationell ämneskategori
Naturgeografi
Forskningsämne
naturgeografi
Identifikatorer
URN: urn:nbn:se:su:diva-128415DOI: 10.1007/s11356-016-6980-yISI: 000433038500004OAI: oai:DiVA.org:su-128415DiVA, id: diva2:914869
Projekt
Swedish International Development Cooperation Agency (Sida) (Ref. No. AKT2010-010) through the Partner Driven Cooperation (PDC) project “Managing Ecosystem Services for Sustainable Aquaculture Development.Tillgänglig från: 2016-03-27 Skapad: 2016-03-27 Senast uppdaterad: 2022-02-23Bibliografiskt granskad
Ingår i avhandling
1. Pesticide use in rice farming and its impacts on climbing perch (Anabas testudineus) in the Mekong Delta of Vietnam
Öppna denna publikation i ny flik eller fönster >>Pesticide use in rice farming and its impacts on climbing perch (Anabas testudineus) in the Mekong Delta of Vietnam
2016 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

The intensification of agricultural production in the Mekong Delta has faced serious challenges with respect to increased use of agrochemicals and especially pesticides. The indiscriminate use of pesticide could potentially impact on the long-term food production, environmental and human health in the delta. The aim of this thesis was to investigate the negative side effects of the current use of pesticides on climbing perch (Anabas testudineus) in rice fields using brain acetylcholinesterase (hereafter referred to as AChE) activity as a biomarker. The empirical work, on which this thesis is based, includes structured questionnaires, laboratory and field experiments. First, a field survey using questionnaires was carried out to gain a better understanding of the current state of rice farming systems, the use of pesticides and attitude to pest management strategies among rice and rice-fish farmers, as well as to provide basic information for the set-up of the laboratory and field experiments. Secondly, laboratory studies were conducted to clarify if the selected insecticides applied alone and in mixtures caused negative side effects on climbing perch fingerlings. Thirdly, further toxicity studies were carried out, under rice field conditions, to further investigate the toxicity effects of the insecticides, applied alone, in mixtures and under sequential applications, on climbing perch fingerlings.

The results showed that although there were a more selective use of pesticides and an increased awareness among farmers of the negative side effects of pesticides in 2007 as compared to 1999, the current use of pesticide in the Mekong Delta still cause many problems to the environment and human health. Chlorpyrifos ethyl (hereafter referred to as CPF) was found to cause a significant and more prolonged inhibition on the brain AChE activity in climbing perch than fenobucarb (hereafter referred to as F). The inhibition by the mixture of CPF and F were significantly higher than the inhibition by only F, but less prolonged and significant lower than the inhibition by only CPF. The results suggest that the combined effect from a mixture of F and CPF can create both additive effects initially and later antagonistic effects.

CPF and F applied at concentrations used by farmers, either as separate doses, in a mixture or in sequential doses, decreased the brain AChE activity, growth and survival rates in climbing perch. The results demonstrate that brain AChE activity in climbing perch is a relevant biomarker for monitoring of exposure to, and sub-lethal impacts from organophosphates and carbamates under tropical conditions. The result also shows that 2-PAM re-activate the brain AChE activity, and can be used as an alternative method to assess the AChE inhibition level in organisms recently exposed to OP’s, in situation where it may be difficult to find unexposed individuals as controls.

In conclusion, this thesis shows that the current use of pesticides in the Mekong Delta has a negative effect on climbing perch living in rice fields. It indicates that a sustained long-term food production in the Mekong Delta must be based on ecological principles, taking advantages of ecosystem biodiversity and productivity, and not through intensified use of pesticides.

Ort, förlag, år, upplaga, sidor
Stockholm: Department of Physical Geography, Stockholm University, 2016. s. 42
Serie
Dissertations from the Department of Physical Geography, ISSN 1653-7211 ; 55
Nyckelord
Mekong Delta, Rice field, Climbing perch, Insecticide, Chlorpyrifos ethyl, Fenobucarb, Mixture, Sequential applications, AChE
Nationell ämneskategori
Naturgeografi
Forskningsämne
naturgeografi
Identifikatorer
urn:nbn:se:su:diva-128856 (URN)978-91-7649-415-8 (ISBN)
Disputation
2016-05-27, William Olsson-salen, Geovetenskapens hus, Svante Arrhenius väg 14, Stockholm, 13:00 (Engelska)
Opponent
Handledare
Anmärkning

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 5: Submitted.

Tillgänglig från: 2016-05-02 Skapad: 2016-04-05 Senast uppdaterad: 2022-02-23Bibliografiskt granskad

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