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901.
Mercury concentration in the muscle of seven fish species from Chagan Lake,Northeast China 总被引:2,自引:0,他引:2
Chagan Lake is located downstream of the Second Songhua River basin in Northeast China. It is one of the top ten inland freshwater
lakes, and an important aquatic farm in China. The lake has been receiving large amounts (currently at 1.5 × 108 m3/a) of water from the river since 1984. This would pose a threat to the aquatic system of the lake because the river was seriously
polluted with mercury in 1970s–1980s. The current study is the first to report the total mercury concentrations in fish found
in the lake. Mercury concentrations in seven fish species collected from the lake in January 2009 were determined. The related
human health risk from fish consumption was also assessed. The average concentration of mercury in the fish was 18.8 μg/kg
of wet weight, ranging from 4.5 to 37.6 μg/kg of wet weight. A large difference in the mercury concentrations among the fish
species was found. The mercury concentration was found to be higher in carnivorous species and lower in omnivorous and herbivorous
species. This demonstrates greater mercury bioaccumulation in fish species at higher trophic levels. Mercury concentrations
in fish showed significant positive correlations with age, length, and weight. No significant relationship was found between
mercury concentrations in fish and the habitat preferences. Mercury concentrations in fish from the lake were within the limits
of the international and national standards of China established for mercury. According to the reference doses established
by the United States Environmental Protection Agency, the maximum safe consuming quantity considering all the fish was 297.3 g/day/person,
which was more than five times as much as the current quantity (50 g/day/person) consumed by the local residents. This investigation
indicates that the historical pollution of the Second Songhua River has not caused mercury bioaccumulation in fish muscle
tissue of Chagan Lake. The present consumption of fish from the lake in the local area does not pose a threat to human health. 相似文献
902.
北方沙尘对四川盆地环境空气质量影响和特征分析 总被引:4,自引:1,他引:3
利用沙尘天气资料和颗粒物浓度、激光雷达监测数据以及后向轨迹,分析浮尘天气的气象特征及传输路径,构建了浮尘天气对四川盆地各城市大气环境质量影响的量化指标,并利用该量化指标分析了浮尘天气对四川盆地各城市大气环境的影响,得出2013—2015年浮尘对四川盆地PM_(10)年均质量浓度的贡献,2013—2015年约为4.82、1.00、0.56μg/m~3;浮尘对PM_(10)年均质量浓度的贡献川西区域最大,川东北区域次之,川中区域最小,其贡献量分别为3.5、2.2、1.4μg/m~3。同时还进一步分析浮尘对区域PM_(10)影响差异的原因。 相似文献
903.
Xiaomin Gu Yong Xiao Shiyang Yin Xingyao Pan Yong Niu Jingli Shao Yali Cui Qiulan Zhang Qichen Hao 《Environmental monitoring and assessment》2017,189(10):514
In this study, the hydrochemical characteristics of shallow groundwater were analyzed to get insight into the factors affecting groundwater quality in a typical agricultural dominated area of the North China Plain. Forty-four shallow groundwater samples were collected for chemical analysis. The water type changes from Ca·Na-HCO3 type in grass land to Ca·Na-Cl (+NO3) type and Na (Ca)-Cl (+NO3+SO4) type in construction and facility agricultural land, indicating the influence of human activities. The factor analysis and geostatistical analysis revealed that the two major factors contributing to the groundwater hydrochemical compositions were the water-rock interaction and contamination from sewage discharge and agricultural fertilizers. The major ions (F, HCO3) and trace element (As) in the shallow groundwater represented the natural origin, while the nitrate and sulfate concentrations were related to the application of fertilizer and sewage discharge in the facility agricultural area, which was mainly affected by the human activities. The values of pH, total dissolved solids, electric conductivity, and conventional component (K, Ca, Na, Mg, Cl) in shallow groundwater increased from grass land and cultivated land, to construction land and to facility agriculture which were originated from the combination sources of natural processes (e.g., water-rock interaction) and human activities (e.g., domestic effluents). The study indicated that both natural processes and human activities had influences on the groundwater hydrochemical compositions in shallow groundwater, while anthropogenic processes had more contribution, especially in the reclaimed water irrigation area. 相似文献
904.
对南通市楼顶式移动基站电磁辐射污染进行了调查。结果表明,南通市418个楼顶站基站周边地面50 m范围内电磁辐射功率密度值均能满足《电磁环境控制限值》(GB 8702—2014)的要求;楼顶美化天线、集束天线和景观塔等建设较晚的楼顶塔形地面电磁辐射强度相对较小,楼顶角钢塔、拉线塔和抱杆等建设较早的塔形地面电磁辐射强度相对较大;楼顶塔所在楼顶平台监测值存在轻度超标的情况。提出,应严格控制楼顶塔所在楼顶的人员可达性,即基站电磁辐射防护区应高出楼顶2 m以上,避免公众进入基站电磁辐射防护区内,受到基站天线的过量辐射影响。 相似文献
905.
906.
907.
908.
溶液中阴离子和腐殖酸对UV/H2O2降解2,4-二氯酚的影响 总被引:2,自引:0,他引:2
研究了UV/H2O2工艺对2,4-二氯酚(2,4-DCP)的去除效果和水中阴离子、腐殖酸对该工艺降解2,4-DCP的影响.结果表明:UV/H2O2工艺可以有效地去除水中2,4-DCP,光降解过程符合一级反应动力学模型;在H2O2投加量为8 mg/L、1个30 W低压汞灯照射下,2,4-DCP在蒸馏水和自来水中反应速率常数分别为0.023 2、0.016 2 min-1;NO-3、Cl-、HCO-3对2,4-DCP光降解有抑制作用,当3种阴离子摩尔浓度为0.5、10.0、20.0 mmol/L时,对2,4-DCP光降解的抑制程度为HCO-3>NO-3>Cl-;腐殖酸在低浓度时,促进光降解反应进行,在高浓度时,2,4-DCP的光降解受到抑制.自来水中的反应速率常数低于蒸馏水中的反应速率常数是由于水中多种阴离子和腐殖酸影响的结果. 相似文献
909.
采取AB型热解两次焚烧(3T控制)和烟气净化处理新技术进行医疗废物无害化处置工艺设计,运行结果表明:该工艺技术能有效地处理医疗废物,具有无二次污染和社会、经济、环境效益好等优点,值得在实践中进一步推广应用。 相似文献
910.