Atrazine is a widely used herbicide for controlling weeds on both agricultural and nonagricultural land,which is equally detected in water supplies beyond safe concentrations.Although the presence of atrazine metaboli...Atrazine is a widely used herbicide for controlling weeds on both agricultural and nonagricultural land,which is equally detected in water supplies beyond safe concentrations.Although the presence of atrazine metabolites is an indication of herbicide degradation,some of them still exhibit toxicity,greater water solubility and weaker interaction with soil components than atrazine.Hence,studies with atrazine in the environment are of interest because of its potential to contaminate drinking water sources.Data on atrazine availability for transport,plant uptake,and microbial degradation and mineralization are therefore required to perform more comprehensive and realistic environmental risk assessments of its environmental fate.This review presents an account of the sorption-desorption phenomenon of atrazine on soil and other sorbents by revisiting the several mechanisms of atrazine-sorbent binding reported in the literature.The retention and transport of atrazine in soils;the influence of organic matter on atrazine sorption;the interactions of atrazine with humic substances,atrazine uptake by plants,atrazine bioccumulation and microbial degradation;atrazine transformation in composting environments;and finally atrazine removal by biosorption are discussed.展开更多
The biodegradation characteristic and potential metabolic pathway for removal of environmental N,N-dimethylacetamide （DMAC） by Rhodococcus sp. strain B83 was studied. Rhodococcus sp. strain B83 was isolated from the...The biodegradation characteristic and potential metabolic pathway for removal of environmental N,N-dimethylacetamide （DMAC） by Rhodococcus sp. strain B83 was studied. Rhodococcus sp. strain B83 was isolated from the rhizosphere of a pagoda tree and proved capable of utilizing DMAC as sole source of carbon and nitrogen. Batch culture studies showed that strain B83 could tolerate up to 25 g/L DMAC and showed distinct growth on possible catabolic intermediates except for acetate. The nitrogen balance analysis revealed that approximately 71% of the initial nitrogen was converted to organic nitrogen. DMAC degradation has led to accumulation of acetate and organic nitrogen, meanwhile traces of nitrate and ammonia was build-up but without nitrite. The growth of strain B83 could be inhibited by adding exogenous acetate. By means of the assay of enzymatic degradation of DMAC, several catabolic intermediates at different intervals were observed and identified. Based on the results obtained from culture solution and enzymatic degradation assay, a detailed pathway is proposed for DMAC biodegradation.展开更多
文摘Atrazine is a widely used herbicide for controlling weeds on both agricultural and nonagricultural land,which is equally detected in water supplies beyond safe concentrations.Although the presence of atrazine metabolites is an indication of herbicide degradation,some of them still exhibit toxicity,greater water solubility and weaker interaction with soil components than atrazine.Hence,studies with atrazine in the environment are of interest because of its potential to contaminate drinking water sources.Data on atrazine availability for transport,plant uptake,and microbial degradation and mineralization are therefore required to perform more comprehensive and realistic environmental risk assessments of its environmental fate.This review presents an account of the sorption-desorption phenomenon of atrazine on soil and other sorbents by revisiting the several mechanisms of atrazine-sorbent binding reported in the literature.The retention and transport of atrazine in soils;the influence of organic matter on atrazine sorption;the interactions of atrazine with humic substances,atrazine uptake by plants,atrazine bioccumulation and microbial degradation;atrazine transformation in composting environments;and finally atrazine removal by biosorption are discussed.
基金supported by the National Natural Science Foundation of China(No.51308440)the Natural Science Foundation of Shaanxi Province(No.2014JM7260)Shaanxi Provincial Department of Education Fund(No.15JK1439)are gratefully acknowledged
文摘The biodegradation characteristic and potential metabolic pathway for removal of environmental N,N-dimethylacetamide （DMAC） by Rhodococcus sp. strain B83 was studied. Rhodococcus sp. strain B83 was isolated from the rhizosphere of a pagoda tree and proved capable of utilizing DMAC as sole source of carbon and nitrogen. Batch culture studies showed that strain B83 could tolerate up to 25 g/L DMAC and showed distinct growth on possible catabolic intermediates except for acetate. The nitrogen balance analysis revealed that approximately 71% of the initial nitrogen was converted to organic nitrogen. DMAC degradation has led to accumulation of acetate and organic nitrogen, meanwhile traces of nitrate and ammonia was build-up but without nitrite. The growth of strain B83 could be inhibited by adding exogenous acetate. By means of the assay of enzymatic degradation of DMAC, several catabolic intermediates at different intervals were observed and identified. Based on the results obtained from culture solution and enzymatic degradation assay, a detailed pathway is proposed for DMAC biodegradation.
