Site-specific bioaccumulation of polychlorinated dibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxins and polychlorinated dibenzofurans (PCDD/PCDFs) in mothers and their infants living in vicinity of Bien Hoa airbase,Southern Vietnam

Bien Hoa airbase is located in Dong Nai Province (Southern Vietnam). Several sites within the airbase are highly contaminated by Agent Orange/Dioxin, and thus, they are also commonly named as an Agent Orange/Dioxin hotpot. In the present study, 36 maternal milk samples were collected from primiparas who have lived at least 5 years in four wards, Buu Long, Quang Vinh, Trung Dung and Tan Phong, which are closed to Bien Hoa airbase in order to investigate the level and distribution of Agent Orange/Dioxin exposure in different local communities. The mean concentrations of PCDD/PCDFs in four investigated wards range from 6.4 to 13.6 pgTEQ/g lipid. The highest mean TEQ of PCDD/PCDFs was observed in Buu Long ward (13.6 pgTEQ/g lipid), followed by Tan Phong ward (12.3 pgTEQ/g lipid), and the lowest value was observed in Trung Dung ward (6.4 pgTEQ/g lipid). The mean concentration of 2,3,7,8-TCDD in Buu Long (7.6 pg/g lipid) was approximately 2–6 times higher than those in Tan Phong (3.9 pg/g lipid), Quang Vinh (2.3 pg/g lipid), or Trung Dung (1.2 pg/g lipid). These results imply site-specific exposure to PCDD/PCDFs in different local communities living around Bien Hoa airbase. The mean values of daily intake of dioxin estimated for the breast fed infants living in Buu Long, Quang Vinh, Trung Dung and Tan Phong were about 80, 37.5, 31.7 and 58 pg TEQ/kg bw/day, respectively.     

Effects of SO<Subscript>2</Subscript> contamination on rising CO<Subscript>2</Subscript> drops under high pressure

Although the flow dynamics of pure liquid drops in other liquids has been well researched, little attention has been paid to the impacts of impurities. Hence, most of research is not directly applicable to the real world. To address this gap, we conducted numerical experiments simulating the rise of pure and contaminated drops. It was selected to study liquid CO₂ drops contaminated with SO₂ under high pressure because such mixtures mimic potential scenarios in which drops may leak from carbon capture and storage (CCS) facilities or pipelines. First, numerical simulation experiments were performed to validate our method by comparing our results with previous research on pure drops. Second, the validated numerical approach was applied to simulations of contaminated drops to investigate how contaminants affect rising drops. The results show that the SO₂ contamination caused changes in deformation, breakup phenomena, rising velocities, surrounding flow fields and drag coefficients. Most importantly, the contamination resulted in the formation of smaller “child drops”; such breakup is not observed in pure CO₂ drops. The formation of child drops in turn affects the streamlines, patterns and areas of wakes behind the contaminated drops. The addition of contaminants also enhances the dissolution rate, which is affected by the contaminant concentration and by the flow dynamics of the rising drop. Our results would improve understanding the rise of impure CO₂ drops, such as drops potentially leaked by future CCS operations.     

水生和陆生生物体中卤系阻燃剂的差异性富集研究:以鲶鱼和家鸽为例

分析了水生(鲶鱼)和陆生(家鸽)生物体中卤系阻燃剂(HFRs)的组成和浓度。鲶鱼中短链氯化石蜡(SCCPs)浓度均值为30 800 ng·g~(-1)lw(脂肪归一化浓度),是最主要的HFRs,然后依次是多溴联苯醚(PBDEs)(2 300 ng·g~(-1)lw)、四溴双酚A(TBBPA)(37 ng·g~(-1)lw)、六溴环十二烷(HBCD)(21 ng·g~(-1)lw)、德克隆(DP)(14 ng·g~(-1)lw)、十溴二苯乙烷(DBDPE)(7.1 ng·g~(-1)lw)和六溴苯(HBB)(6.2 ng·g~(-1)lw);而家鸽中PBDEs含量最高(17 000 ng·g~(-1)lw),其次是SCCPs(7 600 ng·g~(-1)lw)DP(1 600 ng·g~(-1)lw)DBDPE(14 ng·g~(-1)lw)HBB、TBBPA和HBCDs(未检出)。鲶鱼和家鸽HFRs组成比较发现,鲶鱼中具有较高百分含量的低溴代PBDE单体和较低的fanti值,而家鸽中具有较高百分含量的高溴代PBDE单体和较高的fanti值。实验结果初步表明,水生生物较多地富集水溶性较大的化合物,陆生生物则较多地富集疏水性较强的化合物。研究认为以上水生和陆生生物体中污染物的差异性富集现象可能与化合物因不同物理化学性质导致的不同环境迁移行为有关。     

Current pesticide practices and environmental issues in Vietnam: management challenges for sustainable use of pesticides for tropical crops in (South-East) Asia to avoid environmental pollution

Pesticides are widely used in modern agriculture to minimize financial losses and maintain food supplies. In southeast Asia, where agriculture is the principal economic activity, pesticides are considered essential, particularly in tropical regions seeking to enter the global economy by providing off-season fresh fruits and vegetables. The absence of a strong legal framework for pesticides facilitated a significant increase in the use of low-quality pesticides. Farmers ignore the risks, safety instructions, and protective directives when using pesticides. They are only concerned about the effectiveness of the pesticides for killing pests, without paying attention to the effects on their health and the environment. The improper usage of pesticides and the incorrect disposal of pesticide wastes contributed to the pollution of groundwater, surface water, and soil, and induced health problems in local communities. This paper describes the impact of the exposure of pesticides on human health and water resources in connection with the usage of pesticides and their management. Because of availability, the data are mainly taken for Northern Vietnam, and applied to the water quality in the delta; nevertheless, the problem relates to all countries in the delta, and similar situations may be found in other regions, particularly in Asia.     

生物表面活性剂及其在环境修复中的研究进展

生物表面活性剂是由微生物分泌的天然产物,由于其物理性质和化学结构与许多人工合成的表面活性剂相似,并且对土壤、淡水、海洋等生态系统毒性较低,因而在环境污染治理方面,特别是在重金属和石油等有机溶剂污染的原位和异位生物修复方面具有极大的应用潜力.主要综述了近年国内外生物表面活性剂在廉价制备、作用机理、环境修复中的研究进展.     

Particulate matter in the cultivation area may contaminate leafy vegetables with heavy metals above safe levels in Korea

Environmental Science and Pollution Research - Among air pollutants, particulate matter (PM) has been identified as a major cause of environmental pollutants due to the advancement of industrial...     

扶梯乘员坠落的法律归责思考与对策

扶梯乘员坠落事故已经发生多起,如何进行相关风险的辨析并提出防范对策,是电梯从业者难以回避的课题.本文试从生产者、经营管理者之角度就此课题进行“归责”与“对策”的辨析与思考,希冀关注者有所借鉴,防范已经存在或可能发生的风险.     

Recycling nickel from spent catalyst of Phu My fertilizer plant as a precursor for exhaust gas treatment catalysts preparation

In this study, a very promising way of treating and recycling spent nickel catalysts of fertilizer plants in Vietnam was proposed. Firstly, nickel was recovered from spent catalyst using HNO₃—leaching process. Results show that nickel recovery of over 90% with a purity of over 90% can be achieved with HNO₃ 2.1–2.5 M at 100?°C in 75 min. The residue after leaching is not considered as a hazardous waste according to the Vietnamese regulations. Then, the leachate solution was used as a precursor to prepare a model catalyst for exhaust gas (CO, HC, NO_x) treatment. In comparison with the catalyst prepared from the commercial nickel nitrate solution, the catalyst synthesized from recovered nickel exhibits similar properties and activities. The influence of Ni loading of Ni/alumina catalyst as well as the modification of active phase by some metals addition (Mn, Ba, Ce) was also investigated. It is feasible to modify active phase by transition metals such as Mn, Ba, and Ce for complete oxidation of CO and HC at 270?°C and a reduction of NO_x below 350?°C at high volumetric flow condition (GHSV?=?110.000 h^?1).     

The evolving local social contract for managing climate and disaster risk in Vietnam

How do disasters shape local government legitimacy in relation to managing climate‐ and disaster‐related risks? This paper looks at how local authorities in Central Vietnam perceive their social contract for risk reduction, including the partial merging of responsibilities for disaster risk management with new plans for and investments in climate change adaptation and broader socioeconomic development. The findings indicate that extreme floods and storms constitute critical junctures that stimulate genuine institutional change. Local officials are proud of their strengthened role in disaster response and they are eager to boost investment in infrastructure. They have struggled to reinforce their legitimacy among their constituents, but given the shifting roles of the state, private sector, and civil society, and the undiminished emphasis on high‐risk development models, their responsibilities for responding to emerging climate change scenarios are increasingly nebulous. The past basis for legitimacy is no longer valid, but tomorrow's social contract is not yet defined.