湿地植物水蓼(Polygonum hydropiper L.)对镉的富集特征及生理响应

以人工湿地修复镉污染水体时,植物在镉离子的沉淀、吸收和积累等过程中起着关键作用,但当前报道的镉富集植物种类较少,湿地植物对镉胁迫的生长及生理响应缺乏系统研究,限制了湿地植物在镉污染水体修复中的应用。笔者以常见湿地植物水蓼(Polygonum hydropiper L.)为对象,设置了4个镉处理浓度(0、0.5、1和2 mg·L~(-1)),研究了水蓼对镉的富集特征以及生长和生理响应。水蓼根、茎和叶的镉含量(以干重计)随镉处理浓度的增加而升高,处理30 d时,在2 mg·L~(-1)处理下分别达到134、47和48 mg·kg~(-1)。处理30 d时,在1 mg·L~(-1)的镉处理下,水蓼的地上部及地下部富集系数和转运系数最高,地上部和地下部富集系数分别为45.6和111.7,转运系数为0.41。在处理15 d时,水蓼生物量、叶绿素含量和超氧化物歧化酶(SOD)活性在2 mg·L~(-1)处理下显著降低。在处理30 d时,水蓼的总生物量在不同镉浓度下无显著差异,但丙二醛(MDA)含量、SOD和过氧化氢酶(CAT)活性在0.5～2 mg·L~(-1)镉处理下均显著升高,叶绿素含量下降。这些结果表明,水蓼可以通过提高抗氧化酶活性等机理抵抗镉胁迫产生的氧化伤害,并且水蓼对镉的富集和转运系数较高,具有在镉污染水体修复中应用的潜力。     

EDTAD-modified cassava stalks loaded with Fe3O4: highly efficient removal of Pb2+ and Zn2+ from aqueous solution

Environmental Science and Pollution Research - In this study, a novel magnetic cassava stalk composite (M-EMCS) was prepared through modification with ethylenediamine tetraacetic anhydride (EDTAD)...     

Potential metal-binding ability of proteins in the extracellular slime of Laccaria bicolor exposed to excessive Cu and Cd

Environmental Science and Pollution Research - Ectomycorrhizal fungi can enhance the tolerance of plants to heavy metal stress by reducing the accumulation of heavy metals in the aerial parts of...     

Quantification of the Exposure–Lag–Response Association Between Air Pollution and Respiratory Disease Morbidity in Chongqing City,China

Environmental Modeling & Assessment - The health effects of air pollution on respiratory disease morbidity and mortality commonly vary with air pollutants’ intensity and latency after...     

新烟碱类杀虫剂对非靶标生物毒性效应的研究进展

新烟碱类杀虫剂是目前全球市场占有率最高的一类杀虫剂,它们选择性作用于昆虫烟碱型乙酰胆碱受体,以往普遍认为其对非靶标生物毒性较低。然而,越来越多的证据表明,新烟碱类杀虫剂的暴露会对非靶标生物造成负面影响。本文综述了新烟碱类杀虫剂对水生生物、非靶标昆虫、鸟类和哺乳动物等多种非靶标生物的毒性,以及对人类健康的影响。新烟碱类杀虫剂对各类生物均具有急性致死毒性,但不同物种之间半数致死浓度(LC_(50))或半数致死剂量(LD_(50))差别较大,由低至高依次为昆虫(0.01～2.38 mg·L~(-1),3.7～81 ng·bee~(-1))、甲壳动物(0.59～37.75 mg·L~(-1))、鱼类(1.2～241 mg·L~(-1))、鸟类(15～>2 000 mg·kg~(-1))和哺乳动物(82～>5 000 mg·kg~(-1))。新烟碱类杀虫剂对非靶标生物的亚致死毒性表现在降低繁殖力和生长速度、降低活动性、影响神经系统、扰乱代谢平衡、损伤DNA等。总体上看,吡虫啉的毒性最高,呋虫胺和烯啶虫胺的毒性较低。啶虫脒、噻虫啉、噻虫嗪和噻虫胺的毒性大小顺序随物种不同而不同。对于水生生物和非靶标昆虫,噻虫啉和噻虫胺的毒性较高,而对于鸟类和哺乳动物,啶虫脒的毒性较高。最后针对现有研究的不足,提出了今后的研究方向,以期为该类杀虫剂的风险评估和合理施用提供科学依据。     

Catalytic decomposition of dioxins and other unintentional POPs in flue gas from a municipal waste incinerator (MWI) in China: a pilot testing

Unintentionally produced persistent organic pollutants (UPOPs) include polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), pentachlorobenzene (PeCBz), and hexachlorobenzene (HxCBz). With the booming of municipal waste incinerators (MWIs) in China, the emission of UPOPs has generated great concern. As an alternative technology of dioxin control, catalytic decomposition has not been used in China, mainly due to the absence of national demonstration projects. Also, the simultaneous removal of various UPOPs has not been well investigated.In this study, a pilot-scale selective catalytic oxidative (SCO) system using a self-developed honeycomb catalyst was built and tested in a typical municipal waste incinerator (MWI) of China. The original concentration of PCDD/Fs in flue gas after the treatment of activated carbon injection (ACI) still exceeded the national emission standard (0.1 ng I-TEQ/Nm³), while the concentrations of PeCBz and HxCBz were one order of magnitude higher than that of PCDD/Fs. For the testing temperature varying from 300 to 200 °C, the removal efficiency of PCDD/Fs range from 39 to 95 %, followed by dl-PCBs with the range of 56–89 %. PeCBz and HxCBz were also removed, though their removal efficiencies were lower than those of PCDD/Fs and dl-PCBs. Both temperature and degree of chlorination influence the removal efficiencies.     

China’s industrial gray water footprint assessment and implications for investment in industrial wastewater treatment

Industrial wastewater is the largest contributor of toxic pollutants and third-largest contributor of nutrients to bodies of water in China, and understanding the characteristics of such pollution is important for water pollution control. In this study, the industrial gray water footprint (GWF) of each industry sector in China’s 31 provinces in 2015 was calculated to identify the pollution characteristics of industrial wastewater discharge and determine how to efficiently allocate investment to pollution reduction. We show that the total industrial GWF of China was 300 billion m³ in 2015 and that the major pollutants were petroleum pollutant (PP), ammonia nitrogen (NH₃-N), volatile phenol (VP), and chemical oxygen demand (COD). The water pollution level (WPL) was higher than 1 in Ningxia, Shanxi, Hebei, Tianjin, Shanghai, Henan, and Shandong, indicating that industrial pollution exceeded the carrying capacity of local water bodies in these seven regions. Given equivalent total investment, a scenario that takes the total reduction of the industrial GWF weighted by the WPL in each region as the investment target can better allocate funds to control industrial wastewater pollution in regions with high WPLs relative to a scenario in which investment targets the reduction of the unweighted total industrial GWF. For further industrial GWF reduction in regions with high WPLs, it is crucial to adjust the industrial structure and to upgrade relevant technologies.

     

Nano-MnO<Subscript>2</Subscript>-mediated transformation of triclosan with humic molecules present: kinetics,products, and pathways

It has been shown that manganese dioxide (MnO₂) can mediate transformation of phenolic contaminants to form phenoxyl radical intermediates, and subsequently, these intermediates intercouple to form oligomers via covalent binding. However, the reaction kinetics and transformation mechanisms of phenolic contaminants with humic molecules present in nano-MnO₂-mediated systems were still unclear. In this study, it was proven that nano-MnO₂ were effective in transforming triclosan under acidic conditions (pH 3.5–5.0) during manganese reduction, and the apparent pseudo first-order kinetics rate constants (k?=?0.0599–1.5314 h^?1) increased as the pH decreased. In particular, the transformation of triclosan by nano-MnO₂ was enhanced in the presence of low-concentration humic acid (1–10 mg L^?1). The variation in the absorption of humic molecules at 275 nm supported possible covalent binding between humic molecules and triclosan in the nano-MnO₂-mediated systems. A total of four main intermediate products were identified by high-resolution mass spectrometry (HRMS), regardless of humic molecules present in the systems or not. These products correspond to a suite of radical intercoupling reactions (dimers and trimers), ether cleavage (2,4-dichlorophenol), and oxidation to quinone-like products, triggered by electron transfer from triclosan molecules to nano-MnO₂. A possible reaction pathway in humic acid solutions, including homo-coupling, decomposition, oxidation, and cross-coupling, was proposed. Our findings provide valuable information regarding the environmental fate and transformation mechanism of triclosan by nano-MnO₂ in complex water matrices.