Lead (Pb) and arsenic (As) bioaccessibility in various soils from south China

Serious problems are faced in several parts of the world due to the presence of high concentration of fluoride in drinking water which causes dental and skeletal fluorosis to humans. Nalgonda district in Andhra Pradesh, India is one such region where high concentration of fluoride is present in groundwater. Since there are no major studies in the recent past, the present study was carried out to understand the present status of groundwater quality in Nalgonda and also to assess the possible causes for high concentration of fluoride in groundwater. Samples from 45 wells were collected once every 2 months and analyzed for fluoride concentration using an ion chromatograph. The fluoride concentration in groundwater of this region ranged from 0.1 to 8.8 mg/l with a mean of 1.3 mg/l. About 52% of the samples collected were suitable for human consumption. However, 18% of the samples were having less than the required limit of 0.6 mg/l, and 30% of the samples possessed high concentration of fluoride, i.e., above 1.5 mg/l. Weathering of rocks and evaporation of groundwater are responsible for high fluoride concentration in groundwater of this area apart from anthropogenic activities including irrigation which accelerates weathering of rocks.     

Life cycle and economic assessment of enhanced ecological floating beds applied water purification

Environmental Science and Pollution Research - The ecological floating beds (EFB) are widely used in water quality restoration because of its low cost, high efficiency, and green characteristics....     

Mechanochemical synthesis of MAPbBr3/carbon sphere composites for boosting carrier-involved superoxide species

Lead halide perovskites MAPbX₃ (MA = CH₃NH₃ or Cs; X = I, Br, Cl) are well considered to be potential candidates for photocatalytic reaction due to its excellent photoelectrical properties, but they still suffer from the low charge separation efficiency and slow catalytic reaction dynamics. To tackle the drawbacks, herein, MAPbBr₃/carbon sphere (CS) composite photocatalysts using glucose as the carbon source were elaborately designed and fabricated via a dry mechanochemical grinding process. The interfacial interaction Pb-O-C chemical bonds were constructed between MAPbBr₃ and the carbon sphere surface containing organic functional groups. By optimizing the content of CSs, the enhanced photocatalytic degradation kinetic rate of Malachite Green (MG) pollutants (92% within 20 min) for MAPbBr₃/CS_x (x = 17 wt.%) is about 3.6-fold of that for pristine MAPbBr₃, which is attributed to the corporative adsorption and enhanced carrier transportation and separation of MAPbBr₃/CS_x. Furthermore, the possible degradation mechanism was proposed on basis of the electrochemical, mass spectrometry and optical characterization results. Owing to the robust interfacial interaction, effective electron extraction rate (k_et = 4.6 × 10⁷ sec^?1) from MAPbBr₃ to CS can be established, which driven oxygen activation where superoxide radicals (?O₂^?) played an important role in MG degradation. It is expected that mechanochemistry strategy may provide a new route to design efficient lead halide perovskite-carbon or metal oxide or sulfide composite photocatalysts.     

污染土壤中铅、砷的生物可给性研究进展

土壤铅、砷污染已成为重要的环境问题,并可对人体健康造成严重危害。对食物链途径的有效控制使得从口部无意摄入的土壤铅、砷对人体,特别是对儿童铅、砷摄入总量的贡献率越来越大,甚至成为主要来源。土壤中铅、砷直接进入人体的消化系统并可被人体胃肠道溶解出的部分称为其生物可给性。有效、准确地判定土壤中铅、砷的生物可给性已经成为解决儿童铅、砷中毒的关键科学问题。因此,有关土壤中铅、砷的生物可给性及其在人体健康风险评价中的应用受到了越来越多的关注。文章综述了污染土壤中铅、砷生物可给性的研究方法及各方法的优缺点,并从土壤性质、模拟胃肠条件等方面分析了影响土壤中铅、砷生物可给性的主要因素和存在的问题,还进一步论述了土壤中铅、砷生物可给性在人体健康风险评价中的应用。最后,提出了今后该领域应重点加强土壤铅、砷生物可给性的标准参考物、模拟胃肠条件的优化以及土壤铅、砷生物可给性在人体健康风险评价中的应用等方面的研究。以期充分发挥铅、砷等环境污染物的生物可给性研究方法的潜力,更好地为控制土壤污染、保护人类健康服务。     

利用大型蚤和斑马鱼评价腈纶废水好氧-厌氧处理过程的急性毒性和遗传毒性变化

腈纶废水毒性较强且难以去除,对腈纶废水毒性及污水处理过程毒性削减能力进行评价,可为开发该类废水毒性减排技术提供科学依据。利用大型蚤及斑马鱼评价某腈纶废水的急性毒性和遗传毒性,及厌氧-好氧工艺对该废水毒性的削减能力。采用大型蚤活动抑制率和斑马鱼致死率表征废水急性毒性,采用斑马鱼肝细胞彗星尾矩表征废水遗传毒性。腈纶废水处理前对大型蚤和斑马鱼的急性毒性单位(TU)分别为1.2和2.9,经厌氧-好氧工艺处理后分别降至0.4和0.5。遗传毒性结果表明腈纶废水对斑马鱼肝细胞造成DNA损伤作用,经处理后遗传毒性仍显著高于阴性对照组。理化指标与毒性指标相关性分析表明,该废水氨氮与毒性显著相关,推测氨氮可能是该废水中的重要致毒因子之一。研究结果表明该腈纶废水采用现有厌氧-好氧工艺无法有效削减毒性,对受纳水体水生态环境造成潜在危害。     

山区二级公路运营期常态交通风险评价

为客观准确地评价山区二级公路常态交通风险,将风险源分为动态风险源和静态风险源.首先,基于白化权函数的综合评价法建立事故后果模型,基于历史事故数据建立事故概率模型,以评价静态风险;其次,结合白化权函数和层次分析法(AHP)建立事故后果模型,采用有序Logit模型建立事故概率模型,以评价动态风险;最后综合动静态风险结果评价...     

氟工厂附近青少年体内全氟化合物(PFASs)暴露特征分析及其与性征发育水平关联性初探

本研究采用分层随机整群抽样方法选取232名13—16岁在校中学生,进行问卷调查和体格检查,使用超高效液相色谱串联质谱法(UPLC-MS/MS)测定血清中18种PFASs含量,运用有序多分类Logistic回归分析PFASs暴露与性征发育水平的关联性.血清中共检出16种PFASs,其中有11种检出率大于60%.PFOA为主要污染物,占检出PFASs总含量的67.8%—97.7%,中位数为94.2 ng·mL~(-1).男生PFBA和PFHpA浓度高于女生,PFHpA和PFOA浓度随学生家庭至工厂距离增大而下降,P0.05,具有统计学意义.男生阴毛发育与PFOA、PFOS和PFNA有关,PFOA中低浓度组(Q_2)、PFOS中高浓度组(Q_3)、PFNA中高浓度组(Q_3)和高浓度组(Q_4)相对于各自低浓度组(Q_1)与男生阴毛发育负相关,OR(95%CI)分别为0.291(0.091—0.935)、0.214(0.065—0.701)、0.246(0.079—0.771)和0.197(0.058—0.666),P0.05.男生外生殖器发育与PFNA有关,中低浓度组(Q_2)和高浓度组(Q_4)相对于低浓度组(Q_1)与男生外生殖器发育呈负相关,OR(95%CI)分别为0.200(0.058—0.689)和0.179(0.047—0.682),P0.05.女生阴毛发育与PFHxS有关,中低浓度组(Q_2)相对于低浓度组(Q_1)与阴毛发育水平负相关,OR(95%CI)为0.360(0.138—0.938),P0.05.该地区青少年处于PFOA高暴露水平,部分PFASs与青少年性征发育负相关,可能对青春期性发育产生影响.     

A sustainability assessment framework for regional-scale Integrated Coastal Zone Management (ICZM) incorporating Inclusive Wealth,Satoumi, and ecosystem services science

Sustainability has become an increasingly important concept in the last few decades; however, its operational usefulness has not always been clear. In other words, some sustainability assessments may not provide decision makers with the practical information necessary to perform the assessment. This study proposes a novel operational sustainable assessment framework for Integrated Coastal Zone Management (ICZM) on a regional-scale based on a feasibility study in the Seto Inland Sea in Japan. The framework draws upon three separately developed concepts: Inclusive Wealth as the technical framework for the sustainability indicators; Satoumi (a traditional Japanese multifaceted coastal zone concept); and ecosystem services science. These three concepts complement each other when seeking to corroborate an assessment framework. Indicators based on the framework and relevant to the case study site were identified. Although Satoumi is a traditional Japanese knowledge, it is believed that its application may be instructive for other areas, as similar concepts can be found and utilized for the conduct of ICZM sustainability assessments.     

赤泥重金属和放射性元素的毒性浸出和生物可给性

以烧结法和拜耳法生产工艺中产生的赤泥为研究材料,对其重金属和放射性元素含量进行分析,并对两种赤泥中重金属和放射性元素浸出效果进行对比研究.结果表明:两种赤泥显现出不同的理化性质.赤泥中不同重金属的含量差别较大,其中烧结法和拜耳法赤泥中As、Pb、Cr的总含量分别为256.73、120.14、828.02 mg/kg和182.82、165.83、1 043.96 mg/kg,超过我国GB 15618—1995《土壤环境质量标准》.两种赤泥中Zn、As、Pb、Mn、Ni和Th等主要以残渣态的形式存在,可交换态较少,其TCLP浸出量与其存在于交换态金属含量相近.在PBET试验中,胃部消化阶段进行到1 h时,重金属(Cu、Zn除外)及放射性元素的浸出量达到最大,小肠阶段的浸出量明显降低,在胃部消化阶段1 h时拜耳法和烧结法赤泥Pb的浸出率分别达到95.28%和97.80%,表明赤泥中的重金属及放射性元素对人体存在着较大的潜在风险.      

农田土壤中汞的吸附分配行为研究

汞是环境中毒性最强的重金属之一,由于具有持久性、长距离迁移性和生物累积性被列为全球性污染物。土壤是汞重要的源和汇,在汞的生物地球化学循环中发挥关键作用,其理化性质可以显著影响汞的吸附分配行为。本文基于采自全国各地的131份农业土壤样品考察了汞(Hg2+)在土壤中的吸附分配行为,测定了Hg2+的固液分配系数(Kd),并探讨其与p H、有机质(OM)、粒度组成、溶解性有机质(DOM)和总硫等土壤理化性质的关系。利用逐步多元线性回归的方法分析发现旱地土壤对汞Kd的主要影响因素是DOM和土壤粒度,而水田的主要影响因素是总硫。通过淹水实验,进一步探究了土壤氧化还原对Hg2+分配的影响。研究发现,旱地土壤中,大部分土壤在淹水30 d后Kd呈明显增大趋势,继续淹水至60 d的Kd表现为稳定或下降的趋势;大部分水田土壤在淹水条件下Kd未表现出增大的趋势,且随淹水时间呈稳定或下降的趋势。