基于QSAR模型的蒙特卡洛方法分析有机化学物质对大型蚤(Daphnia magna)的毒性

本文建立一系列758种有机化合物对大型蚤(Daphnia magna)毒性的定量结构-活性关系(QSARs)。用简化的分子线性输入系统(SMILES)代表分子结构。用CORAL(关联和逻辑)软件作为工具来开发QSAR模型。这些模型使用蒙特卡罗方法建立,依据的原理是QSAR是一个“随机事件”,假设检验一组随机数据分布在可见的训练集和不可见的验证集。检验了三组分布于可见的训练、校准、测试集中的数据以及不可见的验证集。最佳模型的预测潜能,也就是其不可见的验证集的统计特征如下:n = 87,r² = 0.8377,RMSE = 0.564。建议和讨论了所构建模型的机械解释和适用领域。
精选自Alla P. Toropova, Andrey A. Toropov, Aleksandar M. Veselinovi?, Jovana B. Veselinovi?, Danuta Leszczynska, Jerzy Leszczynski. Monte Carlo based QSAR models for toxicity of organic chemicals to Daphnia magna. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2691–2697, November 2016. DOI: 10.1002/etc.3466
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3466/full
     

Status and fuzzy comprehensive assessment of metals and arsenic contamination in farmland soils along the Yanghe River,China

Concentrations of metals and arsenic in farmland soils along the Yanghe River, upstream of Guanting Reservoir, were evaluated using fuzzy comprehensive assessment (FCA). FCA is an emerging methodology for assessing environmental status based on fuzzy logic which can model linguistic data and represent chaotic conditions. The ratio of concentrations of metals and arsenic (As) in surface soils of farmland along the Yanghe River to the corresponding reference values decreased in the order Cd>Zn>Cr>Ni>Pb>Cu>As. Based on the FCA, 86% of surface soils along the Yanghe River were classified as grade C, which is suitable for forestry with a greater absorption capacity, suggesting that most farmland along the Yanghe River has to be abandoned as farmland. In order to improve the quality of soil along the Yanghe River and avoid degeneration of water quality in the river and the Guanting Reservoir, remediation of farmland soils along the river is suggested.     

Impact of drought on the ecological and chemical status of surface water and on the content of arsenic and fluoride pollutants of groundwater in the province of Salamanca (Western Spain)

The impact of drought on the ecological and chemical status of surface and groundwaters of the River Tormes (River Duero basin, northwestern Iberian Peninsula) was studied to evaluate the evolution of the quality of the river during its passage through the city of Salamanca (Spain). The Water Quality Index (WQI) of the river revealed that the drought period of 2005 did not significantly affect water chemical quality. However, during the study period differences were found in surface water ecological quality, using phytoplankton quality as AN indicator. These differences may be accentuated as a result of regulation of the River Tormes by the Santa Teresa reservoir. Arsenic and fluoride concentrations were measured in water wells, finding higher arsenic concentrations after the drought period and no correlation between the arsenic and fluoride contents. The results are useful for an overall understanding of potential impact of climate change on the ecological and chemical status of water in regional systems.     

Trace elements in tissues of sperm whales stranded along the Italian coast

Five sperm whales (Physeter macrocephalus) stranded along the Italian coast between 2007 and 2009 were analysed for concentrations of trace elements in the muscle, liver, kidney, lung, heart and skin. Essential elements (Zn, Cu, Fe, Cr, As, V and Se) show ranges of variability comparable with the limited data reported in the literature on this species and a homeostatic physiological control. Very low concentrations of nonessential elements (Hg, Cd and Pb) were detected in all tissues, suggesting a minor impact of these pollutants on the sperm whale populations of the Mediterranean Sea. This finding possibly reflects the pelagic lifestyle and deep-sea cephalopod diet of this group of giant cetaceans. In addition, this finding contrasts with the high levels of nonessential elements measured in many other species of cetaceans (e.g. Stenella coeruleoalba, Tursiops truncatus) stranded along Mediterranean coasts and which reflects significant coastal anthropogenic effects. The main result of this work is the compiled dataset which provides a preliminary target for conceptual understanding of the potential effects of open marine pollution on the Mediterranean sperm whale population.     

Microbial hydrolysis of polysaccharides and organic phosphates in the Northern Adriatic Sea

g -glucosidase and alkaline phosphatase, two ectoenzymes involved in the microbial decomposition of polysaccharides and organic phosphates, were evaluated in water samples collected from two areas of the Northern Adriatic Sea during the multidisciplinary Prisma II research project. The distribution of g -glucosidase and alkaline phosphatase is reported together with that of leucine aminopeptidase, an enzyme involved in the degradation of protein compounds. The data obtained showed the prevalence of g -glucosidase in summer months in the northern area, located in front of the Po delta, while in winter it is higher in the southern area (in front of Ancona). Phosphatase activity during February, 1998 had a maximum of 107 r nml m 1 h m 1 at a coastal station in the northern area; this enzyme appeared to be mainly associated with phytoplankton because the increase in alkaline phosphatase was associated with the increase of phytoplankton biomass, measured by chlorophyll a content. The relations between the microbial activities and environmental parameters are discussed.     

Polycyclic aromatic hydrocarbons in soils around Guanting Reservoir,Beijing, China

The concentrations of 16 polycyclic aromatic hydrocarbons (∑ 16PAHs) were measured by gas chromatography equipped with a mass spectrometry detector (GC-MS) in 56 topsoil samples around Guanting Reservior (GTR), which is an important water source for Beijing. Low to medium levels of PAH contamination (mean=394.2±580.7 ng g^?1 dry weight (d.w.)) was evident throughout the region. In addition, localised areas of high PAH contamination near steel and cement factories were identified, with ∑ 16PAHs concentrations as high as 4110 ng/g, dry weight (d.w.). There was a significant positive correlation (r²=0.570, p<0.01) between total organic carbon content and ∑ 16PAHs concentrations. Phenanthrene was the predominant compound, accounting for 27.2% of the ∑ PAH concentration, followed by chrysene>pyrene>benzo[a]anthracene≈ benzo[b]fluoranthene≈ benzo[a]pyrene. Four-ring PAH homologues (39%) were dominant. The higher proportion of 4–6 ring homologues, molecular indices, and the spatial distribution of PAH indicated that industrial discharges, incineration of wastes and traffic discharges were the major sources of soil PAHs around the water reservoir.     

Prevalence of organochlorine pesticide residues in groundwaters of Kasargod District,India

The Kasargod District is the northernmost district of Kerala State and is bound between the north latitudes 12°02′27″ and 12°47′35″ and east longitudes 74°51′54″ and 75°25′25″. The present study highlights the contamination levels of organochlorine pesticides in open wells of the Kasargod District from 2010 to 2011. Maximum contamination of organochlorine pesticides (OCP's) was observed for endosulfan followed by hexachlorobenzene (BHC). Contamination levels of α-endosulfan were higher at Panathur (58?µg?L^?1) and next to Periya (37?µg?L^?1) in the postmonsoon season of 2010. During premonsoon 2011, the residue levels of α-endosulfan were higher at Panathady (56?µg?L^?1) followed by Rajapuram (40?µg?L^?1). Contamination levels of the BHC isomers exhibit the order of γ-BHC?>?α-BHC?>?β‐BHC, showing that γ-BHC represents 62% of the total OCP residues in premonsoon 2010. Among the studied OCP's, concentration levels of DDT were below detection limit. Maximum concentrations of the sum of all OCP residues were observed at Mulleria and Cheemeni (premonsoon 2010), followed by Panathur and Periya (postmonsoon 2010), and lowest in Panathady and Rajapuram (premonsoon 2011). Residues of OCP's were lowest in Paettikundu and Cheravatur in all the three seasons.     

华南某铀矿开采利用对地表水环境质量的影响

以广东省某铀矿区为研究对象,利用电感耦合等离子体发射光谱仪(ICP-OES)测定了矿山、水冶厂及其周边地表水体共42个水样(包括工业废水、池塘水、溪流水、河水和矿区饮用水)中放射性元素(U和Th)和其它一些金属元素(Fe、Mn、Mg、Cu、Zn、Co、Ni、Li、Ca、Na、K、Al、Sr和Ba)的含量.由此确认铀矿区产生高污废水的重要环节和关键污染元素,并了解这些元素的迁移变化规律以及对周边地表水产生的影响.结果表明:(1)铀矿区产生高污外排废水的主要生产环节是采矿、铀矿堆浸和尾矿露天堆积,排放废水中U和Mn含量分别为0.238—8.700 mg.L-1和0.62—94.23 mg.L-1,均高于国家工业废水允许排放标准(GBJ8—74和GB8978—1996)的限定值;(2)铀矿周边用作当地农业灌溉和露天水源的溪流由于受纳了矿区外排废水,明显受到了U和Mn的污染:U含量在枯水期和丰水期分别为(0.415±0.619)mg.L-1和(0.233±0.308)mg.L-1,Mn含量在枯水期和丰水期分别为(8.72±12.8)mg.L-1和(8.56±12.61)mg.L-1;(3)受纳溪流中U、Fe的含量枯水期高于丰水期,而Mn和Cu的含量基本保持不变,且大多数元素的含量随着迁移距离的增加在枯水期和丰水期均呈下降趋势,指示污染源来自铀矿区;(4)铀矿区生产活动引起的地表水污染目前仅局限于铀矿区和周边较小的区域,但仍应引起重视.     

土壤及地下水污染点不同暴露途径的健康风险比较

选择目前国际上应用最为广泛的RBCA模式和Csoil模式,进行土壤污染和地下水污染暴露途径考虑异同的比较,并在此基础上设置典型的污染情景,对不同暴露途径的健康风险进行了计算.Csoil模式比RBCA模式多考虑了3种可能的暴露途径.将2种模式结合进行案例计算的结果表明,表层土壤污染的风险最大;对于浅层土壤污染,考虑淋溶作用时的风险较高.挥发暴露和饮水暴露是土壤及地下水污染点最主要的暴露途径,在RBCA模式中没有考虑的洗澡过程中的暴露也非常重要.对于表层土壤污染,覆土是减小健康风险的有效办法.     

空气环境中汞污染物分析测试的技术进展

阐述了我国空气环境中汞污染的现状,介绍了几种空气环境中汞污染分析测试技术。