定量预测多氯联苯的贝类净化

以量子化学参数为描述符,应用偏最小二乘法(PLS)对多氯联苯(PCBs)在淡水贝类Elliptio complanata体内的净化速率常数(k_d)进行了模拟分析,获得一个五参数定量结构-活性相关(QSAR)模型.模型的交叉验证相关系数(Q_cum2)和标准偏差(SD)分别为0.871和0.112,表明其具有较高的预测能力和可靠性. 模型中具有重要意义的参数包括平均分子极化率(α),分子量(M_w),核核斥能(CCR)和总能(TE). 这些参数表明,偶极-诱导偶极作用和色散力是影响贝类Elliptio complanata净化PCBs的主要因素.      

京尼平对丝素蛋白交联的染色作用

京尼平是一种环烯醚萜类化合物,能够与氨基酸反应生成蓝色素.制备的无色丝素蛋白溶液与京尼平溶液混合后,溶液显蓝紫色.利用紫外可见光光谱和荧光光谱,分析了整个反应过程,考察了温度、酸碱度等影响因素,并对颜色产物对光照的稳定性进行了分析,初步探讨了京尼平对丝素蛋白交联染色作用的机制.结果显示:生成的颜色产物在590 nm处具有特征光吸收,高温和碱性条件有利于反应的进行;交联产物的颜色与反应时pH相关,酸性条件下偏蓝色,碱性条件下偏紫色;生成的颜色产物具有较高的稳定性,于自然光强下放置一个月或5 000 lx光强照射6 h.590 nm吸收值减小不显著.丝素蛋白的内源荧光显著降低,表明反应导致丝素蛋白构象的剧烈变化.京尼平可能与丝素蛋白中某些氨基酸侧链基团反应形成稳定的颜色产物.研究结果对环烯醚萜类化合物用于蚕丝染色具有一定的指导意义.图5表1参18     

Effects of La,Ce on nitrogen removal in sequencing batch reactor

Batch experiments were conducted to study the short-term biological effects of rare earth ions (La³⁺, Ce³⁺) and their mixture on the nitrogen removal in a sequencing batch reactor (SBR). The data showed that higher NH⁺₄―N removal rate, total inorganic nitrogen removal efficiency, and denitrification efficiency were achieved at lower concentrations of rare earth elements (REEs) (<1mg/L). In the first hour of the aeration stage of SBR, the presence of REEs increased the total inorganic nitrogen removal efficiency and NH⁺₄―N removal efficiency by 15.7% and 10%―15%, respectively. When the concentrations of REEs were higher than 1mg/L, the total inorganic nitrogen removal efficiency decreased, and nitrate was found to accumulate in the effluent. When the concentrations of REEs was up to 50.0mg/L, the total inorganic nitrogen removal efficiency was less than 30% of the control efficiency with a high level of nitrate. Lower concentrations of REEs were found to accelerate the nitrogen conversion and removal in SBR.     

全自养脱氮颗粒污泥的培养及脱氮性能的恢复与强化

采用交替限氧-厌氧和低充放比(30%)运行模式,在SBR反应器中成功启动全自养脱氮(CANON)工艺,启动过程经历常规硝化主导阶段、短程硝化主导阶段和全自养脱氮阶段,总氮去除速率和总氮去除效率分别达到(312±15)mg/(L·d)和(71.2±4.3)%.培养得到的污泥中颗粒污泥(粒径3300μm)和絮状污泥(粒径<300μm)体积分别占污泥总体积的39%和61%.在自养脱氮性能恶化的SBR反应器进水中长期添加适量N2H4,反应器脱氮性能得以恢复甚至强化,反应器总氮去除速率升高到(480±34)mg/(L·d),颗粒污泥的比例增加到污泥总体积的51%.     

基于蒙特卡罗模拟的阿特拉津健康风险评价

为评估阿特拉津(ATR)对人体的健康风险,通过文献检索及追溯方式,收集了93篇文献中关于我国环境介质中ATR的检测数据,基于美国环保署健康风险评价方法,并运用蒙特卡罗模拟方法,评价了我国成年男性和女性ATR的健康风险,分析了各参数的敏感性和相关性。结果显示,我国成年男性和女性的非致癌健康风险熵值分别为4.53×10~(-2)和4.30×10~(-2),分别有89.8%的成年男性和89.9%的成年女性风险熵值低于0.10;饮用水中ATR的浓度对其健康风险的贡献(即敏感性)分别为男性88.0%和女性83.3%,与健康风险的关联性(R)分别为男性0.907和女性0.895。我国ATR的非致癌健康风险处于可接受水平,饮用水中ATR对其健康风险的贡献最大。该方法可为有毒有害物质的健康风险预警和精准控制提供方法学参考。     

750kV同塔双回输电线路下电场效应影响因素分析

750 kV同塔双回输电线路下方农田、葡萄田经常发生“电击”现象。通过电场仿真计算、现场实测工频电场强度、工频磁场强度,研究分析750 kV同塔双回输电线路下方地面1.5 m高处电场强度、工频磁场强度的分布及影响因素。电场仿真计算与现场实测电场效应的分布及影响因素基本一致。通过研究输电线路下方电场效应影响因素,为电场效应的抑制措施提供参考。     

青岛市农区地下水硝态氮污染来源解析

为了提高作物产量,肥料大量投入在农业种植区日益普遍,导致了农区地下水硝态氮（NO₃^--N）污染.农业面源污染是地下水硝态氮污染的主要原因.为了保障饮用水安全,明确农区硝态氮污染的来源是十分必要的.本研究分别于2009年和2019年在青岛农区随机选取35个采样点,借助反距离加权法（IDW）对硝态氮含量进行空间分布分析,通过测定氮、氧同位素进行溯源,运用SIAR模型量化污染源的贡献率.结果表明,青岛市地下水硝态氮含量（平均值）由2009年的38.49 mg·L^-1降低为2019年的22.37 mg·L^-1,但仍高于世界卫生组织（WHO）规定的饮用水中硝态氮的最大允许含量.2009年和2019年硝态氮含量都呈现由南向北逐渐增加的趋势,南部污染轻,北部污染重.δ15N-NO₃^-和δ¹⁸O-NO₃^-的交叉图显示青岛市地下水硝态氮主要来源是化肥、土壤氮、粪肥和污水.水同位素表明降水是青岛市地下水的主要来源.贝叶斯混合模型（SIAR模型）表明污染源贡献率为：粪肥和污水（47.42%） > 土壤氮（27.80%） > 化肥（14.35%） > 大气氮沉降（10.43%）.从2009~2019年青岛市地下水质量得到了改善,但硝态氮污染状况仍不容忽视,应根据硝态氮污染来源,有针对性地防治以确保农区饮用水安全和农业的可持续发展.     

邻苯二甲酸二乙基己酯对蚕豆幼苗茎和叶POD活性和MDA含量的影响(Effects of Di-（2-ethylhexyl）Phthalate（DEHP）on POD Activities and MDA Contents in Stem and Leaves of Vicia faba Seedlings)

为了初步研究邻苯二甲酸二乙基己酯（Di-（2-ethylhexy）phthalate, DEHP）对植物幼苗的氧化损伤作用,采用不同浓度（0.2、2、20、200mg·kg-1（细沙））DEHP对蚕豆的根部染毒,分析了DEHP对蚕豆幼苗茎、叶中的过氧化物酶（POD）及丙二醛（MDA）含量的影响. 结果表明,处理7d后,随DEHP浓度的升高,蚕豆幼苗茎、叶POD活性均呈先升高后降低趋势,较高浓度组（茎：≥2mg·kg-1;叶：≥20mg·kg-1）与对照组差异显著（p<0.05）;MDA含量均呈逐渐升高趋势,较高浓度组（≥2mg·kg-1）与对照组差异显著（p<0.05或p<0.01）. 以上结果表明,DEHP可造成蚕豆幼苗氧化损伤.     

藻源型溶解性有机氮的产生及不同时期藻类有机物的特性

研究了铜绿微囊藻藻细胞全生命周期中氮的转化过程以及藻类有机物的性质,结果表明:溶解性有机氮(DON)在藻类生长周期中总体呈现上升趋势,藻细胞在其生长初期释放量小于0.05mgDON/107cells,衰亡期释放能力约为0.40mgDON/107cells;胞外有机物(EOM)中分子量分布在对数期和衰亡期以100kDa为主,稳定期以100kDa范围内.三维荧光光谱分析表明,EOM中荧光物质主要为类腐植酸和溶解性微生物代谢产物;而IOM主要由类芳香蛋白和溶解性微生物代谢产物组成.     

Assessment on contaminations in sediments of an intake and the inflow canals in Taihu Lake,China

As the second largest freshwater lake in China, Taihu Lake provides water supply to approximately 32 million inhabitants around the lake. However, dramatically increased pollution has threatened the safety of drinking water supply in recent years. In the present study, we investigated the contaminations of nutrients and heavy metals in the sediments of an intake and inflow canals in Gonghu Bay, Taihu Lake. Moreover, we also examined the impact of human activities on spatial distribution characteristics of contaminations. Our results showed that the intake presented relatively lower concentrations of phosphorus and nitrogen compared with inflow canals. However, the concentrations of Cr, Ni, Cu, Zn and Pb in the sediments of the intake exceeded the lowest effect level (LEL) values, indicating a potential risk to drinking water resource. In addition, the concentrations of Ni in the sediments of Tianji Canal and Jinshu Canal exceeded the severe effect level (SEL) value. More importantly, the concentrations of Cu in the sediments of Tianji Canal exceeded three times of the SEL value. Multivariate statistical analysis confirmed that the domestic sewage primarily contributed to the nutrient accumulation, and the leakage of electronic trash dominated the enrichment of metals in the sediments. Taken together, more effort should be made to ensure the security of water resources in Taihu Lake, especially for the treatment of domestic sewage and industrial wastewater.