New insights into disruption of iron homeostasis by environmental pollutants

Among the numerous health conditions environmental pollutants can cause, chronic exposure to pollutants including persistent organic pollutants (POPs) and heavy metals has been shown to disturb a specific biological homeostatic process, the iron metabolism in human body. Disorders of iron metabolism are among the common diseases of humans and encompass a broad spectrum of diseases with different clinical manifestations, ranging from anemia to iron overload, and possibly to neurodegenerative diseases and cancer. Hepcidin–ferroportin (FPN) signaling is one of the key mechanisms responsible for iron supply, utilization, recycling, and storage, and recent studies demonstrated that exposure to environmental pollutants including POPs and heavy metals could lead to disruption of the hepcidin–FPN axis along with disordered systemic iron homeostasis and diseases. This article introduces and highlights the accompanying review article by Drs. Xu and Liu in this journal, which elaborates in detail the adverse effects of environmental pollutants on iron metabolism, and the mechanisms responsible for these toxicological outcomes. It also points out the knowledge gaps still existing in this subject matter. Research that will fill these gaps will improve our understanding of the issue and provide useful information to prevent or treat diseases induced by environmental pollutants.     

Aerobic treatment of palm oil mill effluent

In this study treatment of palm oil mill effluent (POME) was investigated using aerobic oxidation based on an activated sludge process. The effects of sludge volume index, scum index and mixed liquor suspended solids during the acclimatizing phase and biomass build-up phase were investigated in order to ascertain the reactor stability. The efficiency of the activated sludge process was evaluated by treating anaerobically digested and diluted raw POME obtained from Golden Hope Plantations, Malaysia. The treatment of POME was carried out at a fixed biomass concentration of 3900+/-200mg/L, whereas the corresponding sludge volume index was found to be around 105+/-5mL/g. The initial studies on the efficiency of the activated sludge reactor were carried out using diluted raw POME for varying the hydraulic retention time, viz: 18, 24, 30 and 36h and influent COD concentration, viz: 1000, 2000, 3000, 4000 and 5000mg/L, respectively. The results showed that at the end of 36h of hydraulic retention time for the above said influent COD, the COD removal efficiencies were found to be 83%, 72%, 64%, 54% and 42% whereas at 24h hydraulic retention time they were 57%, 45%, 38%, 30% and 27%, respectively. The effectiveness of aerobic oxidation was also compared between anaerobically digested and diluted raw POME having corresponding CODs of 3908 and 3925mg/L, for varying hydraulic retention time, viz: 18, 24, 30, 36, 42, 48, 54 and 60h. The dissolved oxygen concentration and pH in the activated sludge reactor were found to be 1.8-2.2mg/L and 7-8.5, respectively. The scum index was found to rise from 0.5% to 1.9% during the acclimatizing phase and biomass build-up phase.     

Assessment of the Effectiveness of Environmental Dredging in South Lake,China

Environmental dredging is a primary remedial option for removal of the contaminated material from aquatic environment. Of primary concern in environmental dredging is the effectiveness of the intended sediment removal. A 5-year field monitoring study was conducted to assess the effectiveness of the environmental dredging in South Lake, China. The concentrations of total nitrogen (TN), total phosphors, and heavy metals (Zn, Pb, Cd, Cu, Cr, Ni, Hg, and As) before and after dredging in sediment were determined and compared. Multiple ecological risk indices were employed to assess the contamination of heavy metals before and after dredging. Our results showed that the total phosphorus levels reduced 42% after dredging. Similar changes for Hg, Zn, As Pb, Cd, Cu, Cr, and Ni were observed, with reduction percentages of 97.0, 93.1, 82.6, 63.9, 52.7, 50.1, 32.0, and 23.6, respectively, and the quality of sediment improved based on the criterion of Sediment Quality Guidelines by USEPA and contamination degree values (C_d) decreased significantly (paired t-test, p < 0.05). Unexpectedly, the TN increased 49% after dredging compared to before dredging. Findings from the study demonstrated that the environmental dredging was an effective mechanism for removal of total phosphorus and heavy metals from South Lake. Nevertheless, the dredging was ineffective to remove total nitrogen from sediment. We conclude that the reason for the observed increase in TN after dredging was likely ammonia release from the sediment impairing the dredging effectiveness.     

Source identification, contamination status and health risk assessment of heavy metals from road dusts in Dhaka, Bangladesh

In this study, concentrations of Cr, Mn, Ni, Cu, Zn, Cd and Pb were determined in road dusts collected from different locations in Dhaka to assess source, contamination status and health risk. Energy-dispersive X-ray fluorescence spectroscopy and energy-dispersive X-ray spectroscopy were used to determine Cr, Mn, Ni, Cu, Zn, Cd and Pb and their mean concentrations were 162.27 ± 29.46, 721.18 ± 180.14, 35.65 ± 12.55, 104.56 ± 128.33, 515.32 ± 321.90, BDL, and 342.82 ± 591.20 mg/kg, respectively. Among the heavy metals, highest concentrations of Cu, Zn and Pb were found at urban sites-7 (municipal waste dumping) and 8 (medical waste incineration). Highest concentration of Cr followed by Cu and Zn was found at site-5 (Tejgaon, urban). Principal component analysis revealed that anthropogenic activities are the potential sources for Cr, Ni, Cu, Zn and Pb while earth crust for Mn. Pollution index and pollution load index results suggested that all the sites were contaminated and/or degraded by Cr, Cu, Zn and Pb except sites-9 (urban), 10 (sub-urban), 11 (rural) while sites-7 and 8 (urban) were extremely degraded. For noncarcinogenic health risk, hazard quotient values for dermal were higher compared to that of inhalation/ingestion. Though hazard index values were less than 1 at all the sites, these were at least one order of magnitude higher for children group than that of adult group, thus the children group may face more noncarcinogenic health risk at sites-7 and 8. Values of incremental lifetime cancer risk were from 10⁻⁹ to 10⁻¹¹ showed no carcinogenic health risk by road dusts contaminated with the heavy metals.     

Novel eco-friendly spherical porous adsorbent fabricated from Pickering middle internal phase emulsions for removal of Pb(II) and Cd (II)

Spherical porous materials prepared from the emulsion template used in the water treat-ment have displayed a vast prospect,as the high surface area,abundant porous structure,convenient operation and excellent adsorption performance.But the tedious fabrication process,high consumption of organic solvent and surfactant limited the application widely.Herein,a facile and eco-friendly spherical porous adsorbent (SPA) is fabricated from the green surfactant-free (corn oil)-in-water Pickering medium internal phase emulsions (Pick-ering MIPEs) via the convenient ion crosslinking procedure.The Pickering MIPEs synergis-tically stabilized with the semi-coke (SC),which is the natural particle produced from the shale oil distillation,and sodium alginate (SA) has excellent storage and anti-coalescence stability.The as-prepared porous adsorbent possessed the abundant pore structure,which provided favorable conditions for effective mass transfer in adsorption,and could be tuned by varying the SA dosage.The saturation adsorption capacities of Pb(Ⅱ) and Cd(Ⅱ) can be achieved with 460.54 and 278.77 mg/g within 45 min at 25℃,respectively.Overall,this study supplied a viable and eco-friendly route for fabricating the spherical porous adsorbent with a tunable porous structure for heavy metal ion wastewater.     

指数模型法在海洋石油设施风险评估中的应用

针对海上油气设施工况复杂、自然环境恶劣、应急救援难度大等特点,通过构建海上采油平台、海底管道和钻修井平台风险评估指数模型,辨识出水深增大、服役期长、腐蚀、疲劳、浅层地质条件变化等是风险等级升高的主要因素,识别出部分采油平台主结构疲劳损伤,海底管道内壁腐蚀及缺陷无法准确掌握、作业平台插桩不到位等问题,并提出检验检测、更换设施、强制退出等风险管控措施和建议。     

高效石油降解菌修复石油污染土壤与强化机制分析

利用定向驯化高效石油降解菌系对石油污染土壤进行为期120 d原位修复,考察生物强化修复效果、土壤理化性质和酶活性的变化,结合宏基因组测序及生物信息学分析揭示其强化机制.结果表明,与空白对照组(Ctrl)相比,生物修复组(Exp-BT)总石油烃降解率显著提升,增幅达81.23%; 高效石油降解菌生物强化修复期间土壤pH变化稳定,体系氧化能力提高,电导率处于适宜农业活动范围内; 脂肪酶和脱氢酶在修复期间保持较高活性; 另对初始污染土壤样本(B0)、驯化所得高效石油降解菌系样本(GZ)和生物修复后土壤样本(BT)的分析显示,门水平上变形菌门与放线菌门相对丰度增加17.1%,属水平上Nocardioides、Achromobacter、Gordonia和Rhodococcus等丰度明显上升,COG和KEGG物种与功能贡献度分析证明以上菌属对石油烃降解有重要贡献; 修复后土壤中发现高丰度的石油烃相关代谢酶及5个降解基因:alkM、tamA、rubB、ladA 和alkB,分析表明外源石油烃降解菌群的引入增强了微生物相关酶的代谢活性与相应功能基因的表达.     

废水重金属在线比对监测研究探讨

简述了废水重金属在线自动监测原理,对在线自动监测的主要应用方法分光光度法和伏安溶出法进行了比较;结合实际对废水重金属在线比对监测的现状进行了分析,并指出比对监测时应注意的问题。     

重金属废水处理技术研究进展

总结近年来重金属废水主要处理技术,指出重金属废水污染治理与重金属的回收利用相结合是未来治理的发展之路,也是技术开发与应用的方向。     

Evaluating the potential of biodiesel (via recycled cooking oil) use in Singapore,an urban city

Singapore has pledged to attain 7–11% Business-As-Usual carbon emissions reduction by 2020. About 19% of CO₂ contribution stemmed from road transport in 2005. Commercial vehicles, which uses mainly diesel, consumed 695 million litres diesel in 2012. An estimated 115,585 tonnes or 127 million litres cooking oils (derived from seeds/fruits) were consumed in 2010, in which the bulk of used cooking oil is re-incorporated into the food preparation process while only a small amount is being recycled into biodiesel or disposed into the sewerage. Nevertheless, the present research reveals that biodiesel derived from spent cooking oil has potential to be a viable fuel supplement. Surveys were carried out involving three market segments – suppliers, processors and end-users – to identify the barriers and obstacles in mass production of biodiesel. A key enabler of biodiesel as a fuel supplement towards a greener environment lies in government mandate/policies in promoting greater biodiesel usage.