Anthropogenic trace metals in sediment and settling particulate matter on a high-energy continental shelf (Sydney,Australia)

The anthropogenic contribution of trace metals to settling particulate matter (SPM) and surficial sediments was determined on the high-energy continental shelf adjacent to Sydney, Australia. Settling particulate matter and surficial sediment was collected in the vicinity of a major sewage outfall and at five control sites on the middle shelf (80-100 m water depth). Sediment traps were deployed on 10 occasions for up to 2 weeks during the summer and winter of 1995 and SPM was analyzed for Ag, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Cobalt, Fe, Mn and Ni act conservatively in SPM and in sediments regionally and are used as normalizing elements to determine anthropogenic enrichment. Surficial sediments and SPM are enriched in Ag, Cr, Cu, Pb and Zn near a major ocean outfall and at four of the five control sites, although sewage particles contribute < 5% of trace metals in the total sample. Silver is the most sensitive trace metal tracer for establishing the presence of sewage particulate matter. Sewage particulate matter flux near the outfall was estimated using a two end-member mixing model and is below 0.5 g m(-2) day(-1) during all deployment periods. The mean sewage particulate matter flux at sampling locations 30 km and 60 km north of the outfall are <0.13 g m(-2) day(-1) and <0.01 g m(-2) day(-1), respectively, indicating an efficient dispersal of anthropogenic material on this high energy continental shelf.     

Bioaccumulation of trace metals in the Antarctic amphipod Orchomene plebs: evaluation of toxicokinetic models

Bioaccumulation of Cd, Co, Cu, Ni, Pb and Zn in Antarctic gammaridean amphipod collectives, Orchomene plebs (Hurley, 1965), was investigated during a cruise of RV "Polarstern" to the Wedell Sea. With the sole exception of Cd the organisms accumulated metals during exposure and depurated them in uncontaminated seawater. Four independent toxicokinetic experiments and one field study were modelled simultaneously to calculate the following size-dependent bioconcentration factors for organisms with body length 10 mm (BCF(10 mm)): 130 (Co), 4030 (Cu), 190 (Ni), 2900 (Pb), and 5210 (Zn). On the time scale of our experiments the data suggest an increased metal uptake by previously exposed test organisms. The collectives investigated may be regarded as potentially suitable biomonitors for Co, Cu, Ni, Pb and Zn but not for Cd. An approach to evaluate the sensitivity of Orchomene plebs as a biomonitor of waterborne metals in the field indicates minimal increments of the ambient exposure concentrations of 0.01 microg Co l(-1), 0.2 microg Cu l(-1), 0.4 microg Ni l(-1), 0.6 microg Pb l(-1) and 0.3 microg Zn l(-1).     

Phytoremediation of small-scale oil spills in fresh marsh environments: a mesocosm simulation

Research was conducted to assess the impact of oiling on fresh-marsh plant communities and to test the efficacy of techniques that may be used to enhance the bioremediation of crude oil spills in these environments while minimizing secondary anthropogenic impacts. To emulate field conditions, a mesocosm facility was used that houses 120 mesocosm vessels, each of 200-1 capacity. A five-way factorial treatment arrangement was used that included two substrates (inorganic, organic), two nutrient regimes (fertilized, not fertilized), two aeration levels (substrate aeration, no aeration), three oiling concentrations (0-, 5-, 10-1 m(-2) of South Louisiana Sweet Crude oil), and four vascular plant species (Alternanthera philoxeroides, Panicum hemitomon, Phragmites australis, Sagittaria lancifolia, and an unplanted control). Under the 5- and 10-1 m(-2) oiling concentrations, S. lancifolia displayed a short-term response of increased productivity, whereas P. hemitomon had the highest biomass production and photosynthetic rates at the end of the 18-month experiment. Overall plant growth and productivity, as well as oil degradation, were significantly higher in the inorganic substrate, indicating that biodegradation of oil spills in organic substrates may require a longer time period. Time-released fertilizer also stimulated plant productivity and resulted in higher soil respiratory quotients, suggestive of greater microbial activity, particularly in aerated mesocosms. The amount of oil remaining after 18 months was lowest in aerated and fertilized mesocosms containing either P. hemitomon or S. lancifolia and a substrate of low organic matter content.     

地铁施工对济南白泉泉群流量的影响

为研究地铁建设对济南白泉泉群的影响，在综合分析白泉泉域地质、水文地质条件的基础上，假定研究区岩溶强径流带位置及水力性质，利用FEFLOW软件建立地下水流数值模型。以规划地铁M1号线为研究对象，分析了济南东站、梁王站、梁王东站分别施工及3个站同时施工4种情景下，采用施工降水或施工降水+人工回灌两种施工方式对白泉泉群流量的影响。结果表明：单独采用施工降水的施工方式使得白泉泉群流量衰减，其中3个站同时施工对泉流量的影响最大，泉流量最大衰减达5.48%；各站分别施工时，济南东站对泉流量影响最大，泉流量较未施工时减少了0.043×10⁴ m³/d。采用施工降水+人工回灌的施工方式，能够有效缓解泉流量的衰减，各车站施工时的泉流量衰减由仅施工降水时的2.26%~5.48%降低至0.08%~1.21%。岩溶强径流带有利于地下水形成优势径流，促进白泉泉群补给，一定程度上缓解因地铁施工引起的泉流量衰减。     

Spatial variations of dimethylsulfide and dimethylsulfoniopropionate in the surface microlayer and in the subsurface waters of the South China Sea during springtime

Spatial variations in dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) were surveyed in the surface microlayer and in the subsurface waters of the low productivity South China Sea in May 2005. Overall, average subsurface water concentrations of DMS and DMSP of dissolved (DMSPd) and particulate (DMSPp) fractions were 1.74 (1.00-2.50), 3.92 (2.21-6.54) and 6.06 (3.40-8.68) nM, respectively. No enrichment in DMS and DMSPp was observed in the microlayer. In contrast, the microlayer showed a DMSPd enrichment, with an average enrichment factor (EF, defined as the ratio of the microlayer concentration to subsurface water concentration) of 1.40. In the study area, none of the sulfur components were correlated with chlorophyll a. An important finding in this study was that DMS, DMSP and chlorophyll a concentrations in the surface microlayer were respectively correlated with those in the subsurface water, suggesting a close linkage between these two water bodies. The ratios of DMS:Chl-a and DMSPp:Chl-a showed a gradually increasing trend from North to South. This might be due to changes in the proportion of DMSP producers in the phytoplankton community with the increased surface seawater temperature. A clear diurnal variation in the DMS and DMSP concentrations was observed at an anchor station with the highest concentrations appearing during the day and the lowest concentrations during the night. The higher DMS and DMSP concentrations during daytime might be attributed to the light-induced increase in both algal synthesis and exudation of DMSP and biological production of DMS. The mean flux of DMS from the investigated area to the atmosphere was estimated to be 2.06 micromo lm(-2)d(-1). This low DMS emission flux, together with the low DMS surface concentrations was attributed to the low productivity in this sea.     

岩溶覆盖层的坍塌：原因与预测

岩溶覆盖层坍塌是天然力或人类活动引起的一种动力地质现象。灾难性坍塌通常是人类活动引起的,例如:矿山排水,挖掘坑道,过量开采岩溶水引起水位大幅度下降或急剧上升,频繁而剧烈的振动等,都能引起大规模的坍塌。岩溶覆盖层的坍塌有三个基本条件,首先,覆盖层之下的是基岩有岩溶发育,岩溶形成的溶蚀洞厅系统上都是开启的;其次,覆盖层是松散沉积物或象土壤、砂或砾石的堆积物;第三,地下水位频繁变化且发生在基岩和覆盖层界面附近。当岩溶区的岩石、土壤、水和空气的天然平衡遭到破坏时,就很可能发生坍塌,就     

中国西南部居民的氟中毒和环境地球化学

地方性氟中毒已被世界许多国家和地区所熟知,它也危及着许多中国居民的健康,到目前为止,关于氟中毒的实例报道大都起因于饮用高氟浓度的地下水。然而,根据作者的调查,中国西南部居民中发现的氟中毒情况是由于在室内烧煤而造成,食物和空气污染而至。作者对这一类型的氟中毒区,从致病途径和规律等方面进行系统的环境特征研究。     

地下水保护及地下水资源保护的一种新方法

在数量、质量和温度上保护地下水资源在所有发达国家以及发展中国家都起着重要作用。在民主德国,地下水资源不足而开采强度很大,在这种特殊条件下,更需最大程度地进行地下水防护管理。最佳保护由许多预防步骤组成,定义为地下水保护设想方法。该方法利用环境同位素,尤其是氚和碳-14和水文地质动力模拟结合基础水文地质分析,同时,考虑任何达到一定浓度的污染物的作用,并提出一个新的参数,这一参数概括了污染物从输入到输出之间影响其混合作用,稳定作用或迁移作用等的所有物理和化学过程。从地下水环境同位素的测量中得出一个重要参数是地下水平均滞留时间,通过这个“同位数”参数,合适模型的研究能将地下水动力学特征用地下水的起源、补给,流动     

1991～1993年美国水资源协会将要举办的国际会议

1 .1991年2月24~28日,将在美国俄亥俄州克利夫兰举行题为“地表水和地下水水质”学术会议,会议总主席及通信地址如下: Davld C .KirkPatriek U .5 EPA 230吕.Dear卜orn St.SWQS Chieago,IL 60604 U .S.A. 该会议包括以下n个专题: 带沼泽地管理口月..1,111,1.|,.!l…11刁1lljee月刃霸1门月..月.1 带水质风险评价 带地下水条例与法规 来地表水与地下水的相互作用 余农业对水质的影响一‘一:】一户 带五大湖水质 带水质模似 余资料收集与管理 带金盆地系统水质管理 带公共机构对水质的影响、:·, 带水污染物的特征和迁移性 2 .1991年6…