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821.
From December 1994 up to October 1995 a “Mussel Watch Project”; was carried out to assess the quality of water of the Ligurian Sea and to identify the possible sources of heavy metal pollution. Several metals and organotin compounds were measured in mussels (Mytilus galloprovincialis, Lam) transplanted in different months from a marine farm to eight sites of the Ligurian coast.

Spatial differences and temporal trends in tissue concentrations of Zn, Cu, Ni, Cr, Fe, Al, V, Cd and Mn were evaluated. Concentrations resulted in the same range as those obtained in a previous Mussel Watch Project carried out in the same area. In general, areas of known pollution display high concentrations of these metals, but also some areas not greatly influenced by human activities showed high concentrations of some metals.

Data from this study show little evidence of any overall seasonal pattern except for Cu, Zn and V, concentrations of which were a function not only of sampling site, but also of reproductive cycle.

Organotin compounds show differences in terms of both concentration and speciation between the investigated sites.  相似文献   
822.
The objective of this study was to determine the blood lead levels (blls) of children under an age of 5 years living in western Uttar Pradesh, India. A total of 100 blood samples, 100 drinking water samples, and 21 vegetable samples were assessed for lead contamination. Blood levels in the range of 30–116?µg?L?1 were observed at Kazipur village. The levels of lead in water samples were reported to be in the range of 0.006–0.095?ppm and identified at up to 9.5 times the stated permissible limit. A significant positive correlation (+0.679) was obtained between blls and water lead levels. All vegetable samples were also contaminated with lead up to 12 times higher than the permissible limit of 2.5?mg?kg?1 of Prevention of Food Adulteration Act (PFA) 1954. The cottage lead battery industry, industrial effluents, and lead paints were identified as possible factors for lead incidence in the study area. Lead may be associated with increased antisocial activities of the children living in western Uttar Pradesh. Children with elevated blls had poorer nutritional status than those with normal levels, and parents did not know that lead causes health problems. A national population-based study is recommended to determine the prevalence of elevated blls.  相似文献   
823.
The objective of this study was to determine the blood lead level (BLL) of children aged under 5 living in western Uttar Pradesh, India. A total of 100 blood samples, 100 drinking water samples, and 21 vegetable samples were assessed for lead (Pb) contamination. BLL was observed in the range of 3–11.58?µg?dL?1 with a maximal level of 11.58?±?0.05?µg?dL?1 in Kazipur village. Lead in water samples was detected in the range of 0.006–0.095?ppm and identified at upto 9.5-fold higher than the stated permissible limit. A significant positive correlation (+0.679) was obtained between BLL and water Pb levels. All vegetable samples were also contaminated with Pb upto 12-fold higher than the permissible limit of 2.5?µg?g?1 of Prevention of Food Adulteration Act (PFA) 1954. Untreated industrial effluents were identified as the responsible factors for Pb occurrence in the study area. The presence of lead may be associated with the increased antisocial activities of children living in western Uttar Pradesh. Children with elevated BLL had poorer nutritional status than those with background Pb levels. There is an urgent need for a national campaign to monitor the BLL of children in India.  相似文献   
824.
Exposure of the general population to lead in the environment is mainly caused by motor traffic exhaust and by industrial pollution. The aim of the study in Greece was to assess lead exposure in children living in point source impacted areas (Lavrion and Aspropyrgos‐Eleusis) using the biological monitoring parameter “blood lead concentration”;.

In addition, workers of a lead smelter, a battery plant and an oil refinery were investigated in these areas at the same time.

Five hundred and thirty‐four children and 105 workers took part in this investigation.

The highest blood lead levels (mean: 24.16 μg/100ml; range: 10.40–60.49 μg/100 ml) were found in children living in a 500m‐area around the lead smelter at Lavrion. Blood lead decreases corresponded to the increasing distance from the emitter. Nevertheless the values of children living in a 1500 m distance to the smelter are significantly higher than those of children living next to other kinds of industrial lead sources.

The mean values of the children living in the two industrial towns were manifold higher than those of the control group.

The blood lead levels of the investigated workers did not exceed the German BAT‐value (Biologischer Arbeitsstoff‐Toleranzwert) of 70 μg/100ml.  相似文献   
825.
The contamination of Sperm Whale Physeter macrocephalus and bottle‐nosed dolphin Tursiops truncatus by lead is less than detection limit, insignificant by cadmium and nickel, not very high by copper and quite high by zinc. On the other hand, the concentration of mercury, very low for Sperm Whale, is very high for bottle‐nosed dolphin.

The pollution of Physeter macrocephalus is significantly lower than that of dolphin Stenella coeruleoalba and probably that of other species of cetaceans living near the coast; this might be due to its pelagic life and its diet.

The mercury pollution of Tursiops truncatus (especially that of one of the two subjects analyzed) is quite similar to that of Stenella coeruleoalba. This might be due to the fact that Tursiops truncatus can live in the open sea just as well as close to the seashore.  相似文献   
826.
运用AWA6288型多功能声级及TmeRTA音频分析软件等仪器对北京4种常见阔叶绿篱球的减噪功能进行了测定,并对其结构特征进行了定量化统计,以探寻与植物减噪密切相关的影响因子。结果表明:小叶黄杨球(Buxus microphylla)平均相对A声级减噪能力最强,为1.76dB/m;紫叶小檗球(Berberis thunbergii cv.atropurpurea)相对最差,为1.05dB/m。紫叶小檗球与大叶黄杨球(Euonymus japonicus)、小叶黄杨球、金叶女贞球(Ligustrum vicaryi)在平均相对A声级减噪能力、减噪率方面均存在冠著差异。影响单株植物减噪排名前5的相关结构因子分别是树冠体积(0.804)、冠高(0.781)、绿篱高度(0.733)、叶质地(0.690)、平均冠宽(0.679);叶大小、冠层、叶质地和倾斜状态、叶密度、枝密度5个主因子的累积方差贡献率已达85.233%,在绿化减噪应用中要重点考虑这5个因子。大叶黄杨球平均相对A声级减噪能力随植株大小变化没有显著变化,与树体各结构因子不相关,这可能与研究的样本量较少或者树体结构特征差异不明显有关;影响不同种类植物减噪的相关因子不尽相同。  相似文献   
827.
在已有后缘为钝形双叶片风电机组噪声预测模型基础上,结合我国风力发电机组叶片形状及其辐射噪声的频谱特性等,对预测模型进行了修正.通过对3台不同型号风电机组13个测点噪声测量值和预测值对比验证表明,修正后模型能较好地反映风电机组噪声的衰减规律.在预测点与风轮中心距离大于1.5倍风轮直径时,修正后模型预测值与实测值差值在±2.5dB(A)范围内.利用修正后预测模型计算确定的风电机组噪声声功率级及指向性指数,将其代入考虑指向性的点声源模型,可用于简化预测与风轮中心距离大于3倍风轮直径处的噪声.  相似文献   
828.
为了探讨甲醛暴露对小鼠骨髓组织的毒性影响,选用SPF级昆明雄性小鼠作为研究对象,用浓度为0.5,1.0,3.0mg/m3的气态甲醛对小鼠进行连续动态染毒72h,染毒后检测骨髓细胞中细胞周期变化、DPC(DNA-蛋白质交联)、DNA稳定性、骨髓细胞分化关键因子Nucleostemin和CYP1B1在各暴露浓度组中的表达情况.结果表明:甲醛暴露造成骨髓细胞的DNA损伤,其DNA稳定性和DPC效应均呈现良好的剂量-效应关系.骨髓细胞分化关键因子Nucleostemin表达量在各浓度染毒组中与空白组相比,1.0mg/m3浓度组有极显著性升高,而0.5和3.0mg/m3浓度组则是极显著性降低,与空白组相比CYP1B1基因在0.5,1.0,3.0mg/m3浓度组中表达,有极其显著性差异,并且1.0mg/m3浓度组上升较多.本次研究表明,甲醛暴露能影响小鼠骨髓组织细胞正常生长代谢.  相似文献   
829.
基于主成分投影法的洪水灾情评价研究   总被引:1,自引:1,他引:0  
洪水灾情等级的合理评估能够为防灾、减灾及备灾工作提供科学的依据,具有重要的现实意义。首先建立主成分投影法评价模型,并给出模型的基本步骤。以受灾面积、受灾人口数、破坏房屋面积和经济损失作为评价因子,构建洪水灾情的主成分投影评价模型。利用该模型,对新疆"96.7"洪水灾害中乌鲁木齐、塔城、博州、哈密、喀什和克州6个城市的灾情进行评价。结果表明:乌鲁木齐和塔城的洪水灾情被评估为重灾;博州、哈密、喀什和克州的洪水灾情被评估为中灾。这些评价结果与集对分析(SPA)理论、贝叶斯随机评价方法、灰色关联法和脉冲耦合神经网络(PCNN)模型评价结果完全一致。  相似文献   
830.
介绍了评价角联分支稳定性的两个指标—风流功率与风量敏感度。利用风流功率指标,衡量角联分支的通风稳定性。根据风量敏感度指标,确定影响角联分支稳定性的关键分支。在角联分支稳定性分析与关键分支确定的基础上,提出提高角联分支稳定性的技术措施,使角联分支的稳定性得到有效提高,矿井通风系统稳定性得到加强。将上述方法在土城煤矿加以应用,取得了良好效果。  相似文献   
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