Exposure to toxic waste containing high concentrations of hydrogen sulphide illegally dumped in Abidjan, C?te d’Ivoire

Introduction

On August 2006, a cargo ship illegally dumped 500?t of toxic waste containing high concentrations of hydrogen sulphide in numerous sites across Abidjan. Thousands of people became ill. Seventeen deaths were associated with toxic waste exposure.

Materials and methods

This study reports on environmental and health problems associated with the incident. A cross-sectional transect study was conducted in five waste dumping site areas.

Results

Of the households, 62.1% (n?=?502) were exposed to the effects of the pollutants and 51.1% of the interviewed people (n?=?2,368) in these households showed signs of poisoning. Most important symptoms were cough (37.1%), asthenia (33.1%), pruritus (29.9%) and nausea (29.1%).

Discussion

The health effects showed different frequencies in the five waste impact sites. Among the poisoned persons, 21.1% (n?=?532) presented symptoms on the survey day (i.e., 4?months after incident). Transect sampling allowed to determine a radius of vulnerability to exposure of up to 3?km from the point of toxic waste disposal.

Conclusion

The area of higher vulnerability is influenced by various environmental factors, such as size and severity of pollution site, duration of toxic waste pollution on the impact site and locally climatic conditions. The surveillance of effects on environment and human health is warranted to monitor the development.     

酸性洗涤塔-生物滤塔-生物曝气池组合工艺处理恶臭气体NH3和H2S

采用酸性洗涤塔、生物滤塔和生物曝气池的组合工艺处理NH3、H2S恶臭混合气体,研究表明,该组合工艺对NH3和H2S有很好的去除效果,在进气流量为35 L/min,喷淋量45 L/h时,NH3进气浓度50.15~525.4 mg/m3,H2S进气浓度10.23~110.36 mg/m3时,NH3单一进气去除率稳定在99%以上,H2S单一进气去除率90%以上。混合进气后,NH3去除率几乎为100%,H2S的去除率提高至98%以上。在一定的浓度范围内,NH3和H2S之间的相互作用对两者的去除效果没有明显的影响,而且起到了相互促进降解的作用。同时,进气流量和填料层高度都会影响NH3、H2S的去除率。系统对进气容积负荷变化的缓冲能力强,在偶尔超负荷条件下运行并不能使系统崩溃,并且微生物对高负荷逐渐表现出适应性。大部分溶于水的氨由生物曝气池去除,去除率达到96.9%。     

Occurrence and distribution of polycyclic aromatic carbons in sludges from wastewater treatment plants in Guangdong, China

In this study, the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) were investigated in six sludge samples collected from Guangdong Province, China. Concentrations of PAHs varying from 2,534.1 to 6,926.6 μg kg^???1 (dry sludge) were observed in three municipal wastewater treatment plants with phenanthrene (Phe), fluoranthene, and pyrene being the main compounds. In addition, 682.6 μg kg^???1 PAHs were detected in one sludge sample from a food processing plant, with fluorene, Phe, and chrysene being the main components. No PAHs were detected in sludge samples obtained from two cosmetic plants. The levels and distributional characteristics of PAHs, polychlorinated biphenyls (PCBs), and polycyclic musks (PMs) from the samples were also compared. The results of this comparison indicated that petrochemical refineries and road traffic played important roles in the PAH loads in sludge, while PMs primarily originated from domestic wastewater and industrial wastewater from cosmetic plants. Finally, the presence of 98.8 μg kg^???1 PCBs in sludge suggested diffusional emission sources from electrical components containing PCBs.     

间歇曝气潜流人工湿地的污水脱氮效果

采用间歇曝气运行方式,提升潜流人工湿地生活污水处理系统中的溶解氧浓度,强化脱氮效果。结果表明,间歇曝气运行方式有效提高了湿地内部溶解氧水平,曝气时溶解氧浓度可达6~9 mg/L,停止曝气后,溶解氧浓度迅速下降至0.5 mg/L以下,在湿地内部营造了一种交替的好氧和缺氧环境,分别促进好氧硝化和缺氧反硝化作用。在水力停留时间为3 d的情况下,间歇曝气潜流人工湿地系统对氨氮、总氮和COD的去除率分别可达到98.0%、87.6%和96.3%,较常规潜流人工湿地系统分别提高了74.1%、56.4%和18.1%,实现了氨氮、总氮和COD的同步高效去除。     

Structural and optical characterization of dissolved organic matter from the lower Athabasca River, Canada

Dissolved organic matter (DOM) is a ubiquitous constituent of natural waters and is comprised of a variety of chemically heterogeneous molecular structures and functional groups. DOM is often considered to be a major ligand for metals in most natural waters and its reactivity is thought to be strongly dependent on its chemical composition and structure. In this study, a combination of UV/visible, emission excitation matrix fluorescence (EEM) and ¹H NMR spectroscopies were used to characterize DOM from the Athabasca River (Alberta, Canada). The chemical characterization of river DOM showed that the most upstream samples located in agricultural areas were blue-shifted and less aromatic and contained more hydrogens connected with oxygen functional groups than those in the wetland dominated area in the Athabasca oil sand deposit region. The presence of paramagnetic ions (Fe and Al) was not found to significantly affect the structural composition of DOM as revealed by ¹H NMR. Such change in the quality of DOM may have a profound impact on metal binding in the Athabasca River watershed.     

Estimation and characterization of unintentionally produced persistent organic pollutant emission from converter steelmaking processes

Unintentionally produced persistent organic pollutants (UP-POPs) including polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) were characterized and quantified in stack gas and fly ash from the second ventilation systems in five typical converters in five different steelmaking plants. The 2378-substituted PCDD/Fs (2378-PCDD/Fs) and dioxin-like PCB (dl-PCBs) toxic equivalents (TEQs) were 1.84–10.3 pg WHO-TEQ Nm^?3 in the stack gas and 5.59–87.6 pg WHO-TEQ g^?1 in the fly ash, and the PCN TEQs were 0.06–0.56 pg TEQ Nm^?3 in the stack gas and 0.03–0.08 pg TEQ g^?1 in the fly ash. The concentrations of UP-POPs in the present study were generally lower than those in other metallurgical processes, such as electric arc furnaces, iron ore sintering, and secondary metallurgical processes. Adding scrap metal might increase UP-POP emissions, indicating that raw material composition was a key influence on emissions. HxCDF, HpCDF, OCDF, HpCDD, and OCDD were the dominant PCDD/Fs in the stack gas and fly ash. TeCB and PeCB were dominant in the stack gas, but HxCB provided more to the total PCB concentrations in the fly ash. The lower chlorinated PCNs were dominant in all of the samples. The 2378-PCDD/F, dl-PCB, and PCN emission factors in stack gases from the steelmaking converter processes (per ton of steel produced) were 1.88–2.89, 0.14–0.76_, and 229–759 μg t^?1, respectively.     

Role of membrane and compound properties in affecting the rejection of pharmaceuticals by different RO/NF membranes

This study was conducted to assess the merits and limitations of various high-pressure membranes, tight nanofiltration (NF) membranes in particular, for the removal of trace organic compounds (TrOCs). The performance of a low-pressure reverse osmosis (LPRO) membrane (ESPA1), a tight NF membrane (NF90) and two loose NF membranes (HL and NF270) was compared for the rejection of 23 different pharmaceuticals (PhACs). Efforts were also devoted to understand the effect of adsorption on the rejection performance of each membrane. Difference in hydrogen bond formation potential (HFP) was taken into consideration. Results showed that NF90 performed similarly to ESPA1 with mean rejection higher than 95%. NF270 outperformed HL in terms of both water permeability and PhAC rejection higher than 90%. Electrostatic effects were more significant in PhAC rejection by loose NF membranes than tight NF and LPRO membranes. The adverse effect of adsorption on rejection by HL and ESPA1 was more substantial than NF270 and NF90, which could not be simply explained by the difference in membrane surface hydrophobicity, selective layer thickness or pore size. The HL membrane had a lower rejection of PhACs of higher hydrophobicity (log D>0) and higher HFP (>0.02). Nevertheless, the effects of PhAC hydrophobicity and HFP on rejection by ESPA1 could not be discerned. Poor rejection of certain PhACs could generally be explained by aspects of steric hindrance, electrostatic interactions and adsorption. High-pressure membranes like NF90 and NF270 have a high promise in TrOC removal from contaminated water.

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秦皇岛地热能梯级利用状况与前景分析

在对秦皇岛地热能资源现状和开发利用调查的基础上,对秦皇岛地区的地热资源分布特征进行了分类,通过对相应的地热资源利用现状进行调查,掌握了地热能利用的现状以及存在的种种问题和不足。为了更加合理高效地利用地热能资源,进行开发利用前景分析,制定了地热能综合梯级利用的规划建议。     

Impact of demographic dynamics on CO_2 emissions in Sichuan,China

Global climate change is one of the major environmental issues faced by humans.Existing evidence indicates that the anthropogenic push for a rise in the atmospheric concentration of greenhouse gases(GHGs)(particularly CO_2)has been a primary cause for global warming.Aside from economic and teclinological factors,demographic dynamics(including human consumption in a broad demographic sense)has been a major driver for CO_2 emissions.In this paper,we performed both nonlinear regression analysis(based on the STIRPAT model)and gray correlation degree analysis(based on gray system theory)on the impact of demographic dynamics on CO_2 emissions.Our results reveal that CO_2 emissions are positively correlated with population size and GDP per capita and negatively correlated with energy intensity.We also show that gray correlation degree with CO_2 emissions for five variables(i.e.,household consumption,urbanization rate,household size,population aging rate,population size)varies substantially:household consumptionurbanization ratehousehold sizepopulation aging ratepopulation size,with household consumption being the highest,and population size the lowest.To mitigate the impact of demographic dynamics on CO_2 emissions,it is of vital significance to nurture people's awareness of sustainable consumption and to adhere to current population control policies.     

洞庭湖湿地土壤持水能力及其影响因素研究

土壤持水能力是反映土壤调节水文和供给植物耗水的重要指标，受土壤有机质、容重、机械组成和植物地下生物量的直接或间接影响。与森林和农田生态系统相比，湿地土壤持水能力关注较少。于2010年12月，对洞庭湖湿地3种主要植被（苔草、芦苇和杨树）土壤持水能力、土壤理化性质和地下生物量进行了调查，并采用主成分分析对影响土壤持水能力的主要环境因子进行了分析。结果表明：除非毛管孔隙度外，3种植被上层土壤的总孔隙度、毛管孔隙度、田间持水量和含水量差异显著，均为苔草＞芦苇=杨树，而中、下层无显著差异。沙粒为苔草≥杨树≥芦苇，而粗粉粒、细粉粒和粘粒均为杨树≥芦苇≥苔草；容重为杨树≥芦苇＞苔草，有机质为苔草=芦苇＞杨树。各级别生物量在植被类型大小顺序不一：总地下生物量、0～1 mm和＞5 mm径级地下生物量均以芦苇最大，而1～5 mm径级地下生物量则以苔草最大。主成分分析表明，上层土壤，容重、有机质和1～5 mm径级地下生物量是影响其持水能力的主要因素，而中层土壤和下层土壤，环境因子对土壤持水能力的影响很小。此研究对于洞庭湖生物多样性保护和湿地管理政策的制定具有重要意义