Factors affecting 210Po and 210Pb activity concentrations in mussels and implications for environmental bio-monitoring programmes

The activity of ²¹⁰Po and ²¹⁰Pb was determined in mussels of the same size (3.5-4.0 cm shell length) sampled monthly over a 17-month period at the Atlantic coast of Portugal. Average radionuclide concentration values in mussels were 759 ± 277 Bq kg⁻¹ for ²¹⁰Po (range 460-1470 Bq kg⁻¹ dry weight), and 45 ± 19 Bq kg⁻¹ for ²¹⁰Pb (range 23-96 Bq kg⁻¹ dry weight). Environmental parameters and mussel biometric parameters were monitored during the same period. Although there was no seasonal variation of radionuclide concentrations in sea water during the study period, the concentration of radionuclide activity in mussels varied seasonally displaying peaks of high concentrations in winter and low concentrations in summer. Analysis of radionuclide data in relation to the physiological Condition Index of mussels revealed that ²¹⁰Po and ²¹⁰Pb activities in the mussel (average activity per individual) remained nearly constant during the investigation period, while mussel body weight fluctuated due to fat storage/expenditure in the soft tissues. Similar variation of radionuclide concentrations was observed in mussels transplanted from the sea coast into the Tejo Estuary. However, under estuarine environmental conditions and with higher food availability throughout the year, transplanted mussel Condition Index was higher than in coastal mussels and average radionuclide concentrations were 210 ± 75 Bq kg⁻¹ (dry weight) for ²¹⁰Po and 10 ± 4 Bq kg⁻¹ (dry weight) for ²¹⁰Pb, therefore lower than in coastal mussels with similar shell length. It is concluded that the apparent seasonal fluctuation and inter-site difference of radionuclide concentrations were mostly caused by mussel body weight fluctuation and not by radionuclide body burden fluctuation. This interpretation can be extended to the apparent seasonal fluctuation in concentrations of lipophilic and lipophobic contaminants in mussels, and provides an explanation for occasional high concentrations of ²¹⁰Po and man-made contaminants measured in mussels far from pollution sources.     

Legal aspects of pesticides and toxic substances testing requirements

Abstract

The United States Environmental Protection Agency administers several laws and progrms through which it reviews the hazard potential of pesticides and other toxic substances which may present a risk to human health or the environment. The Agency's ability to assess hazard as required by law depends in part on test data developed through testing standards in Agency regulations. In reviewing the Agency's actions in this regard, the courts emphasize the importance of reasoned regulatory decisions. The legal requirements to assess risk and provide reasoned decisions in this regard establish the legal importance of testing guidelines and test data, and indicate that sound test methodology is as important legally as it is scientifically.     

如何做好新形势下的淮北市环境监测工作

环境监测工作是环境保护工作的基础工作，在新的形势下，如何做好环境监测工作，是环保工作必须面对的一个重要课题。本文通过总结研究淮北市在环境监测工作中一些富有创造性的做法和所取得的成效，经验，提出了一些有独立见解的工作思路和建议，对广大环保工作者特别是环境监测工作者，有一定的借鉴意义。     

Assessing ecological risk on a regional scale

Society needs a quantitative and systematic way to estimate and compare the impacts of environmental problems that affect large geographic areas. This paper presents an approach for regional risk assessment that combines regional assessment methods and landscape ecology theory with an existing framework for ecological risk assessment. Risk assessment evaluates the effects of an environmental change on a valued natural resource and interprets the significance of those effects in light of the uncertainties identified in each component of the assessment process. Unique and important issues for regional risk assessment are emphasized; these include the definition of the disturbance scenario, the assessment boundary definition, and the spatial heterogeneity of the landscape. Although the research described in this article has been funded wholly or in part by the United States Environmental Protection Agency (EPA) through Interagency Agreement Number DW89932112-01-2 to the U.S. Department of Energy, it has not been subjected to EPA review and therefore does not necessarily reflect the views of EPA and no official endorsement should be inferred.     

Productivity equation for reclaiming surface mines

This article addresses the development of an agricultural productivity equation for predicting new soil (neo-sol) plant growth potential in Clay County, Minnesota, USA. Soil factors examined in the study include percent organic matter, percent slope, percent rock fragments, hydraulic conductivity, electrical conductivity, pH, topographic position, available water-holding capacity, bulk density, and percent clay. Squared terms and two-factor interaction terms were also examined as possible regressors. A best equation was selected that had a multiple coefficient of determination of 0.7399 and has five significant regressors and intercept withP.0001. The regressors are hydraulic conductivity, percent slope squared, bulk density times percent rock fragments, electrical conductivity times percent rock fragments, and electrical conductivity times percent organic matter. The regressors predict soil suitability for a general crop model. The crops included in the model are wheat, oats, barley, soybeans, sugar beets, sunflowers, and grasses/legumes.     

Review and appraisal of concept of sustainable food production systems

Environmental degradation, competition for resources, increasing food demands, and the integration of agriculture into the international economy threaten the sustainability of many food production systems. Despite these concerns, the concept of sustainable food production systems remains unclear, and recent attempts to appraise sustainability have been hampered by conceptual inconsistencies and the absence of workable definitions. Six perspectives are shown to underpin the concept. Environmental accounting identifies biophysical limits for agriculture. Sustained yield refers to output levels that can be maintained continuously. Carrying capacity defines maximum population levels that can be supported in perpetuity. Production unit viability refers to the capacity of primary producers to remain in agriculture. Product supply and security focuses on the adequacy of food supplies. Equity is concerned with the spatial and temporal distribution of products dervied from resource use. Many studies into sustainable agriculture cover more than one of these perspectives, indicating the concept is complex and embraces issues relating to the biophysical, social, and economic environments. Clarification of the concept would facilitate the development of frameworks and analytical systems for appraising the sustainability of food production systems. LRRC Contribution No. 90–46.     

水力旋流除砂器处理油田采出砂技术

我国部分油田原油生产出砂严重，经常造成集输处理系统的严重磨损和堵塞，储油罐严重积砂，不能实现密闭。储油罐清砂完全靠人工完成，劳动强度大，而且造成环境污染。在海上平台，若采出砂含油量不达标排入海洋，则会给海洋带来严重的污染，因此，采出砂处理是急待解决的问题。文章根据国内外采出砂处理技术调研，介绍了水力旋流器除砂技术原理及工艺和在国外应用实例以及该技术在我国油田的开发应用情况。     

浅谈行业环境监测站的任务与作用

我国环境问题日趋严重，环境污染和生态破坏已成为社会发展的制约因素。然而，有些企业忽视环境保护工作，取消或合并环境监测站，削弱环境监测力量。针对这种情况，从行业环境监测站的任务、作用和不可取代性方面阐述了强化行业环境监测站建设的必要性。     

Evaluation of tidal marsh restoration: Comparison of selected macroinvertebrate populations on a restored impounded valley marsh and an unimpounded valley marsh within the same salt marsh system in Connecticut,USA

Macroinvertebrates were examined on an impounded valley marsh in Stonington, Connecticut, that has changed from aTypha-dominated system to one with typical salt-marsh vegetation during 13 years following the reintroduction of tidal exchange. Animal populations on this restored impounded marsh were evaluated by comparing them with populations on a nearby unimpounded valley marsh of roughly the same size. Populations of the high marsh snail,Melampus bidentatus Say, were quantitatively sampled along transects that extended from the water-marsh edge to the upland; those of the ribbed mussel,Geukensia demissa Dillwyn, were sampled in low marsh areas on transects along the banks of creeks and mosquito ditches. The occurrence of other marsh invertebrates also was documented, but their abundance was not measured. The mean density ofMelampus was 332±39.6 SE/m² on the restored impounded marsh and 712±56.0 SE/m² on the unimpounded marsh. However, since snails were larger on the restored impounded marsh, the difference in snail biomass was less pronounced than the difference in snail density. MeanMelampus biomass was 4.96±0.52 SE g dry wt/m² on the restored impounded marsh and 6.96±0.52 SE g dry wt/m² on the unimpounded marsh. On the two marshes, snail density and biomass varied in relation to plant cover and other factors. The density and biomass ofGeukensia at the edge of the marsh were comparable on the restored impounded and unimpounded marshes. Mean mussel densities ranged from 80 to 240/m² and mean mussel biomass varied from 24.8–64.8 g dry wt/m² in different low marsh areas. In contrast, below the impoundment dike, meanGeukensia density was 1100±96.4 SE/m² and meanGeukensia biomass was 303.6±33.28 SE g dry wt/m². A consideration of all available evidence leads to the conclusion that the impounded marsh is in an advanced phase of restoration.     

BAYESIAN MODELS OF FORECASTED TIME SERIES1

Bayesian Processor of Forecasts (BPF) combines a prior distribution, which describes the natural uncertainty about the realization of a hydrologic process, with a likelihood function, which describes the uncertainty in categorical forecasts of that process, and outputs a posterior distribution of the process, conditional upon the forecasts. The posterior distribution provides a means of incorporating uncertain forecasts into optimal decision models. We present fundamentals of building BPF for time series. They include a general formulation, stochastic independence assumptions and their interpretation, computationally tractable models for forecasts of an independent process and a first-order Markov process, and parametric representations for normal-linear processes. An example is shown of an application to the annual time series of seasonal snowmelt runoff volume forecasts.