The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results...The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results show that As, Cd, Pb and Zn are major contaminants in sediments, and average concentrations of these elements significantly exceed both the Control Standards for Pollutants in Sludge of China (GB4284-84) for agricultural use in acidic soils and the effect range median (ERM) values. The average concentrations of As, Cd and Pb in the river water slightly exceed the limit of Surface Water Environment Quality Standard (GB3838-2002). The concentrations of As and Cr in depth profiles extensively change, but slight changes are observed in Pb and Zn. Cd and Zn in most sediment samples can easily enter the food-chain and bring possible ecotoxicological risk to organisms living in sediments according to the risk assessment code.展开更多
Chlorobenzenes （CBs） are a group of organic pollutants that pose a high environmental risk due to their toxicity, persistence and possible transfer in the food chain. Available data in literature show that CBs axe d...Chlorobenzenes （CBs） are a group of organic pollutants that pose a high environmental risk due to their toxicity, persistence and possible transfer in the food chain. Available data in literature show that CBs axe detected in different environmental compartments such as soil, water, air and sediment. The widespread presence of CBs in the environment is related to their former extensive use in agriculture and industry. Some CBs are ranked in the list of priority pollutants by the Stockholm Convention, and their reduction or elimination from the environment is therefore of high importance. Environmental risk assessment of CBs requires knowledge on the role and importance of the main environmental fate processes, especially in soil. Furthermore, development of remediation strategies for reduction or elimination of CBs from the environment is related to the enhancement of fate processes that increase their dissipation in various environmental compartments. The main objectives of the current review were to present up-to-date data on fate processes of CBs in the soil environment and to explore possible remediation strategies for soils contaminated with CBs. Dechlorination of highly-chlorinated benzenes is the main degradation pathway under anaerobic conditions, leading to the formation of lower-chlorinated benzenes. Biodegradation of lower-chlorinated benzenes is well documented, especially by strains of adapted or specialized microorganisms. Development of techniques that combine dechlorination of highly-chlorinated benzehes with biodegradation or biomineralization of lower-chlorinated benzenes can result in useful tools for remediation of soils contaminated with CBs. In addition, immobilization of CBs in soil by use of different amendments is a useful method for reducing the environmental risk of CBs.展开更多
基金Project (20507022) supported by the National Natural Science Foundation of ChinaProject (EREH050303) supported by the Foundation of Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health
文摘The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results show that As, Cd, Pb and Zn are major contaminants in sediments, and average concentrations of these elements significantly exceed both the Control Standards for Pollutants in Sludge of China (GB4284-84) for agricultural use in acidic soils and the effect range median (ERM) values. The average concentrations of As, Cd and Pb in the river water slightly exceed the limit of Surface Water Environment Quality Standard (GB3838-2002). The concentrations of As and Cr in depth profiles extensively change, but slight changes are observed in Pb and Zn. Cd and Zn in most sediment samples can easily enter the food-chain and bring possible ecotoxicological risk to organisms living in sediments according to the risk assessment code.
基金financially supported by the Outstanding Youth Fund of the Natural Science Foundation of Jiangsu, China (No. BK20150050)the National Science and Technology Major Project of China (No. 2016YFD08000204)+2 种基金the National Key Basic Research Program of China (No. 2014CB441105)the National Natural Science Foundation of China (Nos. 21277148, 21677149 and 41671236)the National Council for Science and Technology of Kenya (No. NCST/ST&I/RCD/2ND CALL/POST DOC/039)
文摘Chlorobenzenes （CBs） are a group of organic pollutants that pose a high environmental risk due to their toxicity, persistence and possible transfer in the food chain. Available data in literature show that CBs axe detected in different environmental compartments such as soil, water, air and sediment. The widespread presence of CBs in the environment is related to their former extensive use in agriculture and industry. Some CBs are ranked in the list of priority pollutants by the Stockholm Convention, and their reduction or elimination from the environment is therefore of high importance. Environmental risk assessment of CBs requires knowledge on the role and importance of the main environmental fate processes, especially in soil. Furthermore, development of remediation strategies for reduction or elimination of CBs from the environment is related to the enhancement of fate processes that increase their dissipation in various environmental compartments. The main objectives of the current review were to present up-to-date data on fate processes of CBs in the soil environment and to explore possible remediation strategies for soils contaminated with CBs. Dechlorination of highly-chlorinated benzenes is the main degradation pathway under anaerobic conditions, leading to the formation of lower-chlorinated benzenes. Biodegradation of lower-chlorinated benzenes is well documented, especially by strains of adapted or specialized microorganisms. Development of techniques that combine dechlorination of highly-chlorinated benzehes with biodegradation or biomineralization of lower-chlorinated benzenes can result in useful tools for remediation of soils contaminated with CBs. In addition, immobilization of CBs in soil by use of different amendments is a useful method for reducing the environmental risk of CBs.
