Xiamen Bay in South China has experienced extensive coastal exploitation since the 1950s,resulting in some severe environmental problems.Local authorities now have completed or are implementing many environmental rest...Xiamen Bay in South China has experienced extensive coastal exploitation since the 1950s,resulting in some severe environmental problems.Local authorities now have completed or are implementing many environmental restoration projects.Evaluating the cumulative impact of exploitation and restoration activities on the environment is a complicated multi-disciplinary problem.However,hydrodynamic changes in the bay caused by such coastal projects can be characterized directly and definitively through numerical modeling.This paper assesses the cumulative effect of coastal projects on the hydrodynamic setting using a high-resolution numerical modeling method that makes use of tidal current speeds and the tidal prism as two hydrodynamic indices.Changes in tidal velocity and the characteristics of the tidal prism show that hydrodynamic conditions have declined from 1938 to 2007 in the full-tide area.The tidal current speed and tidal prism have decreased by 40% in the western part of the bay and 20% in the eastern part of the bay.Because of the linear relationship between tidal prism and area,the degraded hydrodynamic conditions are anticipated to be restored to 1972 levels following the completion of current and proposed restoration projects,i.e.33% and 15% decrease in the hydrodynamic conditions of 1938 for the western and eastern parts of the bay,respectively.The results indicate that hydrodynamic conditions can be restored to some extent with the implementation of a sustainable coastal development plan,although a full reversal of conditions is not possible.To fully assess the environmental changes in a region,more indices,e.g.,water quality and ecosystem parameters,should be considered in future evaluations.展开更多
This paper quantifies organochlorine insecticides （OC1） inputs in the Jiulong River and shows the large use in the agricultural activities and analyses specifically the status of soil, fruit and vegetable contaminat...This paper quantifies organochlorine insecticides （OC1） inputs in the Jiulong River and shows the large use in the agricultural activities and analyses specifically the status of soil, fruit and vegetable contamination by these persistent pollutants in some locations of Xiamen region. From this purpose, soil samples collected from Jiulong agricultural catchment have been analyzed for 18 selected OCI using gas chromatography electron capture detection and to identify the factors that may control the distribution and persistence of organochlorines in the area. The main insecticides found in soil samples were Aldrin, Dieldrin, Endosulfan I1, Endrin aldehyde, Endosulfan sulphate and Methoxychlor. The total organochlorines detected in soil samples ranged from 3.14 to 10.35 ng/g soil. The highest values of OC1 were significantly detected in the orange trees＇ leaves, which range from 1203 to 2681 ng/g soil showing recent uses of these agrochemicals. Their distribution in vegetable samples were also monitored and indicating that the concentration ranged from 3.236 to 7.188 ng/g. The contamination of Jiulong River estuary by organochlorine pesticides has been then widely justified by soil runoffs from these agricultural areas. The results therefore, provide important information on the current contamination status and point to the need for urgent actions to stop the use of persistent agrochemicals. The necessity of implementing systematic monitoring of insecticide contamination is emphasized.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.41076001,40810069004)the Fundamental Research Funds for the Central Universities(No.2010121029)
文摘Xiamen Bay in South China has experienced extensive coastal exploitation since the 1950s,resulting in some severe environmental problems.Local authorities now have completed or are implementing many environmental restoration projects.Evaluating the cumulative impact of exploitation and restoration activities on the environment is a complicated multi-disciplinary problem.However,hydrodynamic changes in the bay caused by such coastal projects can be characterized directly and definitively through numerical modeling.This paper assesses the cumulative effect of coastal projects on the hydrodynamic setting using a high-resolution numerical modeling method that makes use of tidal current speeds and the tidal prism as two hydrodynamic indices.Changes in tidal velocity and the characteristics of the tidal prism show that hydrodynamic conditions have declined from 1938 to 2007 in the full-tide area.The tidal current speed and tidal prism have decreased by 40% in the western part of the bay and 20% in the eastern part of the bay.Because of the linear relationship between tidal prism and area,the degraded hydrodynamic conditions are anticipated to be restored to 1972 levels following the completion of current and proposed restoration projects,i.e.33% and 15% decrease in the hydrodynamic conditions of 1938 for the western and eastern parts of the bay,respectively.The results indicate that hydrodynamic conditions can be restored to some extent with the implementation of a sustainable coastal development plan,although a full reversal of conditions is not possible.To fully assess the environmental changes in a region,more indices,e.g.,water quality and ecosystem parameters,should be considered in future evaluations.
文摘This paper quantifies organochlorine insecticides （OC1） inputs in the Jiulong River and shows the large use in the agricultural activities and analyses specifically the status of soil, fruit and vegetable contamination by these persistent pollutants in some locations of Xiamen region. From this purpose, soil samples collected from Jiulong agricultural catchment have been analyzed for 18 selected OCI using gas chromatography electron capture detection and to identify the factors that may control the distribution and persistence of organochlorines in the area. The main insecticides found in soil samples were Aldrin, Dieldrin, Endosulfan I1, Endrin aldehyde, Endosulfan sulphate and Methoxychlor. The total organochlorines detected in soil samples ranged from 3.14 to 10.35 ng/g soil. The highest values of OC1 were significantly detected in the orange trees＇ leaves, which range from 1203 to 2681 ng/g soil showing recent uses of these agrochemicals. Their distribution in vegetable samples were also monitored and indicating that the concentration ranged from 3.236 to 7.188 ng/g. The contamination of Jiulong River estuary by organochlorine pesticides has been then widely justified by soil runoffs from these agricultural areas. The results therefore, provide important information on the current contamination status and point to the need for urgent actions to stop the use of persistent agrochemicals. The necessity of implementing systematic monitoring of insecticide contamination is emphasized.
