污染土壤胶体释放特征及其对锌运移的作用

污染土壤样品采自辽宁省某炼锌企业周边农田。通过室内土柱淋溶实验,研究不同pH和离子强度下土壤胶体的释放特征以及对重金属Zn在土壤中运移的作用。结果表明,土壤胶体的释放均呈现先逐渐增强而后渐弱,并趋于稳定。pH和离子强度对土壤胶体的释放有明显的影响,弱酸(pH=6)条件最有利土壤中胶体的释放,其次是中性(pH=7)和碱性(pH=9)条件,在强酸(pH=4)条件下最弱。随离子强度增加,土壤中胶体的释放能力逐渐减弱。淋出液中胶体结合态Zn浓度均超过总Zn浓度的50%,且淋出液中的总Zn浓度与胶体的浓度相关性显著。经SPSS分析,pH=4、6、7和9时,该线性相关系数r分别为0.749、0.948、0.966和0.927,呈极显著相关关系。钙离子强度为0.001、0.01、0.1和0.5 mmol/L时,相关系数r分别为0.921、0.895、0.947和0.907,也呈现极显著相关关系。说明土壤地下水中Zn的运移主要受胶体释放的控制。     

膜探针的制备及PVA/PEG/PVP在膜污染过程中的作用

为了进一步研究膜的抗污染性能,介绍了一种新型膜探针技术。将二氧化硅颗粒黏附在探针尖端,并将含不同添加剂的铸膜液涂覆于二氧化硅表面以制成一种改性膜探针。采用原子力显微镜测量不同改性膜-污染物和污染物-污染物之间的黏附力。实验结果表明:膜-污染物之间的黏附力远大于污染物-污染物之间的黏附力;膜对二级出水(effluent organic matter,EfOM)通量的衰减幅度与膜-污染物之间黏附力正相关,与污染物-污染物之间黏附力的相关性不明显;(3)膜通量的恢复率与膜-污染物黏附力大小负相关。     

生物质气化发电厂灰渣中微量元素的赋存形态及其析出

分别用Tessier逐级提取形态分离法和模拟酸雨浸提实验,研究了生物质气化发电厂的气化器、淋洗器和旋风分离器底灰中微量元素的赋存形态及其析出规律,探讨了微量元素析出浓度和影响其析出的因素．结果表明,微量元素大部分存在于残渣态,其有机态、Fe-Mn氧化态和碳酸盐结合态的浓度依次减少,可交换态的赋存量极低;元素的析出受浸提液pH值、浸提温度和浸提时间的影响,元素在灰渣颗粒物中的赋存形态及含量的高低也影响元素的释放和析出程度．     

城市地下水流场人工调控与减灾方案

以郑州市为例,针对城市区域长期过量开采地下水导致的一系列严重的环境地质灾害,诸如地下水水位持续下降形成区域地下水降落漏斗并不断扩张、含水层疏干、供水井吊泵、泉水断流、地下建筑工程浸没、地面沉降和塌陷等,探讨了城市地下水流场人工调控的减灾方案。建立了地下水系统的准三维动态数值仿真模型,以非均质各向同性渗流模型仿真地下水流,用不规则三角网格有限差分法求解了三维数值仿真模型。先解逆问题反求参数,再解正问题计算地下水各项资源量,数值仿真预报地下水渗流场至１９９８年。在此基础上,通过地下水渗流场的宏观调控与优化管理,使研究区内不合理开采地下水资源所引发的环境灾害减小到最低程度,为郑州市的环境减灾工作提供了科学依据。     

Enhancement of chlorophenol sorption on soil by geophagous earthworms (Metaphire guillelmi)

Earthworms are the dominant soil biomass of many terrestrial ecosystems and markedly influence the physico-chemical and biological properties of soil; however, little is known about the effects of earthworm activities on the environmental behavior of micropollutants in soil. We studied the sorption and desorption of 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol on geophagous earthworm (anecic Metaphire guillelmi) casts of various aging times and on the parent soil. The casts were characteristic of lower pH and higher content of fine particles (silt and clay) than the parent soil. The sorption of the chlorophenols on the soil and casts were well fitted to linear isotherms, with sorption capacity in the order of pentachlorophenol > 2,4-dichlorophenol > 2,4,6-trichlorophenol. The sorption on the cast with different aging time was quite similar and was higher than on the parent soil. The sorption on the soil did not change between pH 7.07 of the soil and pH 6.76 of the casts. The desorption hysteresis of the chlorophenols on the soil and casts was compound specific and 2,4,6-trichlorophenol showed the highest hysteresis. The higher sorption capacity of the casts was not owing to the lowered pH of the casts, but mainly to the higher fine particles in the casts and the possible changes of nature of the soil organic matter through the earthworm gut passage. Our results indicate that geophagous earthworms may change sorption behavior and thus the bioavailability and transport of chlorophenols in soil. Earthworm effects should be considered when evaluating the environmental behavior and risk of organic pollutants in the ecosystems where earthworms are abundant.     

Urinary concentrations of polycyclic aromatic hydrocarbon and phthalate metabolite mixtures in relation to semen quality among men attending an infertility clinic

Environmental Science and Pollution Research - Previous studies have reported that exposure to phthalates and polycyclic aromatic hydrocarbons (PAHs) is individually associated with altered semen...     

Levels,congener profile and inventory of polychlorinated biphenyls in sediment from the Songhua River in the vicinity of cement plant,China: a case study

This study investigated the contamination levels, homologue, and congener profiles and evaluated the residue inventory of polychlorinated biphenyls (PCBs) in sediment of the Songhua River in the vicinity of cement plant. The total concentration of detected 35 PCB congeners ranged from 1.12 to 2.19 ng/g dry weight (dw) in sediment, with a mean value of 1.56 ng/g dw, and the concentration of PCBs decreased in the following order: the downstream?>?cement plant?>?upstream. The results of total organic carbon (TOC)-normalized PCB concentrations indicate that the sediments have low potential ecological risk in this area. The study results on homologue and congener of PCBs show that the emissions from cement production could be the major sources of PCBs in sediment, and the low-chlorinated PCBs will be exchanged among air, water, and sediment with increasing temperature during summer and flow to downstream with water during the wet season. The spatial density and total burden of PCBs in the surface sediments were 17.2 ng/cm² and 1.2 kg, respectively. To our knowledge, this study is the first to explore the pollution characteristics of unintentionally produced PCB emissions from cement industry by means of monitoring sediment samples.     

杭州城市及其边缘区湿地磷化学特征的研究

对杭州城市及其边缘区湿地土壤的磷形态组成、固磷能力和释放潜力等方面进行了初步的研究。结果表明,杭州城市及边缘地区的湿地由于受人类影响的不同及所处环境的差异,性质已有很大的分异。城区的西湖、水塘和河流底泥中磷的积累、磷的饱和度和零吸附磷平衡浓度均明显高于城市边缘地区的湿地;湿地土壤中的磷主要呈不稳定、或亚稳定态,可提取态磷约占总磷的80%,62%的湿地土壤磷饱和度在25%以上。最大磷吸附量的大小主要与湿地中无定形氧化铁、铝含量有关。零吸附时磷的浓度(EPC)较高,在0.10~2.48mg·L-1之间,具有较强的释放潜力。半透膜渗析法测得的磷释放量与磷积累呈正相关,但当磷饱和度超过25%时,其磷释放量显著增加。研究表明杭州市及其边缘区湿地土壤磷已普遍达到较高水平,这在一定程度上影响磷净化功能的正常发挥。     

Hydrogen peroxide (H2O2) requirement for the oxidation of crude oil in contaminated soils by a modified Fenton's reagent

The oxidation of soil organic matter (SOM) and total petroleum hydrocarbon were investigated in two soils at eight different hydrogen peroxide (H₂O₂) concentrations to determine the optimal H₂O₂ dosage for the efficient remediation of soils contaminated by crude oil with minimal SOM removal. In our study, H₂O₂ concentrations up to 1100 mM increased the SOM destruction up to 10%–15% in the two soils while no improvement of the crude oil removal efficiencies was observed. The results indicate that the destruction of SOM significantly limits the oxidation of crude oil because SOM might consume H₂O₂ more effectively than crude oil at H₂O₂ concentrations above 1100 mM. In addition, H₂O₂ concentrations higher than 1100 mM were not expected for both soils because of the extremely rapid H₂O₂ decomposition, and low H₂O₂ utilization, of both soils.     

城镇圩区排涝模数计算方法及其与河道调蓄库容关系研究

农业圩区原有的排涝模数计算方法已不适用于城镇圩区.针对城镇圩区的排涝特殊性,通过分析排涝计算的原理,充分考虑圩区内河道的调蓄能力,得到适应城镇圩区排涝计算的方法.以南京市江宁区为例,对城镇圩区的排涝模数进行计算,得到排涝模数与调蓄库容之间的定量关系.