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81.
82.
牡蛎和贻贝中二噁英及多氯联苯同类物的分布 总被引:5,自引:0,他引:5
利用同位素稀释、高分辨气相色谱-高分辨质谱联用仪,首次测定了大连湾牡蛎和贻贝等海洋生物体内痕量的二噁英和多氯联苯,并比较了二噁英及多氯联苯的同类物在牡蛎和贻贝中的含量分布。结果表明,所采集的牡蛎和贻贝样品中均含有二噁英和多氯联苯,且多氯联苯的含量明显高于二噁英,反映出环境中多氯联苯背景值大于二噁英的背景值。其中,牡蛎和贻贝中二噁英总质量分数平均值分别为47.8pg/g和216pg/g(以干物质计),毒性当量平均值分别为O.89pg/g和0.87pg/g;12种有毒性的共平面多氯联苯的总质量分数平均值分别为585.5pg/g和818.6pg/g,总毒性当量平均值分别为0.47pg/g和1.18pg/g。牡蛎和贻贝样品中的二噁英及多氯联苯的同类物含量分布基本类似,表明二者摄取的二噁英及多氯联苯可能有相似的来源。可以把牡蛎和贻贝作为生物标志物,以监测海洋环境中二噁英和多氯联苯的污染状况。 相似文献
83.
84.
The most thorough field investigation, to date, of the temporal distribution and fractionation of polychlorinated biphenyl (PCB) congeners in an inland lake has been conducted in Little Lake Butte des Morts, WI. Distinct seasonal variations in dissolved and particle associated PCBs were observed over a two year period at the lake outlet; the lowest values occurred during ice-cover periods while the highest values occurred during summertime. Total dissolved PCBs ranged from 1.4–34 ng/L while total particle associated PCBs varied from 2.1–105 ng/L. An average of 71% of the total PCBs were associated with particles. Both PCB fractions were dominated by ortho-chlorinated di-, tri-, and tetrachlorobiphenyls with IUPAC #28+31 accounting for the greatest portion. Some changes appear to have taken place in the environmental composition of congeners since PCBs first entered this waterway through effluent discharges. 相似文献
85.
Patrik L. Andersson Peter Haglund Mats Tysklind 《Environmental science and pollution research international》1997,4(2):75-81
The internal barrier of rotation (Erot) was calculated for all 209 polychlorinated biphenyls (PCBs) by using a semi-empirical
method, viz. the Austin Model 1 (AMI) Hamiltonian. The difference in total energy between a forced planar state and an optimised
twisted structure was defined as Erot. The Erot values were in the range of 8.33 to 483 kj/mol, and were significantly influenced
by the number of chlorine atoms inortho position. An additional structural characteristic of the PCBs influencing Erot ofortho substituted congeners was substitution by chlorine atoms in vicinalmeta positions, which is assumed to prevent outward bending ofortho substituents. This so-called buttressing effect contributed with 4 to 31 kj/mol per added chlorine atom. In conclusion, the
internal barrier of rotation, calculated for all 209 PCBs, provides an important structure dependent physico-chemical parameter
for multivariate modelling of future quantitative structure-activity and structure-property relationships (QSARs/QSPRs). 相似文献
86.
鱼体内EROD活性对多氯联苯类的指示作用 总被引:16,自引:1,他引:16
运用鱼体肝脏中的EROD(7 ethoxyresorufin O deethylase)活性作为生态标记物 ,来指示大连近海部分水域的多氯联苯 (PCBs)类物质的污染状况。结果表明鱼体肝脏内的EROD活性可被PCBs诱导 ,导致活性异常增高 ,并与环境中特定污染物浓度之间存在着定量响应关系 ,EROD的这个特性可以用来评估海洋生态环境健康并作为预警指标。我们选取大连近海水域部分具有代表性的站位 ,分析测定其鱼样中EROD活性 ,并结合环境化学指标进行综合分析 ,证明将EROD作为指示多氯联苯类污染物的生态标记物是切实可行的 ,该方法在海洋环境监测中具有实际应用价值。 相似文献
87.
88.
多氯联苯(PCBs)污染对秋茄Kandelia candel生长的影响 总被引:1,自引:0,他引:1
通过盆栽实验研究了不同浓度(180×10-9、900×10-9、1 800×10-9和2 700×10-9)的多氯联苯(PCBs)对红树植物秋茄Kandelia candel幼苗生长的影响.结果表明:秋茄的生长指标茎高、茎径、茎体积和生物量的生长量呈现先上升后下降的变化趋势,不过各处理的生长指标均高于对照组;研究表明,秋茄能在PCBs浓度为2 700×10-9的沉积物中正常生长,对PCBs有较强的耐受性和适应性. 相似文献
89.
90.
Diversity of chlorobiphenyl-metabolizing bacteria and their biphenyl dioxygenases in contaminated sediment 总被引:1,自引:0,他引:1
Bacteria and bacterial communities in sites contaminated with polychlorinated biphenyls have been extensively studied in the past decades. However, there are still major gaps in the knowledge of environmental processes, especially in the behavior of previously described bacteria in vitro, their real degradation abilities and the enzymes that are involved in the degradation processes. 相似文献