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Anna Brooks Rehema M. White David C. Paton 《International Journal of Salt Lake Research》1995,4(2):133-163
The hypermarine southern Coorong is threatened by proposals to drain relatively fresh surface water and groundwater from adjacent agricultural areas into the Coorong. These influent waters carry moderate loads of heavy metals. Acute toxicity of heavy metals toDiacypris compacta, an abundant ostracod in the Coorong, was measured in the laboratory at 18°C in a static system using Coorong water (pH 7.8 salinity 50 ppt). At 4 days (96 h) the mean values of LC50 for copper, zinc, lead and, cadmium respectively were 0.8, 2.1, 3.1 and 4.3 mg L–1, and at 8 days the respective mean LC50
s were 0.4, 0.7, 2.2 and 1.1 mgL–1. The effect of two or three metals on mortality was additive in some cases and synergistic in other cases, but generally less than additive. However, in all cases mortality was greater in the presence of two or three metals than in the presence of a single metal. According to ANZECC (1992) guidelines, maximum acceptable concentrations of heavy metals should be no higher than 0.01 x the lowest LC50 value. Using the lowest LC50 values forDiacypris compacta obtained at 8 days, maximum acceptable concentrations in the Coorong would be 4, 5, 9 and 22 gL–1 for copper, zinc, cadmium and lead respectively, the values for zinc and copper failling below those recommended by ANZECC (1992) for marine waters. Reported concentrations of copper and zinc in surface water and groundwater in areas adjacent to the Coorong sometimes exceed these values, hence drainage of these waters into the Coorong represents a significant hazard to the Coorong biota. 相似文献
13.
Supriyo Das 《中国地球化学学报》2006,25(B08):24-25
The Raniganj Coalfield is the oldest coalfield in India that has been continuously and extensively mined since the late eighteenth century. The present study reports a geochemical investigation and environmental quality assessment using soil and water in the area surrounding a stream, locally known as Singaran Nala (Nala means storm water drains in Bengali), in the Raniganj Coalfield. Soil (top soil, mud, silty clay and laterite) and rock samples (sandstone and shale) were collected from the study area and were analyzed for trace metals (Cr, Cu, Fe, Mn, Ni and Zn). Surface waters from the stream and the Damodar River as well as ground waters from hand pumps and underground mine pits were collected. Water samples were analyzed for major ions (Na^+, Ca^2+, Mg^2+, Cl^-, HNO3^- and SO4^2-) and trace metals (Cu, Fe, Mn, Ni, and Zn). Trace metal concentrations in soil samples are found higher than the average world soil composition. Nevertheless, trace metal (Cr, Cu, Ni and Zn) concentrations in soils exceed or reach the maximum allowable concentrations (MAC) proposed by the European Commission for agricultural soils. In particular, Ni concentrations exceed the typical value for cultivated soils. Chromium, Cu and Ni concentrations in laterite and Cr concentration in topsoil exceed the ecotoxicological limit. 相似文献
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Edward Derbyshire 《中国地球化学学报》2006,25(B08):219-219
Fine atmospheric dust includes mineral particles and aggregates, fibrous minerals and fibrous organic material. Generation, dislodgement and transport (deflation) of natural dust with the finer (〈4 microns) components suspended as silt-size aggregates, is widespread in and adjacent to the world's drylands, as well as deriving from volcanic vents. Silica is a highly fibrogenic agent in lung tissue. Long-term inhaling of siliceous dusts can lead to a number of fibrotic lung diseases, including natural (non-occupational) pneumoconioses (notably silicosis, but including asbestosis and others). Different polymorphs of silica show different levels of toxicity in interaction with lung tissue. Particles with highly active surfaces may release radicals, causing cell damage. Some types of inhaled particulates are degraded by macrophages, but many are highly resistant and persist in the lungs, some stimulating fibroblastic cells to deposit collagen. Silicosis is an inflammation of the lung commonly caused by silicate mineral particles, leading to fibrosis. Three types are recognized: nodular pulmonary fibrosis (simple or chronic silicosis), acute silicosis, and accelerated silicosis. Generally, finer particulates have greater oxidative capacity than the coarser fractions. They contain more reactive oxygen species, their greater bioreactivity making them more toxic to pulmonary tissue. Nevertheless, inhalation of large dust particles (〉 10μm) may constitute a health risk if the mineralogy is toxic, regardless of where the grains lodge in the respiratory system. Dust may absorb harmful gases, disease-generating bacteria and carcinogenic hydrocarbon compounds. Silica-related respiratory disease may also an exacerbate cardiac problem, and epidemiology suggests a link with tuberculosis. Quantification of dust loading and exposure requires study of spatial and temporal patterns, supported by meteorological analysis, airflow modeling and satellite-borne imagery. Some acute, short-term health impacts have been assessed using atmospheric and health records both before and after a dust storm or by comparison of populations within and outside such events. Analysis of the size, shape, mineralogy and geochemistry of ambient dust particulates provides information on natural dust sources, dust concentrations, and potential particulate toxicity, as well as providing a datum for assessment of human exposure levels. 相似文献
16.
Thomas Backhaus Rolf Altenburger sa Arrhenius Hans Blanck Michael Faust Antonio Finizio Paola Gramatica Matthias Grote Marion Junghans Wiebke Meyer Manuela Pavan Tobias Porsbring Martin Scholze Roberto Todeschini Marco Vighi Helge Walter L. Horst Grimme 《Continental Shelf Research》2003,23(17-19):1757
Freshwater and marine ecosystems are exposed to various multi-component mixtures of pollutants. Nevertheless, most ecotoxicological research and chemicals regulation focus on hazard and exposure assessment of individual substances only, the problem of chemical mixtures in the environment is ignored to a large extent. In contrast, the assessment of combination effects has a long tradition in pharmacology, where mixtures of chemicals are specifically designed to develop new products, e.g. human and veterinary drugs or agricultural and non-agricultural pesticides. In this area, two concepts are frequently used and are thought to describe fundamental relationships between single substance and mixture effects: Independent Action (Response Addition) and Concentration Addition. The question, to what extent these concepts may also be applied in an ecotoxicological and regulatory context may be considered a research topic of major importance, as the concepts would allow to make use of already existing single substance toxicity data for the predictive assessment of mixture toxicities. Two critical knowledge gaps are identified: (a) There is a lack of environmental realism, as a huge part of our current knowledge about the applicability of the concepts is restricted to artificial situations with respect to mixture composition or biological effect assessment. (b) The knowledge on what exactly is needed for using the concepts as tools for the predictive mixture toxicity assessment is insufficient. Both gaps seriously hamper the necessary, scientifically sound consideration of mixture toxicities in a regulatory context.In this paper, the two concepts will be briefly introduced, the necessity of considering the toxicities of chemical mixtures in the environment will be demonstrated and the applicability of Independent Action and Concentration Addition as tools for the prediction and assessment of mixture toxicities will be discussed. An overview of the specific aims and approaches of the BEAM project to fill in the identified knowledge gaps is given and first results are outlined. 相似文献
17.
顾及拓扑与尖角的分类矢量数据分组压缩算法 总被引:1,自引:1,他引:0
针对现有拆分重组法对存在复杂内环以及复杂相交岛屿多边形的分类矢量数据的压缩结果中包含裂缝、重叠及大量尖锐夹角的问题,提出了一种顾及拓扑一致性与尖角的分组压缩方法。依据分类矢量数据中多边形与多边形及其内环的相交关系对矢量矢量数据分组,以修正后拆分重组法结合直接分割法和间接分割法对分类矢量数据分组压缩,压缩结果中不存在裂缝与重叠现象,维护了分类矢量数据的拓扑一致性;通过取回尖角点前后被删除的点,解决了压缩结果中尖角过多的问题。以Landsat8遥感影像分类矢量数据实验验证了文章算法,并与直接分割法、间接分割法、拆分重组法进行了对比分析,验证了本文方法的有效性。 相似文献
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多环芳烃(PAHs)与纳米材料污染已对沉积物生态系统和人类生存环境构成严重威胁,其复合污染的毒性效应环境危害可能更大。为了深入探讨PAHs与纳米材料对近岸表层沉积物反硝化作用的复合毒性效应,本文选取位于胶州湾(JZB)的大沽河河口区(DRE)E站和湾内S站,分别以菲和纳米银代表PAHs和纳米材料,通过测定不同剂量单一及复合污染下沉积物反硝化潜势(PDA)的变化,结合浓度相加模型(CA)、独立作用模型(IA)和中效/联合指数等效图法(CI)三种复合毒性评价方法,评价菲和纳米银对沉积物反硝化潜势的复合毒性效应,并对评价方法进行了优选。结果表明,两种污染物浓度越高,对研究区域反硝化潜势的抑制作用越大。菲、纳米银单一及复合作用下对河口区沉积物反硝化潜势的EC50值分别为44.62、112.49和64.86 mg·kg-1,对湾内分别为61.79、147.05和96.18 mg·kg-1。菲单一作用对反硝化潜势的抑制效应强于纳米银,但复合污染的抑制效应更强。两种污染物对河口区的沉积物反硝化潜势抑制效应强于湾内,可能与河口区具有较高Eh和沉积物颗粒度及较低的pH、盐度和有机质含量有关。三种毒性效应评价方法的结果表明,菲和纳米银的复合污染对2个站位反硝化潜势的毒性效应均为协同作用,且对大沽河河口区的协同作用更强。此外,CI法对复合效应的预测结果比CA和IA法更为接近实际观测值,且CI不需要考虑污染物作用模式的限制,因此认为CI法更适用于评价混合污染对沉积物反硝化作用复合影响的效果。本研究结果表明,菲和纳米银会增强彼此对反硝化菌及反硝化功能的毒性效应,由此推断,PAHs和纳米材料在环境中同时存在时比其单独存在对沉积环境的危害更大。 相似文献
20.
以体长(1.932±0.204)cm、体质量(1.386±0.055)g的棘胸蛙蝌蚪为实验动物,在水温(24±0.2)℃、DO(7.30±0.01)mg/L、pH 7.30±0.01条件下,采用静水停食法开展了氨氮对蝌蚪的急性攻毒实验,并以此为基础,测定了不同氨氮质量浓度胁迫下棘胸蛙蝌蚪的排氨率、耗氧率、氧氮比及窒息点。结果表明:(1)蝌蚪对氨氮急性攻毒具明显的运动避毒行为,濒死个体的背部皮肤和肝脏均具明显的色变症状;(2)氨氮对蝌蚪的急性致死率具明显的剂量—时间效应,24h、48h、72h、96h LC50依次为177.5、151.7、148.6和146.8mg/L,毒性时段蓄积程度系数呈持续下降趋势,24—48h、48—72h、72—96h的时段MAC值分别为84.04%、10.1%和5.86%;(3)蝌蚪夜均、昼均、日均及时段排氨率随氨氮质量浓度增加均呈阶梯式下降趋势,其中时段排氨率与对照组均无显著差异的为9.80mg/L实验组,夜均、昼均、日均及时段排氨率与对照组均无显著差异的仅为2.45mg/L实验组(P0.05);(4)氨氮对蝌蚪呼吸耗氧具低毒兴奋效应,其夜均、昼均和日均耗氧率随氨氮质量浓度增加均呈先升后降趋势,峰值氨氮质量浓度范围均为4.90—7.35mg/L(P0.05),与对照组均无显著差异的仅为14.70mg/L实验组(P0.05),窒息点含氧量随氨氮质量浓度增加呈先降后升趋势,谷底出现于4.90mg/L实验组(P0.05),与对照组无显著差异的仅为9.80mg/L实验组(P0.05);(5)实验期间,蝌蚪氧氮比(O:N)波动于18.87—25.34之间,昼均和日均氧氮比(O:N)随氨氮质量浓度增加均依次呈"上升—稳定—下降—再稳定"之趋势,两者的峰值氨氮质量浓度范围分别为4.90—14.70mg/L和4.90—9.80mg/L,夜均氧氮比(O:N)呈先升后降趋势,峰值出现于7.35mg/L实验组(P0.05)。 相似文献