Organic pollutants, especially persistent organic pollutants were examined in the water and surface sediments of Taihu Lake, China. Both 12 water and 12 sediment samples were collected over the lake. C-18 solid-phase extraction technique was applied to extract organic pollutants in collected water samples. Soxhlet extraction procedure was used to extract organic pollutants in sediment samples. The analysis was performed by GC-MS controlled by a Hewlett Packard chemstation. Two hundred and seventy-three kinds of organic chemicals in water were examined, 200 more than that detected in 1985; 188 kinds of chemicals in sediments were detected as well. Among them 21 kinds of chemicals belong to priority pollutants as well as 17 kinds to be the endocrine disruptors. The concentrations of the pollutants were more than 2 times higher than that in 1985. The possible source and relation to anthropogenic activity were discussed. 相似文献
The livestock breeding industries face overuse of antibiotics, which has been intensively studied in recent years. However, the occurrence and fate of antibiotics as well as their potential threats to the aquatic environments in alpine and arid regions remain unclear. This study investigated the relationship of the occurrence and concentrations of antibiotics between the Kaidu River and Bosten Lake in a typical alpine basin in China. Hot spots with antibiotic pollution source were explored. The antibiotic concentrations in river water and suspended sediment (SPS) were 2.20-99.4 ng/L and 1.03-176 ng/g. The dominant antibiotics were tetracyclines, sulphacetamide, and ofloxacin in river water and sulfonamides, clarithromycin, roxithromycin, and ofloxacin in SPS. The apparent differences in pollution sources and landscapes in different reaches led to the obvious spatial patterns of antibiotics in the Kaidu River. Higher partition coefficient of antibiotic between SPS and water phases for sulfonamides than tetracyclines was because that tetracyclines strongly responded to clay contents while sulfonamides significantly responded to organic carbon contents in SPS. There were significant differences in detected antibiotic categories between the river and the lake. Fluoroquinolones (especially ciprofloxacin and enrofloxacin) were detected in the lake while sulphacetamide was only detected in the river. Therefore, the surrounding husbandry and aquaculture around the Bosten Lake was an important antibiotic pollution source in addition to inputs from the Kaidu River. This research suggested that alpine lakes could be an important sink of antibiotics in alpine dry regions, and thus impose greater threats to the aquatic ecosystem. 相似文献
Environmental Science and Pollution Research - In this study, a novel magnetic cassava stalk composite (M-EMCS) was prepared through modification with ethylenediamine tetraacetic anhydride (EDTAD)... 相似文献
Objective: This work aims at investigating the influence of some front-end design parameters of a passenger vehicle on the behavior and damage occurring in the human lower limbs when impacted in an accident.
Methods: The analysis is carried out by means of finite element analysis using a generic car model for the vehicle and the lower limbs model for safety (LLMS) for the purpose of pedestrian safety. Considering the pedestrian standardized impact procedure (as in the 2003/12/EC Directive), a parametric analysis, through a design of experiments plan, was performed. Various material properties, bumper thickness, position of the higher and lower bumper beams, and position of pedestrian, were made variable in order to identify how they influence the injury occurrence. The injury prediction was evaluated from the knee lateral flexion, ligament elongation, and state of stress in the bone structure.
Results: The results highlighted that the offset between the higher and lower bumper beams is the most influential parameter affecting the knee ligament response. The influence is smaller or absent considering the other responses and the other considered parameters. The stiffness characteristics of the bumper are, instead, more notable on the tibia. Even if an optimal value of the variables could not be identified trends were detected, with the potential of indicating strategies for improvement.
Conclusions: The behavior of a vehicle front end in the impact against a pedestrian can be improved optimizing its design. The work indicates potential strategies for improvement. In this work, each parameter was changed independently one at a time; in future works, the interaction between the design parameters could be also investigated. Moreover, a similar parametric analysis can be carried out using a standard mechanical legform model in order to understand potential diversities or correlations between standard tools and human models. 相似文献
Environmental Science and Pollution Research - The bacterial community of an anaerobic granular sludge associated with uranium depletion was investigated following its exposure to uranium under... 相似文献