亚铁氧化反硝化生物膜反应器中铁矿物的多样性及其对重金属Cd的吸附

亚铁氧化反硝化过程,是指亚铁氧化和NO₃--N还原相结合的生物矿化过程,该过程不仅可以实现水中NO₃--N脱除,还可以得到对多种污染物有较强吸附去除能力的铁矿物。构建了亚铁氧化反硝化过程的连续流式生物膜反应器,分析了反应器运行3个月后内部生成的颗粒物特性及其对重金属镉(Cd)的吸附效果。结果表明:反应器内不同位置会生成颗粒成分不同的铁矿物,下部和中部以菱铁矿为主,上部以针铁矿为主。这些颗粒均具有较大的比表面积和多种有利于吸附的有机官能团,对于水中Cd2+具有较强的吸附能力,不同位置形成的颗粒物的吸附去除率从大到小依次为出水>上部>中部>下部,去除率均可达到84%以上,吸附动力学和热力学方程更符合准二级动力学方程和Freundlich模型。     

二氯苯醌对斑马鱼胚胎发育及超氧化物歧化酶的影响

2,6-二氯-1,4-苯醌（2,6-dichloro-1,4-benzoquinone,2,6-DCBQ）作为一种新型消毒副产物,因其高检出率及高含量的特点而备受人们关注.本研究以斑马鱼胚胎为实验材料探究了2,6-DCBQ的发育毒性.结果发现：斑马鱼胚胎在8~24 hpf（器官发育形成时期）对2,6-DCBQ暴露最为敏感,死亡率最高;2,6-DCBQ安全浓度为27.15 μg·L^-1,属于极度危险外源化学物.在本实验中,2,6-DCBQ对斑马鱼的生长没有显著影响,但高浓度（100和150 μg·L^-1）2,6-DCBQ会显著增加斑马鱼胚胎及仔鱼的畸形率.在实验过程中还发现,高浓度（≥ 80 μg·L^-1）2,6-DCBQ会明显抑制斑马鱼胚胎的心率.此外,≥ 30 μg·L^-1 2,6-DCBQ可提高超氧化物歧化酶（Superoxide dismutase,SOD）的活性,并影响Cu/ZnSOD和MnSOD的正常转录.本研究较全面地探究了2,6-DCBQ对斑马鱼早期发育阶段的发育毒性,可为2,6-DCBQ的毒性研究提供可靠证据.     

基于大数据分析的杭州市农业源高分辨率氨排放清单研究

基于实地调查并辅以统计的方法获得大数据,采用排放因子法,估算了杭州市2015年农业源氨排放清单,并选取经纬度坐标、土地类型和人口等数据作为权重因子,建立1 km×1 km高精度网格化空间分布,研究了该地区农业排放源氨排放空间分布特征.结果表明:杭州市2015年农业源NH3排放总量为54787.9 t,其中畜禽养殖和农田种植是最主要的氨排放来源,分别占农业源总排放量的86.7%和12.8%.在畜禽养殖各主要环节的氨排放过程中,圈舍固态粪便的氨排放贡献量最大,占总氨排放量的52.8%;其次是存储固态,占总氨排放量的35.1%.氮肥施用主要集中在萧山区、建德市、临安市和余杭区.秸秆堆肥和秸秆焚烧与秸秆综合利用率高低密切相关,两者氨排放量占有率不高,占杭州市农业源氨排放总量的1%以下.     

滦河流域鱼类群落结构空间异质性与影响因子分析

掌握鱼类群落结构与环境因子的关系是河流鱼类多样性保护与恢复的基础.基于2016年10月对滦河流域58个采样点的调查数据,通过聚类分析法及NMS（非度量多维标度法,non-matric multidimentionalscaling）分析了滦河鱼类群落空间格局特征,并采用典范对应分析（CCA,canonical correspondence analysis）探讨了影响鱼类群落结构的环境因子.调查期间共采集鱼类15科41属49种,鲤科鱼类最多,为23种.研究表明:①聚类分析发现鱼类空间分布可分为3组,第1组集中在滦河干流中下游及支流汇入干流附近河段,第2组集中在冀东部独流入海的河流,第3组集中在滦河干支流的中上游河段.②NMS结果也证明3组在空间分布上差异明显,第2组与第3组之间没有重叠.③物种数、Shannon-Wiener多样性指数、Margalef丰富度指数和Simpson多样性指数在第1组与第3组之间存在显著差异,而Simpson多样性在第2组与第3组之间也存在显著差异.④单因素方差分析（one-way ANOVA）显示,第1组与第2组、第3组相比,水温与两组之间都有显著性差异,第2组与第1组、第3组之间在电导率、TDS（总溶解固体）、栖境复杂性、速度-深度结合、堤岸稳定性和河水水量状况有显著性差异.⑤典范对应分析发现,影响滦河流域的环境因子包括TDS、浊度、pH与水温等4个水体理化参数以及底质与堤岸稳定性2个栖息地质量参数.研究显示,基于对滦河流域鱼类空间异质性和相关环境影响因子的理解,可为该流域鱼类多样性保护及管理对策制订提供方向.      

Landscape perceptions and social representations of <Emphasis Type="Italic">Fallopia</Emphasis> spp. in France

Choices have to be made to manage invasive species because eradication often is not possible. Both ecological and social factors have to be considered to improve the efficiency of management plans. We conducted a social study on Fallopia spp., a major invasive plant taxon in Europe, including (1) a survey on the perception of a landscape containing Fallopia spp. using a photoquestionnaire and (2) an analysis of the social representations of Fallopia spp. of managers and users in one highly invaded area and one less invaded area. The respondents to the photoquestionnaire survey appreciated the esthetics of the landscapes less when tall Fallopia spp. were present. Few people were able to identify and name the plant, and this knowledge negatively affected the appreciation of the photos containing Fallopia spp. The central core of the social representation of Fallopia spp. was composed of the invasive status of the plant, its density, and its ecological impacts. The peripheral elements of the representation depended on the people surveyed. The users highlighted the natural aspect whereas the managers identified the need for control. In the invaded area, the managers qualified the species as “unmanageable,” whereas the species was qualified as “foreign” in the less invaded area. Those results provide insights that have to be included when objectives of management plans of these species are selected.     

Theoretical study on the formation mechanism of polychlorinated dibenzothiophenes/thianthrenes from 2-chlorothiophenol molecules

Homogeneous formation of polychlorinated dibenzothiophenes/thianthrenes(PCDT/TAs),sulfurated compounds analogous to polychlorinated dibenzo-p-dioxin/dibenzofurans(PCDD/Fs), has been well-documented to occur via radical–radical coupling reactions from chlorinated thiophenol precursors. However, the current understanding of the formation mechanism of PCDT/TAs is exclusively limited to the inherent point of view that chlorothiophenoxy radicals act as the only required intermediates for PCDT/TAs. This study investigates reaction pathways for the formation of PCDT/TAs involving two new types of radical species, i.e., substituted phenyl radicals and substituted thiophenoxyl diradicals. Taking 2-chlorothiophenol(2-CTP) as a model compound for chlorothiophenols,we found that apart from the mostly discussed chlorothiophenoxy radicals, substituted phenyl radicals and substituted thiophenoxyl diradicals could also be readily formed via the reaction of 2-CTP with H radicals. Furthermore, direct self-and cross-coupling of these radicals can result in the formation of PCDT/TAs, including 1-monochlorothianthrene(1-MCTA), 1,6-dichlorothianthrene(1,6-DCTA), 4,6-dichlorodibenzothiophene(4,6-DCDT)and 1,6-dichlorodibenzothiophene(1,6-DCDT). The pathways proposed in this work are proven to be both thermodynamically and kinetically favorable. Particularly, comparisons were made between the formation mechanisms of sulfurated and oxygenated dioxin systems from an energetic point view, showing that replacing oxygen with sulfur atoms greatly reduces the activation barriers of the rate-controlling steps involved in the PCDT/TA formation processes compared with those involved for PCDD/Fs. The calculated results in this work may improve our understanding of the formation mechanism of PCDT/TAs from chlorothiophenol precursors and should be informative to environmental scientists.     

Anaerobic digestion in mesophilic and room temperature conditions: Digestion performance and soil-borne pathogen survival

Tomato plant waste(TPW) was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS(total solid) concentrations of 2%, 4% and 6% respectively, at mesophilic(37 ± 1°C) and room(20–25°C) temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416 L/kg VS(volatile solids). The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR(polymerase chain reaction) were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA(volatile fatty acid) concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety.     

电解废渣中硒含量及赋存形态的研究

由于电解废渣原始、粗放的堆放,导致了大量重金属离子和有毒有害元素在自然环境中极易迁移并造成污染。为了掌握废渣中硒在多重氧化态中含量及形态分布,对进一步研究其在自然环境中的矿化、迁移规律及毒理学特性等意义重大,该实验采用了改进的SES连续浸提法,提取了电解废渣样品的水溶态、交换态、酸溶态、有机态、单质态及残渣态,以ICP-MS测定提取液中总硒含量,HPLCICP-MS研究了硒赋存形态。研究表明:CCT动态反应碰撞模式优化了ICP-MS检测环境,有效降低了多原子离子造成的干扰;电解废渣的硒含量极高,在自然环境中容易迁移,尤其是酸性环境下;前三态的硒含量超过了总硒的50%,且主要以毒性较高的亚硒酸盐形式存在,小部分以硒酸盐形式存在,含硒电解废渣存在较大的潜在环境风险。     

Detection of Hepatitis E Virus in Sewage After an Outbreak on a French Island

A hepatitis E outbreak, which occurred on a small isolated island, provided an opportunity to evaluate the association between the number of hepatitis E cases in the community and the concentration of virus detected in sewage. Samples were collected from the different sewage treatment plants from the island and analyzed for the presence of hepatitis E (HEV) virus using real-time RT-PCR. We demonstrated that if 1–4 % of inhabitants connected to a WWTP were infected with HEV, raw sewage contained HEV at detectable levels. The finding that such a small number of infected people can contaminate municipal sewage works raises the potential of the further distribution of the virus. Indeed, investigating the routes of transmission of HEV, including the potential for sewage effluent to contain infectious HEV, may help us to better understand the epidemiology of this pathogen, which is considered to be an emerging concern in Europe.     

Are there higher pedestrian fatalities in larger cities?: A scaling analysis of 115 to 161 largest cities in the United States

Objective: In 2012, 4,743 pedestrians were killed in the United States, representing 14% of total traffic fatalities. The number of pedestrians injured was higher at 76,000. Therefore, 36 out of 52 of the largest cities in the United States have adopted a citywide target of reducing pedestrian fatalities. The number of cities adopting the reduction goal during 2011 and 2012 increased rapidly with 8 more cities. We examined the scaling relationship of pedestrian fatality counts as a function of the population size of 115 to 161 large U.S. cities during the period of 1994 to 2011. We also examined the scaling relationship of nonpedestrian and total traffic fatality counts as a function of the population size.

Methods: For the data source of fatality measures we used Traffic Safety Facts Fatality Analysis Reporting System/General Estimates System annual reports published each year from 1994 to 2011 by the NHTSA. Using the data source we conducted both annual cross-sectional and panel data bivariate and multivariate regression models. In the construction of the estimated functional relationship between traffic fatality measures and various factors, we used the simple power function for urban scaling used by Bettencourt et al. (2007 Bettencourt LMA, Lobo J, Helbing D, Kühnert C, West GB. Growth, innovation, scaling and the pace of life in cities. Proc Natl Acad Sci USA. 2007;104:7301–7306.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar], 2010 Bettencourt LMA, Lobo J, Strumsky D, West GB. Urban scaling and its deviations: revealing the structure of wealth, innovation and crime across cities. PLoS ONE. 2010;5:e13541.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) and the refined STIRPAT (stochastic impacts by regression on population, affluence, and technology) model used in Dietz and Rosa (1994 Dietz T, Rosa EA. Rethinking the environmental impacts of population, affluence and technology. Human Ecology Review. 1994;1:277–300. [Google Scholar], 1997 Dietz T, Rosa EA. Effects of population and affluence on CO₂ emissions. Proc Natl Acad Sci USA. 1997;94:175–179.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) and York et al. (2003 York R, Rosa EA, Dietz T. STIRPAT, IPAT and IMPACT: analytic tools for unpacking the driving forces of environmental impacts. Ecol Econ. 2003;46:351–365.[Crossref], [Web of Science ®] , [Google Scholar]).

Results: We found that the scaling relationship display diseconomies of scale or sublinear for pedestrian fatalities. However, the relationship displays a superlinear relationship in case of nonpedestrian fatalities. The scaling relationship for total traffic fatality counts display a nearly linear pattern. When the relationship was examined by the 4 subgroups of cities with different population sizes, the most pronounced sublinear scaling relationships for all 3 types of fatality counts was discovered for the subgroup of megacities with a population of more than 1 million.

Conclusions: The scaling patterns of traffic fatalities of subgroups of cities depend on population sizes of the cities in subgroups. In particular, 9 megacities with populations of more than 1 million are significantly different from the remaining cities and should be viewed as a totally separate group. Thus, analysis of the patterns of traffic fatalities needs to be conducted within the group of megacities separately from the other cities with smaller population sizes for devising prevention policies to reduce traffic fatalities in both megacities and smaller cities.