Tenax萃取技术用于养殖底泥中有机氯农药的生物有效性研究

本研究以经济底栖生物菲律宾蛤仔和河蚬为受试生物,分别对不同浓度梯度的海洋和淡水底泥中9种代表性有机氯农药(OCPs)进行累积实验;同时采用Tenax连续萃取法研究2类底泥中OCPs的脱附动力学,提供简单、快速评价养殖底泥中OCPs生物有效性的方法,并将Tenax萃取结果与2种底栖生物的累积结果进行比较。结果表明,菲律宾蛤仔和河蚬对OCPs的生物-底泥富集因子(BSAF)分别为0.31~1.89和0.12~2.12,且底泥中有机碳标化的OCPs浓度与生物体内脂肪标化的OCPs浓度之间的相关性较差。Tenax脱附动力学的结果表明,2类底泥中OCPs的快速脱附比例(F_(rap))均在50%左右,其快速、慢速和极慢速脱附速率常数数量级分别为10~(~(-1))、10~(-2)和10~(-4)。Tenax快速脱附组分与2种底栖生物累积结果之间具有良好的相关性(r~2=0.75,P0.0001),表明Tenax萃取技术可以预测OCPs在底栖生物体内的累积量,并且该方法克服了大型底栖生物累积实验结果重复性较差等缺点。另外通过与基于热力学平衡的方法对比发现,Tenax萃取技术更适用于滤食性或可消化底泥的底栖生物对底泥污染物的富集;同时Tenax 6 h和24 h单点萃取技术可以作为简单快速评价底泥疏水性有机污染物(HOCs)生物有效性的替代方法,进一步为养殖领域的底泥污染状况以及相关水产品的质量安全和食用风险提供生物有效性评价依据。     

双酚A类似物雌激素干扰效应的定量结构-活性关系模型

由于双酚A(BPA)具有内分泌干扰等毒性效应,有些国家已经开始限制其在部分工业品生产中使用。一些双酚A类似物因用于替代BPA而被大量使用。因其与双酚A具有相似的分子结构,双酚A类似物是否也具有内分泌干扰等毒性效应受到越来越多的关注。采用逐步多元线性回归(MLR)方法,构建了可预测双酚A类似物雌激素效应的定量结构-活性关系模型。模型的决定系数R~2=0.899,去一法交叉验证系数Q_(LOO)~2=0.868,Bootstrapping验证系数Q_(BOOT)~2=0.755,均方根误差RMSE=0.339,表明模型具有较好的拟合优度、稳健性;验证集决定系数Q_(EXT)~2=0.921,外部验证系数Q_(EXT)~2=0.810,均方根误差RMSE=0.638,表明模型具有较好的预测能力。采用欧几里德距离方法和Wil iams图表征了模型应用域,依据分子描述符对模型进行了机理解释,并用所建模型,填补了22种其他双酚A类似物缺失的雌激素干扰效应数据。     

铅对人Bel-7402肝癌细胞毒性及EGFP基因DNA甲基化的影响

以体外培养人Bel-7402肝癌细胞为模型,研究铅的3种常见化合物氯化铅(Pb Cl2)、乙酸铅(Pb(CH3COO)2)、硝酸铅(Pb(NO3)2)的细胞毒性和去甲基化表观遗传毒性。应用MTS方法检测细胞的存活率,以前期研究建立的评价方法评价铅化合物的去甲基化表观遗传毒性。结果显示,Pb Cl2、Pb(CH3COO)2、Pb(NO3)2均会抑制Bel-7402细胞的增值,计算求得Pb Cl2、Pb(CH3COO)2、Pb(NO3)2相应的50%细胞存活浓度(IC50)值分别为2 524μmol·L~(-1)、1 977μmol·L~(-1)、1 899μmol·L~(-1);80%细胞存活浓度(IC80)值分别为264μmol·L~(-1)、221μmol·L~(-1)、281μmol·L~(-1),通过对3种染毒物不同染毒浓度的细胞存活率进行随机区组设计的方差分析显示3种化合物间的差异无统计学意义(F=0.11;P=0.897)。去甲基化表观遗传毒性检测结果显示,Pb Cl2、Pb(CH3COO)2、Pb(NO3)2均可观察到明显的去甲基化表观遗传毒性,其相对于5-氮杂-2-脱氧胞苷(5-Aza-Cd R)的去甲基化表观遗传毒性当量分别为2.82E-03、1.50E-03、5.09E-04,三者间也无显著性差异。结果表明,铅化合物会使Bel-7402细胞的细胞存活率和转染进细胞的质粒上增强型绿色荧光蛋白基因启动子的DNA甲基化水平下降。     

塑料企业周边水体中多溴联苯醚的污染特征

多溴联苯醚(PBDEs)是一种新型的持久性有机污染物(POPs)。采用固相萃取-气相色谱法测定了某塑料企业周边及当地自然水体中的PBDEs浓度,主要针对BDE~(-1)7、28、47、66、85、99、100、138、153、154、183、203及BDE-209共13个PBDE同系物的浓度水平、组成分布和污染特征进行分析。结果显示,使用企业周边水体中除BDE-203在水体中未检出外,其余12种PBDE同系物均有不同程度的检出。Σ13PBDEs质量范围处于未检出~363 ng·L~(-1),各同系物的平均质量浓度为未检出~42.6ng·L~(-1)。其中BDE-209为最大检出质量丰度同系物,但其检出率仅为25.0%,检出率较高的同系物是BDE~(-1)7、BDE-28和BDE~(-1)00,检出率分别为75.0%、75.0%、58.3%,低溴代联苯醚的检出率显著高于高溴代联苯醚。当地自然水体中13种PBDEs均有不同程度的检出,检出浓度在0.161~1.83 ng·L~(-1)。企业周边水体中PBDEs的污染水平显著高于自然水体,是自然水体浓度的5~100倍。因此,企业周边区域水体中PBDEs的污染情况应引起相关部门关注。     

有机氯农药在东方白鹳组织里的浓度

对越冬迁徙期间中途停留在天津北大港的野生鸟类-东方白鹳（Ciconia boyciana）体内肌肉、肝脏、心脏、胃和脾中∑OCPs浓度进行了检测.各组织中检出的∑OCPs平均浓度（浓度范围,以脂重计）在心脏中最高,为955.30ng/g（88.65～4102.577ng/g）,次之为肝脏,平均浓度为465.55ng/g（37.96～1476.17ng/g）,再次之为胃、脾和肌肉,浓度分别为251.64ng/g（102.88～354.61ng/g）、176.5ng/g（158.72～194.50ng/g）和143.96ng/g（10.90～800.51ng/g）.在肝脏和心脏中∑DDTs和浓度高于∑HCHs,在其它组织中则相反.与其它研究相比,本研究所检测鸟体内有机氯浓度较低,表明这批东方白鹳并尚未受到环境中OCPs的严重污染.     

Degradation of carbon tetrachloride in thermally activated persulfate system in the presence of formic acid

The thermally activated persulfate (PS) degradation of carbon tetrachloride (CT) in the presence of formic acid (FA) was investigated. The results indicated that CT degradation followed a zero order kinetic model, and CO ₂ ^– · was responsible for the degradation of CT confirmed by radical scavenger tests. CT degradation rate increased with increasing PS or FA dosage, and the initial CT had no effect on CT degradation rate. However, the initial solution pH had effect on the degradation of CT, and the best CT degradation occurred at initial pH 6. Cl^– had a negative effect on CT degradation, and high concentration of Cl^– displayed much strong inhibition. Ten mmol·L^–1HCO ₃ ^– promoted CT degradation, while 100 mmol·L^–1NO ₃ ^– inhibited the degradation of CT, but SO ₄ ^2– promoted CT degradation in the presence of FA. The measured Cl–concentration released into solution along with CT degradation was 75.8% of the total theoretical dechlorination yield, but no chlorinated intermediates were detected. The split of C-Cl was proposed as the possible reaction pathways in CT degradation. In conclusion, this study strongly demonstrated that the thermally activated PS system in the presence of FA is a promising technique in in situ chemical oxidation (ISCO) remediation for CT contaminated site.     

Enhanced degradation of trichloroethene by calcium peroxide activated with Fe(III) in the presence of citric acid

Trichloroethene (TCE) degradation by Fe(III)-activated calcium peroxide (CP) in the presence of citric acid (CA) in aqueous solution was investigated. The results demonstrated that the presence of CA enhanced TCE degradation significantly by increasing the concentration of soluble Fe(III) and promoting H₂O₂ generation. The generation of HO? and O₂^-? in both the CP/Fe(III) and CP/Fe(III)/CA systems was confirmed with chemical probes. The results of radical scavenging tests showed that TCE degradation was due predominantly to direct oxidation by HO?, while O₂^-? strengthened the generation of HO? by promoting Fe(III) transformation in the CP/Fe(III)/CA system. Acidic pH conditions were favorable for TCE degradation, and the TCE degradation rate decreased with increasing pH. The presence of Cl^-, HCO₃^-, and humic acid (HA) inhibited TCE degradation to different extents for the CP/Fe(III)/CA system. Analysis of Cl^- production suggested that TCE degradation in the CP/Fe(III)/CA system occurred through a dechlorination process. In summary, this study provided detailed information for the application of CA-enhanced Fe(III)-activated calcium peroxide for treating TCE contaminated groundwater.     

Recent advances in pharmaceuticals and personal care products in the surface water and sediments in China

Pharmaceuticals and personal care products (PPCPs) have been regarded as an emerging problem in the surface water environment in the past few decades. In China, although related studies were initiated several years ago, an increasing number of studies on this topic have been conducted in recent years. These studies have expanded knowledge of their occurrence, behavior and associated risk in the surface water environment in China. This review compiles the most recent literature related to the studies of PPCPs in the surface water environment in China. It includes PPCP occurrence in surface water and sediments, their geographical distribution, and outcomes of the associated risk assessment. It shows that antibiotics have received much more attention in both surface water and sediments than other PPCPs. Compared to other countries; most antibiotics in the collected sediments in China showed higher contamination levels. Many more study areas have been covered in recent years; however, attention has been given to only specific areas. Environmental risk assessment based on risk quotients indicated that sulfamethoxazole presents the most significant environmental risk to relevant aquatic organisms; followed by ofloxacin, ciprofloxacin, enrofloxacin, 17α-ethynylestradiol, ibuprofen and diclofenac. Despite limited research on the environmental risk assessment of PPCPs in sediments, higher risks posed by PPCPs in the sediments rather than surface water were identified highlighting the need for further risk assessment of PPCPs in sediment samples.

Open image in new window

     

急性毒性藻红外测试中联合作用评价法的重现性

为认识藻红外联合作用评价法的稳定性,用苯(C6H6)、甲苯(C6H8)、二甲苯(C8H10)、氯苯(C6H5Cl)、三氯甲烷(CHCl3)和羊角月牙藻(Selenastrum capricornutum)进行了重现性实验,通过测试实验藻对5种药品不同组合的响应温差,用联合偏差系数法评价联合作用类型,分析药品联合毒性的重现性及联合作用评价法的评价效果。结果表明:二元组合中,重现性50%的5组,重现性75%的5组,平均重现性62.5%;三元组合中,重现性50%的1组,重现性75%的8组,重现性100%的1组,平均重现性75%;四元组合中,重现性50%的1组,重现性75%的1组,重现性100%的3组,平均重现性85%;五元组合重现性100%,混合药品总平均重现性73.1%。重现性大于阈值的组合19个,占全部26个组合的73.1%。药品组合元数增减与联合作用的重现性正相关。分析可知,藻红外联合作用评价法用于联合作用分析稳定性较好。