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Importance of Internal Biotic Concentrations in Risk Evaluations with Aquatic Systems 总被引：4，自引：0，他引：4
Ecological risk evaluations are commonly performed using aqueous concentrations and aqueous toxicity measurements as a starting point. However risk evaluations could be carried out using internal biotic concentrations and the internal lethal or sublethal concentrations. This has several advantages. Firstly, the internal lethal and sublethal concentrations are relatively consistent in groups of chemicals having a similar mode of action. Thus in field situations the internal concentration, in fish and possibly other biota, can be used to evaluate possible biotic effects. Also other histopathological, biochemical, biomolecular and physiological effects can be assessed and used with this information to give an overall assessment. There are, however, several limitations with this approach including sensitivity, health, age and nutritional status of the biota as well as a lack of data on dose/response relationships with internal concentrations. 相似文献
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Gary Bickford John Toll Judi Hansen Elaine Baker Robert Keessen 《Marine pollution bulletin》1999,39(1-12):335-345
Sydney Water has completed a risk assessment to assess the risks to human health and aquatic organisms in creeks, rivers, estuaries and ocean waters affected by wet weather sewage overflows, stormwater and sewage treatment plant discharges. The risk assessment methodology consists of a comparison of measured and predicted concentrations of chemicals with toxicity reference values. Estimates of receiving water chemical concentrations were derived using data from a 10-year period so that the variable rainfall pattern was represented. Computer models were used to simulate and predict wet weather discharges during this ten year period. Risks were validated by bioassays and bioassessments. Risks to aquatic life from wet weather discharges were attributed to 14 chemicals at one or more of the sites and stormwater was the predominate source of the chemicals. There were no risks to people engaged in water based activities. Noncarcinogenic risks from fish ingestion are predicted at three sites. Predicted cancer risks for most individual chemicals were relatively small. Carcinogenic risks were typically associated with organochlorine compounds, polycyclic aromatic hydrocarbons, dichlorobenzene, and arsenic. The predicted cancer risks also appear to be largely the result of stormwater rather than sewage overflow inputs and largely due to historical contamination by organochlorine pesticides. It is expected the concentrations of these chemicals will decrease over time. 相似文献
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Erik R. Christensen 《Aquatic Sciences - Research Across Boundaries》1984,46(1):100-108
Information about the toxicity of heavy metals and organics to aquatic organisms can be obtained from bioassays. These are
classified according to the type of response obtained: quantal or continuous, and according to whether individual organisms
originate from a single clone or have a tolerance distribution. Basic features of the probit, logit, and Weibull dose-response
models for one toxic substance are considered. It is shown that a version of the logit model is complementary to the Monod
equation for the growth rate of microorganisms under substrate limitation. Multiple toxicity models can be of the non-interactive
or competitive type. The standard water quality criterion for concentration addition is based on the assumption that the toxicants
act on similar biological systems, and that the action tolerances for individuals are fully correlated. Pertinent examples
of the application of the models for one or several toxic substances are discussed. 相似文献
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Water Resources - Due to the saturation of natural waters with nitrogen compounds resulting from natural processes and anthropogenic activities, the problem arises of studying the ways of their... 相似文献
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The specific methods used for recovery of the aquatic ecological system in the shallow lake are proposed. This research has been done from three aspects:1) the design of the species used for the ecological recovery; 2) the design of optimization and allocation of the aquatic communities; and 3) the design of regional arrangement of the aquatic communities. On the basis of research, the pioneer plant and the species used to establish the communities are proposed. The aquatic plant allocation focuses on the emergent aquatic plant and submergent aquatic plant. Meanwhile, the regional arrangement has been done in the aquatic plant recovery area in the Caohai Lake and the east west bank of the outer lake. 相似文献
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The average production capacity of aquatic ecosystems is shown to be proportional to the coefficient of variations of substance concentrations in atmospheric precipitation and the sum of effective temperatures. The values of ichthyomass and primary production of phytoplankton per 1°C of the sum of effective temperatures multiplied by the coefficient of variations of substance concentration in atmospheric precipitation are proposed as ecological thermometers to be used in water bodies in different geographic zones of Europe and North America. 相似文献
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J. P. Dubois G. Blake P. Gerbeaux G. Brun 《Aquatic Sciences - Research Across Boundaries》1988,50(1):96-110
Aquatic vegetation (macrophytes) of lake Annecy has been studied in summer 1981 by underwater observation. Cartography of
the plants has been achieved and compared with earlier studies. Emergent plants have regressed. Submerged vegetation is dominated
by Charophyceae. 相似文献
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广东肇庆星湖仙女湖区水生植被的演变 总被引：5，自引：1，他引：4
通过在人工构建湿地“小宇宙”系统开展受控模拟实验,研究湿地湿生植物对水环境中磷的吸收和去除规律．本 次研究,选择对比四种不同类型挺水植物和浮叶植物,在不同体系环境条件下(如溶解氧、pH)对水环境中磷吸收和去 除．模拟实验通过对比四种不同类型的水生植物系统,结果显示,不同类型湿生植物对环境中磷的吸收强度和作用方式 有较大的差别．总体来看,实验体系水体中正磷酸盐浓度下降趋势大致呈现的“三阶段”变化模式,即：坡降期、陡降期、平 台期,不同期内磷去除率分别为：35．53%、29．98%和7．20%． 相似文献
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Sb, As, Cu, and Zn toxicity and contamination have become a growing concern in recent years. Phytoremediation, a plant based and cost effective technology, may be an effective approach in the cleanup of water contaminated by these metals. In this study, the aquatic macrophyte Eleocharis acicularis was used in laboratory and field experiments to assess its capability to accumulate Sb, As, Cu, and Zn, and thereby investigate its potential application in phytoremediation. The results showed that E. acicularis adapted well to water contaminated by these metals. The removal rates of Sb, As, Cu, and Zn in the laboratory experiment were 3.04, 2.75, 0.417, and 1.49 μg/L/day, respectively. The highest concentrations of these metals accumulated in E. acicularis after 10 days of the laboratory experiment were 6.29, 6.44, 20.5, and 73.5 mg/kg dry weight, respectively. Only 8% of As, 12% of Sb, 87% of Cu and 93% of Zn removed from the water were used by E. acicularis. The highest concentrations of Sb, As, Cu, and Zn accumulated in E. acicularis after 10 wk of the field experiment were 76.0, 22.4, 33.9, and 266 mg/kg dry weight, respectively. The results indicate that E. acicularis has the ability to accumulate Sb, As, Cu, and Zn from contaminated water. 相似文献