Evidence for a mutual effect of biofilms, suspended particles and sediments on DDT sorption

This report shows that biofilms and suspended particles double DDT sorption capacity on surface sediments. Sorption of pollutants by solid materials, such as biofilms, suspended particles and sediments, is a major process controlling the fate of hydrophobic pollutants in natural waters. Most previous studies focused on the sorption of hydrophobic pollutants by single-solid material, whereas few studies considered the mutual effect of different solids on the sorption. Various solid materials often interact with each other when they coexist in the same system. Therefore, pollutants sorption could be different from that in the single-solid sorption system. Here we studied the mutual effect of biofilms, suspended particles and surface sediments on the sorption of dichlorodiphenyltrichloroethane (DDT). Results showed that biofilms and suspended particles double DDT sorption capacity on surface sediments. The different effects were mainly determined by distinct components and structures of the three solid materials, particularly by organic components. Here we show the mutual effect of biofilms, suspended particles and sediments on DDT sorption.     

Coexisting sediments and suspended particles change the sorption of lindane and ciprofloxacin in waters

The real behavior of water organic contaminants such as pesticides and pharmaceuticals is not well known because research experiments usually simplify the conditions by studying the sorption of a pure compound on a single solid. However, in natural waters, biofilms, suspended particles, and sediments are solid substances that coexist, and thus may change the contaminant fate. Therefore, we studied here the sorption of lindane and ciprofloxacin by three single-solid and three double-solid sorbents using batch experiments. We also compared the effect of dissolved organic matter (DOM) between single- and double-solid sorption systems. Results show that the sorption quantity of lindane to the double-solid system of suspended particles and sediments is lower, of 0.99 L/g, than the sum of sorption quantity in the single-solid system, of 1.39 L/g. The sorption quantity of ciprofloxacin is higher, of 2.70 L/g, than the sum of sorption quantity in the single-solid system, of 1.90 L/g. These findings are explained by changes in DOM that suppress or promote sorption. To our best knowledge, this is the first study to present evidence that coexisting river solids modify lindane and ciprofloxacin sorption.     

Processes of distribution of pharmaceuticals in surface freshwaters: implications for risk assessment

The global consumption and production of pharmaceuticals is increasing concomitantly with concern regarding their environmental fate and effects. Active pharmaceutical ingredients are mainly released into the aquatic environment through wastewater effluent discharge. Once in the environment, pharmaceuticals can undergo processes of natural attenuation, i.e. dilution, sorption, transformation, depending on physico-chemical properties of the compound, such as water solubility, lipophilicity, vapour pressure, and environmental conditions, such as pH, temperature and ionic strength. A major natural attenuation process is the sorption on dissolved organic matter, colloids, suspended solids and sediments, which in turn control pharmaceuticals distribution, residence time and persistence in aquatic systems. Here we review studies of sorption capacity of natural sorbents to pharmaceuticals. These report on the importance of several environmental and sorbent-specific properties, such as the composition, quality, and amount of the sorbent, and the environmental pH, which determines the speciation of both the sorbent and compound. The importance of accounting for distribution processes on freshwater sorbents for any determination of environmental concentrations of pharmaceuticals is apparent, while the reliability of surrogate standards for measuring dissolved organic matter (DOM) distribution is evaluated in the context of the need for robust environmental risk assessment protocols.     

生物扰动对沉积物中污染物环境行为与生物可利用性的影响

疏水性有机污染物进入环境水体后易于与沉积物结合,对沉积物中的底栖动物造成危害。底栖动物引起的生物扰动作用可以通过改变沉积物的地球化学性质,对其中污染物的赋存形态、迁移转化和生物可利用性产生重要影响。在综述了国内外生物扰动影响沉积物中污染物环境行为和生物可利用性的最新研究进展基础上,重点讨论了沉积物颗粒交换、水体环境条件改变、疏水有机污染物解吸释放过程以及对生物扰动影响的定量化表征。最后对该研究方向进行了展望,指出应重点研究多种污染物及不同生物共存条件下的生态效应,以及造成沉积物扰动的影响因素的定量化表征等。     

疏水性有机污染物在土壤/沉积物中的赋存状态研究

土壤/沉积物是环境中有机污染物主要的汇,由于土壤-沉积物结构和性质的复杂性,有机污染物进入其中,会结合在不同的位点上,赋存状态发生分化,具有不同的物理流动性、生态风险和化学反应活性.对于土壤-沉积物中有机污染物吸附/解吸的研究是认识其赋存状态并预测其生态风险的重要手段.本文对于疏水性污染物吸附/解吸及赋存状态的国内外研...     

土壤与沉积物对多环芳烃类有机物的吸附作用

吸附作用是疏水性有机物在土壤和沉积物环境中的重要迁移转化行为之一。多环芳烃是环境中一种重要的疏水性有机污染物。文章着重阐述了多环芳烃类有机物在土壤和沉积物中有机质和粘土矿物吸附机理，指出土壤、沉积物有机质的结构异质性是导致非线形吸附的重要原因；分析了影响多环芳烃吸附过程的诸多因素，并提出该研究领域存在的问题以及今后发展的方向。     

土壤有机碳对磺胺甲噁唑吸附的影响

以从云南元阳采集的1个水稻土和1个非耕作土,按颗粒大小分组作为模型吸附剂,探讨磺胺甲噁唑在土壤上的吸附行为与土壤有机质的关系.结果表明,梯田水稻土对磺胺甲噁唑的吸附(Kd:1.33—5.08)明显高于非耕作土(Kd:0.27—1.53).吸附强度与土壤C含量和O+N+S含量呈正相关,相关系数分别为0.953、0.917和0.769、0.809,说明土壤有机碳可能控制了磺胺甲噁唑的吸附,以有机碳为代表的憎水性吸附点位对吸附有较高的影响,憎水性作用为主导机理.     

DDTs对水生哺乳动物的组织残留基准初步研究

作为一种曾经广泛使用的氯化烃杀虫剂,DDT及其主要代谢产物DDE和DDD(合称为DDTs)是一类典型的具有持久性和生物累积性的有毒污染物。亲脂性和持久性使得DDTs可以通过食物链进行生物放大,从而对处于高营养级的水生哺乳动物造成严重的毒害作用。在综述DDTs对哺乳动物的毒性研究基础上,采用物种敏感度分布(species sensitivity distribution,SSD)和毒性百分数排序法(toxicity percentile rank method,TPRM)推导DDTs保护水生哺乳动物的组织残留基准(Tissue Residue Guideline,TRG)。使用SSD和TPRM得到的TRG分别为23.9和22.7 ng·g-1食物(湿重)。相应的,DDTs保护水生哺乳动物的水质基准分别为188.2和178.7 pg·L-1。依据研究得到的DDTs的组织残留基准及其在鱼类体内的含量评估对水生哺乳动物的风险。研究结果可用于评估DDTs对水生哺乳动物的生态风险,并为DDTs的风险管理提供理论依据。     

The role of extracellular polymeric substances on the sorption of pentachlorophenol onto natural biofilms in different incubation times: a fluorescence study

Extracellular polymeric substances (EPS) have been regarded as the most significant components in sorbing organic contaminants onto natural biofilms. However, few investigations have reported the effects of EPS on the sorption of organic contaminants onto biofilms in different incubation times. Here, pentachlorophenol (PCP), selected as a model organic pollutant, was sorbed by biofilms and EPS-free biofilms cultured for 15, 30, and 45 days, to evaluate the role of EPS in the sorption process. EPS were extracted from biofilms to investigate the binding mechanism of PCP to the fluorescence matters in EPS by fluorescence quenching titration. Results showed that EPS, bound with biofilms or released to water, could increase or decrease the sorption amounts of PCP on biofilms in various incubation times. The presence of bound EPS in biofilms enhanced the sorption amounts of 30-day biofilms (6.0?±?0.11?μmol?g^?1) because of the formation of the EPS-PCP complex between PCP and fluorescence matters in EPS, such as protein-like matters. In contrast, the release of PCP-bound EPS in 15- and 45-day biofilms decreased the sorption amounts of PCP on biofilms. All the results suggested that EPS dominated the sorption of PCP onto biofilms.     

水体和沉积物中毒害污染物的生态风险评价方法体系研究进展

人类活动导致大量毒害污染物进入水体和沉积物,从而对水生生物产生诸多不利影响.开展毒害污染物的生态风险评价,筛选高风险毒害污染物,是毒害污染物风险管控和生态系统保护的基础.对美国和欧盟等发达国家和地区毒害污染物的生态风险评价方法进行了综述.水体和沉积物中毒害污染物风险评价的基本方法首先是采用预测或测定环境浓度(PEC或M...     

Untersuchungen zum ökotoxikologischen Schädigungspotenzial und Erosionsrisiko von kontaminierten Sedimenten in staugeregelten Flüssen

Particle-bound pollutants accumulate in river-bottom sediments, a process which results in a significant decrease in the ecotoxicological availability of toxicants for the majority of aquatic organisms. Under normal hydrologic conditions, the release of contaminants from bottom sediments is usually of minor importance. In contrast, flood events may remobilize highly contaminated sediments via in-stream erosion. The objective of this study was to develop a combined ecotoxicological and hydraulic approach to elucidate the ecotoxicological implications associated with the risk of erosion of contaminated sediments. This integrated strategy was applied to the lock-regulated Neckar river in Southern Germany. Both the bottom-sediment cores and suspended matter from two intensive flood events were investigated. Sediment samples below an erosional unconformity showed a sharp increase in the ecotoxicological load. Moreover, it was found that major flood events (HQ₅ and higher) could possibly erode even very old, well-consolidated and highlycontaminated sediments. The suspended matter of the high discharge events investigated (return periods of 15 to 20 years) exerted significantly higher cytotoxicity and mutagenicity than a moderate flood with a 1-year return period. These findings support the conclusion that the observed ecotoxicological effects during major floods may at least in part be due to the in-stream erosion of highly contaminated bottom sediments.     

紫外吸收剂在湖泊中的分布及其对底栖动物的毒性效应

紫外吸收剂大量用于工业材料和个人护理品中,近年来在水体中不断被检出,同时由于其高度亲脂性,易在底泥和水生生物体内富集,产生潜在的毒性效应,已成为一类新型污染物。本文综述了紫外吸收剂在湖泊环境中的分布和生物富集效应,重点分析了二苯甲酮类等典型紫外吸收剂对底栖动物的药物代谢系统、抗氧化系统及其生长发育的影响及其毒性作用机制,并对未来该领域的研究进行了展望。     

Ecotoxicological assessment of sediment from Texcalac River and agricultural soil of riverside area,in Tlaxcala,Mexico

This study assesses the potential risk of Texcalac River and riparian area. The p,p′ DDT and ∑DDTs levels in agricultural soils (3.9–208.0?µg/kg) and in surface sediments (0.6–137?µg/kg) surpassing the guidelines for protection of aquatic life (75% > TEC). The ∑PCBs concentration oscillated from 135 to 93941?µg/kg; the half of sediments exceeded the international guidelines (PEL, PEC), as well as two soils (SQGE?=?500?µg/kg). The TEQ concentration of four PCB-DL varied between 0.1 and 24.9?µg TEQ/kg, chiefly affected by PCB 169. Five sediments were lethal for E. foetida, two resulted to be cytotoxic and the 58% produced genotoxicity higher than negative control (A?=?0.28?±?0.05; DICA?=?72.5?±?16.9 au). Likewise, 31.6% of samples increased the micronuclei frequency in V. faba in comparison with negative control. The analytical data and the bioassays results suggest a significant and immediate risk to exposed biota of this region, highlighting a specific area in Texcalac River and other one in Sambrano Ravine. It is necessity assess the dispersion of pollutants and perform biomonitoring studies that display the exposure levels in biota with the goal to characterise the ecotoxicological risk.     

太湖流域水源地多氯联苯分布特征与污染水平

为系统了解太湖流域主要水源地多氯联苯(PCBs)的污染现状,于2012年3月和6月分别采集水相、悬浮颗粒物和沉积物样品,并利用气相色谱-质谱联用仪(GC-MS)对PCBs的浓度进行了分析。结果表明,3月水相、悬浮颗粒物和沉积物中均未检测出PCBs类物质。6月水相中PCBs质量浓度在ND~1.04 ng·L~(-1)之间,平均值为0.57 ng·L~(-1),悬浮颗粒物和沉积物中PCBs质量浓度分别在0.96~2.72 ng·g-1和0.47~1.29 ng·g-1之间。Aroclor 1016和Aroclor 1260在3种介质中均有检出,且Aroclor1016浓度均为最高。与国内外研究相比较,太湖流域主要水源地PCBs污染水平较低。水相中PCBs浓度水平低于我国地表水环境质量标准;悬浮颗粒物和沉积物中PCBs浓度水平均低于加拿大保护水生环境沉积物化学品风险评价标准的LEL值,说明各样点PCBs对底栖动物无毒性影响。     

Neue Aspekte in der Behandlung von Siedlungsabflüssen

The surface runoff from urban areas is one of the most important sources of pollutants emitted into surface waters. Suspended solids which act as a transport vehicle for many anthropogenic pollutants (e.?g. heavy metals, PAH) are a key factor in this regard. The development of efficient measures of storm water runoff treatment thus requires a further differentiation of suspended solids in a fine (clay and silt) and coarse (sand and gravel) fraction. Both fractions show distinctly different characteristics in pollutant loading, transport and retention on urban surfaces and sewer systems. The primary aim of storm water runoff treatment is the reduction of the fine particles which are always highly loaded with anthropogenic pollutants. In contrast the coarse particles are almost unpolluted especially if they have a low organic share. The widespread sedimentation tanks with surface loadings between 10 and 2?m/h are very inefficient. A significant, save and lasting reduction of the emitted load of fine particles requires a considerable reduction of the surface loads. That can be achieved with the installation of lamellar settler or the utilization of the very large volumes of flood management tanks frequently present in urban areas. Filtration plants are highly efficient but there application in urban areas is limited due to their high space demands.     

Microbial metabolism of chlorobiphenyls

Photochemical reactions induced by sunlight contribute to the overall chemistry of natural water systems in many ways. The degradation of pollutants, dissolution of iron and manganese sediments, cycling of trace metal nutrients, and reactions of aquatic nitrogen and oxygen species are some of the many processes having solar photolysis pathways. This paper reviews recent research concerned with photo‐decomposition of pollutants, photolysis of nitrite and nitrate, photosensitization by humic materials and the generation of reactive intermediates. In addition, background material is presented concerning the basic principles of photochemistry and the limited wavelength range of effective solar radiation.     

阿特拉津在天然水体沉积物中的吸附行为

本文研究了阿特拉津在几种水体沉积物中的吸附、解吸规律,并进一步探讨了沉积物浓度、pH值和离子强度对其吸附行为的影响．结果表明,不同沉积物对阿特拉津的吸附程度由沉积物本身的总有机碳、粘土矿物、阳离子交换容量、比表面积以及铁锰氧化物等理化特性综合作用的结果,有机碳不是影响阿特拉津吸附的唯一重要因素．连续吸附实验结果指出,化合物的起始浓度愈大,吸附时间愈长,阿特拉津的最大吸附容量也愈大,且在解吸过程中表现出一定的滞后性(即不可逆吸附)．沉积物浓度与其吸附量呈负相关;溶液的pH值增大,沉积物对阿特拉津吸附能力减弱;离子强度愈大,沉积物对阿特拉津吸附能力愈强．     

环境中有机紫外防晒剂残留及其生态毒性研究进展

有机紫外防晒剂被广泛添加在个人护理品中,随着日常使用源源不断地进入环境中,成为一类新兴污染物。环境介质中有机紫外防晒剂的检测及其生态毒理是目前的研究热点。概述了个人护理品中常用的有机紫外防晒剂,总结了有机紫外防晒剂在各类地表水、沉积物和生物体等不同介质中的浓度水平,详细分析了有机紫外防晒剂对鱼类的内分泌干扰效应和对水生无脊椎动物的急性毒性,为今后深入研究和科学评价这类新兴污染物提供重要参考。     

珠江水产品中滴滴涕和六六六残留特征及风险评价

以珠江河口水生食物链较顶端的鱼类和虾类作为研究对象,利用气相色谱(GC-ECD)法检测分析了有机氯农药滴滴涕(DDTs)和六六六(HCHs)及其单体在这些水生动物体内的残留水平和特征,以期为珠江流域水生生物生态风险评价提供基础资料和科学依据。结果显示,鱼类肌肉中的DDTs含量(以湿质量计)范围为未检出(nd)～42.73μg.kg-1(平均值为7.61μg.kg-1),在虾类肌肉中的含量范围为nd～9.51μg.kg-1(平均值为1.97μg.kg-1);鱼类肌肉中的HCHs含量范围为nd～1.71μg.kg-1(平均值为0.62μg.kg-1),在虾类肌肉中的含量范围为nd～0.86μg.kg-1(平均值为0.56μg.kg-1)。鱼类肌肉中DDTs和HCHs的残留均值高于虾类,而鱼类和虾类体内DDTs的残留量均高于HCHs的残留量。HCHs、DDTs的单体分别以γ-HCH、p,p'-DDT的含量最高,而且近期都有新的污染源输入。所采集的水产品中DDTs、HCHs残留量尚低于我国的无公害水产品质量安全标准要求(GB18406.4),亦低于日本、欧盟等发达国家和地区相关的最大残留限量,因此,DDTs、HCHs通过膳食的暴露暂时不会对该地区的人体健康产生危害。     

环境微塑料与有机污染物的相互作用及联合毒性效应研究进展

环境微塑料可吸附有机污染物,并与有机污染物进行相互作用从而改变其毒性效应,增加微塑料的治理难度.本文就全球范围内微塑料与有机污染物的相互作用及毒性效应的研究进展进行综述,分析不同介质中微塑料与有机污染物的共存水平、吸附机理、影响因素以及联合毒性效应等.研究表明,微塑料可作为多环芳烃(PAHs)、多氯联苯(PCBs)、六...