Nonpoint Source Pollution Assessment of Wujiang RiverWatershed in Guizhou Province,SW China

The amount of pollution from nonpoint sources flowing in the streams of the Wujiang River watershed in Guizhou Province, SW China, is estimated by a geographic information system (GIS)-based method using rainfall, surface runoff and land use data. A grid of cells of 100 m in size is laid over the landscape. For each cell, mean annual surface runoff is estimated from rainfall and percent land use, and expected pollutant concentration is estimated from land use. The product of surface runoff and concentration gives expected pollutant loading from that cell. These loadings are accumulated going downstream to give the expected annual pollutant loadings in streams and rivers. By dividing these accumulated loadings by the similarly accumulated mean annual surface runoff, the expected pollutant concentration from nonpoint sources is determined for each location in a stream or river. Observed pollutant concentrations in the watershed are averaged at each sample point and compared to the expected concentrations at the same locations determined from the grid cell model. In general, annual nonpoint source nutrient loadings in the Wujiang River watershed are seen to be predominantly from the agricultural and meadow areas. The total annual loadings through the outlet of the watershed are 40,309 and 2,607 tons for total nitrogen (TN) and total phosphorus (TP), respectively.     

MS-Urban大气扩散模型和二重源解析技术联合模型在鞍山市尘源解析中的应用

详细介绍了MS-Urban大气扩散模型和二重源解析技术联合模型应用的基本步骤,并以鞍钢冶炼尘、焦化尘为例,进行了2种模型解析结果分析,为共线性严重的单一源类进行细类解析提供了可以借鉴的方法.     

Spatial Relationships Between Water Quality and Pesticide Application Rates in Agricultural Watersheds

Pesticide applications to agricultural lands in California, USA, are reported to a central data base, while data on water and sediment quality are collected by a number of monitoring programs. Data from both sources are geo-referenced, allowing spatial analysis of relationships between pesticide application rates and the chemical and biological condition of water bodies. This study collected data from 12 watersheds, selected to represent a range of pesticide usage. Water quality parameters were measured during six surveys of stream sites receiving runoff from the selected watershed areas. This study had three objectives: to evaluate the usefulness of pesticide application data in selecting regional monitoring sites, to provide information for generating and testing hypotheses about pesticide fate and effects, and to determine whether in-stream nitrate concentration was a useful surrogate indicator for regional monitoring of toxic substances. Significant correlations were observed between pesticide application rates and in-stream pesticide concentrations (p < 0.05) and toxicity (p < 0.10). In-stream nitrate concentrations were not significantly correlated with either the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.30). Neither total watershed area nor the area in which pesticide usage was reported correlated significantly with the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.14). In-stream pesticide concentrations and effects were more closely related to the intensity of pesticide use than to the area under cultivation.     

Beryllium Concentrations in Ambient Air and Its Source Identification

Beryllium concentrations in atmospheric particulate and soil samples in and around a Beryllium Processing Facility (BPF) have been measured. The mean air concentration level of beryllium in and around the fence line of the BPF is 0.48 ± 0.43 ng m^-3 (n = 397) and is mostly influenced by diurnaland seasonal changes. The observed air concentration levelswere well below the prescribed ambient air quality (AAQ)standard of 10 ng m^-3. The soil concentration levels ofberyllium in the study area were found to be in the range of 1.42–2.75 g g^-1. The mass median aerodynamic diameter (MMAD)of beryllium aerosols in ambient air was found to be 6.9 m.Source identification using the Enrichment Factor (EF) approachindicates soil as the predominant contributory source for air concentrations at the site.     

Comparative Metal Distribution in Hair of Pakistani and Libyan Population and Source Identification by Multivariate Analysis

Using nitric acid-perchloric acid wet digestion based FAAS method ten selected metals (Cd, Co, Cr, Fe, K, Mn, Na, Ni, Pb and Zn) were determined in the scalp hair of male Pakistani and Libyan donors (n = 62), between 3–54 years age and residing in typical urban areas. The study was taken up to identify sources of metal distribution in two diverse population segments exposed to different environments. Sodium emerged with the highest mean hair concentration of 511.0 μg/g and 496.9 μg/g for Libyan and Pakistani donors respectively, followed by K, at 266.2 μg/g and 242.4 μg/g for the two donor categories. Cadmium showed the lowest mean hair concentration for both Pakistani (0.380 μg/g) and Libyan (0.530 μg/g) donors. Levels of Na, K, Pb, Cr and Cd were higher in hair of Libyan donors compared with Pakistani counterparts which showed higher comparative levels of Zn, Fe, Co, Ni and Mn. Strong metal-to-metal correlations were found between Na–K (r = 0.638) and Cd–Co (r = 0.574) for Pakistani donors, while for Libyan donors, Na–K (r = 0.680) and Fe–Mn (r = 0.624) correlations emerged as strongly significant. Only K was found to have a strong positive correlation (r = 0.611) with age for Pakistani donors while this correlation was significantly negative (r = −0.500) for Libyan donors, probably arising from individual food habits. Other metals showed no viable relationship with age. Principal Component Analysis (PCA) and Cluster Analysis (CA) of the data evidenced food, industrial emissions and automobile emissions as possible sources of metal distribution. The results of the present study are compared with those reported for subjects from other regions of the world.     

伊犁州县市饮用水源地水质现状及水安全保障措施

城市饮用水源地水质直接关系到人民群众的健康和经济发展与社会稳定的大局.根据监测资料,采用国家有关标准,本文对伊犁州县市饮用水源地(河流、水库、地下水)的水质状况进行了分析评价,并提出了相应的保护措施和建议.     

新疆县城(区)集中式饮用水源地环境状况调查、评价与对策建议

在新疆县城(区)集中式饮用水源地环境状况专项调查的基础上,对新疆县城(区)集中式饮用水源地水质状况、周边环境状况、环境管理状况进行了较为全面的阐述和评价,分析了水源地水质超标的因为及存在的环境问题,并提出了相应的保护对策和建议.     

Atrazine Transport Within a Coastal Zone in Southeastern Puerto Rico: a Sensitivity Analysis of an Agricultural Field Model and Riparian Zone Management Model

Agrichemical runoff from farmland may adversely impact coastal water quality. Two models, the Agricultural Policy/Environmental eXtender (APEX) and the Riparian Ecosystem Management Model (REMM), were used to evaluate the movement of the herbicide atrazine to the Jobos Bay National Estuarine Research Reserve from adjacent fields. The reserve is located on Puerto Rico’s southeast coast. Edge-of-field atrazine outputs simulated with the APEX were routed through a grass-forest buffer using the REMM. Atrazine DT₅₀ (half-life) values measured in both field and buffer soils indicated that accelerated degradation conditions had developed in the field soil due to repeated atrazine application. APEX simulations examined both the measured field and buffer soil atrazine DT₅₀ and the model’s default value. The use of the measured field soil atrazine degradation rate in the APEX resulted in 33 % lower atrazine transport from the field. REMM simulations indicated that the buffer system had the potential to reduce dissolved atrazine transport in surface runoff by 77 % during non-tropical storm events by increasing infiltration, slowing transport, and increasing time for pesticide degradation. During a large runoff event due to a tropical storm that occurred close to the time of an atrazine application, the REMM simulated only a 37 % reduction in atrazine transport. The results indicate that large storm events soon after herbicide application likely dominate herbicide transport to coastal waters in the region. These results agree with water quality measurements in the reserve. This study demonstrated the sensitivity of these models to variations in DT₅₀ values in evaluating atrazine fate and transport in the region and emphasizes that the use of measured DT₅₀ values can improve model accuracy.     

IFTCIP: An Integrated Optimization Model for Environmental Management under Uncertainty

In this study, an interval-fuzzy two-stage chance-constrained integer programming (IFTCIP) method is developed for supporting environmental management under uncertainty. The IFTCIP improves upon the existing interval, fuzzy, and two-stage programming approaches by allowing uncertainties expressed as probability distributions, fuzzy sets, and discrete intervals to be directly incorporated within a general mixed integer linear programming framework. It has advantages in uncertainty reflection, policy investigation, risk assessment, and capacity-expansion analysis in comparison to the other optimization methods. Moreover, it can help examine the risk of violating system constraints and the associated consequences. The developed method is applied to the planning for facility expansion and waste-flow allocation within a municipal solid waste management system. Violations of capacity constraints are allowed under a range of significance levels, which reflects tradeoffs between the system cost and the constraint-violation risk. The results indicate that reasonable solutions for both binary and continuous variables have been generated under different risk levels. They are useful for generating desired decision alternatives with minimized system cost and constraint-violation risk under various environmental, economic, and system-reliability conditions. Generally, willingness to take a higher risk of constraint violation will guarantee a lower system cost; a strong desire to acquire a lower risk will run into a higher system cost.     

Assessment of a General Finite Line Source Model and CALINE4 for Vehicular Pollution Prediction in Ireland

A comparative evaluation of two Gaussian-based line source models namely, California line source dispersion model version 4 and the general finite line source model, is presented. The concentrations predicted by these models are compared with background-corrected ambient concentrations measured at three different distances from a motorway and performance of both models assessed in the context of integrated transport–environment modelling for regulatory purposes.     

Agricultural Lakes in Finland: Current Water Quality and Trends

Agriculture is the largest source of nutrients into surface waters in Finland, and yet relatively little is known about the actual impact of the agricultural load on the state of lakes. We analysed the water quality data of 20 Finnish agricultural lakes and found that they had higher levels of nutrients, chlorophyll a and turbidity than did the other types of lakes (e.g. those receiving point-source load) in the national monitoring network (the Finnish Eurowaternet). Currently, six of the agricultural lakes can be classified as eutrophic and 14 as hypertrophic. Trend analysis (based on Kendall's tau-b) indicated that during 1976–2002 the water quality of the lakes either remained constant or showed signs of increasing eutrophication and elevated turbidity. Decreasing nutrient concentrations were found only in one intensively restored lake. In none of the lakes had the chlorophyll a concentration decreased. The results of the trend analysis are compatible with the recent finding that, despite vigorous efforts, the nutrient load from agriculture has not declined in Finland. Recovery of the most eutrophied agricultural lakes would call for a drastic reduction in the external nutrient load, possibly supplemented with in-lake restoration.     

Simple Model of Dissolved Oxygen Consumption in a Bay within High Organic Loading: An Applied Remediation Tool

San Vicente Bay is a coastal shallow embayment in Central Chile with multiple uses, one of which is receiving wastewater from industrial fisheries, steel mill effluents, and domestic sewage. A simulation model was developed and applied to dissolved oxygen consumption by organic residues released into this embayment. Three compartments were established as function of: depth, circulation and outfall location. The model compartments had different volumes, and their oxygen saturation value was used as baseline. The parameters: (a) BOD₅ of the industrial and urban effluents, (b) oxygen demand by organic sediments, (c) respiration, (d) photosynthesis and (e) re-aeration were included in the model. Iteration results of the model showed severe alterations in Compartment 1, with a decrease of 65% in the oxygen below saturation. Compartment 2 showed a small decline (10%) and compartment 3 did not show apparent changes in oxygen values. Measures recommended for remediation were to decrease the BOD₅ loading by 30% in the affected sector. Iteration of the model for 200 h following recommendations derived from the preceding results produced an increase in saturation of 60% (5 ml O₂ L⁻¹), which suggested an improvement of the environmental conditions.     

An Alternative Process Model of Preferential Contaminant Travel Times in the Unsaturated Zone: Application to Rainier Mesa and Shoshone Mountain, Nevada

Simulating contaminant transport in unsaturated zones with sparse hydraulic property information is a difficult, yet common, problem. When contaminant transport may occur via preferential flow, simple modeling approaches can provide predictions of interest, such as the first arrival of contaminant, with minimal site characterization. The conceptual model for unsaturated zone flow at Rainier Mesa and Shoshone Mountain, Nevada National Security Site, establishes the possibility of preferential flow through lithologies between potential radionuclide sources and the saturated zone. After identifying preferential flow as a possible contaminant transport process, we apply a simple model to estimate first arrival times for conservatively transported radionuclides to reach the saturated zone. Simulated preferential flow travel times at Rainier Mesa are tens to hundreds of years for non-ponded water sources and 1 to 2 months for continuously ponded water sources; first arrival times are approximately twice as long at Shoshone Mountain. These first arrival time results should then be viewed as a worst-case scenario but not necessarily as a timescale for a groundwater-contamination hazard, because concentrations may be very low. The alternative approach demonstrated here for estimating travel times can be useful in situations where predictions are needed by managers for the fastest arrival of contaminants, yet budgetary or time constraints preclude more rigorous analysis, and when additional model estimates are needed for comparison (i.e., model abstraction).     

Development and Applications of Microbial Ecogenomic Indicators for Monitoring Water Quality: Report of a Workshop Assessing the State of the Science, Research Needs and Future Directions

This article brings forth recommendations from a workshop sponsored by the U.S. Environmental Protection Agency's Science to Achieve Results (STAR) and Environmental Monitoring and Assessment (EMAP) Programs and by the Council of State Governments, held during May 2002 in Kansas City, Kansas. The workshop assembled microbial ecologists and environmental scientists to determine what research and science is needed to bring existing molecular biological approaches and newer technologies arising from microbial genomic research into environmental monitoring and water quality assessments. Development of genomics and proteomics technologies for environmental science is a very new area having potential to improve environmental water quality assessments. The workshop participants noted that microbial ecologists are already using molecular biological methods well suited for monitoring and water quality assessments and anticipate that genomics-enabled technologies could be made available for monitoring within a decade. Recommendations arising from the workshop include needs for (i) identification of informative microbial gene sequences, (ii) improved understandings of linkages between indicator taxa, gene expression and environmental condition, (iii) technological advancements towards field application, and (iv) development of the appropriate databases. Contribution no. 1217 from the NHEERL Gulf Ecology Division. All authors contributed equally to this publication.     

Integrity of Tailings Infrastructure and Information Management: A GIS-Based Conceptual Model

Managing the integrity of tailings infrastructure is an important aspect of handling mine tailings. Unfortunately, little research is directed towards its efficient modeling. This paper presents salient aspects of tailings management. It proposes an integrated geographic information systems (GIS)-based conceptual model for efficient handling of these aspects. The paper also discusses the various integrated modules and comments on the systematic implementation of the model to achieve desired results. The modules include: structural integrity management (SIM), release impact assessment (RIA), and hazardous risk assessment and control (HRAC).     

Aerosol Scavenging: Model Application and Sensitivity Analysis in the Indian Context

Sulfate aerosols have been found to bethe major contributors to precipitation acidity. Thus,in view of the long-term ecological repercussions theyhave on aquatic ecosystems and their acidity-potential,the present analysis focuses on a case study applicationof the layer-averaged aerosol-scavenging model (Okita et al., 1996) for predicting values of the wet scavengingcoefficient and sulfate concentrations in precipitationsamples on the basis of the information available forsome selected Indian cities. Through sensitivityanalysis (Pandey et al., 1997) the scavengingcoefficient has been found to be very strongly dependenton precipitation intensity. Comparison of modelpredictions has been done with the measured values forDelhi, Mumbai, Calcutta and Chennai in India.     

Patchy Distribution Fields: An Interleaved Survey Design and Reconstruction Adequacy

A mathematical model was used to compare the effects of a regular (one-pass) or interleaved (two-pass) acoustic survey on the adequacy of reconstructing patchy distribution fields. The model simulates fish or plankton patches of different shapes and spatial orientations, and a set of parallel or zigzag transects forming a regular or interleaved acoustic survey. The efficiency of a survey is determined by the adequacy of a reconstructed field to that originally generated, which is evaluated by calculating their correlations. Regarding the immovable fields, the efficiency of a regular or interleaved acoustic survey was tested with the following two alternative assumptions: (1) the entire survey was completed; (2) the survey was interrupted for some reason at the moment when one transect remained non-accomplished. In the former case, the efficiencies of both acoustic surveys were nearly the same; in the latter case, the efficiency of an interleaved survey was superior to that of a regular one. With respect to movable fields, the efficiency of the completed interleaved surveys was even higher than that of the regular ones. Thus, the results obtained allow us to conclude that an interleaved survey is expedient in cases where there is no preference regarding the position of a vessel for further work.     

Holling's Figure-Eight Model: A Technical Reevaluation in Relation to Climate Change and Biodiversity

Holling proposed a four-phase conceptual model of ecosystem dynamics that includes exploitation, conservation, and destructive and renewal components to explain the failure of many natural resource management schemes. The model is drawn as a sideways figure-eight i.e. . There are two dimensions in this model, connectivity (abscissa) and the amount of capital stored in the system (ordinate). This conceptual model has been suggested as a guide to thinking about the impact of climate change on biodiversity, but the two dimensions are insufficient and the alignment of the figure-eight model is problematic when compared with actual data. Kay has adjusted the dimensions of the figure-eight model and renamed the abscissa as exergy stored and the ordinate as exergy consumed. We realign the original figure-eight model, labeling the abscissa as carbon stored and the ordinate as nutrients, such that the relative values of both axes are in qualitative agreement with data from four different studies. This new alignment is then shown to fit relatively well with Holling's original labels. This revision of the figure-eight model brings Holling's model into agreement with observations and provides insight into the linkages between biodiversity and climate change.