Assessing Risk in Operational Decisions Using Great Lakes Probabilistic Water Level Forecasts

/ A method adapted from the National Weather Service's Extended Streamflow Prediction technique is applied retrospectively to three Great Lakes case studies to show how risk assessment using probabilistic monthly water level forecasts could have contributed to the decision-mak-ing process. The first case study examines the 1985 International Joint Commission (IJC) decision to store water in Lake Superior to reduce high levels on the downstream lakes. Probabilistic forecasts are generated for Lake Superior and Lakes Michigan-Huron and used with riparian inundation value functions to assess the relative impacts of the IJC's decision on riparian interests for both lakes. The second case study evaluates the risk of flooding at Milwaukee, Wisconsin, and the need to implement flood-control projects if Lake Michigan levels were to continue to rise above the October 1986 record. The third case study quantifies the risks of impaired municipal water works operation during the 1964-1965 period of extreme low water levels on Lakes Huron, St. Clair, Erie, and Ontario. Further refinements and other potential applications of the probabilistic forecast technique are discussed.KEY WORDS: Great Lakes; Water levels; Forecasting; Risk; Decision making     

Drinking water risk assessment in practice: the case of Swedish drinking water producers at risk from floods

To achieve a safe and reliable drinking water supply, water producers need to manage a large range of risks regarding both water quality and quantity. A risk management approach where risks are systematically identified and handled in a preventive manner is promoted by the World Health Organization and supported by researchers and drinking water experts worldwide. Risk assessment is an important part of such a management approach, and a variety of tools for risk assessment are described in the literature. There is, however, little knowledge of how drinking water risk assessment is performed in practice, including which tools that are actually used. This study investigates the use of risk assessment tools, and the approach to risk management, on a local level in the Swedish water sector. It is based on interviews with key persons from a targeted selection of water producers. We find that the application of tools as well as the approach to risk assessment and management differs considerably between the water producers. The tools most frequently used are mainly the ones promoted or required by Swedish national organizations. Although many of the water producers have done some kind of risk assessment, most have not implemented a risk management approach. Furthermore, their knowledge of the concepts of risk and risk management is often limited. The largest challenge identified is to prioritize risk assessment, so that it is actually performed and then used as a basis for managing risk in a systematic way.     

Managing mercury in the great lakes: an analytical review of abatement policies

Mercury, a toxic metal known to have several deleterious affects on human health, has been one of the principal contaminants of concern in the Great Lakes basin. There are numerous anthropogenic sources of mercury to the Great Lakes area. Combustion of coal, smelting of non ferrous metals, and incineration of municipal and medical waste are major sources of mercury emissions in the region. In addition to North American anthropogenic emissions, global atmospheric emissions also significantly contribute to the deposition of mercury in the Great Lakes basin. Both the USA and Canada have agreed to reduce human exposure to mercury in the Great Lakes basin and have significantly curtailed mercury load to this region through individual and joint efforts. However, many important mercury sources, such as coal-fired power plants, still exist in the vicinity of the Great Lakes. More serious actions to drastically reduce mercury sources by employing alternative energy sources, restricting mercury trade and banning various mercury containing consumer products, such as dental amalgam are as essential as cleaning up the historical deposits of mercury in the basin. A strong political will and mass momentum are crucial for efficient mercury management. International cooperation is equally important. In the present paper, we have analyzed existing policies in respective jurisdictions to reduce mercury concentration in the Great Lakes environment. A brief review of the sources, occurrence in the Great Lakes, and the health effects of mercury is also included.     

Environmental Health Policy: Analytic “Framing” of the Great Lakes Picture

/ The International Joint Commission (IJC) has overseen the implementation of the Great Lakes Water Quality Agreement between Canada and the United States for 25 years. Part of its mandate has been to facilitate international cooperation among a diversity of stakeholders focusing on the "waters" and the "ecosystem." In the 1970s policy focused on phosphorus reduction and individual contaminants, with some efforts (after 1978) to take an ecosystem (ecological perspectives) approach. In the last 15 years human health effects from (real and perceived) environmental causes have received considerable recognition. By contrast, less concern has been expressed for what is traditionally considered "environment" issues (such as protecting fish species). This shift at the policy level is well illustrated in the manner in which human health is increasingly used as a way for mobilizing environmental agendas. This paper analyzes nine IJC biennial reports to track how the framing of Great Lakes issues has shifted from concern for its waters to concern for human neurobehavior and reproductive systems. Frame analysis is used to conceptualize the controversies that are expressed through the Great Lakes policy documents. The analysis of the reports also reveals a shift in operational frames, used by the IJC to mobilize decision-makers into action.     

Spatial variations of human health risk associated with exposure to chlorination by-products occurring in drinking water

During disinfection, chlorine reacts with organic matter present in drinking water and forms various undesirable chlorinated by-products (CBPs). This paper describes a study of the spatial variability of human health risk (i.e., cancer effects) from CBP exposure through drinking water in a specific region. The region under study involves nine drinking water distribution systems divided into several zones based on their characteristics. The spatial distribution of cancer risk (CR) was estimated using two years of data (2006-2008) on various CBP species. In this analysis, trihalomethanes (THMs) and haloacetic acids (HAAs) served as surrogates for CBPs. Three possible routes of exposure (i.e., via ingestion, inhalation and dermal contact) were considered for each selected compound. The cancer risk assessment involved estimating a unit risk (R(T)) in each zone of the selected distribution systems. A probabilistic analysis based on Monte Carlo simulations was employed. Risk assessment results showed that cancer risk varied between systems, but also within individual systems. As a result, the population of the same region was not exposed to the same risk associated with CBPs in drinking water. Unacceptable levels (i.e., R(T) > 10(-4)) for the estimated CR were determined for several zones in the studied region. This study demonstrates that a spatial-based analysis performed to represent the spatial distribution of risk estimates can be helpful in identifying suitable risk management strategies. Suggestions for improving the risk analysis procedure are also presented.     

EFFECTS OF DIVERSIONS ON THE NORTH AMERICAN GREAT LAKES1

ABSTRACT: Water level fluctuations of the Great Lakes often have created regional controversies among the states and Canadian provinces that share this vast resource. Even though the 100-year range of their water levels is only four to five feet, episodes of high and low Great Lakes water levels have been a recurring problem throughout the twentieth century. The possibility of increased diversion and consumptive use has exacerbated the existing conflicts over how to manage this water resource. A research project evaluated the effects of interbasin diversion on the Great Lakes system and on the industries that depend on the maintenance of historical water levels, namely hydropower and commercial navigation. The simulation approach employed in this research and some of the important findings are presented. The approach is similar to that used in recent government studies of Great Lakes water level regulation. Several significant modifications were made specifically addressing the diversion issue. Aggregate annual impacts to hydropower and shipping resulting from a diversion of 10,000 cubic feet per second were found to vary from 60 to 100 million dollars. Increases in impacts as a function of diversion rate are nonlinear for the navigation industry.     

MATHEMATICAL MODELS: PLANNING TOOLS FOR THE GREAT LAKES1

The Great Lakes Basin Commission has initiated a Framework Study to assess the present and projected water- and related land-resource problems and demands in the Great Lakes Basin. Poorly defined objectives; incomplete and inconsistent data arrays; unknown air, biota, water, and sediment interactions; and multiple planning considerations for interconnected, large lake systems hinder objective planning. To incorporate mathematical modeling as a planning tool for the Great Lakes, a two-phase program, comprising a feasibility and design study followed by contracted and in-house modeling, data assembly, and plan development, has been initiated. The models will be used to identify sensitivities of the lakes to planning and management alternatives, insufficiencies in the data base, and inadequately understood ecosystem interactions. For the first time objective testing of resource-utilization plans to identify potential conflicts will provide a rational and cost-effective approach to Great Lakes management. Because disciplines will be interrelated, the long-term effects of planning alternatives and their impacts on neighboring lakes and states can be evaluated. Testing of the consequences of environmental accidents and increased pollution levels can be evaluated, and risks to the resource determined. Examples are cited to demonstrate the use of such planning tools.     

Arsenic in the food chain and assessment of population health risks in Bangladesh

The most consumed food samples of cereals (rice, maize and wheat), vegetables (lentil, brinjal, carrot, bean, potato, tomato, onion and chili), fruits (banana, mango and jackfruit), fish (taki, rui, pangas and tilapia), egg (chicken and duck), milk (cow) and meat (chicken, duck, beef and mutton) were collected from some markets of Bogra district northern part of Bangladesh to evaluate the levels of arsenic (As) and associated health risk to the adult’s and child inhabitants. Arsenic is a highly toxic element, and its presence in food composites is a matter of concern to the world scientists. Target hazard quotients (THQs) and target carcinogenic risk were calculated to evaluate the non-carcinogenic and carcinogenic health risk from ingested arsenic. The highest and the lowest mean concentrations of arsenic were noted in the Tilapia fish [(0.94 mg/kg, wet weight (ww)] and beef (0.012 mg/kg, ww). The daily intakes of arsenic via foodstuffs were 1.92 and 3.30 µg/kg-bw/day for rural adults and children and 1.69 and 3.04 µg/kg-bw/day for urban adults and children, respectively. The result shows the highest THQs of arsenic in cereals and vegetables for both the rural and urban inhabitants which exceed the safe limit (>1) indicating that cereals and vegetables are the main food items contributing to the potential health risk. The estimated target cancer risks from ingesting dietary arsenic all exceeded 10^?6, indicating increased risk of cancer for adults and children in the study area.     

MODELING HYDROLOGIC IMPACT OF WITHDRAWING THE GREAT LAKES WATER FOR AGRICULTURAL IRRIGATION1

ABSTRACT: Growing interest in agricultural irrigation in the Great Lakes basin presents an increasing competition to other uses of Great Lakes water. This paper, through a case study of the Mud Creek Irrigation District in the Saginaw Bay basin, Michigan, evaluates the potential hydrologic effects of withdrawing water for agricultural irrigation to the Great Lakes. Crop growth simulation models for corn, soybeans, dry beans, and the FAO Penman method were used to estimate the difference in evapotranspiration rates between irrigated and nonirrigated identical crops, based on climate, soil, and management data. The simulated results indicate that an additional 70–120 mm of water would be evapotranspirated during the growing season from irrigated crop fields as compared to nonirrigated identical plantings. Dependent upon the magnitude of irrigation expansion, an equivalent of about 1 to 5 mm of water from Lakes Huron-Michigan could be lost to the atmosphere. If agricultural irrigation further expands in the entire Great Lakes basin, the aggregated potential of water loss to the atmosphere through ET from all five Great Lakes would be even greater.     

Aquatic Nuisance Species in the New York State Canal and Hudson River Systems and the Great Lakes Basin: An Economic and Environmental Assessment

A total of 154 aquatic alien species have invaded the New York State Canal and Hudson River systems and a total of 162 aquatic species have invaded the Great Lakes Basin. Some of these invasive species are causing significant damage and control costs in both aquatic ecosystems. In the New York State Canal and Hudson River systems, the nonindigenous species are causing an estimated 500 million dollars in economic losses each year. The economic and environmental situation in the Great Lakes Basin is far more serious from nonindigenous species, with losses estimated to be about 5.7 billion dollars per year. Commercial and sport fishing suffer the most from the biological invasions, with about 400 million dollars in losses reported for the New York State Canal and Hudson River systems and 4.5 billion dollars in losses reported for the Great Lakes Basin.     

Contaminants of Emerging Concern in Fish from Western U.S. and Alaskan National Parks — Spatial Distribution and Health Thresholds

Remote national parks of the western U.S. and Alaska are not immune to contaminants of emerging concern. Semivolatile organic compounds (SOCs) such as pesticides and PCBs can selectively deposit from the atmosphere at higher rates in cold, high‐elevation and high‐latitude sites, potentially increasing risk to these ecosystems. In the environment, SOCs magnify up food chains and are known to increase health risks such as cancer and reproductive impairment. One hundred twenty‐eight fish in 8 national parks in Alaska and the western U.S. were analyzed for contaminant concentrations, assessed by region, and compared to human and wildlife health thresholds. SOC concentrations from an additional 133 fish from a previous study were also included, for a total of 31 water bodies sampled. PCBs, endosulfan sulfate, and p,p′‐DDE were among the most frequently detected contaminants. Concentrations of historic‐use pesticides dieldrin, p,p′‐DDE, and/or chlordanes in fish exceeded USEPA guidelines for human subsistence fish consumers and wildlife (kingfisher) health thresholds at 13 of 14 parks. Average concentrations in fish ranged from 0.6‐280 ng/g lipid (0.02‐7.3 μg/g ww). Contaminant loading was highest in fish from Alaskan and Sierra Nevada parks. Historic compounds were highest in Alaskan parks, while current‐use pesticides were higher in the Rockies and Sierra Nevada. This study provides a rigorous analysis of CECs in fish from national parks and identifies regions at potential risk.     

MODELING OF THE GREAT LAKES WATER SYSTEM1

There have been two predominate approaches to the modeling of the Great Lakes water system: physical models and mathematical models. The physical models have been of individual lakes whereas the mathematical models have varied from models of individual processes such as evaporation occurring in one portion of one lake to models which include all water quantity components for all five Great Lakes. The assumptions and limitations of the two approaches are presented along with the kinds of results to be expected from each type of modeling. Examples of previous modeling efforts are given to illustrate these assumptions, limitations, and results. Other areas requiring further research are outlined.     

Assessment of the Water Quality and Ecosystem Health of the Great Barrier Reef (Australia): Conceptual Models

Run-off containing increased concentrations of sediment, nutrients, and pesticides from land-based anthropogenic activities is a significant influence on water quality and the ecologic conditions of nearshore areas of the Great Barrier Reef World Heritage Area, Australia. The potential and actual impacts of increased pollutant concentrations range from bioaccumulation of contaminants and decreased photosynthetic capacity to major shifts in community structure and health of mangrove, coral reef, and seagrass ecosystems. A detailed conceptual model underpins and illustrates the links between the main anthropogenic pressures or threats (dry-land cattle grazing and intensive sugar cane cropping) and the production of key contaminants or stressors of Great Barrier Reef water quality. The conceptual model also includes longer-term threats to Great Barrier Reef water quality and ecosystem health, such as global climate change, that will potentially confound direct model interrelationships. The model recognises that system-specific attributes, such as monsoonal wind direction, rainfall intensity, and flood plume residence times, will act as system filters to modify the effects of any water-quality system stressor. The model also summarises key ecosystem responses in ecosystem health that can be monitored through indicators at catchment, riverine, and marine scales. Selected indicators include riverine and marine water quality, inshore coral reef and seagrass status, and biota pollutant burdens. These indicators have been adopted as components of a long-term monitoring program to enable assessment of the effectiveness of change in catchment-management practices in improving Great Barrier Reef (and adjacent catchment) water quality under the Queensland and Australian Governments’ Reef Water Quality Protection Plan.     

Fuzzy synthetic evaluation of disinfection by-products--a risk-based indexing system

Disinfection by-products (DBPs) are formed when disinfectants such as chlorine, chloramine, and ozone react with organic matter in water. Chlorine being the most common disinfectant used in the drinking water industry worldwide, significant attention has been focused on chlorinated DBPs. A new indexing method using fuzzy synthetic evaluation is proposed to determine the health risk associated with the two major groups of chlorinated DBPs--trihalomethanes (THMs) and haloacetic acids (HAAs). Initially, membership functions for cancer and non-cancer risks associated with THMs and HAAs are used to establish the fuzzy evaluation matrices. Subsequently, weighted evaluation matrices for both types of risks are established by performing cross products on the weighted vectors (founded on the analytic hierarchy process) and the fuzzy evaluation matrices. In the final stage, the weighted evaluation matrices of cancer and non-cancer risks are aggregated to determine the final risk rating. Two case studies are provided to demonstrate the application of this method.     

Risk assessment of aquifer storage transfer and recovery with urban stormwater for producing water of a potable quality

The objective of the Parafield Aquifer Storage Transfer and Recovery research project in South Australia is to determine whether stormwater from an urban catchment that is treated in a constructed wetland and stored in an initially brackish aquifer before recovery can meet potable water standards. The water produced by the stormwater harvesting system, which included a constructed wetland, was found to be near potable quality. Parameters exceeding the drinking water guidelines before recharge included small numbers of fecal indicator bacteria and elevated iron concentrations and associated color. This is the first reported study of a managed aquifer recharge (MAR) scheme to be assessed following the Australian guidelines for MAR. A comprehensive staged approach to assess the risks to human health and the environment of this project has been undertaken, with 12 hazards being assessed. A quantitative microbial risk assessment undertaken on the water recovered from the aquifer indicated that the residual risks posed by the pathogenic hazards were acceptable if further supplementary treatment was included. Residual risks from organic chemicals were also assessed to be low based on an intensive monitoring program. Elevated iron concentrations in the recovered water exceeded the potable water guidelines. Iron concentrations increased after underground storage but would be acceptable after postrecovery aeration treatment. Arsenic concentrations in the recovered water continuously met the guideline concentrations acceptable for potable water supplies. However, the elevated concentration of arsenic in native groundwater and its presence in aquifer minerals suggest that the continuing acceptable residual risk from arsenic requires further evaluation.     

Community Perception of Water Quality in a Mining-Affected Area: A Case Study for the Certej Catchment in the Apuseni Mountains in Romania

Mining-contaminated sites and the affected communities at risk are important issues on the agenda of both researchers and policy makers, particularly in the former communist block countries in Eastern Europe. Integrated analyses and expert based assessments concerning mining affected areas are important in providing solid policy guidelines for environmental and social risk management and mitigation. Based on a survey for 103 households conducted in a former mining site in the Certej Catchment of the Apuseni Mountains, western Romania, this study assesses local communities’ perceptions on the quality of water in their living area. Logistic regression was used to examine peoples’ perception on the quality of the main river water and of the drinking water based on several predictors relating to social and economic conditions. The results from the perception analysis were then compared with the measurements of heavy metal contamination of the main river and drinking water undertaken in the same study area. The findings indicate that perception and measurement results for the water quality in the Certej Catchment are convergent, suggesting an obvious risk that mining activities pose on the surface water. However, the perception on drinking water quality was little predicted by the regression model and does not seem to be so much related to mining as to other explanatory factors, such as special mineralogy of rock and soils or improper water treatment infrastructure, facts suggested by the measurements of the contaminants. Discussion about the implications of these joint findings for risk mitigation policies completes this article.     

重庆市城区饮用水源健康风险评价

通过对重庆市8个饮用水源地枯水期水体中NH3-N、CN、As、Hg、Cr^＋6、Pb、Cd、Cu、F和挥发酚的浓度进行了调查研究,应用美国环保局推荐的健康风险评价模型对重庆市饮用水源水中污染物引起的健康风险作了评价。结果表明,污染物平均浓度范围分别为NH3-N：0．119—0.740mg／L,CN：0．002—0．004mg／L,As：0．001—0．007mg／L,Hg：0．000001—0．00005mg／L,Cr^＋6：0．004—0.023mg／L．Pb：0．004—0．053mg／L．Cd：0．00035—0．005mg／L．Cu：0．0005—0．0254mg/L,F：0．140—0．335mg／L,挥发酚：0．001—0．0027mg／L。重庆市通过饮水途径引起的非致癌健康风险中Pb的风险最大,F次之,两者风险水平在10^-8～10^-9／a;Cr^＋6引起的致癌风险最大达到10^-4／a;以长江为饮用水源的人群总健康风险大于嘉陵江,其健康风险达到EPA要求,但高于国际辐射防护委员会（ICRP）的最大可接受风险水平。     

Great Lakes management: Ecological factors

Although attempts to improve the quality of the Great Lakes generally focus on chemical pollution, other factors are important and should be considered Ecological factors, such as invasion of the lakes by foreign species, habitat changes, overfishing, and random variations in organism populations, are especially influential. Lack of appreciation of the significance of ecological factors stems partly from the inappropriate application of the concept of eutrophication to the Great Lakes. Emphasis on ecological factors is not intended to diminish the seriousness of pollution, but rather to point out that more cost-effective management, as well as more realistic expectations of management efforts by the public, should result from an ecosystem management approach in which ecological factors are carefully considered.     

基于价值创造视角的公司水风险管理研究

随着全球水资源供应不确定性与需求竞争性的加剧,水资源问题已从单纯的环境问题转化为经济问题,水风险逐渐与商业风险挂钩,公司面临的水风险不断上升。公司面临着物理风险、监管风险和声誉风险等水风险,公司水价值体现在业务连续性、经营牌照、声誉与品牌价值和创新价值等无形资产中。水风险与水价值二者相互联系又相互影响,通过公司水价值与水风险评估框架,了解区分水价值的不同方法,明确风险和不确定性如何影响水的价值,并利用水工具评估和管理公司所面临的水风险以及水对公司价值的影响,帮助公司化解其所面临的水风险,实现从公司水风险管理到价值创造的转变。