土壤环境质量生物评价方法探讨

土壤动物是一类终生或经常生物于土壤中的动物，与土壤关系密切，对土壤环境的变化非常敏感，利用其进行土壤环境质量评价具有一定优越性。探讨了利用土壤动物进行土壤环境质量评价的可行性及方法，并对前景进行展望。     

黑龙江省生物多样性保护重要性评价

根据黑龙江省生物多样性现状和国家规定的评价方法与指标对黑龙江省的生态系统进行生物多样性保护重要性评价,评价结果将黑龙江省生物多样性保护重要地区分为4级,即极重要、中等重要、比较重要和一般重要四个级别,并确定了它们的分布区域.这一成果为黑龙江省生态功能区划奠定了基础,提供了科学依据.     

齐齐哈尔市土壤环境质量评价与对策

通过对“十一五”期间齐齐哈尔市辖区环境质量的监测、评价和分析,提出了齐齐哈尔市辖区土壤环境质量保护和改善的时策。     

污染土壤的风险评估研究进展

阐述了我国土壤的污染现状,分析了土壤的主要污染物及污染物的来源,并介绍了污染土壤对农作物、水环境及人体的危害,综述了国内外在污染土壤风险评价方面的研究进展,包括健康风险评价和生态风险评价,污染土壤风险评价技术在污染土壤的风险评价、风险管理方面具有广泛的应用前景,为土壤风险评估系统理论的提出及其方法体系和规范的建立提供参考.     

马鞍山市基本农田区土壤环境质量评价研究

选取马鞍山市范围内在行政区域、作物种类和土壤质量上有明显不同的3个基本农田区作为监测评价对象,监测项目包括土壤理化性质、无机和有机污染物共15项.根据监测结果,采用单项污染指数和综合污染指数来评价土壤环境质量.结果表明：3块基本农田所测的无机和有机污染物含量,全部达标;按污染指数综合平均值评价,3块基本农田均为清洁（安全）等级.最后分析了污染成因并提出建议.     

成渝经济区生态系统服务功能重要性评价

选取了生物多样性保护重要性、水源涵养重要性和土壤保持重要性3个重要生态系统服务功能进行分析评价,综合评价了成渝经济区生态系统服务功能的重要性及其区域分异规律. 结果表明:成渝经济区极重要区面积为19 244.00 km2>/sup>,占区域总面积的9.25%,主要为生物核心栖息地、极重要水源涵养区以及土壤保持极重要区;重要区面积为46 814.76 km2>/sup>,占区域总面积的22.56%;一般重要区面积为141 344.08 km2>/sup>,占区域总面积的68.19%.      

天津地区土壤中萘的生态风险分析

以天津地区表土188个样点的实测萘浓度以及萘对10种代表性土壤生物的半致死浓度为基础资料,尝试用3种方式评价了该地区土壤中萘的生态风险.并进行了方法学比较.研究结果发现,暴露浓度和毒性效应概率密度函数的重叠面积与联合概率曲线一致地反映出很低的生态风险,准确计算的暴露浓度超过LC50的概率仅为1.67%.结果说明该地区土壤萘的生态风险极低,仅严重污染的局部地区可能发生最敏感生物种受害.用于进行风险评价的3种方法各有利弊.     

基于生态供受体理论的全国水土保持重要区识别

科学评估土壤保持功能是生态保护红线划定的基础.依据生态供受体理论,针对土壤保持服务对应的水土流失这一生态问题,从水土流失的供体（水土流失量）、受体（人口密度）、辐射传输（距离水体距离）三个方面构建模型,分析土壤保持功能的重要性.结果表明全国潜在侵蚀量577.34×10¹⁰t/a,潜在土壤侵蚀随着坡度和降水量的增加而增加.土壤保持功能极重要区面积98.98×10⁴km²,主要分布在西南地区的无量山和哀牢山,黄土高原东部,东南地区的浙闽丘陵,东部地区的鲁中山区、鲁东半岛,以及辽东半岛.西南地区山高、谷深、坡陡、流急、地形稳定性差等因素造成水土流失严重,维持该地区的水土保持功能极为重要;西北地区的黄土高原土质疏松且多暴雨导致水土流失比较严重,维持该地区土壤保持功能非常重要.对比常用的生态保护功能模型,供受体理论模型除考虑自然影响因素之外,突出了人类活动的因素,对评估生态保护功能与水土保持生态风险更客观.依据供受体理论构建的土壤保持模型适用于土壤保持功能和土壤潜在侵蚀风险的评估,可作为评估生态系统安全和划定生态保护红线的重要依据.     

杭州蔬菜基地重金属污染及风险评价

为掌握杭州市蔬菜基地土壤中重金属污染状况,采用野外调查结合室内分析法,就杭州市10个区县30个蔬菜基地中203个土壤样品进行了Cu、Zn、Pb、Cd、Cr、As和Ni含量的分析及评价,并就重金属含量与土壤理化指标进行了相关分析.结果表明,杭州市菜地土壤中Zn、Cr、As、Ni含量均未超标,但部分土壤中Cu、Pb和Cd含量有超标现象.污染指数评价表明,杭州市菜地土壤重金属综合污染等级多为轻度污染,且主要以Cd污染为主.累积评价表明,杭州市菜地土壤重金属多呈中高度累积,亦主要由土壤Cd累积所致.潜在生态风险评价表明,杭州市菜地土壤中Cu、Zn、Pb、Cr、As和Ni的生态风险轻微,综合潜在生态风险处于中等水平,但Cd存在较强的潜在生态风险.相关分析表明,土壤中Cu、Zn、Pb、As、Cd含量受土壤理化性质影响较大.综上,杭州市要做好菜地土壤重金属的污染防治工作,尤其要防范Cd的污染风险.     

基于生态供受体理论的全国水土保持重要区识别

科学评估土壤保持功能是生态保护红线划定的基础.依据生态供受体理论,针对土壤保持服务对应的水土流失这一生态问题,从水土流失的供体（水土流失量）、受体（人口密度）、辐射传输（距离水体距离）三个方面构建模型,分析土壤保持功能的重要性.结果表明全国潜在侵蚀量577.34×10¹⁰t/a,潜在土壤侵蚀随着坡度和降水量的增加而增加.土壤保持功能极重要区面积98.98×10⁴km²,主要分布在西南地区的无量山和哀牢山,黄土高原东部,东南地区的浙闽丘陵,东部地区的鲁中山区、鲁东半岛,以及辽东半岛.西南地区山高、谷深、坡陡、流急、地形稳定性差等因素造成水土流失严重,维持该地区的水土保持功能极为重要;西北地区的黄土高原土质疏松且多暴雨导致水土流失比较严重,维持该地区土壤保持功能非常重要.对比常用的生态保护功能模型,供受体理论模型除考虑自然影响因素之外,突出了人类活动的因素,对评估生态保护功能与水土保持生态风险更客观.依据供受体理论构建的土壤保持模型适用于土壤保持功能和土壤潜在侵蚀风险的评估,可作为评估生态系统安全和划定生态保护红线的重要依据.     

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.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

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.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

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

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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.     

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.