Mobilities and leachabilities of heavy metals in sludge with humus soil

Chemical forms of Zn, Ni, Cu, and Pb in municipal sewage sludge were investigated by adding humus soil to sludge and by performing sequential extraction procedures. In the final sludge mixtures, Zn and Ni were mainly found in Fe/Mn oxide-bound (F3) and organic matter/sulfide-bound (F4) forms. For Zn, exchangeable (F1), carbonate-bound (F2), and F3 forms were transformed to F4 and residual forms (F5). For Ni, F1 and F2 forms were transformed to F1, F2, and F3 forms. Both Cu and Pb were strongly associated with the stable forms F4 and F5. For Cu, F2 and F3 forms were major contributors, while for Pb, F3 and F4 forms were major contributors to F5. Humus soil dosage and pH conditions in the sludge were strongly correlated with the forms of heavy metals. Five forms were used to evaluate metal mobilities in the initial and final sludge mixtures. The mobilities of the four heavy metals studied decreased after 28 days. The metal mobilities in the final sludge mixtures were ranked in the following order: Ni > Zn > Cu = Pb. Leaching tests showed that the mobilities of Zn and Ni in lower pH conditions (pH 4) were higher than those in higher pH conditions (pH 8).     

改性灰岩除氟的实验研究

采用改性灰岩作为除氟材料,通过批实验和柱实验,考察不同条件下的除氟效果,并探讨了其实际应用的可能性。结果表明:FeCl3溶液联合灰岩除氟,可使高氟水中的氟浓度达到国家饮用水标准,在含氟水样中加灰岩后,直接加FeCl3会促进灰岩对氟的去除效率。在氟离子浓度为5 mg/L,粒径0.2～0.5 mm的灰岩为1 g的条件下,铁离子含量为0.016 mmol/L时,即可达到去除的最佳效果,除氟率可达95.74%。柱实验说明在FeCl3溶液浓度一定时,除氟率随着总出水量的增加而提高;填充的灰岩总量不变时,随着FeCl3溶液浓度的增加,除氟效果明显增加,说明本实验具有实际应用的可能性。     

超声波辅助提取雨水管道沉积物中磷的存在形态

在SMT法的基础上采用超声波技术对实验条件进行优化,用于雨水管道沉积物中磷的提取。通过对提取时间、提取温度等影响提取效率的因素进行分析,确定了提高闭蓄态磷提取效率的条件,从而建立了管道沉积物中磷形态分析的最佳条件。在确定的最佳提取条件下对北京城区雨水管道内沉积物中磷的存在形态进行提取,并对不同形态磷的污染水平和分布状况进行分析,结合环境状况等因素对不同形态磷的污染特性进行了综合研究。     

水中汞形态分析研究进展

水环境中的汞毒性很大,不同形态的汞毒性不同,测定汞总量不能揭示汞的毒性,需要进行汞形态分析的研究。文章介绍了近年来水环境中汞形态分析的前处理技术及检测进展。     

燃煤电厂脱硫粉煤灰理化特性及排放特征

以徐州某电厂脱硫粉煤灰为研究对象,分别研究了脱硫粉煤灰的粒径分布、微观形态、矿物组成和元素含量4方面的物理化学特性,并在此基础上研究了该电厂脱硫粉煤灰颗粒及其中所含元素的排放特征.结果显示,该电厂粉煤灰颗粒物以拉径在3～45 μm的颗粒为主,数量占80％以上,并以表面光滑的球形颗粒居多,并含有少量表面附着小颗粒晶体的球形颗粒和表面有孔的球形颗粒,以及一些不规则颗粒,其主要的矿物组成是莫来石和石英.该电厂粉煤灰颗粒物的排放因子达到了1.95 kgt.粉煤灰的元素组成选取了Mn,Zn,Cr,Cu,Pb,Ni,Cd 7种元素,其中Mn在粉煤灰中的含量最高,相对应的Mn元素的排放因子也高,达到了125.04 g/t.由于该厂粉煤灰含有一定量的重金属元素,随意堆放和处理会对人体和环境产生一定的影响,因此必须做好粉煤灰的处理与处置,降低粉煤灰对人体和环境的危害作用.     

蒙脱石对有机物料施入土壤磷形态和有效性的影响

以冷砂黄泥和矿子黄泥为研究对象,猪粪沼渣为有机物料,分别添加0%、5%、7.5%和10%质量分数的蒙脱石,采用室内培养试验研究了蒙脱石对施有机物料土壤pH、磷形态和有效性的影响.结果表明,有机物料对两种土壤pH无显著影响,而蒙脱石使土壤pH显著提高.施加有机物料使两种土壤铝结合态磷(Al-P)含量和分布比例提高,铁结合态磷(Fe-P)含量培养后期提高、比例略有下降,闭蓄态磷(O-P)含量无明显变化、比例下降.有机物料对冷砂黄泥中钙结合态磷(Ca-P)的含量无明显影响、比例下降,却使矿子黄泥Ca-P含量和比例提高.在施加有机物料基础上添加蒙脱石后,冷砂黄泥Al-P和O-P含量和比例下降,Fe-P含量无明显变化、比例下降,Ca-P含量和比例大幅度提高;矿子黄泥Fe-P和O-P含量和比例下降,Al-P含量无明显变化、比例下降,Ca-P含量和比例大幅度提高.培养过程中,有机物料使冷砂黄泥和矿子黄泥有效磷含量分别提高了17.9%~38.0%和17.1%~33.7%,土壤磷的活化系数也显著提高,添加蒙脱石后使两种土壤有效磷含量分别降低8.8%~35.5%和1.1%~11.6%.相关分析结果表明,蒙脱石通过提高pH和Ca-P含量、降低Al-P含量降低冷砂黄泥磷的有效性,通过提高pH、降低Fe-P含量降低矿子黄泥磷的有效性,对冷砂黄泥磷有效性的影响较矿子黄泥大.     

三峡库区(重庆-宜昌段)沉积物中钒的污染特征及生态风险评价

为全面了解三峡库区(重庆—宜昌段)干支流沉积物中钒的含量水平、空间分布、赋存形态、污染程度,在三峡库区采集水体沉积物样品67个,测定了沉积物中钒的含量及其化学赋存形态,并采用地积累指数法和潜在生态危害指数法进行分析和评价.结果表明:1三峡库区研究区范围内沉积物中钒的含量范围为89.4~175.2 mg·kg-1,平均值为123.7 mg·kg-1,略高于长江沉积物背景值;2库区沉积物中钒的空间分布特征主要呈现库区干流含量大于支流,干流下游沉积物中钒含量高于上游;3沉积物中钒含量的极值点出现在较发达县(区)附近,考虑其来源可能是人为源汇入;4库区沉积物中钒的赋存形态主要以残渣态为主,所占质量分数为80%~89%,并与总量呈现显著正相关关系;5沉积物中钒污染程度较小,潜在环境危害影响较弱.     

海岸带表层沉积物中磷的地球化学特征

通过连续提取法对莱州湾主要入海河流及近岸海域表层沉积物中5种形态磷进行了定量分析.结果表明,近海沉积物自生钙结合磷含量(45.6%)高于河流(37.3%),而铁结合磷(Fe-P)含量(18.2%)却低于河流(31.3%).在近海,可交换或弱结合磷含量和粉砂比例呈正相关,表明该形态磷主要吸附于细粒粉砂.河流沉积物Fe-P与Fe浓度呈显著正相关(P0.01),表明河流沉积物Fe-P分布受沉积物活性铁含量的控制.河口处Fe-P普遍低于相应河流,这可能与海相泥沙输入及河口厌氧区硫酸盐还原或硫化物累积有关.近海沉积物总可提取态磷平均浓度总体呈现出由海洋向河口方向递减的趋势.     

Mutagenic and cytotoxic potential of Endosulfan and Lambda-cyhalothrin - In vitro study describing individual and combined effects of pesticides

Excessive use of pesticides poses increased risks to non target species including humans. In the developing countries, lack of proper awareness about the toxic potential of pesticides makes the farmer more vulnerable to pesticide linked toxicities, which could lead to diverse pathological conditions. The toxic potential of a pesticide could be determined by their ability to induce genetic mutations and cytotoxicity. Hence, determination of genetic mutation and cytotoxicity of each pesticide is unavoidable to legislate health and safety appraisal about pesticides. The objective of current investigation was to determine the genotoxic and cytotoxic potential of Endosulfan（EN） and Lambda-cyhalothrin（LC）; individually and in combination. 3-（4,5-Dimethylthiazol-2-yl）-2,5-Diphenyltetrazolium Bromide（MTT） assay was utilized to determine cytotoxicity, while two mutant histidine dependent Salmonella strains（TA98, TA100） were used to determine the mutagenicity of EN and LC.Moreover, mutagenicity assay was conducted with and without S9 to evaluate the effects of metabolic activation on mutagenicity. Even though a dose dependent increase in the number of revertant colonies was detected with EN against both bacterial strains, a highly significant（p 〈 0.05） increase in the mutagenicity was detected in TA98 with S9. In comparison, data obtained from LC revealed less mutagenic potential than EN. Surprisingly,the non-mutagenic individual-concentrations of EN and LC showed dose dependent mutagenicity when combined. Combination of EN and LC synergistically induced mutagenicity both in TA98 and TA100. MTT assay spotlighted comparable dose dependent cytotoxicity effects of both pesticides. Interestingly, the combination of EN and LC produced increased reversion and cytotoxicity at lower doses as compared to each pesticide, concluding that pesticide exposure even at sub-lethal doses can produce cytotoxicity and genetic mutations, which could lead to carcinogenicity.     

Acute and chronic toxic effects of Pb2+ on polychaete Perinereis aibuhitensis：Morphological changes and responses of the antioxidant system

Perinereis aibuhitensis was used to assess adverse biological effects caused by acute and chronic Pb2＋exposure in artificial seawater under controlled laboratory conditions. In 96-hr acute toxicity experiments,the morphological changes showed a positive time/dose-dependent tendency,and the 96-hr LC50 value of Pb2＋was 686.41 mg/L. The responses of enzymatic and non-enzymatic antioxidants in tissues including catalase（CAT）,peroxidase（POD）,superoxide dismutase（SOD）,glutathione peroxidase（GSH-PX）,malondialdehyde（MDA） and the content of total soluble protein（TSP）,were investigated on days 1,4,7 and 10 after Pb2＋exposure under chronic toxicity testing. Results showed that the activation of the antioxidant system in P. aibuhitensis depended on the Pb2＋concentration and the duration of exposure time.Specifically,POD and SOD activities were induced on the first day of the exposure and decreased to the control level on day 10 after exposure. Therefore,these two indexes could be used to indicate oxidative stress associated with P. aibuhitensis exposure to Pb2＋.