珠江三角洲典型区域农产品中邻苯二甲酸酯(PAEs)污染分布特征

在珠江三角洲典型区域(中山市、珠海市、东莞市和惠州市)内共采集了131个农产品样品,进行了6种优先控制污染物邻苯二甲酸酯(PAEs)含量水平分析及风险评价.结果表明,珠三角地区农产品样品中6种邻苯二甲酸酯累计含量(∑PAEs)范围为nd~79.86 mg·kg~(-1),平均含量为2.84 mg·kg~(-1),检出率为98.5%.各类农产品中∑PAEs平均含量的顺序依次为蔬菜(3.03 mg·kg~(-1))水稻(2.52 mg·kg~(-1))水果(1.26 mg·kg~(-1)).各城市产区内农产品中∑PAEs平均含量顺序为:珠海(6.53 mg·kg~(-1))东莞(2.59 mg·kg~(-1))惠州(1.53 mg·kg~(-1))中山(1.12 mg·kg~(-1)).农产品中PAEs的主要成分为邻苯二甲酸二正丁酯(DBP)、邻苯二甲酸二(2-乙基)己酯(DEHP)和邻苯二甲酸二正辛酯(DnOP),三者的累计含量占∑PAEs总量的90.8%.其中生菜(珠海)和芥兰(东莞)二者中∑PAEs的总量以及生菜、油麦菜(珠海)样品中DEHP的含量均超过美国和欧洲的建议标准,存在潜在的健康风险.芥兰、生菜等叶菜类蔬菜在14种不同蔬菜样品中的∑PAEs总量较高,而菜心和苋菜的∑PAEs含量最低.蔬菜品种间结构特征和生长环境(大气和土壤)的差异是影响其对PAEs的吸收及在体内累积的主要因素.     

不同粒径零价铁活化过硫酸钠氧化降解酸性橙7的影响及动力学研究

以偶氮染料酸性橙7(AO7)为目标污染物,研究了不同粒径零价铁(包括1 mm-ZVI、150μm-ZVI、50 nm-ZVI)对活化过硫酸钠(PS)氧化降解AO7的影响,并探讨了这3种不同粒径的零价铁活化体系中AO7的降解动力学及中间产物.结果表明,3种粒径零价铁均可以高效活化PS氧化降解AO7,反应90 min后,1 mm-ZVI、150μm-ZVI和50 nm-ZVI活化体系对AO7的去除率分别为43%、97%和100%.AO7动力学方程拟合结果表明,1 mm-ZVI和150μm-ZVI活化PS降解AO7是一级反应,50 nm-ZVI活化体系中AO7的降解是二级反应,这3种粒径零价铁活化PS降解AO7的速率常数大小顺序为50 nm-ZVI>150μm-ZVI>1 mm-ZVI.反应过程中1 mm-ZVI反应后主要生成α-Fe2O3和少量Fe3O4,150μm-ZVI表面的腐蚀产物主要是Fe3O4,而50 nm-ZVI的主要氧化物为α-Fe2O3和α-FeOOH.GC/MS检测出AO7降解中间产物有2-萘酚、邻甲酚、3-甲基-4-乙基苯酚、邻苯二甲酰亚胺、邻苯二甲酸等,AO7溶液吸收光谱的变化特征及GC/MS检测结果表明3种粒径零价铁活化PS氧化降解AO7的途径可能存在差异.     

磺胺甲基异恶唑的好氧生物降解研究现状

磺胺甲基异恶唑是广泛应用的抗生素,属于药品及个人护理品（Pharmaceutical and Personal Care Products,PPCPs）污染物的典型代表物质.近年来,该物质在环境中的检出率逐渐增加,成为了一种新兴污染物,对人体及生态环境造成危害.磺胺甲基异恶唑具有难于生物降解的特性,然而目前在好氧条件下,利用生物方法处理该物质已初见成效,它将成为今后的研究热点.本文对磺胺甲基异恶唑的好氧生物降解研究现状进行了系统的综述,包括具有降解该物质能力的微生物类群、该物质好氧降解的影响因素及降解产物分析,在此基础上提出了磺胺甲基异恶唑好氧生物降解未来进一步研究的方面.     

四溴双酚A好氧降解菌的筛选及其降解特性研究

为了解四溴双酚A(TBBPA)的微生物降解特性,采用TBBPA为单一碳源的选择性培养基从苯酚降解颗粒污泥中筛选出4株对TBBPA具有良好降解性的好氧菌株,其中菌株H经16S rDNA测序鉴定为红球菌属.正交试验得出其最优降解条件为:温度30℃,摇床转速150 r.min-1,pH 6.5,腐殖酸浓度200 mg·L-1,K+浓度1 000 mg·L-1;此条件下21 d降解脱溴率达20.75%.LC-MS结果表明,TBBPA好氧降解的主要产物是分子中异丙基与苯环断裂后脱溴产生的一溴苯酚.聚丙烯酰胺蛋白凝胶电泳(SDS-PAGE)结果表明,该菌株H的蛋白系列中含有一条介于(90～117)×103间的条带,对比同期考察的葡萄糖培养与TBBPA无机盐溶液培养菌,结合粗酶液的降解实验,该蛋白可能是受TBBPA激活的特异性降解酶.     

海河干流水产品汞污染特征及摄入风险评估

通过现场实地采样和实验测定分析了天津市海河干流水产品中汞含量水平及食用人群的暴露风险.结果表明,海河淡水水产品中甲基汞和总汞的含量(以湿重计)分别为42.51 ng·g~(-1)和77.31 ng·g~(-1),甲基汞是水生生物中汞的最主要存在形式,且与鱼体中总汞含量水平显著相关.鱼体在不同器官中和不同养殖方式下的汞含量水平差异显著.海河淡水鱼类和底栖动物的甲基汞富集系数(BCF)分别为1.00×105m L·g~(-1)和4.23×104m L·g~(-1),与总汞相比,甲基汞具有更强的生物富集特性.海河淡水生物生物链中的甲基汞和总汞营养级放大系数分别为1.38和1.36.水产品中的甲基汞和总汞含量最大允许含量均低于我国国家标准限定值,但同时应该注意,以海河淡水野生鱼类为食的儿童,汞摄入风险相对较高,其总汞和甲基汞摄入量分别达到154.07 ng·(kg·d)~(-1)和81.11 ng·(kg·d)~(-1).     

DBP formation from degradation of DEET and ibuprofen by UV/chlorine process and subsequent post-chlorination

The formation of disinfection by-products(DBPs) from the degradation of N,N-diethyl-3-methyl benzoyl amide(DEET) and ibuprofen(IBP) by the ultraviolet irradiation(UV)/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H_2O_2 process.The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times higher than those by the UV/H_2O_2 process, respectively, under the tested conditions. This was due to the significant contributions of both reactive chlorine species U(RCS) and hydroxyl radicals(HO) in the UV/chlorine process. Trichloromethane, 1,1,1-trichloro-2-propanone and dichloroacetic acid were the major known DBPs formed after 90% of both DEET and IBP that were degraded by the UV/chlorine process. Their yields increased by over 50%after subsequent 1-day post-chlorination. The detected DBPs after the degradation of DEET and IBP comprised 13.5% and 19.8% of total organic chlorine(TOCl), respectively, and the proportions increased to 19.8% and 33.9% after subsequent chlorination, respectively. In comparison to the UV/H_2O_2 process accompanied with post-chlorination, the formation of DBPs and TOCl in the UV/chlorine process together with post-chlorination was 5%–63% higher,Ulikely due to the generation of more DBP precursors from the attack of RCS, in addition to HO.     

Environmental impact of two electrical products with reference to the energy-using products directive

High energy consumption is one of the major factors that contributes to global warming. Connected to this, a directive has been approved by the European Union for establishing a legal framework to govern eco-design of energy-using products. This technical note reveals life cycle analysis of two electrical products, which rely on the same rechargeable battery system (i.e. the same energy source) for operations, with respect to the requirements of the aforementioned directive. Results concur with the argument that energy consumption of this sort of product plays a dominant role in terms of a variety of environmental impacts (like emission to air). Based on the results of this study, eco-design alternatives can be derived accordingly so that energy consumption and the existing solution can be benchmarked, as required by the directive.     

人造板加工中质量安全控制仿真技术的研究

根据实验室加工人造板的情况,针对人造板的工艺加工过程中温度和压力的控制模型难以建立的问题,运用模糊判别与神经网络技术相结合,通过神经网络实现模糊逻辑,同时利用神经网络的自学习能力,动态调整隶属函数,采用反向传播算法和最小二乘法的混合算法,设计基于模糊神经网络技术的仿真模型,根据输入输出数据自适应调节隶属度函数的各种参数,从而调整隶属度函数的形状,保持规则的完整性,避免出现人为规则空档,使该模型具有较高的精度,并用未经训练的数据进行模型验证,得到较理想的工艺数据效果仿真模型。该模型有利于人造板加工过程的优化控制,为提高人造板质量与产量提供可参考的优化工艺。     

Eco-friendly aspects associated with friction welding of tube-to-tube plate using an external tool process

The competitiveness among the manufacturers has been forcing the manufacturing processes to be eco-friendly so as to deliver products with lesser impact on the environment, energy demand and other resources consumption. In this regard, this article presents the unique environmentally friendlier aspects associated with an innovative welding process namely friction welding of tube-to-tube plate using an external tool (FWTPET). This process is capable of generating robust weld joints with lesser energy consumption. A comparative analysis of FWTPET with conventional tungsten inert gas welding process has been narrated.     

生命周期评价在玉米种植及深加工产品中的应用

对LCA在玉米种植环境影响研究中的目标与范围定义、清单分析、环境影响指标与计算方法、结果解释等方面的研究进行了梳理分析，其中大部分文献均对碳足迹进行了计算，CML（Institute of Environmental Sciences of the University of Leiden）、ReCiPe（许多LCA领域研究人员共同开发）和IPCC（Intergovernmental Panel on Climate Change）方法是应用最多的3种方法，经分析计算得到国外玉米种植单位产量碳足迹均值为0.50kg CO₂-eq/kg，我国的均值为0.58kg CO₂-eq/kg.同时本文也对LCA在玉米深加工产品中的研究进展进行了分析整理，对今后LCA应用于玉米种植及深加工产品中的发展方向进行了展望.