Håkan berg stockholm
The overall aim of this project is to analyse if less intensive rice farming strategies, such as rice-fish farming could provide sustainable alternatives to more intensive rice monocropping in the Mekong Delta.
Håkan Berg
The overall aim of this project is to explore the link between mangrove ecosystem services MES and community livelihoods and well-being, changes in MES and associated drivers of change, adaptation options and their management in Tanzania, using the Rufiji Delta and Pangani Estuary as case studies. A selection from Stockholm University publication database. Thanh Tam Nguyen et al.
Bulletin of Environmental Contamination and Toxicology 97 1 , This study assesses the effects of sequential applications of the insecticides Bassa 50EC fenobucarb-F and Vitashield 40EC chlorpyrifos ethyl-CPF , sprayed at concentrations used by rice farmers in the Mekong Delta, on the brain acetylcholinesterase AChE in climbing perch fingerlings.
After spraying the pesticides on the rice fields, the water concentrations of both insecticides decreased below the detection levels within three days.
Department of Physical Geography
The sequential applications caused significant inhibition on the brain AChE activity in the exposed fish. The inhibition by F was quicker, but less prolonged, than for CPF. Environmental science and pollution research international. Organophosphates e. 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.
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 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.
Håkan Berg - Stockholm University - Stockholms universitet
Archives of Environmental Contamination and Toxicology 69 4 , The high use of pesticides in intensive rice farming in the Mekong Delta constitutes a potential hazard to the environment and to people's health. Chlorpyrifos ethyl CPF is a commonly used organophosphate OP insecticide, but information about its potential negative impacts on the aquatic environment in the Mekong Delta is scarce.
Both acute and subacute toxicity tests were performed in a static nonrenewable system to investigate the effects of CPF on brain acetylcholinesterase AChE activity in native climbing perch fingerlings Anabas testudineus, Bloch, Environmental parameters, such as dissolved oxygen, water temperature, and pH, were similar to field conditions in the Mekong Delta. In a h lethal concentration LC50 test, fingerlings of climbing perch were randomly exposed to five levels of CPF ranging from 0.
The recovery of brain AChE activity in fish placed in CPF-free water was very slow, and after 7 days the brain AChE activity was still significant lower in fish from the four highest concentrations compared with the control. The results from this study indicate that OP insecticides, such as CPF, can have long-lasting sublethal effects on aquatic species in the Mekong Delta.
Ecotoxicology and Environmental Safety , 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.
Håkan Berg - Google Scholar
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 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.
Chau Thi Da et al. Agroecology and Sustainable Food Systems 39 5 ,