武陵山区域典型生态保护城市饮用水源地水质人体健康风险评价

选择武陵山区域黔江区的2个城市集中式饮用水源地为研究对象,通过2010-2014年每月进行水质监测,获取120组有效数据,运用US EPA推荐的健康风险评价模型对13项水质指标（如Cd、As、Hg等）进行健康风险评估.结果表明:2010-2014年,黔江区小南海、洞塘水库监测指标均满足GB 3838-2002《地表水环境质量标准》 Ⅲ标准,水质状况良好.2个饮用水源地的成人总致癌风险均在0.87×10-7~1.19×10-7 a-1之间,儿童总致癌风险均在2.86×10-7~3.91×10-7 a-1之间,成人和儿童的水质总健康风险均值低于US EPA和ICRP（1×10-4和5×10-5 a-1）的最大可接受风险水平2个数量级以上.健康风险排序为致癌物>非致癌物.计算健康风险指标贡献率表明,通过饮水暴露途径引起健康风险应优先控制Cr6+.黔江区2个城市饮用水源地对儿童产生的人体健康总风险值大于成人,因此儿童更易受到化学物质引起的健康危害.不确定分析结果表明,该研究健康风险评价结果具有可信性,但污染物浓度、人体单位体质量、日均饮水量以及暴露时间的变动将会影响健康风险水平的高低.      

大连市水环境健康风险评价

利用美国环保署提出的水质健康风险评价模型,对大连市近5a的生活饮用水环境进行评价,探究水体中所含物质对人体健康的潜在影响。以国际辐射委员会推荐的最大可接受限值为参考进行分析,结果表明,区域内的水中化学致癌物主要是Cr＋6,致癌风险超过了国际辐射委员会推荐的最大可接受值5.0×10-5/a;非致癌物中只有氟化物风险超标;致癌物的风险大于非致癌物的风险。根据评价结果可知在水质治理过程中,应优先治理致癌物Cr＋6。     

重庆市北碚区乡镇集中式饮用水水源地水质综合分析与评价

运用综合水质指数(WQI)模型和水质健康风险评价模型对重庆5个乡镇集中式饮用水水源地进行评价。结果表明:重庆5个乡镇饮用水水源地综合水质指数WQI都在10～30范围内,以良好为主。其中D监测点最好,全年的综合污染指数WQI20,说明全年水质优良,基本上没有污染;躯体毒物质总健康危害风险介于(6.00×10~(-12)～3.941×10~(-9))a~(-1),与ICRP推荐的有毒有害物质健康危害风险最大可接受值(5.0×10~(-5)a~(-1))相比,差4个数量级。这表明非致癌化学物质引起的健康风险甚微,不会对当地居民构成明显危害。化学致癌物砷的健康危害风险度虽未超过ICRP推荐的可接受水平,但仍与ICRP推荐值位于同一数量级。与瑞典EPA、荷兰EPA推荐的最大可接受水平1.0×10~(-6)a~(-1)相比,最高健康危害风险度是它的127倍。A、B、C监测点基因毒物中As占总风险度99.99%,表明是产生健康风险的主要污染物,因此应优先考虑防治As对重庆乡镇集中式饮用水源地的污染。     

长江武汉段水质重金属健康风险初步评价

对长江武汉段水质中19种重金属含量进行了连续3年(2009-2011年)调查研究,并应用水环境健康风险评价模型,对该流域内的水体经饮水途径、皮肤接触途径造成的健康风险进行计算和评价。结果表明:非致癌物对人体健康危害的个人年风险水平小于10-8a-1,因此可忽略由非致癌物所致的个人年风险。化学致癌物质所致健康危害的个人年风险:砷>镉,且化学致癌物质对人体健康危害的年总风险在1.41×10-5~2.42×10-5a-1之间,远大于非致癌物,但低于国际放射防护委员会(ICRP)和美国环境保护署(US EPA)的推荐值(5×10-5a-1和1×10-4a-1)。此外,通过饮水途径所致健康危害的个人年风险要远大于通过皮肤接触途径所致的风险。     

湖泊饮用水源地水环境健康风险评价

根据某湖泊饮用水源地水环境质量监测资料,采用美国环境保护署(US EPA)推荐的水环境健康风险评价模型,对2处饮用水源地原水通过饮水途径引起的水环境健康风险进行了评价.结果表明:在2处饮用水源地水环境质量监测项目中,对人体有健康风险的有毒污染物主要是化学致癌物As和Cr(Ⅵ);个人化学致癌物总年风险远大于非致癌物总年风险;2003─2007年2处饮用水源地水环境健康个人总年风险均超过国际辐射防护委员会(ICRP)推荐的标准,主要原因是化学致癌物As和Cr(Ⅵ)的质量浓度过高;因此,加强治理和控制化学致癌物特别是As和Cr(Ⅵ)是降低该湖泊饮用水源地水环境健康风险的有效途径.      

上海市主要饮用水源地水重金属健康风险初步评价

对上海市主要饮用水源地(黄浦江上游地区和陈行水库)水中重金属含量进行了调查研究,并应用水环境健康风险评价模型对其进行健康风险的初步评价.结果表明,黄浦江上游和陈行水库由致癌物质Cr,As,Cd通过饮水途径引起的个人年健康风险平均值分别表现为Cr>As>Cd和As>Cr>Cd,风险值为10-7~10-5 a-1,Cr和As的风险值高于部分机构推荐的最大可接受风险水平(1×10-6 a-1),而低于国际放射防护委员会(ICRP)和美国环境保护署(US EPA)的推荐值(5×10-5和1×10-4 a-1),成为上海市饮用水源地主要的致癌因子;黄浦江上游和陈行水库由非致癌物质Pb,Cu,Zn,Hg导致的个人年健康风险平均值分别表现为Pb>Cu>Zn>Hg和Hg>Cu>Pb>Zn,风险值为10-12~10-10 a-1.各采样点重金属类致癌物质的风险值明显高于非致癌物质.      

昆明市松华坝水库水质健康风险评价

根据昆明市主要供水水源地松华坝水库水质的实测资料,对水质健康风险进行了分析与评价.研究结果表明:(1)重金属致癌物通过饮水途径所致健康危害的个人年风险极小,未对暴露人群构成危害;(2)非致癌物由饮水途径所致健康危害的个人年风险,2001～2005年按大小顺序排列均为氟化物＞硝酸盐＞亚硝酸盐＞非离子氨,所引起的健康风险甚微,不会对暴露人群构成明显危害;(3)松华坝水库水质健康危害的个人年总风险为7.24E-10a-1,远远低于国际辐射防护委员会(ICRP)推荐的最大可接受值5.0×10-5a-1和瑞典、荷兰建设和环境部推荐的最大可接受水平1.0×10-6a-1,即水库水质对暴露人群所致健康危害较小.结论对水源地水质健康风险管理、水环境监测和保护措施的制定具有较高的参考价值.     

伊通河水环境健康风险评价

根据2006年吉林省水环境检测资料,针对水体中污染物质经饮水途径对人体的健康危害风险进行分析与评价.结果表明:水体中化学致癌物质对人体健康危害的风险较大,砷和镉对人体的致癌风险均超过5×10-5,即U.S.EPA的致癌风险评价指南中推荐的人体年风险最大可以接受的风险值,危险程度极高.另外,4类非致癌物对人体健康危害风险较小,其健康风险排列由高到低顺序为氟化物＞氨氮＞铜＞挥发酚.结论揭示了该河段水质的健康风险水平,对伊通河水源健康管理与保护措施的制定有一定的参考价值.     

黔江区供水水源地水质健康风险评价

以黔江区9个饮用水源地水质作为健康风险评价对象,选取2009年水质监测的部分资料,运用健康风险评价模型,对该地区9个饮用水源地经饮水途径造成的健康风险进行计算和评价.结果表明：饮用水源地健康风险主要来源于化学致癌物,其中以铬（六价）的风险值最大.     

长治市某县乡镇集中式饮用水源水质健康风险评价

文章采用美国环境保护署(U.S.EPA)提出的水质健康风险评价模型,对长治市某县6处乡镇集中式饮用水水源水质进行评价,探讨了水体中所含污染物对人体健康潜在影响。结果表明,该县6处饮用水水源所含污染物对人体健康潜在危害均高于国际辐射委员会(ICRP)推荐的最大可接受限值5.0×10-5 a-1;化学致癌物是该县饮用水中危害人体健康的主要风险来源,对人体健康危害的风险度排序为:Cr6+﹥As﹥Cd。水环境健康风险评价模型较传统的水质等级评价体系能够量化表征水体中各污染物对人体健康的潜在危害,有利于明确水体污染物治理的优先顺序,为水环境管理提供科学依据。     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.