Genotoxicity of oxy-PAHs to Japanese medaka (Oryzias latipes) embryos assessed using the comet assay

Polycyclic aromatic hydrocarbons (PAHs) have long been recognized as important environmental toxicants. Despite a plethora of information on the fate and effects of parent PAHs, relatively little is known about the environmental fate and toxicity of ketone- and quinone-substituted PAH oxidation products (termed oxy-PAHs), particularly in the aquatic environment. This study begins to fill that gap using embryos of the Japanese medaka (Oryzias latipes) as a model species. The genotoxic potential of two environmentally relevant oxy-PAHs, acenaphthenequinone and 7,12-benz[a]anthracenquinone, was assessed using the comet assay. We found that both oxy-PAHs could cause significant increases in DNA damage after only 48 h of exposure at the lowest concentrations tested (5 μg/L). Comparisons of the genotoxic potential between these oxy-PAHs and their corresponding parent PAHs (acenaphthene and benz[a]anthracene) and a well-known mutagenic PAH, benzo[a]pyrene, indicated similar potencies among all five of these compounds, particularly after longer (7 day) exposures. This study demonstrates the mutagenic potential of oxy-PAHs to an in vivo fish embryo model and points out the need for further study of their environmental occurrence and biologic effects.     

响应面法优化UV/H_2O_2光氧化法处理高浓度LAS废水

采用响应面法对UV/H2O2光氧化法处理高浓度LAS废水的工艺参数进行了系统研究。根据Box-Behnken Design(BBD)设计原理,以初始pH与H2O2投加量、反应时间和温度为主要影响因素,设计4因素3水平共29个实验点的实验方案,并建立了二次响应面拟合模型。方差分析表明,初始pH与H2O2投加量、反应时间和温度以及初始pH和H2O2投加量、H2O2投加量和温度之间的交互作用,对实验结果具有显著性影响。实验得到的光氧化高浓度LAS废水最佳工艺条件,pH为4.0,H2O2投加量为40 mmol/L,反应时间为90 min,温度为25℃,在此条件下,LAS的平均去除率为98.1%。     

不同粒径炉渣对磷的静态吸附

研究了不同粒级炉渣对含磷废水的静态等温吸附性能,为其在污水处理领域的有效利用和合理级配提供理论依据。经筛分得到<0.2 mm、0.2~0.45 mm、0.45~0.9 mm、0.9~2 mm、2~4 mm、4~6 mm、≥6 mm的7个粒级的供试炉渣,其中0.9~4 mm粒级占总量的64.54%。XRD、XRF分析显示,各粒级炉渣物相组成相似,<0.2 mm粒级炉渣中活性铝含量最高。静态吸附实验表明,炉渣对磷素的最大吸附量为4 021 mg/kg,最佳吸附时间为24 h;Langmuir和Freundlich吸附等温线可较好地拟合各粒级炉渣对溶液中磷素的吸附,而小于0.9 mm粒级炉渣具有更高的拟合度;炉渣粒径越小,吸附能力越强,<0.2 mm粒级炉渣的理论饱和吸附容量达14 084 mg/kg,≥6 mm粒级炉渣吸附磷素能力差;受粒径、溶液含磷浓度等因素影响,炉渣的平均理论吸附容量为1 142.4 mg/kg。     

羽毛角蛋白海绵材料对亚甲基蓝的吸附去除

以羽毛角蛋白提取后产生的残渣为原料,采用简单物理法制得角蛋白海绵材料,通过扫描电镜和红外光谱对其表观形貌和表面结构进行表征,同时以亚甲基蓝染料作为实验对象,考察制得的海绵材料对其吸附特性和去除效果。结果表明,当吸附平衡时间为1 440 min、亚甲基蓝溶液初始浓度为100 mg/L、海绵材料投加量为0.06 g、反应温度为25℃、溶液pH为7.0时,海绵材料对亚甲基蓝的吸附去除率可达98%以上,同时由Langmuir等温吸附模型拟合结果可知,海绵材料对亚甲基蓝的最大吸附量可达151.5 mg/g。因此,将羽毛角蛋白提取后产生的残渣可制备良好的染料吸附剂,取得良好的环境效益。     

白腐菌改性的中药渣对Cr（Ⅵ）的吸附性能

以白腐菌的典型菌种黄孢原毛平革菌为改性菌种,对中药渣进行改性处理,研究了改性中药渣对Cr（Ⅵ）的吸附性能。采用SEM技术对改性中药渣进行表征。研究了废水pH、改性中药渣加入量、吸附温度和吸附时间对Cr（Ⅵ）吸附效果的影响。表征结果显示,中药渣经过改性后表面出现许多孔隙,比表面积增大,为吸附Cr（Ⅵ）提供了更多的吸附位。实验结果表明：在初始Cr（Ⅵ）质量浓度50 mg/L、改性中药渣加入量5 g/L、废水pH 2、吸附温度45 ℃、吸附时间20 h的条件下,改性中药渣对Cr（Ⅵ）的去除率达99.5%,吸附量可达9.82 mg/g;改性中药渣对Cr（Ⅵ）的吸附等温线符合Langmuir等温吸附方程和Freundlich等温吸附方程;准二级动力学方程能很好地对改性中药渣吸附Cr（Ⅵ）的数据进行拟合。     

铈离子光催化降解茜素绿的性能和机理

主要研究了简单铈离子（Ce3＋）在紫外光（uv）的作用下对蒽醌染料茜素绿（AG）的光催化降解效果和反应机理。结果表明,UV／Ce3＋体系能够有效降解AG,初始反应速率随AG浓度的倒数值和Ce3＋浓度的增加而线性增加,随初始溶液pH的增加先降低后增加,在酸性条件下有很高的TOC去除率。荧光探针实验表明,反应过程中可以产生·OH自由基。UV／Ce3＋体系对其他类型染料和对硝基苯酚都有较好的降解效果。     

天氧污泥对问二氯苯的吸附性能

为了研究灭活厌氧污泥和活性厌氧污泥对问二氯苯（m-DCB）的吸附,考察了吸附平衡时间、吸附动力学、吸附等温线、吸附热力学、污泥投加量和pH对吸附m-DCB的影响。结果表明,2种污泥对m-DCB的吸附在1h内达到平衡。应用伪一级、伪二级反应动力学对实验数据进行验证,表明厌氧污泥吸附m-DCB更符合伪二级反应动力学模型。2种污泥对m-DCB的吸附都可以用Langmuir和Freundlich吸附模型拟合,但Langrnuir吸附模型的拟合结果要好于Freundlich模型,且活性厌氧污泥的吸附性能显著高于灭活厌氧污泥。从吸附热力学上看,该吸附为放热反应,低温有利于吸附反应的进行。pH值对2种污泥吸附m-DCB的影响很小。     

2种填料作为生物膜载体修复微污染河水的比较

采用序批式生物反应器(SBBR),在水温为(19.0±1.5)℃,DO≥4.5 mg/L条件下,比较基于2种生物膜填料(竹丝和空心塑料球)上的微生物对微污染河水中高锰酸钾指数(COD Mn)、总氮(TN)和总磷(TP)等的去除效果。结果表明,经过4 h的运行,竹丝作为生物膜载体时,COD Mn、TN的去除分别为17.5%~48.8%和49.38%~70.93%,但TP的去除效果不明显;而基于空心塑料球的生物膜对COD Mn的去除率仅为2.4%~42%,对TN和TP去除效果均不明显。通过显微分析发现,基于竹丝填料生物载体上微生物种类、数量明显多于空心塑料球。     

石油降解菌的筛选优化及其对油污土壤的修复特性

分别以牛肉膏蛋白胨-布氏哈斯培养基、蓝色凝胶培养基作为初筛和复筛培养基,从石油污染土壤中筛选出2株可产生微生物表面活性剂的石油烃降解菌。并将菌株投加到油污土壤中进行修复研究,考查了不同影响因素对修复效果的影响。研究结果表明,(1)2株菌对中度石油污染土壤有较好的修复效果,向油污土壤中直接投加菌株修复70 d时对石油烃的去除率为52%;(2)向油污土壤中投加降解菌并同时补充氮营养液,修复70 d时对土壤中总石油烃的去除率可达到75%;对土壤中正构烷烃的去除率为66%;(3)与土壤的含水率及土著菌的降解效果相比,向油污土壤中投加降解菌以及补充氮磷营养液是影响石油污染土壤修复效果的关键因素。     

Occurrence and environmental implications of pharmaceuticals in Chinese municipal sewage sludge

The presence of pharmaceuticals in aquatic environment has become a topic of concern because of their potential adverse effects on human health and wildlife species. A total of 45 dewatered sewage sludge samples were collected throughout China and analyzed for 30 commonly consumed pharmaceutical residues. Ofloxacin was found to be the dominant contaminant with concentrations up to 24 760 μg kg⁻¹, followed by oxytetracycline (5280 μg kg⁻¹), norfloxacin (5280 μg kg⁻¹) and ketoprofen (4458 μg kg⁻¹). The concentration of pharmaceutical residues varied greatly depending on the operation conditions of wastewater treatment plants and sampling locations. Poor agreement was found between the predicted (calculation based on the annual consumption and coefficient of sludge water partition) and detected concentrations of the pharmaceuticals indicating that the occurrence of pharmaceutical residues was affected by various factors such as loading rates, sewage properties and the chemical properties such as the contribution from polar groups. National wide fate and ecotoxicity study is required for the development of control strategies.