Distribution of PAEs in the middle and lower reaches of the Yellow River, China

Samples of water, sediment and suspended particulates were collected from 13 sites in the middle and lower reaches of the Yellow River in China. Phthalic acid esters (PAEs) concentrations in different phases of each sample were determined by Gas Chromatogram GC-FID. The results are shown as follows: (1) In the Xiao Langdi–Dongming Bridge section, PAEs concentrations in water phase from the main river ranged from 3.99 × 10⁻³ to 45.45 × 10⁻³ mg/L, which were similar to those from other rivers in the world. The PAEs levels in the tributaries of the Yellow River were much higher than those of the main river. (2) In the studied branches, the concentration of PAEs in sediment for Luoyang Petrochemical Channel (331.70 mg/Kg) was the highest. The concentrations of PAEs in sediment phase of the main river were 30.52 to 85.16 mg/Kg, which were much higher than those from other rivers in the world. In the main river, the concentration level of PAEs on suspended solid phases reached 94.22 mg/Kg, and it reached 691.23 mg/Kg in the Yiluo River – one tributary of the Yellow River. (3) Whether in the sediment or on the suspended solid phases, there was no significant correlation between the contents of PAEs and TOC or particle size of the solid phase; and the calculated Koc of Di (2-Ethylhexyl) Phthalate (DEHP) in the river were much less than the theoretical value, which inferred that PAEs were not on the equilibrium between water and suspended solid phases/sediment. (4) Among the measured PAEs compounds, the proportions of DEHP and di-n-butyl phthalate (DBP) were much higher than the others. The concentrations of DEHP exceeded the Quality Standard in all the main river and tributary stations except those in the Mengjin and Jiaogong Bridge of the main river. This indicates that more attention should be paid to pollution control and further assessment in understanding risks associated with human health.     

地表水环境质量标准有机物指标检测分析方法整合

分析地表水环境质量标准68项有机指标分析方法的不足,概述其分析方法整合优化的研究现状,并归纳总结目前地表水中68项有机指标的最新分析方法,结合经典分析方法,将68项有机指标的分析方法由40余种整合为20种。     

有机物渗透管的研制

介绍了用Wh聚四氟乙烯膜作为渗透材料制作有机物渗透管的方法,并且针对所研制的渗透管的特性、影响渗透率的主要因素及渗透率的稳定性等方面进行了探讨.     

淮河流域江苏平原区浅层地下水污染分析

以淮河流域江苏平原区浅层地下水为研究对象,通过对当地影响较大的污染源调查采样,分析了该地区所采602组水样的无机和有机污染状况。研究表明,区内浅层地下水无机污染较严重,基本形成面状污染,地下水超标率高达83．4％,超标率最高为碘化物。有机污染物检出率34．2％,主要包括二氯甲烷、萘和1,2-二氯乙烷等,以点状分布为主。在此基础上阐述了大气降水、污水灌溉、农业施肥以及地下水开采等人类活动对浅层地下水的影响和污染状况。     

某化工厂致癌有机污染物分层健康风险评估

以某化工厂污染场地为例,根据《污染场地风险评估技术导则》(HJ 25.3-2014),运用HERA风险评估软件,将污染场地分为4层分别进行人体健康风险评估,结果表明:该场地存在高致癌风险,需要修复后才能开发再利用;关注污染物氯仿、苯,在地下0 m~3 m的风险控制值分别为0.07 mg/kg、0.83 mg/kg,在地下3 m~5 m的风险控制值分别为0.15 mg/kg、1.91 mg/kg,在地下5 m~9 m的风险控制值分别为0.40 mg/kg、5.05 mg/kg,在地下9 m~18 m的风险控制值分别为0.73 mg/kg、7.82 mg/kg。与以往计算单一的风险控制相比,分层计算污染物的风险控制值能有效减少治理土方量,降低治理成本。     

典型恶臭有机污染自动监测技术与应用探究

对比6种主流有机硫自动监测仪的4种有机硫混标测试结果,表明80%仪器的性能指标能满足国家恶臭排放标准中厂界监测的定量要求。复杂环境适用性研究显示,有机硫化物间测定影响相对较小,高浓度标气有残留,定性受到常见挥发性有机物中个别物质干扰。优选3种检测器为FPD的仪器现场连续实测,结果表明甲硫醇、甲硫醚、二甲二硫醚和二硫化碳为石化园区的有机硫常检出物种;3种仪器的监测数据可较好地反映该石化园区空气恶臭污染特征。     

Release of methane from aerobic soil: an indication of a novel chemical natural process?

Methane (CH₄) formation under aerobic conditions has been intensely debated, especially since the discovery of CH₄ generation by both dried plant material and living plants. In this study we test the hypothesis that non-microbial CH₄ formation also occurs in soils. All lyophilised soil samples investigated under aerobic conditions released CH₄ at temperatures ranging from 30 to 70 °C exceeding that allowing normal enzymatic activity to proceed. No emissions were observed for single mineral soil components such as quartz sand, clay mineral and iron oxide. Methane release rates from the soils investigated were found to increase both with increasing temperature and higher organic carbon content. Addition of water to dried soils increased CH₄ release rates up to 8-fold those observed with the dried material. Our results suggest the existence of a chemical process in soils that produces CH₄ under aerobic conditions, a finding which has not been hitherto reported.     

A dynamic contaminant fate model of organic compound: a case study of Nitrobenzene pollution in Songhua River, China

A one-dimensional dynamic contaminant fate model, coupling kinematic wave flow option with advection-dispersion-reaction equation, has been applied to predict Nitrobenzene pollution emergency in Songhua River, China that occurred on November 13, 2005. The model includes kinetic processes including volatilization, photolysis and biodegradation, and diffusive mass exchange between water column and sediment layer as a function of particles settling and resuspension. Four kinds of quantitative statistical tests, namely Nash-Sutcliffe efficiency, percent bias, ratio of root-mean-square to the standard deviation of monitoring data and Theil’s inequality coefficient, are adopted to evaluate model performance. The results generally show that the modeled and detected concentrations exhibit good consistency. Flow velocity in the river is most sensitive parameter to Nitrobenzene concentration in water column based on sensitivity analysis of input parameters. It indicates flow velocity has important impact on both distribution and variance of contaminant concentration. The model performs satisfactory for prediction of organic pollutant fate in Songhua River, with the ability to supply necessary information for pollution event control and early warning, which could be applied to similar long natural rivers.     

Polychlorobiphenyls and organochlorine pesticides in conventional and organic brands of milk: occurrence and dietary intake in the population of the Canary Islands (Spain)

The population of the Spanish archipelago of the Canary Islands has been studied in depth regarding its levels of contamination by organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs). Foodstuffs of animal origin, such as milk, are prominent contributors to the body burden of these contaminants. As this population presents one of the highest milk-intake in Spain and Europe, we evaluated the level of OCs and PCBs in 26 commercially available brands of milk (16 conventional and 10 organic brands) present in the market of these Islands, in order to estimate the relevance of milk as a source of these chemicals for the Canary population. Our findings showed that hexachlorobenzene, trans-chlordane, and PCB153 were present in almost all the samples with independence of the type of milk. For both types of milks, the concentration of OCs was very low, showing organic milks lower levels than conventional ones. As a consequence, the estimated daily intake for OCs was lower than the tolerable daily intake (TDI) established by International Agencies. The levels of PCBs in milk were also found to be very low, but, in this case, the situation was the opposite: there were higher levels of PCBs in organic than in conventional brands of milk. Unexpectedly, levels of dioxin-like PCBs (DL-PCBs) reached values higher than 25 pg WHO-TEQ g⁻¹ fat in percentile 75 for both types of milk indicating the existence of a number of brands of milk highly contaminated by these toxicants. Consequently, the population who consume the most contaminated milk brands could have estimated daily intakes well above the recommended TDI (2 pg WHO-TEQ kg⁻¹ b.w. d⁻¹) established by European Union Authorities. These results are of concern if we consider the well known adverse health effects exerted by dioxin-like compounds.     

Purification of carbonic anhydrase from bovine erythrocytes and its application in the enzymic capture of carbon dioxide

This work presents a study of industrially applicable techniques to obtain a biologically supported carbon dioxide capture system, based on the extraction of carbonic anhydrase from bovine blood. Carbonic anhydrase is a metalloenzyme which catalyzes the reversible hydration of carbon dioxide. The objective of this study was to establish conditions to obtain carbonic anhydrase from bovine erythrocytes and apply it in the capture of carbon dioxide. To achieve this, two different purification techniques were evaluated: one by extraction with the organic solvents chloroform and ethanol, where different solvent proportions were studied; and the other by ammonium sulfate precipitation, testing percent saturations between 10% and 80%. Carbon dioxide was enzymatically captured by its precipitation as calcium carbonate with the enzyme obtained by both techniques. The enzyme extracted by ethanol and chloroform showed an activity of 2623 U mL⁻¹, recovery of 98% and purification factor of 104-fold. That precipitated by ammonium sulfate showed an activity of 2162 U mL⁻¹, recovery of 66% and purification factor of 1.4-fold using 60% ammonium sulfate saturation. The results obtained in the carbon dioxide capture experiments showed that the carbonic anhydrase extracted in this study not only enhanced the hydration of CO₂, but also promoted the formation of CaCO₃.