Influence of Lead on Atrazine Uptake by Rice (Oryza sativa L.) Seedlings from Nutrient Solution (7 pp)

Background Atrazine is a widely used herbicide, and its persistence in soil and water causes environmental concerns. In the past, plat uptake processes are mainly investigated for single contaminants. However, in many cases, contaminants co-exist in environmental matrix, such as soil, and plant uptake of one contaminant may be influenced by its co-existing ones.Methods The uptake of atrazine by rice seedlings (Oryza sativa L.) from nutrient solution through the roots was investigated in a solution culture, over an exposure period of 4 weeks. Atrazine accumulation in plant tissues was determined by gas chromatography, and lead was determined using atomic absorption spectrometry.Results and Discussion With different ratios of atrazine and Pb2+ concentrations in solution, the observed atrazine concentrations in shoots and roots varied significantly. In atrazine-Pb2+ mixture systems, the added Pb2+ either increased or decreased the concentrations or BCFs of atrazine in seedlings (relative to those without Pb2+), depending on the atrazine-Pb2+ ratio in nutrient solution. The enhanced atrazine uptake results presumably from atrazine-Pb2+ complex formation. The reduced atrazine uptake, which occurred mainly at high atrazine concentrations, is attributed to atrazine toxicity that inhibited seedling growth and transpiration. Conclusion The formation of atrazine-Pb2+ complex both in the solution and within plant tissues may affect the accumulation of both contaminants by rice plants.     

Chromium in intertidal sediments of the Clyde,UK: potential for remobilisation and bioaccumulation

Detailed surveys of intertidal sediments have been performed along the north and south shores of the Inner Clyde estuary, UK. Surface sediment data reveal significant spatial variation in Cr content and an association with major sediment characteristics and location within the estuary. Depth variation for Cr and other heavy metals cannot be explained by variation in major geochemical controls such as grain size and organic matter and highlights the impact of historical contamination on sediment quality. These elevated levels at depth may still have environmental impact through redox-reactivity, in association with iron and manganese. Sequential extraction of sediments and pore water analysis of Cr(VI) and Cr(III) provide detailed information on release potential from the sediments. The implication of Cr mobility for biota in the estuary has been assessed by the analysis of a common marine bivalve, Mytilus edulis (Blue Mussel) and a burrowing polychaete, Nereis diversicolor (rag worm) from a number of survey sites. Bioconcentration factors for Mytilus indicate that the weakly held portion of sediment Cr is available for uptake and in the case of Nereis, bioaccumulation appears to be inhibited by sediment organic matter.     

有机锡的生物富集作用与生物效应

作为船只防污漆有效成分的有机锡化合物广泛存在于港口、海洋中，而生物富集是其迁移转化的重要途径之一。本文综述了有机锡特别是毒性最强的三丁基锡化合物在一些生物体内的检出水平、富集系数以及可能对生物造成的危害。     

戊唑醇在环境中的降解迁移和生物富集性研究

戊唑醇属于内吸性三唑类杀菌农药,在国内广泛用于田间病虫防治,故其在环境中的归趋备受关注。采用室内模拟试验方法,研究了戊唑醇在水-沉积物中的降解特性、土壤中的吸附性和在斑马鱼中的生物富集性。结果表明:好氧条件下,戊唑醇在河流与湖泊水-沉积物系统中农药总量的降解半衰期分别为533.2、433.2 d;厌氧条件下,河流与湖泊水-沉积物系统中降解半衰期分别为364.8、1 732.9 d;沉积物系统降解半衰期较长,降解速率主要受水中戊唑醇的降解速率影响。戊唑醇在江西红壤、太湖水稻土、常熟乌杉土、东北黑土中的吸附性符合Freundlich方程,Kd值分别为7.4、11.8、11.2和15;吸附性大小次序为东北黑土太湖水稻土常熟乌杉土江西红壤;以有机碳含量表示的土壤吸附常数KOC在698.9~1 635.5之间;影响戊唑醇土壤吸附性的主要因素为土壤有机质含量和p H。戊唑醇在斑马鱼中的生物富集系数BCF8 d为21.52~25.30,具有中等富集性。戊唑醇在水体环境中具有较强稳定性,不易被土壤吸附,且具有一定的生物富集性,可能会对水体和水体生物造成一定的污染。     

绿藻对硝基苯类化合物的富集与释放研究

测定了硝基苯、2,4-二硝基甲苯、2,6-二硝基甲苯及硝基氯苯(邻、间、对)在绿藻体内富集及释放趋势。其生物富集因子由小到大的顺序为:硝基苯<2,6-二硝基甲苯<2,4-二硝基甲苯<硝基氯苯(邻、间、对)。富集与释放曲线表明,所有化合物在实验开始的0.5～1h即达到最大富集量,2h后基本达到稳态。硝基苯、2,4-二硝基甲苯及2,6-二硝基甲苯的释放速率很快,0.5～1h达到最大释放量。6种有机物的生物富集因子与辛醇/水分配系数相关很好,生物富集过程符合脂水平衡分配模型。      

4种典型羟基化多溴联苯醚对斑马鱼胚胎的毒性和生物富集性

羟基化多溴联苯醚(OH-PBDEs)是近年来发现的一种新型有机污染物,它的存在与人类生产的PBDEs有着密切的关系,因而备受关注.本文以斑马鱼胚胎为受试生物,研究了2'-羟基-2,3',4,5'-四溴联苯醚(2'-OH-BDE-68)、3-羟基-2,2',4,4'-四溴联苯醚(3-OH-BDE-47)、5-羟基-2,2',4,4'-四溴联苯醚(5-OH-BDE-47)、6-羟基-2,2',4,4'-四溴联苯醚(6-OH-BDE-47)4种典型OH-PBDEs对斑马鱼胚胎毒性效应和富集规律,测定了孵化率、存活率、正常率、心率、体长等指标和斑马鱼早期生活阶段体内的生物富集系数.结果表明,4种OH-PBDEs暴露引起斑马鱼胚胎孵化率、心率、存活率下降,畸形率升高并抑制生长发育.组织病理学研究显示,受试组斑马鱼与空白相比,出现鳃结构紊乱、腮丝上皮增厚、组织残损、脱落甚至坏死及脊椎变形等症状.2'-OH-BDE-68、3-OH-BDE-47、5-OH-BDE-47、6-OH-BDE-47的生物富集系数(45 d-BCF值)分别为424、244、588和144.     

Tributyltin distribution and producing androgenic activity in water,sediment, and fish muscle

This study investigated the concentrations of Tributyltin (TBT) in water, sediment, and fish muscle samples taken from Kaohsiung Harbor and Kaoping River estuary, Taiwan. TBT concentrations in water and sediment samples ranged from less than 18.5 to 34.1 ng Sn L^?1 and from 2.44 to 29.7 ng Sn g^?1 weight per weight (w/w), respectively. Concentrations in the TBT‐contaminated fish muscle samples ranged from 10.8 to 79.6 ng Sn g^?1 w/w. The TBT concentrations in fish muscle were higher than those in water and sediment samples. The fish muscle/water TBT bioconcentration factor (BCF) ranged from 590 to 3363 L kg^?1. Additionally, the water samples were assessed for androgenic activity with an MCF7‐AR1 human breast cancer cell line. The androgenic activity ranged from 0.94 to 3.1 ng‐dihydrotestosterone per litre water (ng‐DHT L^?1). Higher concentrations of TBT in water and sediment samples occurred in the dry season, but the androgenic activity had higher values in the rainy season.     

Laboratory studies on the accumulation of inorganic mercury and methylmercury by the mussel (Mytilus galloprovincialis Lam) in relation to the presence of sediment

A comparative study on the accumulation of inorganic mercury and methylmercury by the mussel Mytilus galloprovincialis was based on nine days of exposure to 25 µg L^?1 HgCl₂ or to 2.5 µg L^?1 methylmercury in laboratory microcosms. Mercury (Hg) content was evaluated in the gills, digestive gland, and mantle. A higher accumulation occurred in the gills than in other tissues. The effect of the sediment on the bioaccumulation of the Hg species was evaluated. The results showed that the sediment accumulated the inorganic Hg more efficiently than the methylmercury. In both cases, the bioaccumulation in the tissues was reduced. The observed differences emphasized the need for caution when field results are compared with the results of laboratory experiments. The fate of either inorganic or organic Hg was depicted considering the absolute total amount given and the amount found in all the matrices (organism, sediment, and seawater).     

单独与混合暴露条件下褶纹冠蚌对Cu、Zn的积累与分布

采用室内模拟方法,在单独与混合暴露条件下研究了褶纹冠蚌(Cristaria plicata)对Cu、Zn的积累与分布特征.结果表明:褶纹冠蚌对水环境中的Cu、Zn具有良好的积累能力,持续暴露8d内,体内各组织重金属积累量基本呈线性上升,其中鳃与外套积累速率最快(p<0.05).Cu在褶纹冠蚌鳃、内脏团和生殖腺中的积累速率与Zn之间存在显著差异(p<0.05),且Cu、Zn之间在各组织中的积累拮抗作用明显.暴露前,Cu含量在褶纹冠蚌体内依次为:生殖腺>外套、内脏团>鳃、足>肌肉(p<0.05),变化幅度为10倍左右;Zn含量依次为:鳃>内脏团>生殖腺>足、外套>肌肉(p<0.05),变化幅度为4倍左右.暴露后,外套和鳃对Cu、Zn的积累量最高,且Cu、Zn含量在不同组织间的变化幅度明显增加.暴露前后,Cu含量在不同组织间的变化幅度均高于Zn.不同暴露条件下,褶纹冠蚌不同组织对Zn的浓缩系数(BCF)明显高于Cu.     

有机化学品生物富集性-构效关系研究进展

近年来,越来越多的有机化学品被排放到环境中,这些有机化学品被动植物摄取并富集,严重危害人类健康。有机化学品在生物体内的富集趋势可以用生物富集因子(BCF)表示,它是评价化学品环境行为的重要参数。通过定量-活性关系(QSAR)预测BCF值,可解决传统实验测定BCF值耗时长、成本高等问题。文章主要综述了近几年来国内外在这领域的研究进展,对现有的有机化合物的结构与生物富集因子定量关系模型进行系统的总结、评价,分析了模型研究中存在的具体问题,并提出了进一步改进的几点建议,展望了其在环境保护规划、预警及评估等方面的应用前景。