生活垃圾焚烧飞灰矿物学特性及重金属分布

生活垃圾焚烧飞灰的矿物学特性是飞灰中重金属赋存环境的直观反映,与重金属在处置环境中的释放和迁移行为密切相关.为掌握重金属在生活垃圾焚烧飞灰中的分布规律,结合X射线衍射、扫描电镜等常规矿物学研究工具及矿物解离分析系统对飞灰的矿物学宏观属性和微观属性进行全面测试.结果表明,飞灰是由矿物相和非矿物相组成,两者之间紧密连生,主要矿物相包括氯盐和方解石、氢氧钙石等多种含钙矿物.重金属元素在飞灰中主要以3种形式存在:均匀分布在无定形的非矿物组分中,以同晶置换赋存在方解石等矿物中以及吸附在特殊矿物如石英、赤铁矿等表面.难挥发性重金属Cu和Cr绝大部分分布在非矿物相中;半挥发性重金属Zn和Cd各有43.92%和60.61%的含量分布在矿物相中,其中,方解石对Cd、赤铁矿对Cr及硅酸盐对Zn存在较强的富集作用.     

不同钝化剂对碱性镉污染土壤钝化效果研究

该研究以河南栾川石宝沟典型铅锌矿区镉污染农田土壤作为供试土壤,采用室内培养试验法,分别添加熟石灰、方解石、白云石、沸石、蒙脱石、生物炭等6种钝化材料,采用Tessier修正顺序七步提取法进行镉形态含量分析,研究不同钝化剂在1%、3%、5%添加量条件下对典型北方碱性土壤镉的钝化效果。结果显示,试验选用的6种钝化材料在不同程度上提升了土壤pH值,对p H值提升效果排序为熟石灰蒙脱石沸石白云石生物炭方解石。不同钝化剂对离子交换态Cd的钝化作用具有一定的差异性,钝化效果排序为熟石灰方解石生物炭沸石白云石蒙脱石,其中碱性物质熟石灰对离子交换态Cd的降低效果显著,同为碳酸盐矿物的方解石明显优于白云石,同为黏土矿物的沸石优于蒙脱石,生物炭钝化效果居中。其中5%添加量熟石灰、3%添加量方解石、1%添加量沸石、1%添加量生物炭钝化效果最为明显,对土壤离子交换态Cd含量分别降低了61.11%、25.32%、14.84%、24.76%。6种钝化剂的添加在不同程度上改变了Cd在土壤中的形态含量比例,总体来看,离子交换态镉含量显著降低,碳酸盐结合态、腐殖酸结合态、铁锰氧化物结合态镉含量明显增加,硅酸盐残余态镉含量小幅上升,强有机结合态略微下降。     

长江口柱状沉积物中磷的存在形态及其分布特征研究

对长江口的柱状沉积物进行了总磷测定,并运用SEDEX方法分析了长江口柱状沉积物中5种形态磷的含量和分布。研究结果表明,柱状样沉积物不同站位各种形态磷的垂直分布各不相同,由表至底呈现多种分布状态,与沉积环境、沉积后的成岩作用有关。长江口柱状样沉积物有机磷的降解速率常数变化结果表明,长江口海域有机磷的降解主要发生在沉积物表层和次表层。2个柱状样沉积物中氮磷比远低于16:1,说明长江口近岸海域沉积物中的磷主要来自陆源。对柱状样的年代分析表明,总磷含量随年代的变化有明显的区域特征性,长江口总磷含量的髙值与长江较大输沙量的年份具有一致性。     

长山群岛海区现代沉积特征

以１９８９￣１９９２年辽宁省海岛资源综合调查中海洋地质，海洋沉积资料为基础，通过对表层沉积物类型，粘土矿折的６个柱样＾２１０Ｐｂ沉积速率的分析，研究了长山群岛海区现代沉积特征。结果表明，该区沉积物类型分布与一般浅水海域近岸粗远岸细的泥沙分布规律截然不同，呈现出近岸细远岸粗、从西北向东南变粗的总趋势；４种主要粘土矿物的含量伊利石〉高岭石〉绿泥石〉蒙脱石，矿物组成明显受控于大陆沿岸河流输砂；沿岸河口区     

三亚湾沉积柱有机氯农药的垂直分布特征

采用GC-ECD内标法测定了三亚沉积柱状样中有机氯农药的含量,并以210Pb同位素法对柱样定年,探讨了柱样中有机氯农药的垂直分布特征及可能来源.结果表明:沉积物中HCHs和DDTs的含量分别为0.04～1.46和0.01～0.59ng.g-1(以干重计,下同);自20世纪60年代开始大量使用OCPs后,沉积柱中OCPs在1965年、1971年和1975年分别出现了3个峰值;在我国禁止生产和使用OCPs后,柱样中OCPs含量自1986年后略有降低;自1990年起,OCPs含量明显增加,变化幅度较大,其含量变化与三亚发展建设有关.研究区域调查显示,近年来有林丹的输入,HCHs在沉积柱样表层富集较明显;在该偏氧化的沉积环境中,(DDD+DDE)/DDTs的值逐渐变小,且大部分均小于0.5,说明可能有新的DDTs输入.     

长江口岸带柱状沉积物中磷的存在形态及其环境意义

通过对长江河口岸带柱状沉积物中P的分析，揭示了沉积物中P的存在形态和分布特征。柱状沉积物中P的存在形态主要有DP、Al-P、Fe-P、Ca-P和OP等5种，其中以Ca-P（约占TP的28%-52%）和OP（约占TP的43%-68%）为主。研究发现，在近排污口的柱状沉积物中Al-P和有机碳（TOC）具有相似的变化趋势，具Al-P含量明显高于非排污口处的朝阳柱样，反映了柱状沉积物中各形态P的分布特征受人类活动的影响比较明显。此外，柱状沉积物中P的存在特征受沉积速率的影响显著。     

曹妃甸近岸表层沉积物粒度和粘土矿物分布特征研究

为探讨曹妃甸近岸海区表层沉积物粒度和粘土矿物组成和分布特征,利用激光粒度仪和X-射线衍射(XRD)分析的方法对曹妃甸近岸海区15个表层沉积物样品进行分析。结果表明:曹妃甸近岸海区沉积物以粉砂为主(45.2%),其次是砂(30.2%)和粘土(24.6%);研究区内四种粘土矿物含量依次为伊利石(55.8%)蒙皂石(24.9%)绿泥石(9.9%)高岭石(6.7%)。研究表明曹妃甸近岸表层沉积物含量和分布特征受物源、水动力等自然因素和围填海工程等人为因素共同影响;其中,围填海工程的长期实施对研究区表层沉积物中较细颗粒(粉砂和粘土)的分布影响较为明显;伊利石、高岭石和绿泥石分布特征与围填海导致的水动力改变密切相关。研究结果对曹妃甸近岸海区的沉积特征及沉积物物源、了解围填海工程对海洋沉积环境的影响有着一定的科学意义。     

安徽池州地区下蜀组沉积环境及成因探讨

采用磁化率、黏土矿物测试及粒度分析等手段,结合区域第四纪地质特征,从气候演变和岩相古地理等角度探讨了安徽池州地区下蜀组的沉积环境及成因。该区下蜀组磁化率曲线呈波峰、波谷旋回特征;黏土矿物以伊利石为主,个别层位以蒙脱石、高岭石、绿泥石为主;粒度以粉砂为主,个别层位以粉砂及中粗砂为主。下蜀组沉积期间存在多次寒冷干燥到温暖潮湿的气候转换,整体为寒冷干燥气候的风成沉积,受古地理位置影响,沿江局部地区夹温暖潮湿气候条件下的长江水系冲积沉积。     

广西隆华铝土矿的矿物学特征研究

广西隆华铝土矿是一水硬铝石型铝土矿 ,该矿的矿物组成主要为硬水铝石 ,其次有三水铝石、软水铝石、高岭石、伊利石、鲕绿泥石、锐钛矿、金红石、铝赤铁矿及锂硬锰矿等。硬水矿石中主要元素为铝 ,且分布较均匀 ,适应于高压拜耳法溶矿。本矿床的底泥中发现有一未知矿物 ,经X射线衍射分析及格林 -凯利 (Greene-Kelly,1 95 3 )方法鉴别 ,该矿物为贝得石 ;经蒙脱石 -贝得石系列的蒙脱石群定量法 (Jones,1 964 )测定 ,该矿物的含量为 1 5 .4 5 %。     

海水条件下Cd-CaCO_3共沉淀过程的动力学表达:文石

采用稳定加液系统,在海水条件下模拟了Cd随文石(CaCO3)的共沉淀过程,并对这一过程中Cd的分异行为进行了定量评估。实验结果显示,Cd介于文石和海水之间的分异系数(DCd)仅在0.2至0.9范围内变化,Cd表现为一种不相容元素。随着文石沉淀速率的增加,DCd值呈逐渐上升趋势。这些分异行为显著区别于Cd在方解石-海水体系中的分异行为,表明Cd随碳酸钙的共沉淀过程受到相应CaCO3矿物晶体结构的影响。在运用海相CaCO3沉积物中Cd/Ca比值作为古海洋研究指标的时候,应严格区分相关载体(CaCO3)的晶体矿物学差异。     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.