Adaptation to osmotic stress provides protection against ammonium nitrate in Pelophylax perezi embryos

The negative effects of pollution on amphibians are especially high when animals are additionally stressed by other environmental factors such as water salinity. However, the stress provoked by salinity may vary among populations because of adaptation processes. We tested the combined effect of a common fertilizer, ammonium nitrate (0-90.3 mg N-NO₃NH₄/L), and water salinity (0-2‰) on embryos of two Pelophylax perezi populations from ponds with different salinity concentrations. Embryos exposed to the fertilizer were up to 17% smaller than controls. Survival rates of embryos exposed to a single stressor were always below 10%. The exposure to both stressors concurrently increased mortality rate (>95%) of embryos from freshwater. Since the fertilizer was lethal only when individuals were stressed by the salinity, it did not cause lethal effects on embryos naturally adapted to saline environments. Our results underscore the importance of testing multiple stressors when analyzing amphibian sensitivity to environmental pollution.     

Positive vs. false detection: A comparison of analytical methods and performance for analysis of cyclic volatile methylsiloxanes (cVMS) in environmental samples from remote regions

Contamination and analytical variation can significantly hinder trace analysis of cyclic methyl volatile siloxanes (cVMS); potentially resulting in the report of false positives at concentrations approaching detection limits. To assess detection and variation associated with trace cVMS analysis in environmental matrices, a co-operative laboratory comparison for the analysis of octametylcyclotetrasiloxane (D4), decamethylcylcopentasiloxane (D5), and dodecametylcyclohexasiloxane (D6) in sediment and biota from the Svalbard Archipelago was conducted. Two definitions of detection limits were evaluated in this study; method detection limits (MDL, matrix defined) and limits of detection (LOD, solvent defined). D5 was the only cVMS detected above both LOD (0.08–0.81 ng g⁻¹ ww) and MDL (0.47–2.36 ng g⁻¹ ww) within sediment by all laboratories where concentrations ranged from 0.55 to 3.91 ng g⁻¹ ww. The percentage of positive detects for D5 decreased by 80% when MDL was defined as the detection limit. D5 was also detected at the highest frequency among all laboratories in fish liver with concentrations ranging from 0.72 to 345 ng g⁻¹ ww. Similar to sediment, percentage of positive detects for D5 decreased by 60% across all laboratories for fish livers when using MDL (0.68–3.49 ng g⁻¹ ww). Similar observations were seen with both D4 and D6, indicating that sample matrix significantly contributes to analytical response variation. Despite differences in analytical methods used between laboratories, good agreement was obtained when using MDL to define detection limits. This study shows the importance of incorporating variation introduced by sample matrices into detection limit calculations to insure data accuracy of cVMS at low concentrations.     

ABR-生物滴滤池组合工艺处理农村生活污水

采用ABR-生物滴滤池组合工艺,研究在水力停留时间为3 d、滴滤池水力负荷为5 m3/（m2·d）的条件下,组合工艺对生活污水中主要污染物的去除效果、滴滤池内部污染物浓度变化和微生物的沿程分布规律。实验结果表明,组合工艺对COD、TN、NH＋4-N和TP的平均去除率分别可达73%、32%、58%和30%;滴滤池内各层污染物浓度除TP在中层略有升高外,其余均沿程逐渐降低。滴滤池底层对各种污染物的去除能力均较强,原因是果壳活性炭填料较强的截留吸附能力以及底层微生物优势菌属较好的降解作用。总氮的去除依靠滴滤池内填料的物理化学作用和微生物同步硝化反硝化作用,其中微生物作用约占60%,成为脱氮的主要途径。     

Investigating traffic fatality trends and restraint use among rear-seat passengers in the United States, 2000–2016

Introduction: Motor-vehicle crash is one of the leading causes of unintentional injury death in the United States. Previous studies focused on fatalities among drivers and front-seat passengers, with a limited number of studies examining rear-seat passenger fatalities. The objectives of this study were to assess trends in rear-seat passenger motor-vehicle fatalities in the United States from 2000 to 2016 and to identify demographic factors associated with being unrestrained among fatally injured rear-seat passengers. Methods: Rear-seat passenger fatality data were obtained from the Fatality Analysis Reporting System (FARS) database. The fatality rate ratios for overall rear-seat passengers and for different age and sex groups were determined by comparing fatality rates in 2000 and 2016 using random effects models. Risk ratios of being unrestrained for age and sex groups were obtained using general estimating equations. Results: Compared to 2000, the overall rear-seat passenger fatality rate in 2016 decreased by 44% (95% confidence interval [CI]: 39–49%). In particular, the fatality rate among rear-seat passengers decreased more in males than females, and passengers aged 14–19 years experienced a larger decline than all other age groups. Fatally injured male rear-seat passengers had a higher risk of being unrestrained (adjusted risk ratio: 1.06, 95% CI: 1.04–1.07) than their female counterparts, and both youngest (≤13 years) and oldest (65–85 years) passengers were less likely to be unrestrained than those aged 20–64 years. Conclusions: Overall, fatality rates among rear-seat passengers have declined, with differential degrees of improvement by age and sex. Practical Applications: Continued restraint use enforcement campaigns targeted at teenagers and males would further preserve them from fatal injuries and improve traffic safety for the overall population.     

古运河营养元素分布特征及富营养化趋势分析

根据2005～2009年各季度对镇江古运河水体多项指标的监测资料,分析了古运河水体中N、P营养元素的时空分布特征,选用营养状态质量指数法对水体营养状态进行了评价,并预测了古运河水体的富营养化趋势。结果表明,古运河水体中营养元素随年度呈先增后减的特征,而年内季度分布不明显,空间分布基本呈从上游向下游递增的规律;2005～2009年,古运河水体连年处于富营养水平,2007年最为严重,但自2007年以来,水体营养水平逐年下降,水体富营养化趋势有所减缓。     

和谐流域建设的理论基础和基本路径

流域经济是以流域水资源的开发和利用为重点，以流域范围内的资源优化配置为核心的特殊类型区域经济。由于学者对流域经济的自然特性和人文特性认识差异较大，导致人们对流域经济的本质特征认识不统一，认为流域经济表述了人们在配置流域资源时引起的经济关系，流域经济的特征表现为：稀缺性、效益性、边际产出递减性、层次性。和谐流域建设是流域经济的发展趋势，构建和谐流域是落实科学发展观的重要体现，是支撑流域经济可持续发展的首要条件，是构建和谐社会的重要组成部分     

乌鲁木齐市蔬菜基地土壤有效态镍的空间变异特征

以乌鲁木齐市北郊蔬菜基地为典型区甜干旱区绿洲城市郊区土壤有效态镍含量的结构特征进行分析，得出该区有效态镍的空间分布格局并揭示了引起这种分布格局的成因，结果表明：乌鲁木齐市北郊蔬菜基地有效态镍属中等变异。半方差函数模型拟合表明有效态镍含量可以用球状函数拟合，具有高度的空间自相性，有效态Ni主要受内在因子（土壤形成因子，如气候、地形、土壤类型等）控制。采用Kriging最优内插法得到了有效态镍含量的空间分布格局，呈现明显的北高南低分布规律。     

我国三峡库区高温天气的变化分析

根据三峡库区及其周围30个气象站1961～2010年的逐日气温资料，采用常规统计方法分析了50 a来三峡库区高温的时空变化特征。结果表明: 过去50 a，三峡库区年均高温日数为2407 d，存在23和31 a尺度的周期振荡，于1979 年发生了由多到少的突变；高温日平均最高气温为3669 ℃，具有3 a尺度的变化周期。8月的高温日数最多且高温日平均最高气温最高。20 世纪80年代高温日数与高温日平均最高气温为负距平，在21 世纪最初10 a，高温日数显著增加，高温日平均高温气温增高。三峡库区高温日数呈峡谷多，山区和丘陵少，库区北部多、南部少的分布特点。三峡库区蓄水后高温趋势变化不显著     

“十一五”期间上海市金山区环境空气污染特征分析

对金山区2006-2010年环境空气质量监测数据进行统计分析和综合评价,找出"十一五"期间金山区环境空气中主要污染物变化规律及环境空气主要污染特征,并进行污染趋势分析,就环境空气中TSP和PM₁₀以及SO₂、NO₂和酸雨之间的相关性进行了探讨,均具有显著相关性。     

Dust deposition in a sub-tropical opencast coalmine area, India

This paper provides baseline information about the total annual dust fall, and its constituents and seasonal variation, from a sub-tropical opencast coalmine area in Bina, India. Dust samples were collected monthly for 2 years (June 2002-May 2004) from five sampling sites in the region and analyzed in the laboratory for water-soluble and -insoluble matter. Water-insoluble components constituted the major fraction of the total annual dust fall. Two-way ANOVA indicated significant variations in dust fall at different sites, over the months and in their interactions. The dust deposition rate was highest during summer (March-June), followed by winter (November-February) and lowest in the rainy season (July-October). Maximum dust fall was observed near the coal handling plant (at site 2) followed by the receiving pit of the coal handling plant (site 3), near the main sub-station (site 4), Jawahar colony (site 1) and Gharasari village (site 5). An inverse and significant relation was observed between dust fall and precipitation. Our studies have shown that the main residential areas are experiencing higher levels of dust fall which makes them unsuitable for living. We suggest that residential areas should be moved farther away from the mining area in the opposite direction of prevalent winds.