Pesticides applied to sloping farmland may lead to surface water contamination through rapid transport processes as influenced by the complex topography and high spatial variability of soil properties and land use in hilly or mountainous regions. However, the fate of pesticides applied to sloping farmland has not been sufficiently elucidated. This article reviews the current understanding of pesticide transport from sloping farmland to surface water. It examines overland flow and subsurface lateral flow in areas where surface soil is underlain by impervious subsoil or rocks and tile drains. It stresses the importance of quantifying and modeling the contributions of various pathways to rapid pesticide loss at catchment and regional scales. Such models could be used in scenario studies for evaluating the effectiveness of possible mitigation strategies such as constructing vegetated strips, depressions, wetlands and drainage ditches, and implementing good agricultural practices. Field monitoring studies should also be conducted to calibrate and validate the transport models as well as biophysical-economic models, to optimize mitigation measures in areas dominated by sloping farmland. 相似文献
Many chemicals are released into the environment, and chemical contamination has been suggested as a contributing factor to
amphibian declines. To add to a growing body of knowledge about the impact of individual chemicals on non-target organisms,
we examined the specificity of deformities induced by exposure to four pesticides (atrazine, 2,4-dichloropheoxyacetic acid (2,4-D),
triadimefon, and glyphosate) in the model amphibian species, Xenopus laevis. We focused on the period of organ morphogenesis, as it
is frequently found to be particularly sensitive to chemical exposure yet also commonly overlooked.We found similar levels of intestine
malformations and edemas, as well as disruption of skeletal muscle, in atrazine and triadimefon exposed tadpoles. The e ects of 2,4-D
were only apparent at the highest concentrations we examined; glyphosate did not induce dramatic malformations at the concentrations
tested. While researchers have shown that it is important to understand how chemical mixtures a ect non-target organisms, our results
suggest that it is first crucial to determine how these chemicals act independently in order to be able to identify consequences of
individual pesticide exposure. 相似文献
In this study, preliminary tests were conducted aiming to validate the use of ceramic porous cup for collecting soil water samples and monitoring pesticides contents, as usually made for nitrates. Interactions between porous cup and pesticides were examined under different experimental conditions for three herbicides (atrazine, isoproturon, 2,4-D) and one insecticide (carbofuran).
The results showed that ceramic was not inert for pesticides : as much as 80% of the applied pesticide could be retained during the flowing of the first tenth milliliters of solution. Interactions were attributed to sorption and “screening” of molecules by the porous walls and were related to the ionic character of pesticides. However, retention was not irreversible, since pesticides were quickly released by rinsing with distilled water.
After these tests, porous ceramic cups could be considered as suitable samplers for pesticide determinations in soil solution, contingent on gaining further informations about soil - porous cup - pesticide interactions. 相似文献
The effect of various pesticides on the biofilm formation by the phytopathogenic bacterium Clavibacter michiganensis ssp. sepedonicus (Cms), the potato ring rot causative agent, was explored for the first time. Systemic herbicides: 2,4-D, diuron, glyphosate, clopyralid, fluorodifen, as well as the commercial preparations “Lazurite,” “Ridomil Gold,” and the mitochondria inhibiting pesticides analog, sodium monoiodoacetate, were studied. These pesticides' effect on the Cms biofilm formation was shown to be distinct and dependent on the agent under question. Cms biofilm formation was reduced when exposed to sodium monoiodoacetate, as well as “Lazurite” preparation, that could be due to the bactericidal effect of these agents. 2,4-D and “Ridomil Gold” preparation stimulated the biofilm formation. Systemic herbicides diuron, glyphosate, clopyralid, fluorodifen did not exert appreciable influence on the process of bacterial biofilm formation. 相似文献