Triclosan in Fresh Water Fish Gibelion Catla from the Kaveri River,India, and Its Consumption Risk Assessment

Triclosan is a common antimicrobial agent that is found in significant levels in the aquatic environment and may elicit effects on aquatic organisms through unexpected modes of action. In this study, triclosan was quantified in fish from the Kaveri River, India, by using the gas chromatography and mass spectrometry technique and it was found in the range of 0.73–50 ng/g wet weight (ww). The mean bioaccumulation factor based on water (BAF_w 820) and sediment (BAF_s 2.12) in the Kaveri River showed that triclosan is accumulative in fish, and reflects its feeding behavior. The bioaccumulation indicates triclosan's persistence or prevalence throughout the river stretch. Human risk assessment through dietary intake demonstrated that the triclosan exposure is five orders of magnitude lower than the acceptable daily intake (50 μg/kg bw) and US EPA reference dose (300 μg/kg bw/day). This investigation is the first to report the bioaccumulation of triclosan in freshwater fish from India. Further, the results indicate that this fish acts as a biomarker of exposure for triclosan and thus shall be used to report triclosan pollution in the future.     

火电厂降低PM2.5排放措施研究

简要介绍了几种新型实用的火电厂降低PM2.5排放的控制技术,为火电厂最大限度的降低PM2.5排放提供系统的设计方案。     

Mobility of dimethoate residues from spring broccoli field

Dimethoate [O, O-dimethyl-S-(N-methylcarbamoyl-methyl) phosphorodithioate] is a broad-spectrum systemic insecticide currently used worldwide and on many vegetables in Kentucky. Dimethoate is a hydrophilic compound (log K_OW = 0.7) and has the potential of offsite movement from the application site into runoff and infiltration water. The dissipation patterns of dimethoate residues were studied on spring broccoli leaves and heads under field conditions. Following foliar application of Dimethoate 4E on broccoli foliage at the rate of 0.47 L acre^?1, dimethoate residues were monitored in soil, runoff water collected down the land slope, and in infiltration water collected from the vadose zone. The study was conducted on a Lowell silty loam soil (pH 6.9) planted with broccoli under three soil management practices: (i) soil mixed with municipal sewage sludge, (ii) soil mixed with yard waste compost, and (iii) no-mulch rototilled bare soil. The main objective of this investigation was to study the effect of mixing native soil with municipal sewage sludge or yard waste compost, having considerable amounts of organic matter, on off-site movement of dimethoate residues into runoff and infiltration water following spring rainfall. The initial deposits of dimethoate were 6.2 and 21.4 μ g g^?1 on broccoli heads and leaves, respectively. These residues dissipated rapidly and fell below the maximum residue limit of 2 μ g g^?1 on the heads and leaves after 10 and 14 d, respectively, with half-lives of 5.7 d on broccoli heads and 3.9 d on the leaves. Dimethoate residues detected in top 15 cm of soil (due to droplet drift and wash off residues from broccoli foliage) one day (d) following spraying, were 30.5 ng g^?1 dry soil in the sewage sludge treatment, and 46.1 and 134.5 ng g^?1 dry soil in the yard waste and no mulch treatments, respectively. Water infiltration was greater from yard waste compost treatment than from no mulch treatment, however concentrations of dimethoate in the vadose zone of the three soil treatments did not differ.     

Evaluation of the Impact of Long-range Transport and Aerosol Concentration Temporal Variations at the Eastern Coast of the Baltic Sea

Ambient particles vary greatly in their ability to affect visibility, climate and human health. The fine fraction of aerosol is responsible for greater and wider effects on human health; thus, investigation of this fraction is very important. Continuous measurements of PM2.5 (particulate matter below 2.5 μm in size) concentrations at the Preila monitoring station started in 2003. During a period of 2 years, the episodes of high daily and semi-hourly concentrations of PM2.5 were measured. These episodes did not depend on the season or time of day. The substantial role of long-range transport of pollutants to these increases in concentration was shown using chemical and statistical analysis. It was found that most of the severe episodes occurred when air masses came from a specific site besides it was established that air masses of different origin were characterized by different mixing layer depth. Lower mixing depth was observed in air masses characterized by higher observed concentrations at the measuring site and vice versa. PM2.5 concentrations showed diurnal and seasonal variations whose pattern reflected the regional origin of the aerosol. The regional pollution level was evaluated by the statistical analysis of PM2.5 concentrations. The background annual average of PM2.5 mass concentration for the eastern coast of the Baltic Sea was 15.1 ± 0.8 μg m⁻³.     

Solid phase extraction of gold(III) on Amberlite XAD-2000 prior to its flame atomic absorption spectrometric determination

A solid phase extraction method for the determination of gold(III) at trace levels by flame atomic absorption spectrometer (FAAS) was developed. The method was based on retention of gold as chloro complexes through the Amberlite XAD-2000. The effect of some analytical parameters including hydrochloric acid concentration, sample volume, sample and eluent flow rates, eluent volume, eluent concentration and interfering ions on the recovery of gold(III) was investigated. The retention of gold(III) from 1.5 mol l⁻¹ HCl solution and the recovery of gold with 0.07 mol l⁻¹ NH₃ solution were quantitative (≥95%). The relative standard deviation (RSD) was calculated as 3.2% (n = 10). The detection limit for gold was 2 μg l⁻¹. The accuracy was checked with the determination of gold spiked an artificial seawater and a pure copper samples.     

Estimating nutrient loadings using chemical mass balance approach

The river Hindon is one of the important tributaries of river Yamuna in western Uttar Pradesh (India) and carries pollution loads from various municipal and industrial units and surrounding agricultural areas. The main sources of pollution in the river include municipal wastes from Saharanpur, Muzaffarnagar and Ghaziabad urban areas and industrial effluents of sugar, pulp and paper, distilleries and other miscellaneous industries through tributaries as well as direct inputs. In this paper, chemical mass balance approach has been used to assess the contribution from non-point sources of pollution to the river. The river system has been divided into three stretches depending on the land use pattern. The contribution of point sources in the upper and lower stretches are 95 and 81% respectively of the total flow of the river while there is no point source input in the middle stretch. Mass balance calculations indicate that contribution of nitrate and phosphate from non-point sources amounts to 15.5 and 6.9% in the upper stretch and 13.1 and 16.6% in the lower stretch respectively. Observed differences in the load along the river may be attributed to uncharacterized sources of pollution due to agricultural activities, remobilization from or entrainment of contaminated bottom sediments, ground water contribution or a combination of these sources.     

全二维气相色谱/飞行时间质谱联用监测环境空气中VOCs

采用全采样系统-全二维气相色谱/飞行时间质谱联用技术监测环境空气中的VOCs,优化了调制周期、升温程序、进样体积等分析条件.39种目标化合物在0 μg/m3～10.0 μg/m3范围内线性良好,检出限范围为0.03 μg/m3～0.09 μg/m3,标准气体平行测定的RSD为1.1％ ～5.3％.应用于化工园区环境空气样品测定,与热脱附-气相色谱/质谱法相比,目标物的分离效果更佳.     

搅拌棒萃取-热脱附/气质联用法测定水中2-MIB和土臭素

采用搅拌棒萃取-热脱附/气质联用法测定水中2-甲基异莰醇和土臭素,优化了搅拌棒萃取和热脱附进样的条件。试验表明：两种目标化合物在1．00 ng/L～200 ng/L范围内线性良好,2-甲基异莰醇的相关系数为0．9993,土臭素的相关系数为0．9997,方法检出限分别为0．31 ng/L和0．15 ng/L;空白和实际样品的加标回收率为82．4％～116％,测定结果的RSD＜10％。     

乌鲁木齐冬季气溶胶散射吸收特性

采用积分式浑浊度仪于2012年1月在乌鲁木齐市中区和市北区对气溶胶的散射系数和吸收系数进行连续观测,分析了市中区与市北区气溶胶散射系数和吸收系数的变化特征,结合同期的相关气象资料对变化特征进行了讨论。结果表明,市中区和市北区气溶胶的散射系数、吸收系数具有相同的变化趋势。总体上呈"W"型;峰值分别出现在0:00和12:00前后,谷值则出现在5:00和17:00前后。散射系数远大于吸收系数,说明大气气溶胶的消光作用主要由散射作用完成。相对湿度与散射系数、吸收系数不具有显著相关性,而风速对散射系数、吸收系数影响较大,且对市北区的影响大于市中区。     

X射线荧光光谱分析空气滤膜颗粒物中多种元素

采用X射线荧光光谱分析空气滤膜采集悬浮颗粒物中的多种元素,样品不需要前处理,不使用试剂,测量1个样品中40余种元素约耗时1 h。重复测量10次NIST SRM 2783空气滤膜标准样品,多数元素的测量值与标准值基本一致,测量值的标准偏差较小;测量20个空气滤膜实际样品,并与ICP-MS法作比对,大多数元素两种方法测量结果的相对偏差较小,测量值基本一致。