分流进样-GC-NCI-MS测定土壤样品中高溴代联苯醚

采用分流进样模式,以GC-NCI-MS法测定土壤样品中7种高溴代联苯醚,对比了分流、不分流2种进样模式下的灵敏度、峰形、回收率、检出限。结果表明,在分流进样模式下,高溴代联苯醚在进样口的热分解率大大降低,色谱峰形尖锐无拖尾,测定结果线性范围宽,7种高溴代联苯醚的基质加标回收率为83.25%~94.71%,RSD为2.91%~7.37%,检出限为0.26~2.71 ng/g,与不分流进样模式相比,该方法灵敏度、检出限更高,适用于环境样品中高溴代联苯醚的检测分析。     

固相萃取-LC-MS/MS测定土壤中多溴联苯醚

采用快速溶剂萃取-固相萃取-液相色谱串联质谱法(LC-MS/MS)测定土壤中8种多溴联苯醚类(PBDEs)化合物,通过优化试验条件,使方法在10.0μg/L～1000μg/L范围内线性良好,方法检出限为0.85μg/kg～1.25μg/kg.不同土壤样品的8种多溴联苯醚回收率为68.6％ ～127％,4次测定结果的RS...     

辽宁省淡水鱼类体内多溴联苯醚和六溴环十二烷的富集特征及健康风险评估

分析了辽宁省4个典型城市淡水鱼类中多溴联苯醚（PBDEs）和六溴环十二烷（HBCDs）的富集特征,并进行了健康风险评估。结果表明：淡水鱼类体内PBDEs和HBCDs检出率均为100%,PBDEs和HBCDs的平均质量分数分别为9.73 和21.81 ng/g（脂重）。PBDEs中的单体BDE 183、BDE 209和BDE 153在辽河流域不同鱼类的同源种中占优势,分别占PBDEs的26.8%～40%,17%～44%和14%～22%。在HBCDs的3种同系物中,α-HBCD是主要的单体,其相对贡献率为45.15%~84.71%。辽河流域的工厂企业生产活动对淡水鱼类产生了影响,居民通过消费水产品摄入PBDEs和HBCDs。健康风险评估结果显示：PBDEs和HBCDs的健康风险指数均＜1,说明当地水产品中PBDEs和HBCDs的非致癌风险处于可接受水平。     

测量土壤中多溴联苯和多溴联苯醚含量不确定度评定

通过对气相色谱-质谱联用法测定土壤中多溴联苯和多溴联苯醚类化合物含量的不确定度进行评定,分析了测量过程中引入的不确定度来源,求出各不确定度分量,最后合成标准不确定度并计算相对扩展不确定度。结果表明,各化合物最大的不确定度分量是方法回收率,约占50%~90%,方法相对扩展不确定度为0.12~0.20。     

加速溶剂同时萃取和净化-气相色谱-三重四极杆串联质谱测定土壤和沉积物中8种多溴联苯醚

建立了土壤和沉积物中8种多溴联苯醚(PBDEs,BDE-28、BDE-47、BDE-99、BDE-100、BDE-153、BDE-154、BDE-183和BDE-209)加速溶剂同时萃取和净化-气相色谱-三重四极杆串联质谱(ASE-GC-MS-MS)的分析方法。通过优化加速溶剂萃取与弗罗里硅土在线净化和串联质谱多反应监测模式的条件,较好地去除基质干扰,并提高了三重四极杆串联质谱定性的准确性及定量的灵敏性。该方法采用改进的色谱柱能同时分析包括高溴代联苯醚BDE-209在内的8种PBDEs,其浓度范围为1～100 ng/mL(BDE-209为10～1 000 ng/mL),线性良好,线性回归系数均大于0.997。方法检出限为0.004～0.1 ng/g,方法回收率为75%～110%,方法精密度为2.4%～15.6%。适于批量处理土壤和沉积物中含有多组分痕量PBDEs的样品。     

利用转基因斑马鱼探究四溴联苯醚(BDE-47)的神经毒性作用

为探究2,2’,4,4’-四溴联苯醚（BDE-47）对斑马鱼的早期神经毒性作用,采用中枢神经特异性标记的转基因斑马鱼Tg(elavl3:EGFP)作为模式生物,研究了BDE-47短期暴露对斑马鱼幼鱼的运动行为轨迹、中枢神经发育和神经发育关键基因表达的影响。结果表明,BDE-47暴露6 d后,5和10μmol/L暴露组斑马鱼幼鱼运动行为和神经发育关键基因（elavl3和mbp）的表达受到显著抑制,同时斑马鱼幼鱼的神经细胞的发育受到显著抑制。结果提示,神经系统特异性标记的转基因斑马鱼可作为一种筛选神经毒性化合物的理想动物模型,BDE-47对斑马鱼具有早期神经发育毒性。     

环境中多溴联苯醚(PBDEs)的代谢转化研究现状

多溴联苯醚(PBDEs)作为一种溴系阻燃剂(BFRs),在多种环境介质和生物体内广泛存在且浓度逐年增加,因而越来越多地受到研究者关注.综合PBDEs各方面研究报道,认为其在环境中存在生物和非生物两种转化方式.非生物转化主要是光降解,即PBDEs在光照条件下可通过自由基反应脱溴生成低溴同系物及多溴联苯呋喃(PBDFs).生物转化则包括微生物转化、生物体内转化和生物体外代谢,其转化代谢途径除脱溴外,还有醚键断裂、羟基化和羟基化/脱溴等.对PBDEs在环境中不同转化方式的转化速率、转化途径和转化产物等的研究现状进行综述,对今后PBDEs在环境中归趋、生态风险和健康评价研究将起到一定的指导作用.     

土壤中铁氧化物对铅吸附-解吸的影响

选择上海地区广泛分布的水稻土,通过静态吸附平衡试验,比较土壤去除非晶质氧化铁和去除游离氧化铁后对Pb2+的吸附-解吸行为,采用数学模型拟合,探讨3种土壤的最佳拟合方程、最大吸附的理论值和亲和能力,进而研究非晶质氧化铁和游离氧化铁对Pb2+吸附-解吸的影响。结果表明,去除氧化铁后吸附能力和亲和能力均减弱,原土的最大吸附量为29.21 g/kg,非晶质氧化铁的贡献值为3.52 g/kg,游离氧化铁的贡献值为8.32 g/kg。     

气相色谱法测定空气和废气中联苯-联苯醚

研究了气相色谱法测定环境空气和废气中的联苯-联苯醚.气体样品由中性氧化铝吸收,二硫化碳洗脱,FID检测.方法有较好的精密度(变异系数联苯12.4%,联苯醚10.6%;回收率联苯86.6%～100%,联苯醚88.6%～95.7%)和低的检出浓度(联苯0.056mg/m3,联苯醚0.044mg/m3);方法具有简便、快速、准确的特点.     

混合溶剂解吸土壤中多环芳烃的研究

对比了水溶性有机溶剂乙醇、正丙醇、丙酮、已戊醇和水对土壤中多环芳烃(PAHs)的解吸效果,结果综合实验效果、安全性和经济等因素,主要采用了乙醇和戊醇作为混合试剂的主要成分。对比了乙醇、戊醇和水不同配比的混合试剂对土壤的解吸效果,最终选用混合试剂(5%戊醇+20%水+75%乙醇)研究污染土壤中PAHs的解吸行为,分别进行了解吸动力实验、分阶段解吸实验和pH值影响实验。结果表明,土壤中PAHs的解吸是一个快速反应,5h基本达到解吸平衡,高环物质(4～6环PAHs)比低环物质(2～3环PAHs)的解吸速率慢。分步解吸率表明,随着环数的增加,第一步解吸率逐渐降低,第二、三步的解吸率则逐渐增大,第二、三步的解吸作用对高环PAHs更为明显。pH值对混合溶剂解吸土壤中PAHs有显著影响,pH值在5 5～7之间时,对土壤中PAHs的解吸影响最明显,碱性环境(pH>7)有利于土壤中PAHs的解吸,酸性环境则不利于解吸实验的进行。     

Occurrence, distribution, and source of polybrominated diphenyl ethers in soil and leaves from Shenzhen Special Economic Zone, China

Polybrominated diphenyl ethers (PBDEs) were measured in soil and three plant species samples taken at different land use areas in Shenzhen China. The concentrations of ??₇BDEs (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-183) and BDE-209 in the surface soils ranged from 0.23 to 271 and 8.9 to 5,956 ng/g dry weight (dw), respectively. These figures are comparable to that in the soils of electronic waste dismantling sites. BDE-209 was the predominant congener (contributes 85?C99% of ??₈PBDEs (??₇PBDEs plus BDE-209)) in soils. The regression slopes of total organic carbon and individual BDE congeners were rather gentle, indicating that factors other than soil organic matter regulated the soil concentrations. Proximity to sources of deposition processes might be the major factors. In the plant leaves, ??₇BDEs and BDE-209 concentrations ranged from 1.29 to 5.91 and 5.49 to 28.2 ng/g dw, respectively. BDE-209 is also the dominant component, but the contribution was much lower compared with that in soils. Bauhinia purpurea Linn. and Michelia alba DC. show some similarities on the uptake of PBDEs, while Ficus microcarpa var. pusillifolia is different from them. The correlations between plant leaf concentrations and predicted gaseous concentrations were moderate, indicating that gaseous concentration did not influence the leaf concentration significantly.     

Sorbed metals fractionation and risk assessment of release in river sediment and particulate matter

Fractionation of metals in natural sediment and suspended particulate matter (SPM) of Tadjan River is investigated. Competitive sorption, sorption capacities of sediment and SPM as well as fractionation of metal-loaded sediment and SPM are also examined. A risk assessment code (RAC) is applied to estimate the risk of heavy metals release into the environment during the sorption process. Results revealed that sediments and SPM containing more than 25 % of clay minerals and higher amounts of calcite have great capacity of metal sorption, particularly for Cu, Ni, and Mn. Assessing the risk of metals release prior to and following sorption tests indicates that RAC of metals would significantly increase from the level of no or low risk in natural sediment and SPM to high or very high risk after sorption. The Langmuir model reveals that the highest affinity for Cu, Mn, and Ni in sediment is the organic fraction. The classic isotherm models of Freundlich and Langmuir can fit the data from chemical extraction studies of adsorbed metals, indicating that although sorption was apparently a physical and chemical process in the river, isotherm models can be used to simulate the sorption and accumulation in different geochemical phases within the particulate matter.     

New evidences in the complexity of contamination of the lagoon of Venice: polybrominated diphenyl ethers (PBDEs) pollution

This study presents the first evaluation of the current pollution by polybrominated diphenyl ethers (PBDEs) of surface sediments from the Lagoon of Venice. We focused the research on tri-to hepta-BDEs, the main components of penta- and octa-mixtures, which are considered to be the most toxic for the biocoenosis. The results pointed out a quite homogeneous contamination of this keystone European transitional environment, with ∑ ₁₃PBDEs values ra nging from 0.39 to 6.78 ng/g dry weight; these values reflect low to moderate pollution levels, which is in conformity to other coastal European ecosystems. The average PBDE profile of the lagoon sediments follows this decreasing trend of congeners: BDE-47>BDE-99> >BDE-190>BDE-28>BDE-153>BDE-154>BDE-138, BDE-183, and BDE-17, which is similar to the worldwide distribution pattern. BDE-47 and BDE-99 revealed a recent use of a penta-BDE mixture, while the presence of hepta-BDEs (BDE-183 and BDE-190) in all of the sites can indicate the actual use of a deca-BDE formulation, because these congeners are considered to be debrominated byproducts of BDE-209 degradation.     

Mobilization and plant accumulation of prometryne in soil by two different sources of organic matter

Prometryne is a selective herbicide of the s-triazine chemical family. Due to its weak absorption onto soil, it readily leaches down through the soil and contaminates underground water. Application of organic manure to soil has become a widespread practice as a disposal strategy to improve soil properties. In this study, we demonstrated the effect of pig manure compost (PMC) and lake-bed sludge (SL) on the sorption/desorption, mobility and bioavailability of prometryne in soil using comprehensive analysis approaches. Downward movement of prometryne was monitored in the packed soil column. Addition of PMC or SL decreased considerably the mobility and total concentration of prometryne in the soil leachate. Bioavailability analyses with wheat plants revealed that addition of the organic matter reduced accumulation of prometryne in tissues and increased plant elongation and biomass. These results indicate that the organic amendments are effective in modifying adsorption and mobility of the pesticide in soil.     

Effects of salinity and organic matter on the partitioning of perfluoroalkyl acid (PFAs) to clay particles

The influence of salinity and organic matter on the distribution coefficient (K(d)) for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in a brackish water-clay system was studied. The distribution coefficients (K(d)) for PFAs onto inorganic clay surfaces increased with salinity, providing evidence for electrostatic interaction for the sorption of PFAs, whereas the relationship between K(d) and organic carbon content (f(oc)) suggested that hydrophobic interaction is the primary driving force for the sorption of PFAs onto organic matter. The organic carbon normalized adsorption coefficient (K(oc)) of PFAs can be slightly overestimated due to the electrostatic interaction within uncoated inorganic surfaces. In addition, the dissolved organic matter released from coated clay particles seemed to solvate PFA molecules in solution, which contributed to a decrease in K(d). A positive relationship between K(d) and salinity was apparent, but an empirical relationship for the 'salting-out' effect was not evident. The K(d) values of PFAs are relatively small compared with those reported for persistent organic pollutants. Thus, sorption may not be a significant route of mass transfer of PFAs from water columns in estuarine environments. However, enhancement of sorption of PFAs to particulate matter at high salinity values could evoke potential risks to benthic organisms in estuarine areas.     

Investigation of polybrominated diphenyl ethers in old consumer products in India

Polybrominated diphenyl ethers (PBDEs) used extensively over the past 3 decades as flame retardants in most types of polymers, all over the world, have been identified as global pollutants. PBDEs pose various health problems such as thyroid hormone disruption, permanent learning and memory impairment, behavioral changes, hearing deficits, delayed puberty onset, fetal malformations, and possibly cancer. Many measurements of PBDEs in various matrices from Sweden, Holland, Japan, the USA, and elsewhere have been reported, but few measurements are available for India. In this study, a preliminary screening of different congeners of PBDEs has been performed in different old electronic and consumer products with an objective to build capacity in order to analyze PBDEs and BFRs. Six different samples, foam from upholstery, motherboard of a computer, children toy composite sample, old vanishing window blind sample, electrical wire sample, and PVC flooring sample, were collected and analyzed for the presence of the following PBDE congeners: BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209. It was found that three out of six samples were positive for the presence of PBDEs. Three congeners were detected in the samples, i.e., BDE-47, BDE-153, and BDE-209, of which, highest concentration was of BDE-209. Among the samples, motherboard of computer showed the highest concentration of BDE-209 followed by window blind and foam from upholstery. The results of this preliminary investigation indicate that PBDEs are still present in the old consumer products which can be an important additional source of exposure to the population.     

Predicting potentially plant-available lead in contaminated residential sites

Lead (Pb)-based paints pose a serious health problem to people living in residential settings constructed prior to 1978. Children are at a greater risk to Pb exposure resulting from hand-to-mouth activity in Pb-contaminated residential soils. For soil Pb, the most environmentally friendly, potentially cheap, and visually unobtrusive in situ technology is phytoremediation. However, the limiting factor in a successful phytoremediation strategy is the availability of Pb for plant uptake. The purpose of this study was to establish a relationship between soil properties and the plant-available/exchangeable Pb fraction in the selected Pb-based paint-contaminated residential sites. We selected 20 such sites from two different locations (San Antonio, Texas and Baltimore, Maryland) with varying soil properties and total soil Pb concentrations ranging between 256 and 4,182 mg kg^?1. Despite higher Pb levels in these soils that exceeds US EPA permissible limit of 400 mg kg^???1, it is known that the plant-available Pb pools are significantly lower because of their sorption to soil components such as organic matter, Fe?CMn oxides, and clays, and their precipitation in the form of carbonates, hydroxides, and phosphates. Principal component analysis and hierarchical clustering showed that the potentially plant-available Pb fraction is controlled by soil pH in the case of acidic Baltimore soils, while soil organic matter plays a major role in alkaline San Antonio soils. Statistical models developed suggest that Pb is likely to be more available for plant uptake in Baltimore soils and a chelant-assisted phytoextraction strategy will be potentially necessary for San Antonio soils in mobilizing Pb from complexed pool to the plant-available pool. A thorough knowledge of site-specific factors is therefore essential in developing a suitable and successful phytoremediation model.     

A Probabilistic Screening Model for Evaluating Pyrethroid Surface Water Monitoring Data

Synthetic pyrethroids have been detected in recent California surface water monitoring. Filtration is avoided during sample workup because pyrethroids are extremely hydrophobic, tending to sorb to most surfaces. The resultant analytical pyrethroid concentrations reflect both dissolved pyrethroid and pyrethroid associated with suspended sediment in the water column. Such “whole-water” analytical data are not directly comparable to aquatic acute toxicity effect concentrations measured in laboratory sediment-free water. Consequently, any potential aquatic toxicity risk is indeterminate. In this study a simple probabilistic model was developed to allow a screening-level assessment of pyrethroid whole-water monitoring data. The results suggest that water column toxicity of pyrethroids is possible in California's agriculturally-dominated tributaries, and indicate that additional monitoring to better characterize pyrethroid water-column concentrations are warranted. Model refinement will depend on future work that more firmly establishes the relationship between pyrethroid partitioning and bioavailability, and that addresses the potential influence of dissolved organic carbon on pyrethroid sorption and bioavailability.     

Persistence and behavior of pesticides in cotton production in Turkish soils

Turkey is the sixth largest producer of cotton in the world. Two of the most commonly applied pesticides used in cotton production are trifluralin and endosulfan. Although both are very effective at controlling pests, their persistence in the environment poses risks to human health and the environment. Four loam soils and one silty-loam soil were studied to evaluate the persistence of trifluralin and endosulfan in relation to soil characteristics. Degradation with trifluralin reached as high as 70% of the applied doses. Soils with the highest organic matter content had the lowest degradation rate, indicating a tighter sorption of trifluralin. Endosulfan degradation was a function of soil type and the specific isomer, with β-endosulfan depicting the highest degradation.