Simultaneous elimination of cyanotoxins and PCBs via mechanical collection of cyanobacterial blooms: An application of “green-bioadsorption concept”

In this study, the distribution, transfer and fate of both polychlorinated biphenyls (PCBs) and cyanotoxins via phytoplankton routes were systematically investigated in two Chinese lakes. Results indicated that PCB adsorption/bioaccumulation dynamics has significantly positive correlations with the biomass of green alga and diatoms. Total lipid content of phytoplankton is the major factor that influences PCB adsorption/bioaccumulation. Cyanobacterial blooms with relatively lower lipid content could also absorb high amount of PCBs due to their high cell density in the water columns, and this process was proposed as major route for the transfer of PCBs in Chinese eutrophic freshwater. According to these findings, a novel route on fates of PCBs via phytoplankton and a green bioadsorption concept were proposed and confirmed. In the practice of mechanical collections of bloom biomass from Lake Taihu, cyanotoxin/cyanobacteria and PCBs were found to be removed simultaneously very efficiently followed this theory.     

中国东海水体中多氯联苯的浓度及其组成特征

东海由于受到长江和闽浙沿岸工业污水输入以及电子垃圾处理场排放的影响,被认为是多氯联苯重污染区域。本研究利用"科学三号"科学考察船,于2012年10月执行的东海航次期间,从中国东海不同区域采集到11个表层水样,测定其中溶解态多氯联苯的浓度。中国东海水体中多氯联苯浓度为（0.59~1.68）ng/L,相比国内外海域,属于中低等水平。研究结果表明,海水多氯联苯浓度和盐度之间存在显著负相关性,说明沿岸河流冲淡水搬运的多氯联苯是东海水体中多氯联苯的重要来源;此外其组成以三氯,四氯和五氯为主,这与我国历史上多氯联苯的使用情况吻合。通过水体中不同氯代化合物浓度和对应K_OW理论浓度值的比较发现,两者之间整体吻合较好,表明化合物的物理化学属性是控制其在水体中浓度的重要因素。然而,东海近岸水体中六氯联苯污染程度略高于理论浓度值,这一潜在的污染来源可能和东海沿岸省市电子垃圾处理场有关。     

氯代苯在鱼体内富集和释放行为的研究

运用快速测定ＢＣＦ的方法,研究了７种氯代苯在鲤鱼体内富集和释放的行为。实验结果表明,用脂肪含量标化的ＢＣＦＬ与辛醇分配系数Ｋｏｗ吻合较好,吸收速率常数（Ｋ１２）、释放速率常数（Ｋ２１）和生物富集系数的对数值与ｌｇＫｏｗ有较好的相关关系;对于高脂溶性氯代苯,由于其结构的庞大,影响富集过程,所以本文采用了分子表面积对拟合的线性方程进行了校正．改善了ｌｇｋ１２和ｌｇＫｏｗ之间的线性关系。     

Preparation and characterization of a lipoid adsorption material and its atrazine removal performance

A novel adsorbent named lipoid adsorption material (LAM), with a hydrophobic nucleolus (triolein) and a hydrophilic membrane structure (polyamide), was synthesized to remove hydrophobic organic chemicals (HOCs) from solution. Triolein, a type of lipoid, was entrapped by the polyamide membrane through an interfacial polymerization reaction. The method of preparation and the structure of the LAM were investigated and subsequent experiments were conducted to determine the characteristics of atrazine (a type of HOC) removal from wastewater using LAM as the adsorbent. The results showed that LAM had a regular structure compared with the prepolymer, where compact particles were linked with each other and openings were present in the structure of the LAM in which the fat drops formed from triolein were entrapped. In contrast to the atrazine adsorption behavior of powdered activated carbon (PAC), LAM showed a persistent adsorption capacity for atrazine when initial concentrations of 0.57, 1.12, 8.31 and 19.01 mg/L were present, and the equilibrium time was 12 hr. Using an 8 mg/L initial concentration of atrazine as an indicator of HOCs in aqueous solution, experiments on the adsorption capacity of the LAM showed 69.3% removal within 6–12 hr contact time, which was close to the 75.5% removal of atrazine by PAC. Results indicated that LAM has two atrazine removal mechanisms, namely the bioaccumulation of atrazine by the nucleous material and physical adsorption to the LAM membrane. Bioaccumulation was the main removal mechanism.     

Trapp模型在典型区PCBs蔬菜吸收及人体健康风险评估中的应用

对某电子垃圾拆解地大气、土壤、蔬菜进行采样,分析其中PCBs的含量;根据获得的大气中气态及土壤中PCBs的含量,应用Trapp作物吸收模型对该地区叶菜类蔬菜中PCBs的含量进行模拟预测;根据模型机制,分析了叶菜类蔬菜中PCBs的来源、构成及影响蔬菜对PCBs吸收的因素;利用美国EPA人体健康风险评估方法,分析了环境中PCBs被蔬菜吸收后经食物链对人体健康的影响.结果表明,Trapp作物模型可较好地依据土壤及大气中PCBs含量预测叶菜类蔬菜中PCBs含量,实测值与预测值相近,蔬菜中7种PCBs总和实测值为51.2μg.kg-1,模型预测值为39.9μg.kg-1;大气中气态PCBs是叶菜类蔬菜中PCBs的主要来源,模型预测表明其贡献率高达98.8%;蔬菜吸收PCBs的途径、辛醇-水分配系数(Kow)及辛醇-大气分配系数(Koa)影响蔬菜中PCBs含量及构成比例;蔬菜吸收PCBs达到平衡所需时间与lgKow、lgKoa有很好的乘幂相关性,多元线性回归表明lgKoa是更重要的影响因素.大气气态PCBs被蔬菜吸收后对人体健康的致癌风险是气态PCBs的10 000多倍,非致癌风险则增加了近200倍,原因主要在于:一是蔬菜吸收、积累了空气中毒性更高的高氯代PCBs,经口摄入PCBs的毒性因子极大增加;二是成人每天食用蔬菜摄入PCBs的量相当于正常情况下成人通过呼吸空气摄入PCBs量的71倍多.     

A model and experimental study of phosphate uptake kinetics in algae: Considering surface adsorption and P-stress

Phosphorus is an important limiting nutrient in many ecosystems. Consequently, there is increasing interest on phosphate uptake and algal growth due to the increasing frequency and magnitude of algal blooms induced by eutrophication. The co-existence of surface adsorbed and intracellular phosphorus pools indicate that phosphate uptake by phytoplankton is, to some extent, a two-stage kinetic process. However, almost all previous uptake models considered the internal uptake stage only and ignored the possible impact of surface adsoption. In this article, a two-stage kinetic uptake model considering both surface adsorption and P-stress on phosphate uptake by algae was constructed and compared to conventional one-stage models, based on experimental data on short-term uptake kinetics of a green algae S. quadricauda. Results indicated that with suitable parameters, the two-stage uptake model not only fit the experimental data better, but also gave more reasonable and realistic explanations to the phosphate uptake process. The results are meaningful as surface-adsorption of phosphate may a ect the uptake process of phosphate and assist in understanding realistic phosphate uptake kinetics in phytoplankton.     

Relationship between metabolic enzyme activities and bioaccumulation kinetics of PAHs in zebrafish (Danio rerio)

Many studies have investigated bioaccumulation and metabolism of polycyclic aromatic hydrocarbons (PAHs) in aquatic organisms. However, lack of studies investigated both processes simultaneously, and the interaction between these two processes is less understood so far. This study investigated the bioaccumulation kinetics of PAHs and metabolic enzyme activities, including total cytochrome P450 (CYPs) and total superoxide dismutase (T-SOD), in zebrafish. Mature zebrafish was exposed to the mixture of phenanthrene and anthracene under constant concentration maintained by passive dosing systems for 16 days. The results showed that PAH concentrations in zebrafish experienced a peak value after exposure for 1.5 days, and then decreased gradually. The bioaccumulation equilibrium was achieved after exposure for 12 days. Both of the uptake rate constants (k_u) and the elimination rate constants (k_e) decreased after the peak value. The variation of PAH concentrations and metabolic enzyme activities in zebrafish had an interactive relationship. CYPs and T-SOD activities increased initially with the increase of PAH concentrations, but decreased to the lowest state when PAH concentrations reached the peak value. When the bioaccumulation equilibrium of PAHs was achieved, CYPs and T-SOD activities also reached the steady state. In general, CYPs and T-SOD activities were activated after exposure to PAHs. The decrease of PAH concentrations in zebrafish after the peak value may be attributed to the great drop of k_u and the variation of CYPs activities. This study suggests that an interactive relationship exists between bioaccumulation kinetics of PAHs and metabolic enzyme activities in aquatic organisms.     

亚硫酸盐/紫外体系的还原脱卤效能

水合电子(e-aq)是已知活性最强的还原物种之一.基于SO_3~(2-)受紫外光激发活化会释放e-aq的性质,提出了SO_3~(2-)/UV高级还原体系,用于降解稳定污染物.以7种卤乙酸为目标物,从卤素取代种类、卤代程度、实际水质本底影响等角度,考察了该体系对毒性卤代有机物(HOCs)的降解及脱卤效能,并探讨了相关机理.结果表明:HOCs的降解至少有直接光解和e-aq还原两条途径.卤素取代种类与卤化程度决定了HOCs的直接光解特性,其速率随氯、溴、碘取代顺序及卤化程度的增加而加快.SO_3~(2-)/UV体系显著提高了HOCs的降解及脱卤效率;对于直接光解慢的HOCs,其降解与脱卤主要由e-aq还原引起.SO_3~(2-)/UV体系在两种地表水质本底下仍具有较高的脱卤效能.     

玉米和小麦对城市污泥施用土壤中多氯联苯的吸收和传输特征

城市污泥施用农田能够改善土壤性状及促进作物生长,但也会使农田存在重金属和有机污染物等污染风险. 多氯联苯(polychlorinated biphenyls, PCBs)作为一类持久性有机污染物,被作物吸收、累积后经食物链传递,潜在威胁着人体健康. 为探究城市污泥施用农田后PCBs在土壤和作物(玉米和小麦)中的分布特征,解析玉米和小麦对土壤PCBs的吸收和传输规律与差异,以关中地区城市污泥施用土壤为研究对象,设置不同植物种属、污泥施用量和污泥类型的土壤盆栽培养试验. 结果表明:①城市污泥施用后造成土壤、玉米和小麦的PCBs污染,土壤、植物根和地上部分以低氯代PCBs〔一氯代PCBs(mono-PCBs)~五氯代PCBs(penta-PCBs)〕为主,且百分含量呈依次增加趋势. ②与种植前相比,种植植物后土壤中更低氯代的PCBs占主导;且土壤∑PCBs消减了20.00%~79.30%,各处理对∑PCBs的消减差异表现为玉米高于小麦、单倍污泥施用量高于双倍污泥施用量、有机质含量最高的污泥施用处理∑PCBs的消减率最高. ③植物根可以吸收土壤PCBs并向地上部分传输,且吸收和传输能力与植物种属、污泥施用量和污泥类型有关,小麦对污染土壤∑PCBs及各PCBs同系物的吸收能力均强于玉米,而传输能力较弱;双倍污泥量施用下植物根对∑PCBs、一氯代PCBs(mono-PCBs)~四氯代PCBs(tetra-PCBs)和六氯代PCBs(hexa-PCBs)的吸收减弱;有机质含量最低的污泥施用下植物根对∑PCBs的吸收能力最强. 研究显示,城市污泥施用会引起土壤和作物PCBs污染,种植作物能消减污染土壤PCBs,而小麦和玉米对土壤∑PCBs及各PCBs同系物的消减和吸收传输存在种属差异.      

Sorption mechanism of naphthalene by diesel soot: Insight from displacement with phenanthrene/p-nitrophenol

The nonlinear sorption of hydrophobic organic contaminants (HOCs) could be changed to linear sorption by the suppression of coexisting solutes in natural system, resulting in the enhancement of mobility, bioavailability and risks of HOCs in the environment. In previous study, inspired from the competitive adsorption on activated carbon (AC), the displaceable fraction of HOCs sorption to soot by competitor was attributed to the adsorption on elemental carbon fraction of soot (EC-Soot), while the linear and nondisplaceable fraction was attributed to the partition in authigenic organic matter of soot (OM-Soot). In this study, however, we observed that the linear and nondisplaceable fraction of HOC (naphthalene) to a diesel soot (D-Soot) by competitor (phenanthrene or p-nitrophenol) should be attributed to not only the linear partition in OM-Soot, but also the residual linear adsorption on EC-Soot. We also observed that the competition on the surface of soot dominated by external surface was different from that of AC dominated by micropore surface, i.e., complete displacement of HOCs by p-nitrophenol could occur for the micropore surface of AC, but not for the external surface of soot. These observations were obtained through the separation of EC-Soot and OM-Soot from D-Soot with organic-solvent extraction and the sorption comparisons of D-Soot with an AC (ACF300) and a multiwalled carbon nanotube (MWCNT30). The obtained results would give new insights to the sorption mechanisms of HOCs by soot and help to assess their environmental risks.     

西安城区大气中多氯联苯的气粒分配研究

为了解西安城区大气中多氯联苯(PCBs)的气粒分配规律,于2012年春季对西安城区大气中气态和颗粒态样品进行每周一次的主动采样.结果表明,西安城区大气中PCBs的总浓度(气态和颗粒态)为62.05~454.18pg/m3,主要以气态为主.由Clausius-Clapeyron方程得到的斜率较陡(-5193.24),表明春季大气中的PCBs主要受西安城区附近地面挥发释放的影响.PCBs的气粒分配系数(KP)与过冷饱和蒸汽压(PoL)高度相关,由logKP和logPoL线性回归得到的斜率mr(-0.46~-0.37)均高于平衡状态理论值-1,说明西安城区大气中的PCBs气粒分配尚未达到平衡状态.采用Junge-Pankow吸附模型和Harner-Bidleman吸收模型对PCBs颗粒态百分比(φ)及KP进行了模拟,结果显示两种模型均较好地预测了PCBs的气粒分配行为,但与实验测得的值相比,两种模型均高估了φ值及KP值.     

辽东湾网采浮游植物粒级结构的胁迫响应

基于2012~2014年春、夏、秋、冬季辽东湾网采浮游植物及环境因子的调查资料,对辽东湾南、北2个区域的浮游植物粒级结构分布规律及其环境胁迫响应进行了分析,并评估了浮游植物群落结构的稳定性.结果表明,辽东湾海域浮游植物春、夏、秋季丰度主要集中在小粒径范围,冬季主要集中在中粒径范围;生物量春、夏、秋季主要集中在中粒径范围,冬季主要集中在大粒径范围,南部区域浮游植物粒径整体上大于北部区域.寡营养水域以及较低的水温环境更适于大粒径浮游植物生存.春、秋、冬季浮游植物群落结构比较稳定,但夏季偏离平衡点.南部区域群落结构整体上比北部区域稳定,网采中、大粒径组的W统计量可以作为浮游植物群落结构稳定性的评估指标.     

我国西南地区森林土壤中有机氯农药和多氯联苯残留的初步研究

对西南地区森林土壤中有机氯农药和多氯联苯的分布和剖面进行了区域尺度分析。相比较发达国家和地区,我国西南地区森林土壤中有机氯农药含量水平较高,多氯联苯则相对较低。这与我国此类持久性有机污染物历史使用情况吻合。多氯联苯和有机氯农药在腐殖质层的含量一般高于表层土壤中,说明淋溶作用导致污染物向下移动。DDTs和HCHs是土壤样品中有机氯农药的主要成分,说明我国历史上长期施用农药对森林土壤农药的组成有显著影响。环境参数（包括TOC、降雨量和海拔高度）对大多数有机氯农药的区域空间分布的作用并不显著,周边污染源是控制有机氯农药在腐殖质层土壤中分布的关键因素;尤其是DDTs,比值分析结果显示仍有新鲜的工业滴滴涕输入。多氯联苯在腐殖质层中的含量明显要高于其在表层土壤中的含量,多氯联苯在土壤中的空间分布和土层中的垂直分布主要受土壤TOC含量的控制。以大气干湿沉降来源贡献为主的多氯联苯与土壤中的有机质有效结合会降低它们的再挥发过程,表明西南地区山地森林对多氯联苯具有一定森林过滤效应。     

广东电子垃圾污染区水体底层鱼类对PCBs的富集效应

采用GC/MS分析方法测试了广东电子垃圾回收地水体沉积物中多氯联苯(PCBs)含量,并利用以前测定的底栖性鱼类(鲮鱼、鲫鱼和乌鳢)PCBs含量数据,计算了生物/沉积物富集因子(BSAF)和生物放大因子(BMF),研究底栖性鱼类对PCBs的富集能力及其影响因素.研究表明,沉积物中总PCBs含量达到24.5~38.6μg/g干重,证实当地环境已受到PCBs严重污染.鲮鱼、鲫鱼和乌鳢的BSAF范围分别为0.05~2.52、0.01~1.20和0.01~5.03.根据乌鳢/鲮鱼和乌鳢/鲫鱼食物关系计算的BMF范围分别为0.14~2.23和0.14~4.93, 其中大部分PCB同系物的BMF>1,表明乌鳢对PCBs具有生物放大作用.BSAF及BMF均与PCBs的KOW和氯原子取代数具有显著相关性,说明化合物的理化性质是控制其生物富集的主要因素.     

泉州湾食用鱼中有机氯农药和多氯联苯污染状况与食用安全性的研究

于2013年采集泉州湾海域10种食用鱼样品,分析其中的20种有机氯农药（OCPs）和28种多氯联苯（PCBs）的含量、组成、生物富集以及对人体健康的危害进行风险评估。结果显示,鱼体中OCPs和PCBs的浓度分别为（11.20~74.51）×10-9和（4.48~20.44）×10-9（湿重）,不同鱼种类中污染物含量差别较大,其中棱鮻和斑鰶体中OCPs和PCBs含量最高。鱼体中OCPs主要以DDTs为主,其他化合物含量均较低,且分子标志示踪来源显示,OCPs主要来源于历史残留;而PCBs主要以高氯代PCBs为主。泉州湾食用鱼对DDTs具有较强的富集能力;对PCBs的富集能力随着氯原子数的增加而增强,但氯原子数大于7时富集能力下降。评估显示,泉州湾鱼类体中PCBs的量可能会危及人体健康。并且,棱鮻、斑鰶、黄姑鱼、叫姑鱼、白姑鱼和四指马鲅的每日允许最大摄入量和每月最大允许餐数均低于安全阀值142.2 g/d和16餐/月,建议消费者不要过度食用这些海产品。     

表面活性剂溶液中多氯联苯溶解的特性

对表面活性剂溶液中多氯联苯的溶解特性进行了研究.发现非离子型表面活性剂对多氯联苯增溶效果优于阴离子型表面活性剂;在浓度大于临界胶束浓度(CMC)范畴,不但表面活性剂的增溶效果远较其浓度低于CMC时为佳,而且表面活性剂浓度与多氯联苯的溶解度成正比地线性相关,此结果说明,表面活性剂主要通过形成胶束来增加多氯联苯的溶解度.多氯联苯在非离子型表面活性剂胶束溶液中与在正己烷中的紫外-可见光谱相似,进一步说明胶束内的多氯联苯分子主要分布于类似正己烷的疏水胶核区域.在十二烷基醇聚氧乙烯(10)醚溶液中,所试多氯联苯的辛醇-水分配系数(K_ow)与其胶束-水分配系数(K_m)存在很好的线性相关关系.     

不同基因型水稻吸镉差异及其与根表铁氧化物胶膜的关系

采用琼脂培养方法，模拟铁在不同基因型水稻根表的氧化与淀积，研究了不央水稻吸镉的差异及其有表铁氧化物胶膜的关系，结果表明不同水稻基因型其根表淀积换的氧化物数量存在显著性差异，根表富集的镉量及根部，地上部合镉量均存在显著性差差，且镉在不同水稻植株体内转移运输能力不同；不同水稻基因型根膜中的含铁量与根表铁氧化物富集的镉量、根部的含镉量、地上部的含量存在显著性年线相关。     

变电站多氯联苯污染源的治理

本文介绍典型的秦安变电站PCB治理情况,建立了一套土壤和空气中PCB残留量的测定方法,完成了该电站内外环境样品中PCB残留量的测定,对污染状况作了评价,设计了相应的治理方案,完成治理一年后的跟踪监测结果证实,污染基本消除,环境得到改善,该方案方法简便,适合我国国情。     

基于铜锈环棱螺的生物炭修复沉积物中BDE-47生物积累动力学预测模型

研究了铜锈环棱螺对沉积物颗粒的摄取速率、从水和沉积物中摄取BDE-47的效率,以及在BDE-47污染沉积物中添加玉米秸秆生物炭后对这些生理学参数和间隙水中BDE-47平衡浓度的影响.构建了基于铜锈环棱螺摄取和消除BDE-47的相关生理学参数和沉积物地球化学参数的生物动力学预测模型,同时评价了该模型预测BDE-47生物积累的效力.结果显示,铜锈环棱螺对沉积物的摄食率为6.04 g·g^-1·d^-1,对水中BDE-47的摄取效率为38.41%.在BDE-47污染沉积物中添加4%的玉米秸秆生物炭（CSB）可以显著降低间隙水中BDE-47的平衡浓度,降幅达到81%.铜锈环棱螺对添加CSB的沉积物中BDE-47的生物积累显著低于未添加CSB的沉积物,暴露28 d后,添加CSB的沉积物中BDE-47的生物积累下降了66%.本研究构建的生物动力学模型的预测结果与暴露测试中观察到的铜锈环棱螺对BDE-47的摄取情况基本一致.BDE-47的28 d生物积累对沉积物颗粒摄食率、从沉积物中摄取BDE-47的效率、沉积物中BDE-47的浓度和BDE-47的消除速率常数等4个参数的响应表现出较好的敏感性.根据模型的预测,铜锈环棱螺从沉积物中摄取的BDE-47占总积累量的80%以上.当沉积物中添加CSB后,模型显示出更好的预测效力.因此,在已知沉积物和间隙水中BDE-47浓度的前提下,利用该模型可以有效地预测铜锈环棱螺体内BDE-47的积累量,从而减少沉积物生态毒性风险评价和利用生物炭进行原位修复效果评估的不确定性.     

PCBs和PBDEs的生物效应及人体健康影响的研究现状

环境中的多氯联苯(PCBs)和多溴联苯醚(PBDEs)通过食物链,可以在水生生物实现生物积累。而人类食用这些含有污染的食品,可以造成对人体的健康危害的摄食暴露,导致癌症、内分泌失调等疾病,并影响生育能力和儿童智力发育。但由于生物体内在因素的复杂性,PCBs和PBDEs在生物体内的代谢、放大等机制仍不明确,有待进一步的研究。