Distribution,sources and potential risk of HCH and DDT in soils from a typical alluvial plain of the Yangtze River Delta region,China

Spatial distribution, sources and potential health risks of organochlorine pesticides (OCPs), including hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), in surface soils (n = 544) collected from a typical alluvial plain of the Yangtze River Delta region, China, were elucidated. Concentrations of ΣHCH and ΣDDT in soils ranged from less than the limit of detection (<LOD) to 99.0 ng g^?1, dry weight (dw) (mean 3.23 ng g^?1 dw) and <LOD to 600 ng g^?1 dw (mean 88.8 ng g^?1 dw), respectively. Historical applications of HCH and DDT were the major sources of the residue in soils. HCH was mainly distributed in Anthrosols in the southern part of the watershed, while DDT was mainly distributed in Cambosols in the northern part. The 95 % cumulative probability incremental lifetime cancer risks (ILCRs) of different age groups such as children, youths, and adults all exceeded the acceptable risk level of 10^?6 recommended by USEPA for carcinogenic chemicals. The spatial distributions of ∑ILCRs were consistent with concentrations of OCPs in soils, while they were slight different for the different age groups. Adult females had the greatest risk of OCPs in soils, followed by children, while youths had the least risk. The ingestion of OCPs in soils was the more important route of exposure compared with dermal and inhalation exposures. The concentration of OCPs in soils, the particulate emission factor, the fraction of dermal exposure ratio, and the soil ingestion rate were the major contributing variables to total ILCRs according to sensitivity analyses.     

城市固体有机废物堆肥实验装置设计

根据城市固体有机废物的特点和性质 ,设计了一种堆肥的实验装置 ,该设计包括空间结构设计、通风系统设计和搅拌系统设计。空间结构设计的特点是小型的、用于实验室研究的、仓式动态好氧结构 ;通风系统的设计则是以供氧、散热和去除水分所需通风量为基础 ;搅拌系统设计包括搅拌器的结构设计和所需动力设计     

地下渗滤系统在污水处理中的应用研究进展

地下渗滤系统是一种基于自然生态原理的污水净化技术 ,在我国有着良好的可行性和发展前景。本文总结介绍了地下渗滤系统的类型 ,概括分析了地下渗滤系统中的关键性问题———土壤的选择与配制、水力负荷的选取、氮磷去除问题和土壤堵塞问题     

Concentrations, distribution, and bioaccumulation of synthetic musks in the Haihe River of China

Seven typical synthetic musks (SMs) in the samples from the surface water, sediment and fish of the Haihe River were measured. The SM concentrations in the sediment and surface water of the Haihe River were significantly lower than those in the Dagu Drainage River and Chentaizi Drainage River (p < 0.05). Along the flow direction, the SM concentrations in surface water and sediment tended to increase from the upstream to the downstream of Dagu Drainage River. The Bioaccumulation factors (BAFs) of galaxolide (HHCB) and tonalide (AHTN) were calculated at high levels in the muscles of crucian carp, common carp, and silver carp. Most of the biota-sediment accumulation factors (BSAFs) for HHCB and AHTN were higher than 1.7, suggesting magnification possibly exist in the musk bioaccumulations of the three fishes in the Haihe River. No significant differences in HHCB/AHTN ratios were observed among the water, fish, and sediment samples (p > 0.05). However, the HHCB/AHTN values in the Haihe River were much lower than those in the Dagu Drainage River and Chentaizi Drainage River (p < 0.05). Compared with several typical persistent organic pollutants (POPs), the musk concentrations were higher or comparable in the Haihe River.     

微波辅助催化湿式氧化技术降解高浓度苯酚废水

以纳米CuO为催化荆,采用微波辅助催化湿式过氧化氢氧化方法对高浓度苯酚废水(1 000 mg/L)进行降解处理,并与传统的催化湿式过氧化氢氧化技术进行比较,研究了微波强化作用对该技术的处理工艺条件、降解效率及机制的影响.结果表明,在微波的辅助作用下,当温度仅为60℃、压力为0.3 MPa时,催化湿式氧化反应15.0 min,苯酚废水的TOC去除率即达到90.8%.这表明微波促使催化湿式氧化反应可以在温和的条件下实现,而且效率高、速率快.进一步的降解机制研究发现,在微波的作用下,苯酚于2.0min内完全氧化转化,主要发生直接开环反应,生成短链羧酸,所经历氧化过程更为简单.     

强化污泥中木质纤维素产甲烷实验研究

为考察剩余污泥中木质纤维素降解、转化甲烷的潜力,通过富集培养投加方式及与预处理相结合等手段分别实验研究了富集微生物对木质纤维素组分降解的强化作用以及预处理对污泥木质纤维素结构的破稳作用。结果表明,富集微生物投加确实可以有效促进污泥中木质纤维素的降解,且载体投加方式效果最好。对真实污泥实施酸、碱、热、超声波等预处理后再投加富集微生物厌氧消化,使木质纤维素组分转化甲烷能力进一步提高,证实预处理对木质纤维素结构有着很好的破稳作用。虽然各种预处理方式对木质纤维素结构破稳均具有不同程度的作用效果,但热解与超声波显示出更好的破解作用,以至于破解程度胜过纤维素和半纤维素可降解组分的单一释放,还出现了较多易降解的更小分子结构。     

电动与渗透反应格栅联合修复镉污染地下水实验

通过实验方法研究了地下水中镉污染的电动力学修复效果,并分析其迁移变化特征。实验结果表明,电动修复中由于阴阳两极的氧化还原反应造成电极附近pH值产生明显变化,其中阳极附近的pH值由开始时的7.0逐渐变小到6.8,而阴极附近则相反,由开始时6.9逐渐增大到9.1,表明土壤的酸碱条件变化明显。Cd浓度变化反映在自然渗透条件下含水层中重金属污染物的迁移能力较弱,阳极附近地下水中Cd的去除率仅8.4%,而在电场作用下地下水中重金属的浓度发生明显变化,使得重金属污染物能在电极附近富集而被去除,当实验电场强度为0.5 V/cm时,Cd在阴极的累积使得阳极附近地下水中去除率为72.9%,说明电动修复重金属Cd污染地下水的效果明显好于自然渗透状态。     

铜污染土壤电动修复研究

应用实验方法研究了土壤重金属污染的电动力学修复方法,分析了土壤重金属污染物的迁移和变化特征。实验结果表明,在电场作用下土壤中重金属的浓度分布发生明显变化,使得大部分重金属能在电极附近富集而被去除。当实验的电场强度为0.5 V/cm时,在阳极附近土壤中铜的去除效率达到71.1%。阳极附近的pH值由开始时的6.8逐渐变小到4.4,而阴极附近则相反,由开始时的6.6逐渐增大到9.1,此外电动修复过程中电极附近的温度会发生相应的变化。     

论促进企业环境守法的制度建构

企业是市场经济中重要的市场主体,其环境守法除了要求环境法律、法规、政策的完善,也有赖于环境执法工作的稳妥开展对企业守法的推动。通过制度和利润两方面分析企业环境守法困境,期望通过环境执法模式的改革,借鉴美国环境执法模式的经验,借助执法理念的变化实现企业自觉的环境守法。     

城市绿地综合效益评价方法探讨：——天津实例应用

本文从复合生态系统理论出发，建立了城市绿地综合效益评价指标体系并将ＡＨＰ决策分析方法同模糊评价方法相结合，提出了一种城市绿地综合效益评价方法，同时，阐述了这一方法在天津的实际应用。