贵州汞矿矿区不同位置土壤中总汞和甲基汞污染特征的研究

为了深入理解汞矿矿区土壤中总汞和甲基汞的污染特征,应用AAS、GC-CVAFS方法,分别对贵州万山、务川和滥木厂汞矿矿区不同位置土壤以及对照区土壤中的总汞(THg)和甲基汞(MeHg)进行了测定.结果表明,万山汞矿区土壤THg和MeHg含量范围分别为1.1～790 mg·kg^-1和0.19～15μg·kg^-1,务川汞矿区土壤THg和MeHg含量范围分别为0.33～317mg·kg^-1和0.41～20μg·kg^-1,滥木厂汞矿区土壤THg和MeHg含量范围分别为0.41～610 mg·kg^-1和0.70～8.8μg·kg^-1.对照区土壤汞含量明显低于矿区土壤,其THg和MeHg含量范围分别为0.14～1.2 mg·kg^-1和0.09～0.23μg·kg^-1;对照区土壤THg含量接近或稍高于全球背景土壤THg含量0.01～0.5 mg·kg^-1.研究表明,汞矿区稻田土壤具有较强的汞甲基化能力,其MeHg含量明显高于菜地和旱田土壤;万山汞矿区土壤汞污染程度明显高于滥木厂和务川汞矿区土壤汞污染.     

古水稻土中多环芳烃的分布特征及其来源判定

测定了马家浜文化(距今约6 000a)遗址2个剖面表层土壤、古代水稻土和古代旱地土壤、以及底层土壤中15种多环芳烃的含量,并对其可能来源进行了判定.结果表明,表层土壤中PAHs的含量分别为202.9μg·kg^-1和207.7μg·kg^-1,主要来源于大气沉降;古水稻土中PAHs含量明显降低,仅为56.0μg·kg^-1,但高于古旱地土壤及底层土壤。古旱地土壤及底层土壤PAHs含量在32.0～36.9μg·kg^-1.古水稻土中,2环和3环所占比例较大,达63%,萘和菲含量最高,而4环以上的多环芳烃含量较低.Phe/Ant和BaA/Chr比值和有机质¹³C-NMR图谱显示,古水稻土中的多环芳烃主要来源于水稻秸秆的焚烧,同时还原条件下的生物合成可能是其另一个重要来源.     

近海潮间带水体及沉积物中重金属的含量及分布特征

利用ICP-MS分析技术,系统测定了天津沿海潮间带表层海水、悬浮物、沉积物及沉积物间隙水中13种重金属元素的含量.结果表明,不同介质中重金属总含量和个体含量差别较大,最大相差4～7个数量级(水和悬浮物中).在相同介质中,各采样点重金属总含量差别不大,变异系数小于30%,个体重金属浓度除间隙水中差别较大外,变异系数均小于50%.潮间带海水中溶解态重金属含量均值为41.2μg·L^-1,原水、沉积物间隙水、悬浮物和沉积物中重金属含量均值分别为62.7μg·L^-1、112.7μg·L^-1、345.0mg·kg^-1和262.3 mg·kg^-1.潮间带各介质中重金属构成有显著差别,典型重金属元素Zn、Cu、Pb和Cr在原水和过滤水中约占40%～50%,而在悬浮物、沉积物及其间隙水中约占到50%～80%.潮间带水体、悬浮物、沉积物与滨岸土壤中重金属元素组成和分布模式的相似性表明其污染来源为陆源污染物.对悬浮物和沉积物中重金属含量与有机质含量的相关分析结果显示二者间相关性较弱,但各重金属含量之间有显著的相关关系,说明它们有相似的地球化学行为.     

点源排放六氯苯在植物中的分布研究

以武汉某工业区为对象, 分析了排污渠、周围大河和农田植物及根际土壤中六氯苯(HCB)的分布特征及影响因素. 结果表明, 采样区内植物和土壤均受到不同程度的HCB污染, 植物中HCB浓度(以干重计,下同)为4.45～1 189.89　μg·kg^-1, 根际土壤中为27.93～3 480.71　μg·kg^-1. 排污渠和大河沿岸植物和根际土壤中HCB含量相对较高. 排污渠内木本植物对HCB富集程度大于草本植物,富集系数(RCF)分别为0.41～2.55和0.01～1.34. 不同农田植物中HCB含量差异很大(4.45～333.1　μg·kg^-1), 而同种植物不同部位对HCB的富集也不相同,例如,芋头果实、根和茎叶HCB含量分别为318.77、 281.02和10.94　μg·kg^-1. 排污渠和农田植物中HCB含量与根际土壤中HCB含量无相关性, 与脂肪含量显著相关.大河南岸植物和根际土壤中HCB含量随着与排放口距离的增加呈现显著降低趋势, 植物根和茎叶中HCB含量与根际土壤中的HCB显著相关, 但与脂肪含量无相关性. 植物中HCB分布特征受到污染源强、脂肪含量和HCB在植物体内的分配-迁移模式影响.     

普者黑岩溶湿地干湿季沉积物氮、磷、有机质分布及污染风险评价

探究典型岩溶湿地沉积物营养物质的污染状况及其富营养化风险,以期为岩溶湿地水-沉积物污染的控制与治理提供参考和依据.以典型岩溶流域普者黑为研究区,运用抓斗式底泥采样器对流域内河流湿地、湖泊湿地、沼泽湿地和库塘湿地的表层沉积物进行采样,并采用国家标准方法对沉积物中总氮（TN）、总磷（TP）及有机质（OM）的含量进行测定,并运用单因子指数法、有机指数法及有机氮指数法对普者黑岩溶流域不同类型湿地沉积物的污染程度进行评价.结果表明：①在干季,河流湿地TP含量最高,为1.18 g·kg^-1,沼泽湿地TN和OM含量最高,分别为2.93、2.71 g·kg^-1;库塘湿地TN、TP和OM含量最低,分别为1.44、0.63、1.43 g·kg^-1.在湿季,河流湿地TP和OM含量最高,分别为0.95、2.16 g·kg^-1,湖泊湿地TN含量最高,为2.22 g·kg^-1;沼泽湿地TP和OM含量最低,分别为0.42、1.28 g·kg^-1,库塘湿地TN含量最低,为1.22 g·kg^-1.②普者黑不同类型湿地沉积物TN、TP、OM在干、湿季下的污染程度不同.在干季,河流湿地和沼泽湿地沉积物磷污染均为重度污染,4种湿地沉积物氮污染均为重度污染,有机污染除库塘湿地属于轻度污染外,其他3种湿地均为中度污染.在湿季,河流湿地沉积物磷污染为重度污染,河流湿地和湖泊湿地沉积物氮污染均为重度污染,湖泊湿地沉积物有机污染属于重度污染.总体上看,各类湿地沉积物氮磷污染干季的污染程度比湿季严重,干季以外源为主,湿季以内源为主;故干季湿地沉积物营养盐潜在释放风险较湿季大.     

白洋淀沼泽区与开阔水域区颗粒物组分特征与沉降通量研究

选取白洋淀的沼泽区（烧车淀）与开阔水域区（采蒲台）为研究区域,分析了水体中新生沉降颗粒物组分组成、沉降通量及其来源.结果表明,两种典型水域中水体颗粒物组分差异显著,其中,烧车淀水域颗粒物成分以有机质（OM）为主,质量占比达到49.59%~74.14%;而采蒲台水域颗粒物以无机组分为主,占比为54.52%~79.27%.烧车淀沉降颗粒物中总碳（TC）、总氮（TN）含量分别为（221.16±39.73） g·kg^-1和（21.10±1.67） g·kg^-1;采蒲台沉降颗粒物中TC和TN的含量分别为（172.28±91.22） g·kg^-1和（15.72±8.12） g·kg^-1.由固相¹³C CP/MAS NMR光谱结果分析出白洋淀沉降颗粒物中碳组分以烷基碳、烷氧基碳为主,其中,烧车淀淀面水域颗粒物中以易分解碳烷氧基碳为主（65.65%）,采蒲台淀面水域颗粒物中以较稳定烷基碳为主（50.76%）.开阔水域区颗粒物沉降通量高于沼泽化区,均值分别为10.63 g·m^-2·d^-1和6.07 g·m^-2·d^-1;开阔水域区不同水域类型颗粒物沉降通量排序为水道（（19.91±8.87） g·m^-2·d^-1）>沟壕（（7.06±2.94） g·m^-2·d^-1）>淀面（（4.92±3.48） g·m^-2·d^-1）.沉降颗粒物的C/N和 C/P比值结果表明,白洋淀沉降颗粒物中有机质主要来源可能为维管束植物和浮游植物.颗粒物沉降通量与组分特征研究有利于剖析白洋淀典型区域湖泊沉积和物质转化过程,为白洋淀能量流动和物质流动研究提供支撑.     

珠江三角洲4种代表性土壤/沉积物中自由态与结合态有机氯农药的含量与分布特征

有机氯农药在土壤/沉积物中主要以自由态和结合态存在.本研究选取珠江三角洲地区4种代表不同沉积环境的典型土壤/沉积物样品,先采用碱萃取、盐酸/氢氟酸去矿物等方法对样品进行了组分分离,再采用有机溶剂萃取法对不同组分中自由态和结合态有机氯农药进行了系统分析.结果显示,4种土壤/沉积物总有机氯农药含量为20.96～134.22 μg·kg^-1,其中HCHs总含量为5.66～22.87　μg·kg^-1,DDTs总含量为1.51～11.70　μg·kg^-1,β-HCH、七氯、艾氏剂、异狄氏剂、硫丹硫酸盐和甲氧滴滴涕等6种农药为主要成分,占总有机氯农药的53.56%～77.26%.自由态有机氯农药含量为8.46～88.45　μg·kg^-1,占总有机氯农药的40.37%～65.90%.结合态有机氯农药含量为11.46～45.77　μg·kg^-1,占总有机氯农药的34.10%～59.63%,主要存在于土壤/沉积物的腐殖酸和胡敏素组分,反映了环境中结合态有机氯农药的大量存在.自由态DDT和HCH类有机氯农药的分布情况表明,4种样品均没有新鲜HCH类农药输入而部分样品仍有新鲜DDT类农药输入.结合态有机氯农药在腐殖酸和胡敏素间的分布与有机质碳含量相关,占总有机碳57.71%～80.55%的胡敏素结合了94.78%～97.48%的结合态有机氯农药.风险评价结果表明,部分游离态有机氯农药如γ-HCH、艾氏剂、异狄氏剂、DDT类农药可能存在一定的生态风险.由于单个化合物的总量要比自由态高出约1～30倍,同时结合态农药在一定条件下有释放到环境的可能,因此有机氯农药的环境风险评价和环境标准建立均需考虑结合态有机氯农药.     

贵阳城市污水及南明河中氯霉素和四环素类抗生素的特征

采用固相萃取-高效液相色谱（UV检测）分析了贵阳城市污水、南明河水和沉积物中氯霉素和四环素类抗生素的特征.结果显示,南北两岸污水中氯霉素、土霉素、四环素和金霉素的平均含量分别为27.0、 2.3、 11.0、 1.1 μg·L^-1和21.2、 2.1、 9.5、 0.5 μg·L^-1,其中以氯霉素的污染为主;污水中抗生素的含量呈现明显的季节变化,这与用水量和疾病特点有关.南明河已广泛受到包括农业、养鱼塘、城市污水等来源的抗生素污染,其中城市污水是最重要的来源,受其影响,污水口下游的抗生素污染尤为严重.河水中氯霉素、土霉素和四环素在冬季的含量范围分别在2.1～19.0、ND～3.0、 0.8～6.8 μg·L^-1之间,夏季分别在0.2～1.3、ND～0.03、 0.2～0.3 μg·L^-1之间,金霉素只在冬季检出,含量范围在0.09～0.14 μg·L^-1之间;沉积物中4种抗生素在冬季的平均含量分别为147.6、 76.6、 99.2和1.6 μg·kg^-1;在夏季分别为195.8、 89.1、 34.4和9.0 μg·kg^-1.数据表明,河水中抗生素的含量受河水流量及来源特点的影响很大,冬季河水中抗生素的含量明显高于夏季;沉积物中抗生素的季节变化不明显.     

利用KOC*值判别杭州市地面水中多环芳烃污染来源

测定了2002年12月杭州市钱塘江和运河杭州段地面水、底泥和土壤中10种多环芳烃的含量,计算了底泥和土壤中PAHs富集倍数K和有机碳标化表观分配系数K_OC^*.结果表明,地面水中PAHs总浓度范围为1.104～9.663μg·L^-1,底泥中为132.7～7343μg·kg^-1(干重),土壤为59.71～219.5μg·kg^-1(干重),污染较为严重.钱塘江底泥PAHs的K值随水流而降低,而运河杭州段则增大.钱塘江底泥和土壤的K_OC^*比值接近1,PAHs主要来自土壤淋溶输入,污染历史不长.运河在城区(如拱宸桥和卖鱼桥)的KK_OC^*比值远大于1,地面径流输入少,而工业排放输入多,且污染历史较长.     

低温期浅水湖泊氮的分布及无机氮扩散通量:以白洋淀为例

本文以我国华北地区最大的浅水湖泊白洋淀为研究对象,探究其低温期沉积物-水界面无机氮的分布特征,分析沉积物孔隙水中无机氮扩散通量对上覆水水质的影响.结果表明,低温期白洋淀表层水总氮（TN）平均浓度范围为4.83~8.23 mg·L^-1,氨氮（NH₄⁺-N）平均浓度维持在0.21~0.34 mg·L^-1之间,硝氮（NO₃^--N）平均浓度在0.01~2.75 mg·L^-1之间.TN污染较严重,超过地表水Ⅴ类水质标准.表层沉积物TN平均含量在681~4365 mg·kg^-1之间,其中有机氮（TON）为氮素的主要存在形式,占总氮比例61.6%~93.1%.NH₄⁺-N为无机氮（TIN）的主要存在形式,平均含量范围为28.9~116.3 mg·kg^-1,NO₃^--N含量整体较低,平均值范围为5.2~23.7mg·kg^-1.低温期白洋淀0~30 cm沉积物孔隙水中NH₄⁺-N浓度是上覆水中的3~16倍,呈现逐渐累积趋势.沉积物-水界面NH₄⁺-N、NO₃^--N和NO₂^--N扩散通量范围分别为-0.55~4.09、-1.44~3.67和-0.88~0.04 mg·（m²·d）^-1,冬季低温期仍具有潜在释放风险.低温期沉积物中积累大量的NH₄⁺-N,可能会在温度升高后影响白洋淀上覆水体水质.因此研究低温期白洋淀沉积物-水界面氮的分布特征和沉积物中无机氮的内源释放风险对于改善白洋淀水质和认识浅水湖泊内源氮污染具有重要意义.     

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.     

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.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.