中国十条主要入海河流河口汞的形态分布特征与入海通量估算

为了解我国河流向海洋汞的输送通量,选取我国沿海10条大型河流的河口作为采样点,采集水体和沉积物,测定水中不同形态汞,包括总汞（THg）、溶解态汞（DHg）、颗粒态汞（PHg）、总氮（TN）、总磷（TP）和溶解有机碳（DOC）等,测定了沉积物THg和甲基汞（MeHg）等.结合河流的径流量,对陆地经河流向海洋汞的输入量进行了粗略的估算.结果显示：我国十条主要入海河流地表水THg含量为2.79~145.15 ng·L^-1,DHg含量为0.61~4.44 ng·L^-1,PHg含量为1.28~143.54 ng·L^-1.PHg约占THg含量的41%~99%,DHg约占THg含量的1%~35%.表层沉积物THg含量为0.02~0.3 mg·kg^-1,MeHg含量为0.04~2.00 μg·kg^-1.MeHg百分含量为0.1%~1.2%.沉积物THg、MeHg和 TOC之间呈显著相关性（p<0.01）.我国主要河流经径流输入THg的入海通量为10.01~29.92 t·a^-1,长江是我国河流向海洋汞输送通量的贡献量最大,约占到我国主要河流入海汞通量的58%~69%.本研究基于实测数据的估算值与前人的估算结果对比,我国主要河流的入海汞通量仅占全球入海汞通量0.2%~15%;对比前人对中国河流向海洋汞的输送通量实测结果以及模型模拟结果显示,实测结果在同一数量级,且实测结果比模拟结果更可靠.     

贵州万山汞矿区汞的环境污染及对生态系统的影响

通过对贵州万山汞矿地区环境样品(水、土壤、植物、农作物和动物)的系统研究,发现该地区的环境汞污染以土壤、大气污染为主,水体基本处于正常范围.土壤汞含量为24.31～347.52mg·kg^-1,比全国土壤平均值高出2～3个数量级;水中汞含量除了冶炼厂荷花池中含量较高外,其它水体为0.10～0.68ng·mL^-1.由于矿山长期的开采和冶炼,整个环境的汞污染严重,当地的植被、农作物、动物中存在明显的汞蓄积,各种植物不同部位的汞含量为0.47～331.4mg·kg^-1;苔藓可以高度富集汞.     

节肢动物体内的总汞和甲基汞含量研究

分析了汞污染区河流沿岸草本植物及节肢动物样品中的汞含量.结果表明,节肢动物飞蝗、中华蚱蜢总汞含量分别为0 .032～0 .402 mg·kg^-1、0 .023～0 .362 mg·kg^-1,高于非污染区1个数量级.飞蝗、中华蚱蜢甲基汞含量分别为0 .003～0 .031mg·kg^-1、0 .004～0 .015 mg·kg^-1,占总汞比例分别为3 .5%～49 .7%和2 .0%～44 .4%.飞蝗、中华蚱蜢体内（一级消费者）汞含量低于其食物草本植物,与未受污染地区不同;螳螂体内（二级消费者）汞明显累积.飞蝗体内总汞含量随着个体长度增长呈下降的趋势,在中华蚱蜢体内则先增长后下降,甲基汞随着个体长度增长呈上升趋势;节肢动物个体不同部位中汞含量明显不同,腹>胸>头.节肢动物体内汞和甲基汞可能导致野生鸟类、家禽、两栖类生态风险.     

万山汞矿区稻田土壤甲基汞的分布特征及其影响因素分析

运用等温气相色谱冷原子荧光技术(GC-CVAFS)对贵州万山汞矿区主要河流范围内稻田土壤甲基汞(MeHg)等含量进行了测定,并从区域层面对土壤甲基汞(MeHg)的分布特征及影响因素进行了研究。结果表明:万山汞矿区稻田土壤MeHg和总汞(THg)含量范围分别为0.72~6.70ng/g和0.49~188.00μg/g,甲基化率范围为0.002%~0.470%;在水平空间分布上,6个检测区域的土壤MeHg含量均随着远离汞矿核心区而降低,但是不同区域之间的降低变化程度不尽相同。通过对稻田土壤SiO2、Al2O3、Fe2O3、TS、TP、TN、有机质、pH等土壤性质与土壤MeHg以及甲基化率进行相关性分析发现,MeHg与THg、TS、TP、TN、有机质存在显著的正相关关系,与SiO2表现出显著性负相关,表明土壤甲基汞不但和总汞含量有关,还受到土壤其它理化因子,尤其是一些营养因子所控制。     

珠三角地区生活垃圾焚烧厂汞的排放特征

利用OH法对珠三角8家垃圾焚烧厂(6家采用炉排炉工艺,2家采用流化床工艺)进行烟气采样,同时采集飞灰、底渣、煤炭样品进行分析.研究结果表明,珠三角炉排炉焚烧烟气平均总汞(THg)排放浓度为(51.4±28.3) μg·Nm^-3,流化床为(19.5±13.6) μg·Nm^-3.炉排炉飞灰THg含量为6674 μg·kg^-1,流化床飞灰THg含量为2135 μg·kg^-1,底渣中炉排炉THg含量为70 μg·kg^-1,流化床为30 μg·kg^-1.飞灰中的汞含量要远远高于底渣.垃圾焚烧过程中炉排炉70.8%的汞由烟气排放,26.3%存在飞灰中,底渣中的汞仅占2.9%.流化床工艺烟气汞排放占总汞排放的33.2%.利用质量平衡法计算珠三角垃圾中汞含量平均值为0.293 mg·kg^-1,流化床工艺因添加燃煤所产生的汞排放占到垃圾焚烧总汞排放的31.6%.     

锌冶炼-氯碱复合污染区木本植物中的汞

研究了葫芦岛市13个不同地点的154个木本植物样品的汞含量.葫芦岛市木本植物受到严重的汞污染.叶汞含量为0.029～2.700 mg·kg^-1,平均为0.182 mg·kg^-1,植物叶汞中的浓度李树＞梨树＞柳树＞杉树＞榆树＞槐树＞丁香＞杨树＞松树＞柏树;茎汞含量为0.009～0.342 mg·kg^-1,平均为0.066 mg·kg^-1.植物树茎、树叶汞含量呈显著正相关,树叶>树茎.植物汞含量与其距离污染源的远近及风向有关,距离污染源越近,植物总汞含量越高.表明大气沉降作用对植物汞的含量有显著的影响,锌冶炼厂是植物汞含量的主要来源.     

万山汞矿区地表与大气界面间汞交换通量研究

采用动力学通量箱与高时间分辨率大气自动测汞仪联用技术对万山汞矿区不同季节、不同地表与大气界面间汞交换通量和大气汞含量进行了测定.结果显示,受人为活动和地表强烈释汞的影响,万山地区大气汞含量高出背景区1～3个数量级,在冶炼厂附近平均值可达1 101.8 ng/m³,最低平均值达17.8 ng/m³,显示万山汞矿区已遭受较严重的大气汞污染.万山汞矿区土壤与大气界面汞交换非常强烈,土壤向大气的释汞通量最高可达27 827 ng/(m².h),大气汞干沉降通量最高可达9 434ng/(m²·h).万山汞矿区土壤与大气汞交换通量主要受光照强度、大气汞含量影响.光照在土壤释汞过程中起促进作用,而较高的大气汞含量则抑制了土壤向大气的释放,并导致大气汞强烈的干沉降.不同的地表类型对地表释汞影响较大,植被覆盖土壤释汞通量显著低于无植被覆盖地区,而冶炼后的矿渣堆则成为大气汞的净源.     

铜仁汞矿区土壤汞污染现状调查研究

为了进一步对废弃汞矿污染区的生态环境进行跟踪调查及科学的评价,2015年通过对铜仁市废弃汞矿区周围的稻田、旱田及菜地土壤汞污染现状调查分析。采用S型随机抽样方式,并使用原子荧光光度法对研究对象进行分析。结果表明:万山镇、云场萍及路腊村汞矿区稻田土壤总汞(THg)含量平均值分别为123.75、79.33、21.89 mg/kg;其旱田土壤THg含量平均值分别为:117.20、73.34、19.90 mg/kg;其菜地土壤THg含量平均值分别为129.40、81.78、26.50 mg/kg;且,万山汞矿区甲基汞(Me Hg)含量平均值分别为6.48(稻田)、4.80(旱田)、6.40μg/kg(菜地);云场萍汞矿区Me Hg含量平均值分别为3.73(稻田)、2.47(旱田)、6.40μg/kg(菜地);路腊村汞矿区Me Hg含量平均值分别为1.92(稻田)、0.87(旱田)、2.47μg/kg(菜地)。以上结果说明万山废弃汞矿区的污染程度高于云场萍废弃汞矿区及路腊村废弃汞矿区。     

三峡库区消落带沉积物对鱼体富集汞的影响

水体环境中的汞（Hg）容易被鱼体富集.为了研究三峡库区消落带沉积物对鱼体Hg含量的影响,采用不同Hg含量的消落带沉积物进行了为期90 d的模拟淹水实验.结果表明沉积物淹水后,水体总汞（THg）和甲基汞（MeHg）含量显著增加,鱼体肌肉中THg和MeHg含量不断增加,而内脏和头部中THg和MeHg含量前期不断增加,后期则有轻微减小的趋势.肌肉对Hg的富集量大于内脏和头部,后两者的富集量没有显著性差异.与对照组（无沉积物）相比沉积物的存在明显增加了鱼体富集Hg的量,而且当沉积物中Hg含量较高时,鱼体对Hg的富集量也显著增加.鱼体各部位THg和MeHg含量变化曲线高度相似,各部位对MeHg的富集系数（bioaccumulation factors,BCF）在1.93×10⁵~8.89×10⁵之间,对无机Hg的BCF在1.3×10³~12.8×10³之间,表明鱼体所富集的Hg形态上主要为MeHg.鱼体各部位MeHg和THg含量均为极显著相关,线性回归方程表明,在富集Hg的量中,MeHg占THg比例分别为：肌肉80.1%、内脏79.3%、头部66.7%.消落带沉积物再淹水后会发生一定程度的净甲基化现象产生MeHg,由于扩散作用使水体MeHg浓度在一段时间内升高,这导致了鱼体对Hg的富集量增加.因此对三峡库区大面积消落带可能存在的Hg污染风险不可忽视.     

湘西汞矿区土壤中重金属的空间分布特征及其生态环境意义

采用HG-ICP-AES和ICP-MS法测定了湘西茶田汞矿区典型土壤剖面（远离矿口处的自然土壤剖面P₁、矿口附近的自然土壤剖面P₂和汞矿渣下覆土壤剖面P₃）不同层次的土壤及矿区的矿石、废矿和矿渣等环境样品中Hg及其它重金属的含量,在此基础上,结合富集系数法和相关分析等地统计学方法,探讨了汞矿区土壤中Hg等重金属的来源、分布及迁移特征.结果表明,Hg在P₁剖面中呈底层富集趋势,而在P₂、P₃剖面中均表现出明显的表层富集现象;P₂、P₃剖面土壤都遭受了Hg的污染,但P₃的污染更为严重,其土壤表层的Hg含量达到640 　μg·g^-1,剖面Hg平均含量为(76.74±171.71) 　μg·g^-1,Hg向下迁移的深度超过100 cm,分别高于P₂的6.5 　μg·g^-1、(2.74±1.90) 　μg·g^-1和40 cm;除成矿元素Hg污染严重外,矿区土壤中还存在着Cd、As、Pb、Zn的污染,且以Cd的污染较为严重;矿区土壤剖面中重金属的迁移能力为Hg>Cd>As>Zn ≈ Pb,并受元素在表土层的含量及土壤理化参数的影响.研究表明,矿区土壤剖面中重金属的来源、分布及迁移既受原生地质环境的影响,更与人类采选矿活动密切相关.     

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.     

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.     

Effect of sorbed and desorbed Zn(Ⅱ) on the growth of a green alga (Chlorella pyrenoidosa)

Toxic effect of Zn(Ⅱ) on a green alga (Chlorella pyrenoidasa) in the presence of sepiolite and kaolinite was investigated.The Zn-free clays were found to have a negative impact on the growth of C.pyrenoidosa in comparison with control samples (without adding any clay or Zn(Ⅱ)).When Zn(Ⅱ) was added,the algae in the presence of clays could be better survived than the control samples,which was actually caused by a decrease in Zn(Ⅱ) concentration in the solution owing to the adsorption of Zn(Ⅱ) on the clays.When the solution system was diluted,the growth of algae could be further inhibited as compared to that in a system which had the same initial Zn(Ⅱ) concentration as in the diluted system.This in fact resulted from desorption of Zn(Ⅱ) from the zinc-contaminated clays,although the effect varied according to the different desorption capabilities of sepiolite and kaolinite.Therefore the adsorption and desorption processes of Zn(Ⅱ) played an important part in its toxicity,and adsorption and desorption of pollutants on soils/sediments should be well considered in natural eco-environmental systems before their risk of toxicity to aquatic organisms was assessed objectively.