滇池铜绿微囊藻对重金属的富集和氨基酸含量的变化

研究滇池铜绿微囊藻对水体中重金属（Hg,Cd,Cu,Pb)的富集。结果表明，该藻对Hg的富集力量强，其次为Cd,Cu,Pb。氨基酸含量测定的结果是：采自滇池水体中的铜绿微囊藻的氨基酸含量比室内培养的低。但其所含种类相同。     

南京市主要水系表层沉积物重金属污染潜在的生态风险评价

监测了南京市的主要水系：长江、秦淮河和玄武湖水体表层的沉积物中Hg、Cd、Pb、Cu、As、Cr和zn等7种元素含量,分析了元素的富集程度,采用Hakanson潜在生态危害指数法对其生态危害程度进行了评价。结果表明：长江和玄武湖水系沉积物中,7种元素含量属于低潜在生态风险,秦淮河沉积物则呈较高潜在生态风险;7种元素的富集系数均为,秦淮河〉玄武湖〉长江,长江Cd元素的富集系数最大,为3．18,秦淮河和玄武湖两水系都是Hg的富集系数最大,分别为11．78和3．33;就元素的生态风险而言,长江水体表层沉积物中,7种元素属低潜在生态风险,玄武湖表层沉积物中,除Hg属中潜在生态风险外,其余6种元素属低潜在生态风险,秦淮河表层沉积物的7种元素生态风险由高到低,依次为Hg〉Cd〉Cu〉As〉Zn〉Pb〉Cr,Hg和cd分别属高潜在生态风险和较高潜在生态风险,其余5种元素属低潜在生态风险。     

地钱对木油厂汞矿区重金属污染的指示潜力

对贵州木油厂汞矿区地钱及其基质中的Cu、Zn、Ca、Mg、Cd、Pb、Hg和As 8种元素进行测定分析,以揭示地钱指示基质中重金属污染的潜力。结果表明:(1)基质中Cu、Cd、Hg和As元素的含量分别是相应标准值的1.34、1.79、331.80、1.12倍,该汞矿区受到复合污染,且Hg污染最严重。(2)地钱对Pb的富集系数是所测重金属元素中最高的,可用于治理该汞矿区Pb污染。(3)地钱对Cu的富集是同一水平,说明可以指示其基质含Cu量;对Cd的富集系数多为同一水平,说明趋向于指示其基质含Cd量。(4)地钱对Hg和As的富集系数多为贫化,说明地钱对这2种元素有抵抗作用。(5)相关分析显示,Cu与Mg、Mg与Cd之间显著负相关(显著性概率水平为0.05),它们之间有拮抗作用;Zn与As之间显著正相关(显著性概率水平为0.05),它们之间有协同作用。     

长荡湖沉积物重金属污染特征及生态风险评价

为明确长荡湖重金属污染特征及生态风险,于2018年9月至2019年8月采集长荡湖入湖河流、湖泊水体及表层沉积物样品,分析8种重金属(Cr、Ni、Cu、Zn、As、Cd、Pb和Hg)含量,采用正定矩阵因子(PMF)模型和主成分分析多元线性回归(PCA-MLR)模型对湖泊重金属污染来源进行解析,评估长荡湖沉积物重金属污染程度及风险等级。结果表明,8种重金属有7种超出江苏省土壤环境本底值,秋季长荡湖沉积物中重金属含量普遍较低。Cr、Cd、Zn和Ni的分配系数较高,现阶段不易从沉积物中释放到水体中,但由于Cd多为可交换态且在沉积物中含量较大,因此仍具有从沉积物中释放到水体中的潜力;Cu、As和Hg的分配系数较低,具有从沉积物中释放到水体中的潜力。Hg、Cd、As和Cu污染来源中农业生产占比最高,Pb和Zn交通污染占比最高,Ni自然来源占比最高,Cr工业活动占比最高。长荡湖春季和夏季受重金属污染程度更高,Cd和Hg的生态风险较高,需重点关注。     

铜绿山矿区菜地土壤重金属污染特征

以铜绿山矿区菜地为研究对象,测定了土壤和蔬菜中Cu、Zn、Pb、Cd 4种重金属的含量,分析了土壤-蔬菜体系重金属的污染特征和蔬菜对重金属的富集能力。结果表明:矿区菜地土壤中重金属Cu、Zn、Pb、Cd的污染因子分别为10.63、1.12、1.10、0.06,表明Cu污染非常严重,Zn、Pb属轻度污染,Cd无污染;参考《食品中污染物限量》(GB 2762—2017)、《食品中铜限量卫生标准》(GB 15199—94)以及《食品中锌限量卫生标准》(GB 13106—91),蔬菜中Cu、Zn污染较严重且具有普遍性;蔬菜中Cd含量虽均未超出食品安全限值,但明显高于蔬菜根部土壤中的Cd含量;叶菜类、根茎类蔬菜中Pb均未超标,瓜果类蔬菜中Pb超标;蔬菜可食部位对重金属的富集能力为CdZnCuPb;蔬菜中重金属含量与土壤重金属含量总体表现出较弱的相关性,表明蔬菜中重金属的积累不完全决定于土壤重金属的含量,还与土壤中重金属的生物有效性、环境行为及其他环境因素有关。     

碳源对铜绿微囊藻生理特性及微囊藻毒素产率的影响

为研究水体中不同碳源对铜绿微囊藻生理特性的影响,以Na2CO3与葡萄糖分别作为铜绿微囊藻生长的无机碳源与有机碳源,将铜绿微囊藻于光照下进行培养,并对其一系列的生理特性与微囊藻毒素产率进行检测。实验结果表明,同等碳浓度下,有机碳源更能促进铜绿微囊藻的生长,经过30 d的培养,铜绿微囊藻在有机碳源中的产量为187.55 g,比其在无机碳源中的产量提高了6.06%;微囊藻毒素在有机碳源中的产量为969.00μg/g,而在无机碳源中的产量却升高至1 193.60μg/g。参与藻毒素合成的3种氨基酸在无机碳源中的浓度要比有机碳源中的浓度高,但是其余几种氨基酸的含量与之情况相反。而有机碳源培养的铜绿微囊藻总可溶性蛋白含量为387.00μg/g,比无机碳源培养的铜绿微囊藻的蛋白含量提高了93.60%。     

传统活性污泥法处理城市污水过程中重金属的变化研究

研究了污水处理厂传统活性污泥工艺不同处理工段污水和污泥中Cu、 Zn、 Pb、 Cd、 Hg和As含量变化及其在污水中的形态分布特征,进一步了解重金属在不同处理工段的去除情况.整个工艺流程污水中Hg的去除率最大,平均达76.4%,Pb的去除率最小,平均为29.7%.不同处理工段各重金属去除率差异较大,从进水到初沉池出水Zn去除率最大,平均达55.4%,其次为Hg和Cu,平均去除率分别为40.0%与34.2%;由初沉池出水到二沉池出水Cd、Hg和Cu平均去除率达36.1%～38.5%.进水、初沉池出水和二沉池出水中颗粒态Zn占其总量的比例(以质量分数计,下同)均在98.1%以上,颗粒态Hg占其总量的比例由84.1%降低到39.7%,颗粒态As占其总量的比例由11.7%上升至56.5%.初沉池污泥、曝气池活性污泥和脱水消化污泥中Zn含量最高,初沉池污泥中Cd含量最低,曝气池活性污泥和脱水消化污泥中As含量最低.脱水消化污泥中Zn、Cu、Pb和Cd含量高于初沉池污泥和曝气池活性污泥,Hg和As含量低于初沉池污泥而高于曝气池活性污泥.大部分Zn和Pb在初沉池中被除去,大部分Cd在二沉池中被除去,Hg和Cu在初沉池与二沉池中的去除效果相当.     

8种观赏水湿生植物对重金属Cd和Pb的吸收固定能力

水体沉积物是水体污染物的重要汇和源,水湿生植物具有净化水体的重要功能。采用人工污染土壤的盆栽方法,对8种不同生活型水湿生植物吸收富集土壤Cd和Pb的分析结果发现,莎草地上部分和地下部分Cd含量随着土壤中Cd浓度的增加而增加,在土壤中Cd添加浓度(干重)为5 mg·kg-1时,Cd的累积浓度分别1.13 mg·kg-1DW和1.63 mg·kg-1DW;供试植物的地下部分Pb含量是地上部分的10~20倍,莎草和香蒲的地下部分Pb含量在高浓度Pb土壤中达到20 mg·kg-1DW左右。黄花鸢尾、莎草以及睡莲这3种植物对土壤Cd的转运系数和富集系数大于1,结合生物量因素可以认为,莎草具有富集土壤Cd能力,而莎草和香蒲具有固定土壤Pb的能力。     

龙口市污灌区重金属污染影响因子分析

在龙口市污灌区采集70个土壤样品测定Cr、Ni、Pb、Zn、Cu、Co、As和Cd含量,利用富集因子法分析各重金属的空间分布情况,采用地理探测器模型评估7个影响因子对重金属空间分布的影响及各影响因子间的交互作用.结果表明:(1)Cu、Pb、Zn、As、Cd的富集程度较大,Co、Cr、Ni富集程度较低,8种重金属富集系数...     

重庆西部农业区大气沉降特征及其对地表的影响

从2009年4月至2010年4月,在重庆西部农业区采集了50个大气干、湿沉降样品,分别测试干、湿沉降样品中K、Ca、Mg、N、P、S、Fe、As、Cd、Cr、Cu、Hg、Ni、Zn、Pb、B、Mo、Mn 18种元素的含量,计算各元素的年沉降通量。研究发现,重庆西部农业区各元素年沉降通量均低于重庆主城区和成都经济区。采用富集因子分析得出,S、Cd、N、Pb、P、Hg、Mo、Zn、Cr、As明显受人为活动影响,其中S、Hg、As、Pb是典型的燃煤元素,Cd、Cr、Zn主要来源于工业排放、汽车尾气等,N、P与农业施肥密切相关。相关性分析表明,大气沉降输入Hg引起土壤中Hg含量显著增加,大气沉降输入S引起地表水中SO2-4浓度显著升高。     

Modeling the spill in the Songhua River after the explosion in the petrochemical plant in Jilin

An explosion in a petrochemical plant in Jilin in the northeast of China on 13 November 2005 was responsible for the discharge of large quantities of benzene and nitrobenzene into Songhua River. This endangered the water supply of Harbin city and influenced the daily life for millions of people. The dispersion-advection equation was solved analytically and numerically and used to simulate the concentration of benzene and nitrobenzene in the Songhua River after the accident. Both solutions gave practically identical results. The main elimination process for both compounds was volatilization. The model results are quite close to the results obtained by measurements at monitoring stations. Arrival time of the pollutant wave, peak concentrations and end of the pollutant wave at Harbin and along the river were predicted successfully. The peak concentrations of nitrobenzene at Harbin were more than 30 times above the permissible limits for drinking water.     

Determining the role of humic substances in the fate of pesticides in the environment

Abstract

The data presented in this paper emphasize that the behavior and fate of pesticides in the environment is influenced by humic substances. Various methods most frequently used for the characterization of humic substances are discussed. Both humic acid and fulvic acid can solubilize in water certain organic compounds and are important carriers of some pesticides in soil. Humic substances have the potential for promoting the nonbiological degradation of many pesticides. Several methods of bleaching humus color from drinking water, including chlorination, ozonation, and UV‐radiation, are described. Finally, the photochemical stability to UV‐radiation of certain pesticides in aqueous fulvic acid solution is discussed.     

Determining the role of human substances in the fate of pesticides in the environment

The data presented in this paper emphasize that the behavior and fate of pesticides in the environment is influenced by humic substances. Various methods most frequently used for the characterization of humic substances are discussed. Both humic acid and fulvic acid can solubilize in water certain organic compounds and are important carriers of some pesticides in soil. Humic substances have the potential for promoting the nonbiological degradation of many pesticides. Several methods of bleaching humus color from drinking water, including chlorination, ozonation, and UV-radiation, are described. Finally, the photochemical stability to UV-radiation of certain pesticides in aqueous fulvic acid solution is discussed.     

Imposex in the commercial snail Bolinus brandaris in the northwestern Mediterranean

A survey of the degree of imposex in populations of the commercial muricid Bolinus brandaris (L.) was carried out at six locations along the Catalan Coast (NW Mediterranean). Imposex was found to be a widespread phenomenon; the occurrence of a penis was observed in all females studied with the exception of those from St. Carles (South of Catalunya) where only 37% were affected. Other indices such as Relative Penis Length (RPL) and Vas Deferens Sequence (VDS) were applied; RPL varied from 4.5% in St. Carles--the least affected area--to 29.8% in the vicinity of Barcelona; similar results were obtained for VDS. Tissue organotin residues ranged from 6 to 140 ng g(-1) w.w. as Sn. Despite legislation restricting the use of tributyltin (TBT) in antifouling paints, this paper evidences the occurrence of organotin pollution far from the source, with levels of both TBT and triphenyltin (TPhT) high enough to cause environmental concern.     

Uncertainties in the role of land vegetation in the carbon cycle

Since the late 1950s the CO2 concentration of the atmosphere has been increasing by around 0.5-3 ppm per year. Understanding of carbon sinks is vital to understanding this trend and its future behaviour. Here we examine some of the factors which may affect the proportion of anthropogenic CO2 ending up in the atmosphere in the present and in the future, and variability in the CO2 increase from one year to another. We also examine the evidence for the potential of terrestrial ecosystem carbon sinks to take up or release CO2. In some cases, a careful re-examination of the research methods used to deduce present and future feedbacks may be necessary. The most advanced technology and the most complex models do not necessarily produce reliable results. They should be carefully checked against a general background knowledge of ecological processes before their results are accepted.     

Targeting lead in the multimedia environment in the continental United States

The U.S. Environmental Protection Agency's (EPA) lead attainment strategy for air is being expanded to address geographic areas with the potential for multimedia, multipathway exposures to lead. Geographic Information Systems (GIS) technology is used to coordinate information from various databases to identify areas of potential concern. The data retrieval and decision processes used in identifying priority sources from each medium and in evaluating identified areas of concern are described in this paper. Only EPA databases with reliable locational information were used to facilitate accurate mapping and allow correlation with other data sources. The sources of lead loadings to air, water, and soils were mapped using either latitude and longitude or zip code, or county centroids for data lacking longitudinal and latitudinal coordinates (such as the drinking water data). A multimedia cluster of lead sources was identified at the county level, since all the facility data in the five databases could be mapped to this level. An impact factor and weighting system was devised to combine the information on the number of facilities and their relative size in developing a ranking of the multimedia lead clusters of concern in each region. The counties with the highest number of points were considered clusters of highest concern for multimedia lead sources. Two separate lists of the clusters were developed according to a point system. One identified 10 multimedia lead clusters in each of the 10 EPA regions, and the other identified the 100 clusters of highest concern in the country as a whole. The project is designed to be a first step in targeting future efforts to identify potential environmental problems associated with lead. The analyses presented in this paper provide a first look at the areas in the country where there is a potential for multimedia exposure to lead. A more refined analysis at the zip code level was subsequently developed to provide a good understanding of the issues pertaining to potential exposure at the neighborhood level. The results of this analysis will ultimately help the EPA and the states to target implementation and enforcement in areas of high potential lead exposures.     

An assessment of the aggregate impacts of the proposed reduction in the motor fuels tax in the United States

The analysis in this paper examines the impact of reducing the excise tax on gasoline and diesel fuel on the United States economy. The analytical approach used consists of a computable general equilibrium model composed of fourteen producing sectors, fourteen consuming sectors, six household categories classified by income and the government. The effects of a 4.3 cents per gallon reduction in the excise tax on gasoline and diesel fuel on prices and quantities are examined. The results suggest, for example, that a decrease in the tax would result in higher output by the producing sectors (by about $2.86 billion), and expansion in the consumption of goods and services (by about $3.48 billion), and an increase in welfare (by about $3.59 billion). The government would realise a decrease in revenue of about $2.37 billion. When subjected to a sensitivity analysis, the results are reasonably robust with regard to the assumption of the values of the substitution elasticities.     

Air protection programmes in Poland in the context of the low emission

Environmental Science and Pollution Research - The protection of the air against pollutants from individual boiler plants is a big challenge in Poland. It results mainly from the preference for...