污泥农用后有机复合污染土壤强化修复初步研究

通过室内模拟试验,以持久性有机污染物（POPs）中毒性较强的多氯代有机污染物多氯联苯（PCBs）和有机氯农药（OCPs）为目标污染物,以不同碳源和水分条件为调控因子,研究了淀粉和葡萄糖等不同来源的碳、水分条件及其联合措施对污泥农用后多氯联苯（PCBs）和有机氯农药（OCPs）复合污染的长江三角洲地区土壤中两种有机污染物的削减影响及其贡献大小.结果表明,土壤水分含量为正常田间持水量时,加入淀粉和葡萄糖等碳源均一定程度地促进了真菌和细菌数量的增加,从而促进了土壤中PCBs和OCPs的降解;淹水可促进土壤中PCBs的降解,在一定程度上也促进了土壤中OCPs的降解.     

电动强化过硫酸钠修复多氯联苯污染土壤的研究

选取PCBs实际污染土壤为研究对象,研究了电动增强Na₂S₂O₈氧化修复PCBs污染土壤的效果,同时考察了两端投加、反转电场和碱活化Na₂S₂O₈对土壤中PCBs降解的影响。结果表明,从阴、阳极分别加入10%的Na₂S₂O₈,增大了电流强度和电渗流量,电场能够促进Na₂S₂O₈在土壤中的迁移以及对土壤中PCBs的降解。从土壤中残留PCBs的分布可以看出,电渗流对氧化剂的迁移作用要高于电迁移。由于阴极的去极化作用,反转电场没有促进Na₂S₂O₈对土壤中PCBs的降解。碱活化Na₂S₂O₈对土壤中PCBs的去除效率最高,达28.7%.PCBs的去除率较低跟土壤的异质性和氧化剂的损失有关。     

土壤中多氯联苯的生物有效性及其影响机制研究

多氯联苯(PCBs)属于环境中广泛存在的持久性有机污染物(POPs),威胁生态系统安全与人体健康。为评价典型土壤中PCBs的生态风险,揭示其生物有效性以及影响生物有效性的分子机制将具有重要科学意义。本文以赤子爱胜蚓(Eisenia fetida)为土壤模式生物,模拟土壤中6种典型PCBs化合物(PCB-18、PCB-20、PCB-28、PCB-101、PCB-105、PCB-114)的富集动力学过程,并分析了蚯蚓吸收累积对土壤中PCBs总量的影响。结果表明,对于PCB-18、PCB-20和PCB-28,蚯蚓富集15天能够达到动力学过程的近平衡状态,而PCB-101、PCB-105和PCB-114则在30天达到近平衡状态,这可能是由于分子体积增大致使PCBs自由穿越生物膜并为生物体有机脂相富集的过程受到一定程度的限制,吸收速率变慢。PCBs生物有效性与典型分子性质(α、Kow)之间高度线性相关,从微观层面上揭示了影响生物有效性的分子机制,进一步表明PCBs分子体积、分子极化率及其疏水作用是影响生物有效性的主要因子,为典型土壤中PCBs污染物的生态风险预测与评价提供科学依据。     

多氯联苯污染土壤的Fenton试剂化学修复效应

采用室内模拟实验,研究了0.5mol/LFeSO4溶液与1.0mol/LH2O2溶液组成的Fenton试剂对污染土壤中PCBs的去除效果。结果表明:20ml FeSO4+40ml H2O2的Fenton试剂对PCBs污染土壤处理336h后,PCBs总量的去除率达71.9%,继续增加Fenton试剂剂量或延长Fenton反应时间对PCBs去除效果影响较小。Fenton试剂对三氯、四氯、五氯、六氯等PCBs同系物去除效果较好,去除率分别为92.5%、75.8%、51.4%、39.5%。加入Fenton试剂后,供试土壤的pH值出现明显降低,而对土壤有机质含量的影响不明显。可见,该剂量的Fenton试剂对PCBs污染土壤的修复有明显的效果,是一种可利用的环境修复材料。     

Use of tissue and sediment‐based threshold concentrations of polychlorinated biphenyls (PCBs) to protect juvenile salmonids listed under the US Endangered Species Act

• 1. Under the Endangered Species Act, the National Marine Fisheries Service has authority to protect listed species from any adverse actions that may jeopardize the population's ability to recover and increase to sustainable levels. Listed salmon species in the northwest United States are known to travel through urban areas in their migration from river to ocean. Species such as the chinook salmon (Oncorhynchus tshawytscha) often spend several weeks in these urban estuaries where they can be highly exposed to urban‐related contaminants that reside in the sediments and accumulate in their prey species. The concern is that these contaminants are bioaccumulated to levels that may impact the ability of individual salmon to grow and mature normally. This paper provides a framework for determining the tissue and sediment concentrations of polychlorinated biphenyls (PCBs) that are likely protective against adverse effects in listed salmonid species.
• 2. The relevant ecotoxicological literature was examined and 15 studies were selected that met the pre‐established criteria outlined here. For each study, the lowest tissue concentration (residue) of total PCBs associated with a biological response was selected. The tissue concentration associated with the 10th percentile of these 15 studies was chosen to represent the residue effect threshold (RET) above which wild juvenile salmonids would be expected to exhibit adverse sublethal effects from accumulated PCBs. This value (2.4 μg PCBs g^?1 lipid) is expressed in terms of the lipid‐normalized concentration because of the large effect lipid can have on the expressed toxicity and the substantial variability in lipid content observed in salmonids over their life cycle.
• 3. A sediment concentration that is expected to produce the RET was then determined using the biota‐sediment accumulation factor approach. The sediment effect threshold, which varies with the total organic carbon content in sediment, is the level above which adverse effects may be expected in juvenile salmonids due to accumulation of PCBs from environmental exposure. Bioaccumulation of PCBs was examined in one river system as a model for determining an appropriate bioaccumulation factor for wild juvenile chinook salmon.
• 4. Evaluation of exposure to potentially deleterious concentrations of PCBs based on tissue residues is the preferred approach; however, the sediment effect threshold may also be used in cases where bioaccumulation has been characterized in an estuary. The threshold values presented here are intended as interim guidelines that should be modified as more data become available. Additionally, because of the uncertainty around many of the factors and assumptions that comprise the single threshold effect values, it is recommended that future studies be employed to help determine a range of acceptable values that would afford protection under various environmental and biological conditions.

Published in 2002 by John Wiley & Sons, Ltd.     

气相色谱法测定城市污泥中多氯联苯与有机氯农药

建立了以丙酮和石油醚超生提取,用硫酸尧高纯铜粉和硅胶柱净化的可同时检测长江三角洲地区城市 污泥中有机氯污染物的气相色谱法。与传统方法相比,在保证足够准确度尧精确度和灵敏度的前提下,该方法具有前 处理简单尧测定成本低尧样品用量少的特点,且可同时测定城市污泥中有机氯农药（OCPs）和多氯联苯类（PCBs）化合 物。应用该方法对我国长江三角洲地区城市污泥中PCBs 和OCPs 进行测试,结果表明,方法最低检出限为0.09~ 0.33 滋g/kg,达到了微量分析要求。加标回收试验中,PCBs 回收率为59.50%~101.51%,OCPs 回收率为57.21%~ 89.62%,相对标准偏差为1.89%~14.67%。     

多氯联苯污染土壤植物修复的机理、遗传缺陷及转基因技术

综述了多氯联苯污染土壤植物修复研究的主要进展,包括植物提取、植物转化和根际效应等方面的修复机理,自然植物及其根际微生物在多氯联苯污染修复功能方面存在的遗传缺陷,采用转基因技术对植物和根际微生物的修复功能进行遗传改造。同时对相关研究进行了评述,探讨了今后的发展趋势和重要研究方向。     

福建省东山湾生态环境中多氯联苯的残留特征

对福建省东山湾海域的水质、沉积物和养殖贝类中的多氯联苯（polychlorinated biphenyls,PCBs）残留进行气相色谱法检测,并对其在水域环境及贝类中的残留水平、生态风险及食用安全进行了探讨。结果表明： 1）海水中PCBs浓度底层高于表层;夏季（8月）高于春季（5月）。总体上,东山湾海水中PCBs浓度的平面分布从湾内到湾外呈递减趋势。底层海水中PCBs与悬浮物浓度之间具有极显著的相关性。2）表层沉积物中PCBs浓度平面分布呈近岸高、湾中部和湾外低的格局;PCBs与总有机碳（TOC）之间呈极显著正相关。PCBs残留量产生的生物有害效应的风险低。3）养殖贝类体中PCBs的残留量种间差异明显,对PCBs富集能力的大小,僧帽牡蛎、缢蛏和波纹巴非蛤最高,泥蚶和华贵栉孔扇贝次之,菲律宾蛤仔和杂色鲍最低。养殖贝类致癌风险指数在可接受风险范围内,贝类体中的PCBs残留水平居福建省沿海养殖贝类中等水平。     

气相色谱-串联质谱法测定植物样品中17种有机氯农药和8种多氯联苯

建立了植物样品中17种有机氯农药和8种多氯联苯单体的气相色谱-串联质谱(GC-MS/MS)分析方法。样品以 V(丙酮):V(乙酸乙酯)=1:1为溶剂进行提取,采用石墨化炭黑及氨基联合SPE小柱净化,GC-MS/MS测定。25种化合物的平均添加回收率在66.6%~113.1%之间,相对标准偏差(RSD)在4.1%~14.1%之间,方法检出限(MDL)在0.03~0.29 ng/g之间。该方法灵敏度高,满足环境调查的需求。对污染区采集的植物样品进行检测,发现被变压器油污染地区的植物体内含有较高质量分数的PCB28和PCB52,最高达108 ng/g,说明多氯联苯能够通过迁移等途径从土壤传递到植物中。     

Fe/Zn双金属对地下水中PCBs的还原脱氯研究

[目的]研究Fe/Zn双金属对地下水中PCBs的还原脱氯效果。[方法]以Fe、Zn构建二元金属还原体系,以PCBs降解率为考察指标,研究了添加羟丙基-β-环糊精(HP-β-CD)时,Fe/Zn双金属对PCBs的降解效果,同时考察了负载率、金属投加量对PCBs脱氯的影响。[结果]合成的HP-β-CD对PCBs有很好的增溶作用,PCBs表观溶解度随HP-β-CD浓度增加而线性增加,形成1∶1的包结物;10℃下,当混合金属投加量为10 g,Zn质量分数为7%时,321μg/L PCBs降解7 d后的去除率为47.6%。[结论]该研究为PCBs污染的地下水原位修复提供了理论指导。