Synthetic TiO2 nanoparticle emission from exterior facades into the aquatic environment

We present direct evidence of the release of synthetic nanoparticles from urban applications into the aquatic environment. We investigated TiO₂ particles as these particles are used in large quantities in exterior paints as whitening pigments and are to some extent also present in the nano-size range.TiO₂ particles were traced from exterior facade paints to the discharge into surface waters. We used a centrifugation based sample preparation which recovers TiO₂ particles between roughly 20 and 300 nm. Analytical electron microscopy revealed that TiO₂ particles are detached from new and aged facade paints by natural weather conditions and are then transported by facade runoff and are discharged into natural, receiving waters. Microscopic investigations are confirmed by bulk chemical analysis. By combining results from microscopic investigations with bulk chemical analysis we calculated the number densities of synthetic TiO₂ particles in the runoff.     

Comparing growth development of <Emphasis Type="Italic">Myriophyllum</Emphasis> spp. in laboratory and field experiments for ecotoxicological testing

BACKGROUND, GOALS AND SCOPE: Risk assessment of herbicides and the evaluation of contaminated sediments based on algae and the macrophyte Lemna sp. alone may underestimate the potential hazard of certain compounds. Therefore, various test systems with Myriophyllum spp. have been developed recently to assess the phytotoxicity in surface waters and natural sediments. In the present study, experiments investigating the growth development of Myriophyllum spp. were performed in the laboratory under defined conditions and in mesocosms under environmentally realistic exposure conditions to evaluate the suitability of these species as potential standard test organisms in ecotoxicological testing. This study provides data on the endpoints biomass, plant length and root development. MATERIALS AND METHODS: Six independent experiments were performed to investigate the plant development of Myriophyllum spp. under control conditions. The main difference in the experiments was the complexity of the test systems ranging from simple laboratory experiments to complex outdoor mesocosm studies. At the start of each experiment, uniform cuttings of Myriophyllum spp. were placed in vessels with or without sediments to reduce variability between replicates. The endpoints considered in this investigation were biomass (fresh weight of the whole plant), length of the main shoot, length of the side shoots, total length of the plant (calculated from the length of the main and side shoots) and root formation. Root to shoot ratios were calculated as a further measure for plant development. Relative growth rates (RGR) based on plant length (RG(L)R) and on biomass (RG(B)R) were calculated. RESULTS: Despite the various experimental conditions, comparable growth was obtained in all test systems and the variability of endpoints, such as total length and biomass of plants, was low. It was observed that the RGR of M. spicatum in the simple laboratory test system with sediment were comparable to growth data obtained for M. verticillatum and M. spicatum grown in indoor and outdoor mesocosms, thus indicating that Myriophyllum growth tends to increase by the addition of sediment. High variability was determined for the endpoints length of the side shoots, total root length and biomass of roots. DISCUSSION: One challenge for a test design to investigate phytotoxicity on aquatic plants is to obtain good growth of the plants. From the results, it can be concluded that the experimental conditions in the various test systems were suitable to study the plant development of Myriophyllum spp. because obtained growth rates were comparable between laboratory and field investigations. Another challenge for developing a plant biotest system is the definition of sensitive endpoints. Low variability is preferred to detect minor effects of chemicals or polluted sediments on plant development. In our studies, the variability of the endpoints biomass and total length of plant was low and, therefore, they have much potential as endpoints for assessing toxicity. CONCLUSIONS: The methodologies presented in this study have applications within the risk assessment for aquatic plants and have the advantage of assessing effects taking into account the relevant exposure pathways via water and/or sediment for compounds under investigation. RECOMMENDATIONS AND PERSPECTIVES: Setting safe quality criteria for surface water and sediments is one of the challenges authorities are facing today. Myriophyllum spp. is recommended as suitable test species to investigate phytotoxicity in surface water and sediments. These results, thus, might serve as a basis for the compilation of a new harmonised guideline for ecotoxicological testing with aquatic macrophytes.     

Suitability of a magnetic particle immunoassay for the analysis of PBDEs in Hawaiian euryhaline fish and crabs in comparison with gas chromatography/electron capture detection-ion trap mass spectrometry

A gas chromatograph/electron capture detector-ion trap mass spectrometer (GC/ECD-ITMS) was used for the determination of polybrominated diphenyl ethers (PBDEs) in euryhaline fish and crabs. GC/ECD-ITMS results showed that average recoveries from the spiked fish samples are in a range of 58-123% with relative standard deviations (RSDs) of 5-19%. PBDE concentrations obtained from GC/ECD-ITMS ranged from 28 ng/g to 1845 ng/g lipid weight (lw) in all aquatic species collected from Hawaiian brackish waters. The general BDE congener concentration profile observed in this study is BDE-47 > BDE-100 > BDE-154 > BDE-99 > BDE-153 > BDE-28 > BDE-183. The ELISA results expressed as BDE-47 equivalents correlated well with those of GC/ECD-ITMS, with a correlation coefficient (R² = 0.68) and regression coefficient (slope = 0.82). Comparison of ELISA with GC/ECD-ITMS results demonstrated that ELISA provides a timely and cost-effective method to screen PBDEs in fish and crab samples.     

POP bioaccumulation in macroinvertebrates of alpine freshwater systems

This study serves to investigate the uptake of POPs in the different trophic levels (scrapers, collectors, predators, shredders) of macroinvertebrate communities sampled from a glacial and a non-glacial stream in the Italian Alps. The presented results show that the contaminant concentrations in glacial communities are generally higher compared to those from non-glacial catchments, highlighting the importance of glaciers as temporary sinks of atmospherically transported pollutants. Moreover, the data also suggests that in mountain systems snow plays an important role in influencing macroinvertebrate contamination. The main chemical uptake process to the macroinvertebrates is considered to be bioconcentration from water, as similar contaminant profiles were observed between the different trophic levels. The role of biomagnification/bioaccumulation is thought to be absent or negligible. The enrichment of chemicals observed in the predators is likely to be related to their greater lipid content compared to that of other feeding groups.     

大伙房水库输水工程水生生物水质生态评价

对大伙房水库输水工程沿线地表水体中的藻类、浮游动物、底栖动物 (水生昆虫 )进行了监测 ,从生物学的角度对其水质进行了评价 ,并对引水后水生生物多样性的变化进行分析     

有机废弃物氢发酵制备生物氢气的研究

在批式培养实验中以有机废弃物为原料,通过厌氧生物发酵制备生物氢气研究了菌种来源、有机废弃物种类对产氢能力的影响,以及生物氢发酵过程中液相组成的变化以活性污泥为菌种来源,以淀粉为底物,在30L改进的UASB反应器中进行了放大实验,生物气中氢气浓度达40%～51%,CO₂浓度为49%～60%,且没有检测到甲烷气体,生物气经碱液吸收后氢气纯度大于97%持续产氢时间超过120d.     

应用物种敏感度分布法研究中国无机汞的水生生物水质基准

基于中国的水生生物区系特征,筛选了包括植物、无脊椎动物和脊椎动物等90个水生生物的急性毒性数据,使用物种敏感度分布法探讨了各类物种的敏感度分布特征,推导了中国无机汞的水生生物水质基准.结果表明,甲壳类生物对无机汞最为敏感,Log-Slogistic3对各组数据拟合效果最佳.基于对全部数据的拟合结果,得出无机汞的急性水质基准和慢性水质基准分别是1.743和0.467μg.L-1.该基准值与其他国家使用类似统计外推法得到的基准值在同一数量级,但也存在着差异,反映了各国水生态系统物种组成的差异.中国无机汞水生生物水质基准的建立,旨在保护中国地表水生态系统中的水生生物免受无机汞的高浓度急性暴露以及低浓度慢性暴露产生的毒害效应.比较不同水体无机汞的浓度水平发现,除嘉陵江水体溶解态汞可能会对水生生物具有潜在风险外,西南地区地表水活性汞均不会对水生生物产生危害.     

O2、NO-3、NO-2为电子受体的生物除磷比较

通过平行运行3个分别以O₂、NO^-₃、NO^-₂为电子受体的SBR除磷系统,探讨了反硝化除磷区别于好氧除磷的工艺特征及其内在微生物竞争机制.NO^-₂不会对经驯化后反硝化聚磷菌（DPAO）的缺氧吸磷产生直接抑制作用,但其作为反硝化除磷电子受体的效能远低于NO^-₃;具备利用NO^-₃而缺乏NO^-₂反硝化酶系的DPAO（DPAO₅）流失及聚糖菌（GAO）增殖是根本原因.而NO^-₃是一种高效电子受体,其反硝化除磷效能与以O₂为受体的好氧除磷系统相当,两者在除磷计量学和功能菌群构成上十分接近.作为聚磷菌（PAO）的竞争者,GAO在3个研究系统中均大量存在.基于对不同电子受体的利用能力,PAO包含P_O、P_N、P_n、P_Nn、P_ON、P_ONn等6个种类.P_ON和P_ONn等兼性PAO是生物除磷的主体,其在污泥中比例越高,系统的除磷负荷也越大,即SBR_o＞SBR_n5＞SBR_n3.     

景观生态评价法在南京沿江化工开发规划环评中的应用

介绍了景观生态评价法的基本原理,即依据景观生态学理论,通过建立栖息地预测模型来评估规划可能造成的生态影响,提出了应用该方法的基本程序,最后以南京沿江化工开发规划为例,以鲤鱼作为指示生物,苯酚作为栖息地限制因子,评估了南京沿江化工开发3种规划方案对水生生态环境可能造成的影响,并根据评价结果提出了区域优化开发的建议。     

太湖流域水生态环境功能分区管理指标达成效率评估和预警研究

太湖流域严峻的水生态环境形势备受关注,而水生态环境功能分区管理体系实施现状和效果无法被准确把握。以太湖流域水生态环境功能分区为研究对象,基于四象限法则和二维向量结构指标体系等方法论,综合障碍因子分析与目标可达性分析,对太湖流域水生态环境功能分区管理绩效评估目标达成效率进行评估和预警,为水生态环境功能分区管控提供技术指导。结果表明,江苏省太湖流域目标达成效率情况较好,"高效"、"一般"、"低效"的比例依次下降,高预警级别的区域较少;环境效率指标中单位面积污染物减排管控效率较高,环境质量指标整体表现良好,须谨防向"低效"转变。