In field arsenic removal from natural water by zero-valent iron assisted by solar radiation

An in situ arsenic removal method applicable to highly contaminated water is presented. The method is based in the use of steel wool, lemon juice and solar radiation. The method was evaluated using water from the Camarones River, Atacama Desert in northern Chile, in which the arsenic concentration ranges between 1000 and 1300 μg L⁻¹. Response surface method analysis was used to optimize the amount of zero-valent iron (steel wool) and the citrate concentration (lemon juice) to be used. The optimal conditions when using solar radiation to remove arsenic from natural water from the Camarones river are: 1.3 g L⁻¹ of steel wool and one drop (ca. 0.04 mL) of lemon juice. Under these conditions, removal percentages are higher than 99.5% and the final arsenic concentration is below 10 μg L⁻¹. This highly effective arsenic removal method is easy to use and inexpensive to implement.     

Modulation of steroidogenesis by coastal waters and sewage effluents of Hong Kong, China, using the H295R assay

BACKGROUND, AIM, AND SCOPE: The presence of a variety of pollutants in the aquatic environment that can potentially interfere with the production of sex steroid hormones in wildlife and humans has been of increasing concern. The aim of the present study was to investigate the effects of extracts from Hong Kong marine waters, and influents and effluents from wastewater treatment plants on steroidogenesis using the H295R cell bioassay. After exposing H295R cells to extracts of water, the expression of four steroidogenic genes and the production of three steroid hormones were measured. MATERIALS AND METHODS: Water samples were collected during the summer of 2005 from 24 coastal marine areas and from the influents and effluents of two major waste water treatment plants (WWTPs) in Hong Kong, China. Samples were extracted by solid phase extraction (SPE). H295R cells were exposed for 48 h to dilutions of these extracts. Modulations of the expression of the steroidogenic genes CYP19, CYP17, 3betaHSD2, and CYP11beta2 were determined by measuring mRNA concentrations by real-time polymerase chain reaction (Q-RT-PCR). Production of the hormones progesterone (P), estradiol (E2), and testosterone (T) was quantified using enzyme linked immunosorbent assays (ELISA). RESULTS: Extracts from samples collected in two fish culture areas inhibited growth and proliferation of H295R cells at concentrations greater or equal to 10(5) L equivalents. The cells were exposed to the equivalent concentration of active substances in 10,000 L of water. Thus, to observe the same level of effect as observed in vitro on aquatic organisms would require a bioaccumulation factor of this same magnitude. None of the other 22 marine samples affected growth of the cells at any dilution tested. Twelve of the marine water samples completely inhibited the expression of CYP19 without affecting E2 production; inhibition of CYP17 expression was observed only in one of the samples while expression of CYP11beta2 was induced as much as five- and ninefold after exposure of cells to extracts from two locations. The expression of the progesterone gene 3betaHSD2 was not affected by any of the samples; only one sample induced approximately fourfold the production of E2. Although more than twofold inductions were observed for P and T production, none of these values were statistically significant to conclude effects on the production of these two hormones. While influents from WWTPs did not affect gene expression, an approximately 30% inhibition in the production of E2 and a 40% increase in P occurred for the exposure with influents from the Sha Tin and Stonecutters WWTPs, respectively. Effluents from WWTPs did not affect the production of any of the studied hormones, but a decrement in the expression of the aldosterone gene CYP11beta2 was observed for the Sha Tin WWTP exposure. No direct correlation could be established between gene expression and hormone production. DISCUSSION: Observed cytotoxicity in the two samples from fish culture areas suggest the presence of toxic compounds; chemical analysis is required for their full identification. Although effluents from WWTPs did not affect hormone production, other types of endocrine activity such as receptor-mediated effects cannot be ruled out. Interactions due to the complexity of the samples and alternative steroidogenic pathways might explain the lack of correlation between gene expression and hormone production results. CONCLUSIONS: Changes observed in gene expression and hormone production suggest the presence in Hong Kong coastal waters of pollutants with endocrine disruption potential and others of significant toxic effects. The aromatase and aldosterone genes seem to be the most affected by the exposures, while E2 and P are the hormones with more significant changes observed. Results also suggest effectiveness in the removing of compounds with endocrine activity by the WWTPs studied, as effluent samples did not significantly affect hormone production. The H295R cell showed to be a valuable toll in the battery required for the analysis of endocrine disrupting activities of complex environmental samples. RECOMMENDATIONS AND PERSPECTIVES: Due to the intrinsic complexity of environmental samples, a combination of analytical tools is required to realistically assess environmental conditions, especially in aquatic systems. In the evaluation of endocrine disrupting activities, the H295R cell bioassay should be used in combination with other genomic, biological, chemical, and hydrological tests to establish viable modes for endocrine disruption and identify compounds responsible for the observed effects.     

从"珠三角火力发电厂排污交易试验计划"看粤港区域环境管理制度创新机遇

总结排污交易在中国的发展历程,展望"珠三角火力发电厂排污交易试验计划实施方案"实施,粤港区域环境管理将面临着一次新的挑战,也是区域环境保护制度创新的重大机遇.     

全球变化对跨境淡水资源利用和管理的影响

跨境淡水资源的合理利用和协调管理,已成为当今国际区域经济发展、跨境资源和市场共享、世界生态维护的合作主题,成为下世纪制约区域可持续发展和避免地区冲突的一个关键因素,受到国际社会广泛关注。从边界变化、国际区域合作和经济一体化、气候变化、人口增长、可持续发展等全球趋势对此主题的影响进行了探讨。     

水体中的微生物对壬基酚聚氧乙烯醚的生物降解

为有效控制水体中壬基酚聚氧乙烯醚的污染 ,以芽孢杆菌、假单胞菌、诺卡氏菌和假丝酵母为试验菌株 ,研究了其对壬基酚聚氧乙烯醚的生物降解特性。试验结果表明 ,4菌株在一定的条件下对水体中的壬基酚聚氧乙烯醚均有一定的降解率。若按体积比 1∶ 2∶ 1∶ 1的比例将四菌株组合成复合菌群 ,可大幅度提高处理效率 ,降解率可达 61 %。应用该复合菌对影响壬基酚聚氧乙烯醚降解的各种主要因素进行了研究 ,发现降解菌在θ为 2 5～ 30℃ ,p H值为 5.5～ 8.5及壬基酚聚氧乙烯醚初始质量浓度ρ(NP1 0 EO)为 0～ 1 0 0 mg/ L范围内保持高活性 ;当底物质量浓度大于 1 0 0 mg/ L 时 ,平均降解速率线性下降 ;当接种量标准为 1× 1 0 8CFU/ m L (即菌悬液 /反应液为1 0 % )时壬基酚聚氧乙烯醚的降解是高效与经济的     

珠海市近岸海域水环境现状及可持续利用对策

近岸海域水环境对沿海城市的可持续发展具有重要意义 .根据实测资料分析了珠海市近岸海域水环境质量的基本现状以及污染物的主要来源 ,认为造成近海环境污染的主要原因是随着经济的发展 ,污染源增加 ,加上缺乏海洋环境保护意识 ,盲目开发利用海洋环境资源所致 .海洋环境监测和抗污染技术落后也是造成珠海市近岸海域水质超标的重要原因 .为此针对性地提出了珠海市海洋环境资源的可持续利用对策对建议 .     

粤西海域浮游植物种类的动态变化及多样性

根据1998～1999年4个航次粤西海域浮游植物的调查资料，分析了该海域浮游植物的种类组成、季节变化和平面分布特征，并对浮游植物的多样性水平进行了初步评价。结果显示，调查期间共鉴定浮游植物267种，其种类组成以细弱海链藻(Thalassiosira subtilis)的数量最多，占总数量的29．5％，其次为短角弯角藻(Eucampia zoodiacus)，占21．8％。不同季节浮游植物的优势种即有交叉又有演替。根据多样性阈值的评价，粤西海域绝大部分沿岸水域的浮游植物均处于多样性差或一般水平，而离岸水域基本处于多样性丰富或非常丰富水平。     

我国典型海域主要生物体微量元素含量的统计研究

研究了微量元素Fe、Mn、Zn、CM、Sr、Ba在我国典型海域主要生物类别中的概率分布特征，并与常量元素Ca、Mg进行了比较。结果表明，微量元素的概率分布曲线具正偏态性质，概率分布类型大多为对数正态分布或近似对数正态分布，表明对某一特定微量元素，大多数生物体中的含量都比较低，只有个别生物有不成比例的高含量。常量元素Ca与微量元素相似，表现为对数正态分布，而Mg却具正态分布特征。本文给出了我国典型海域生物体中元素含量的总体分布特征。     

黄河断流对三角洲附近海域生态环境影响的研究

本文根据多年调查监测数据研究成果，以及经济和社会统计资料，论述了黄河断流的历史与现状，定性定量地评价了黄河断流对三角洲附近海域生态环境的影响，并提出了缓解和预警对策。