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761.
Luzardo OP Almeida-González M Henríquez-Hernández LA Zumbado M Alvarez-León EE Boada LD 《Chemosphere》2012,88(3):307-315
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. 相似文献
762.
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. 相似文献
763.
白糖为共基质处理有机磷农药废水的试验研究 总被引:3,自引:0,他引:3
有机磷农药废水是一种极难处理的高浓度有机废水,因为该废水含有大量的难降解有机物,其中的有机磷对微生物代谢具有很强的抑制作用。采用高效好氧生物反应器(HCR)对有机磷农药废水进行处理试验,对比研究了以白糖为共基质和有机磷农药废水为单基质的两种不同条件下,系统中活性污泥的特性及系统对有机磷农药废水COD去除效果的变化规律。结果表明,白糖为共基质可大大提高HCR系统中活性污泥的活性和系统对有机磷农药废水COD的去除效果。 相似文献
764.
765.
766.
Yong-Jin Park Hiroshi Tsuno Taira Hidaka Ji-Hoon Cheon 《Journal of Material Cycles and Waste Management》2008,10(1):46-52
In this study, the effect of operational parameters, such as solids retention time (SRT), pH, and substrate total solids (TS)
concentration, on acid fermentation efficiency was investigated. From batch tests, it was shown that the appropriate pH range
for thermophilic acidogens was around 6–7 and that the optimum pH condition was 6. From the continuous experiment, pH and
SRT were shown to be the most important operational parameters for solubilization and organic acid production. In contrast,
TS concentration did not show any obvious effect on chromium chemical oxygen demand (CODcr) solubilization when TS was in
the range 3.5%–10%. The optimum operational conditions for thermophilic acid fermentation were an SRT of 2 days and a pH of
6.
This research was carried as a part of the CREST project of Japan Science and Technology Agency. 相似文献
767.
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。 相似文献
768.
典型恶臭有机污染自动监测技术与应用探究 总被引:1,自引:0,他引:1
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。 相似文献
769.
某化工厂致癌有机污染物分层健康风险评估 总被引:2,自引:0,他引:2
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。 相似文献
770.