Developing a Standardized Water Quality Index for Evaluating Surface Water Quality1

Abstract: There is a significant need for a science‐based approach to interpret water‐monitoring data and to facilitate the rapid transfer of information to water resource managers and the general public. The water quality Index (WQI) is defined as a single numeric score that describes the surface water quality condition at a particular time and location. The objective of this paper is to describe the WQI concept and the approach for developing an ecoregion‐specific standardized WQI that meets the needs described above. The premise of the proposed WQI is based on categorizing scientifically documented aquatic life responses to changes in instream water chemistry. The method uses an aggregated procedure that matches the entire range of standardized probable biological responses to standardized narrative water quality evaluation categories and standardized rank score categories. The calculation of WQI and decision‐making process are performed within an Excel spreadsheet software program. The article includes examples of the proposed WQI applications that could enhance effective water resource management and facilitate timely communication of water quality conditions to water resource managers and the general public.     

RIVER AMENITY EVALUATION: A REVIEW AND COMMENTARY1

ABSTRACT: During the past 15 years a number of methods have been developed that purport to evaluate the amenity values of rivers. Most methods are designed to identify the physical, biological, cultural, and esthetic features of a river or river corridor that are conducive to recreation, preservation, and other amenity values. This paper reviews and comments on 13 methods that evaluate amenity values. The methods are reviewed and discussed under three general headings: River Recreation Potential Evaluation, River Esthetic Evaluation, and River Preservation Evaluation. A final section of the paper identifies areas where improvements and further research are needed.     

Managing bog environments for recreational experiences

Bogs are of interest to outdoor recreationists, but little information exists concerning how recreation resource managers might manage these areas to enhance visitor benefits. This study evaluates bog visitor characteristics and experiences, visual preferences, and reasons for visiting. Implications for recreational resource management of bogs include the location and design of boardwalk trails and management of understory vegetation to meet the visual preferences and motives of bog visitors.     

Public reaction to the risks of energy technology

Implicit in every government decision on energy technology is a trade-off of a certain amount of risk in return for societal benefits. As a result of growing public concern over such risks, environmental analysts are increasingly being requested not only to describe potential adverse consequences but also to quantify their probability. However, this task is frustrated not only by inadequate experience with, and incomplete knowledge of, the causality of environmental impacts, but also by a disparity between individual and societal views of risk. While the societal view is based on objective risk functions andnet societal benefit, individuals tend to rely on subjective judgment, and consider the distribution as well as the amount of benefit. Thus, environmental risk assessments, produced by analysts on behalf of society as a whole, are likely to be quite speculative, and are unlikely to be reliable indicators of the acceptability of risk to the public.     

Application of the Braun-Blanquet cover-abundance scale for vegetation analysis in land development studies

To document environmental impact predictions for land development, as required by United States government regulatory agencies, vegetation studies are conducted using a variety of methods. Density measurement (stem counts) is one method that is frequently used. However, density measurement of shrub and herbaceous vegetation is time-consuming and costly. As an alternative, the Braun-Blanquet cover-abundance scale was used to analyze vegetation in several ecological studies. Results from one of these studies show that the Braun-Blanquet method requires only one third to one fifth the field time required for the density method. Furthermore, cover-abundance ratings are better suited than density values to elucidate graphically species-environment relationships. For extensive surveys this method provides sufficiently accurate baseline data to allow environmental impact assessment as required by regulatory agencies.     

Urban waterfowl population: Ecological evaluation of management and planning

An urban population of ducks in Puyallup, Washington, USA was studied for 14 consecutive months beginning in November 1978. Observations were made weekly from four study sites where ducks would congregate at early morning hours. Factors contributing to the presence of waterfowl in Puyallyup included abundant food supplies and a creek corridor that connected fragmented habitats in the urban area to the larger rural populations of waterfowl. Mallards (Anas platyrhynchos) were the most abundant of the 13 species observed and were the only ducks remaining during the nesting season. Habitat size and complexity were important factors influencing the species diversity of a particular site. Nesting success of mallards was poor due to limited distribution of nesting habitat, intraspecific aggression, and human disturbance. Both site-specific and more broad-based strategies are suggested for managing and planning for duck populations in urban areas.     

人工神经网络在水环境质量评价中的应用

为了将人工神经网络应用于水环境质量评价，应用了人工神经网络Ｂ—Ｐ算法，构造了水环境质量评价模型，该模型应用于实例评价结果表明，人工神经网络用于环境质量评价具有客观性，通用性和实用性。     

地表移动与变形预计在矿山开发项目环境影响评价中的应用

阐述了地表移动与变形预计理论在矿山开发项目环境影响评价工作中的必要性，着重介绍了典型曲线预计法建立的方法及预计的步骤．     

Levels and risk assessment of chemical contaminants in byproducts for animal feed in Denmark

With aim to provide information on chemical contaminants in byproducts in animal feed, the data from an official control by the Danish Plant Directorate during 1998–2009, were reviewed and several samples of citrus pulp and dried distillers grains with solubles (DDGS) were additionally collected for analysis and risk assessment. The levels of contaminants in the samples from the official control were below maximum limits from EU regulations with only a few exceptions in the following groups; dioxins and dioxin-like polychlorobiphenyls (PCBs) in fish-containing byproducts and dioxins in vegetable and animal fat, hydrogen cyanide in linseed, and cadmium in sunflowers. The levels of pesticides and mycotoxins in the additionally collected samples were below maximum limits. Enniatin B (ENN B) was present in all DDGS samples. The hypothetical cases of carry-over of contamination from these byproducts were designed assuming total absorption and accumulation of the ingested contaminant in meat and milk and high exposure (a byproduct formed 15–20% of the feed ration depending on the species). The risk assessment was refined based on literature data on metabolism in relevant animal species. Risk assessment of contaminants in byproducts is generally based on a worst-case approach, as data on carry-over of a contaminant are sparse. This may lead to erroneous estimation of health hazards. The presence of ENN B in all samples of DDGS indicates that potential impact of this emerging mycotoxin on feed and food safety deserves attention. A challenge for the future is to fill up gaps in toxicological databases and improve models for carry-over of contaminants.