中国环境风险现状及发展趋势分析

基于国内2000-2009年以来环境污染事故统计资料,深入分析了中国现阶段环境风险类型、事故高发区域、事故损失、环境风险事故诱因等特征,并对其环境风险演变趋势进行了判断。新时期中国经济增长方式处于转变阶段,以布局型环境隐患和结构型环境风险为首要威胁,风险类型更加复杂化,事故影响范围进一步扩大,由于居民消费转型与科技发展带来的新型环境风险更是不可预知,环境风险压力进一步增大。     

突发性水污染事故应急健康风险评价

基于US NAS健康风险评价理论,构建包括危害鉴别、剂量效应评价、暴露评价和风险表征4部分内容的突发性水污染事故应急健康风险评价技术体系.该技术体系充分考虑突发性水污染事故污染物对于人体健康“短时间、高剂量”的暴露特点,提出了突发性水污染事故污染物应急参考浓度的计算方法,以健康危害商值定性描述突发性水污染事故的健康风险,并通过统计推断健康危害商值的概率分布定量描述突发性水污染事故的健康风险,并实现风险分级.以松花江硝基苯水污染事故为例,对突发性水污染事故应急风险评价技术进行验证,计算获取的以保护成人和儿童的应急参考浓度分别为0.175,0.05mg/L,污染事故的健康风险值分别为29%和62%,分别隶属于中级和高级风险水平.实例表明应急健康风险评价技术体系能够有效表征突发性水污染事故的健康风险,在一定程度上可以为突发性水污染事故的应急管理提供依据.     

合成氨-尿素生产建设项目环境风险评价

环境风险评价是化工建设项目环境影响评价的重要内容。以合成氨-尿素生产为例,按照环境风险评价技术导则的程序和方法进行化工项目环境风险识别和源项分析,指出液氨储罐燃烧爆炸、储罐或阀门破裂液氨泄漏、中压氨罐火灾爆炸及中压氨罐泄漏是合成氨-尿素生产中的重要风险事故,并利用多烟团模式对液氨储罐燃爆和泄漏两项最严重风险事故进行风险影响分析和最大风险值计算,结果表明,该项目事故风险最大值小于化工行业风险统计值,并提出事故风险的防范措施和对策。     

烟草企业生产安全事故风险评估方法研究

合理、真实地评估企业事故的风险等级,对减少风险矩阵法评估时产生的风险结具有重要的作用。以某烟草公司为例,通过德尔菲法遴选风险评估专家,针对事故类型和火灾事故风险因素两方面,采用风险矩阵法和Borda序值法相结合的方式对烟草企业生产安全事故风险等级进行了评估,建立了事故风险综合评估模型,从而减少了风险矩阵中风险结的数量。结果表明:从事故发生可能性(F)、事故后果严重程度(C)和风险值(R)三方面得出的评估结果具有较高的一致性,得出12种事故类型和8个火灾事故风险因素风险等级的排序,可为烟草企业确定主要事故风险、配备应急资源、制定事故风险防范和控制措施提供依据,为提高应急预案编制的针对性提供借鉴。     

石化企业环境风险评价研究

随着环评的不断发展,环境风险这一问题也日益受到关注,细化石化行业的环境风险评价方法和内容也显得十分必要。本研究结合长庆石化500万吨常压蒸馏装置项目对石化企业进行环境风险的工作程序和方法进行论述,介绍了常压蒸馏的工艺流程,对本项目进行风险识别,源项分析,事故后果预测及分析,风险计算和评价,最后得出了最大风险值,该项目事故风险最大值小于化工行业风险统计值,并且提出事故风险的防范措施和对策及应急预案,以期为石化企业进行环境风险评价提供方法依据。     

自来水厂液氯贮罐氯气泄漏事故风险评价初探

针对自来水厂液氯贮罐发生泄露的事故风险,应用烟团模式进行了液氯泄露后污染物浓度预测,并根据预测浓度从环境标准和化学物质危险度两方面进行了事故风险评价探讨,得出致死风险.     

大型磷铵企业环境风险评价的探讨

大型磷铵企业一般包括合成氨、硫酸、磷酸、磷铵等化工过程,生产工艺复杂,涉及氨、硫酸、磷酸、氟化氢等化学品,环境风险较大,笔者以某大型磷铵企业为例,对该企业重点污染风险因子进行识别,同时介绍了风险事故概率确定、事故环境影响预测、事故减缓措施及风险事故应急预案等,并提出了大型磷铵企业环境风险的防范措施.     

关于环境风险评价中事故池容积的探讨

通过对建设项目环境风险评价的分析,提出事故池是环境风险评价中的一项重要防范措施,其容积既要满足事故状态下对消防水的收集又要体现经济合理性。对环境风险评价中的事故池的容积设置进行了探讨。     

亚磷酸项目环境风险评价实例分析

环境风险评价是化工项目环境影响评价的重点工作之一,结合对亚磷酸生产过程中工艺过程及产污环节进行分析,了解原辅料及主副产品的理化特性,通过对工程潜在的环境风险环节进行识别和风险类型确定,从而科学准确地进行风险源项分析,确定事故发生的最大概率,进而完成事故状态下的后果影响分析,并根据事故产生的后果,提出防范和减缓事故发生后的风险,从组织措施、技术措施等诸多方面提出风险管理方案和应急防范预案,来保障事故一旦发生对环境的影响降低到最小程度。     

合成氨-尿素生产建设项目环境风险评价

环境风险评价是化工建设项目环境影响评价的重要内容。以合成氨-尿素生产为例,按照环境风险评价技术导则的程序和方法进行化工项目环境风险识别和源项分析,指出液氨储罐燃烧爆炸、储罐或阀门破裂液氨泄漏、中压氨罐火灾爆炸及中压氨罐泄漏是合成氨-尿素生产中的重要风险事故,并利用多烟团模式对液氨储罐燃爆和泄漏两项最严重风险事故进行风险影响分析和最大风险值计算,结果表明,该项目事故风险最大值小于化工行业风险统计值,并提出事故风险的防范措施和对策。     

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.     

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.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.