CRITIQUE—Consumer product safety: Risk assessment of exposure to asbestos emissions from hand-held hair dryers

The paper by Dr. William Hallenbeck of the University of Illinois on pp. 23–32 of this issue ofEnvironmental Management contains an estimate of the risk of respiratory cancer resulting from exposure to asbestos fibers emitted from asbestos-containing hairdryers. The study, which is described as a worst case analysis, concludes that the use of these hairdryers would result in a maximum of 0.15 deaths from respiratory cancer per year in the United States, based on a median case estimate of asbestos fiber emission from hair-dryers. This estimate of risk was developed using data from one epidemiologic study.In this critique, we suggest that the use of other epidemiologic studies and the inclusion of other minor, reasonable changes to the basic assumptions made by Hallenbeck could significantly change the estimate in the direction of greater risk. Indeed, the use of other epidemiologic studies in the risk estimate results in an increase in the predicted risk of up to 3 orders of magnitude. Inclusion of changes both in the epidemiologic study used and in certain model assumptions results in an increased risk prediction of over 4 orders of magnitude in the extreme.Since there is no definitive basis on which to include or exclude certain assumptions or relevant studies, the risk estimate at best must be represented as a range of values. Such a range demonstrates the inherent uncertainties associated with estimating the risk to humans from known carcinogens. The size of the range developed in this analysis may actually be underestimated since no attempt has been made to evaluate the uncertainty associated with the choice of the dose-response model.The material found within this paper contains the views of the authors who are employees of the Consumer Product Safety Commission and does not necessarily reflect official opinions or policies of the U.S. Consumer Product Safety Commission.This paper was prepared in the course of the official duties of the authors as employees of the U.S. Consumer Product Safety Commission. It is in the public domain and may be freely copied and reproduced.     

Consumer product safety: Risk assessment of exposure to asbestos emissions from hand-held hair dryers

The United States Consumer Product Safety Commission (CPSC) is concerned that consumer exposure to asbestos from consumer products may present an unreasonable risk of injury. Recently, CPSC has obtained agreement by industry to cease production and distribution of hair dryers containing asbestos heat insulation. CPSC intends to broaden its investigation by selecting consumer products containing asbestos for priority attention. The Commission does not intend to make quantitative estimates of cancer risks posed by exposure to asbestos fibers in making regulatory decisions. This position may lead to a serious waste of resources for the Commission, industry, and society. The Commission should focus its initial attention on those products for which the release of asbestos is significant enough to cause an unreasonable health risk. To make a risk assessment for a particular use of asbestos, CPSC must acquire or request data on asbestos emissions and define unreasonable risk to health.In an attempt to give some meaning to the phrase risk assessment, the primary goal of this paper is to present a detailed risk assessment of exposure to asbestos from hand-held hair dryers. Several scenarios of use are presented using various assumptions regarding time of operation, mixing of fibers in a small room, rate of fiber emission, and time of exposure. The worst case analysis of the health risk of exposure to hair dryer emissions is based on several conservative assumptions and shows that the increased number of deaths per year due to respiratory cancer is 4 for the entire United States population. A more representative case analysis shows the increased number of deaths to be on the order of 0.15 per year.     

Risk management: Time for innovative approaches

Risk management practices under the current environmental regulations is a long, complex process that considers scientific, technologic, and management factors to develop various regulatory standards and pollution control measures. Using the mandatory enforcement approach, sometimes referred to as “command-and-control”, a set of preliminary environmental goals, such as better air and water qualities, were achieved. However, the information-intensive nature of the risk management process and the lack of flexibility in conventional regulatory methods to changing economic and technologic realities of the decade has created interest among risk managers to examine some innovative management approaches. Above all, environmental problems of a global scale require novel management methods while striving to achieve the desired environmental goals. As the principal analytical tool in risk management, quantitative risk assessment exerts considerable influence on the risk management process. Therefore, advances in risk management are closely associated with scientific developments that enhance the risk assessment process, particularly those efforts aimed at improving human exposure and toxicity assessments. Market incentives, information dissemination, creative enforcement practices, and interagency and intergovernmental interactions were identified as the key elements of innovative environmental risk management practices. This paper will present an overview of the emerging innovative risk management approaches.     

ENVIRONMENTAL AUDITING: An Approach for Characterizing Tropospheric Ozone Risk to Forests

/ The risk tropospheric ozone poses to forests in the United States is dependent on the variation in ozone exposure across the distribution of the forests in question and the various environmental and climate factors predominant in the region. All these factors have a spatial nature, and consequently an approach to characterization of ozone risk is presented that places ozone exposure-response functions for species as seedlings and model-simulated tree and stand responses in a spatial context using a geographical information systems (GIS). The GIS is used to aggregate factors considered important in a risk characterization, including: (1) estimated ozone exposures over forested regions, (2) measures of ozone effects on species' and stand growth, and (3) spatially distributed environmental, genetic, and exposure influences on species' response to ozone. The GIS-based risk characterization provides an estimation of the extent and magnitude of the potential ozone impact on forests. A preliminary risk characterization demonstrating this approach considered only the eastern United States and only the limited empirical data quantifying the effect of ozone exposures on forest tree species as seedlings. The area-weighted response of the annual seedling biomass loss formed the basis for a sensitivity ranking: sensitive-aspen and black cherry (14%-33% biomass loss over 50% of their distribution); moderately sensitive-tulip popular, loblolly pine, eastern white pine, and sugar maple (5%-13% biomass loss); insensitive-Virginia pine and red maple (0%-1% loss). In the future, the GIS-based risk characterization will include process-based model simulations of the three- to 5-year growth response of individual species as large trees with relevant environmental interactions and model simulated response of mixed stands. The interactive nature of GIS provides a tool to explore consequences of the range of climate conditions across a species' distribution, forest management practices, changing ozone precursors, regulatory control strategies, and other factors influencing the spatial distribution of ozone over time as more information becomes available.KEY WORDS: Ecological risk assessment; GIS; Ozone; Risk characterization; Forests; Trees     

Risk assessment as a management tool for inactive hazardous materials disposal sites

A protocol for risk assessment at inactive hazardous material disposal sites has been developed by using mathematical modeling and estimation techniques. Compared with ranking models, the protocol yields quantitative results with a minimum of input data that may be used to select among management, scientific, or engineering alternatives for the site. This article reviews the background, presents the protocol, illustrates the application of the protocol, and demonstrates the use of the protocol in conjunction with thecritical environmental area concept. Comparisons are also presented with other model systems such as the EPA HRS.     

Cadmium: Simulation of environmental control strategies to reduce exposure

The effects of selected environmental control strategies on human dietary and respiratory exposure to environmental cadmium (Cd) have been simulated. For each control strategy, mean Cd dietary and respiratory exposures are presented for a twenty-year simulation period.Human exposures related to cadmium are associated with both process waste disposal and product disposal. Dietary exposure is by far the dominant mechanism for Cd intake. Dietary exposure related to aqueous discharges is primarily a result of municipal sludge landspreading, whereas that associated with emissions to the atmosphere derives mainly from the deposition on cropland of airborne particulates from product incineration. Only relatively small dietary exposure reductions are possible through restrictions on anysingle Cd use. Combinations of waste management and environmental control measures promise greater reductions in dietary and respiratory exposure than those achievable through use restrictions.Work supported by Office of Toxic Substances U.S. Environmental Protection Agency.     

A framework for assessing the impact of land use policy on community exposure to air toxics

Our research focuses on the linkage between land use planning policy and the spatial pattern of exposure to air toxics emissions. Our objective is to develop a modeling framework for assessment of the community health risk implications of land use policy. The modeling framework is not intended to be a regulatory tool for small-scale land use decisions, but a long-range planning tool to assess the community health risk implications of alternative land use scenarios at a regional or subregional scale. This paper describes the development and application of an air toxic source model for generating aggregate emission factors for industrial and commercial zoning districts as a function of permitted uses. To address the uncertainty of estimating air toxics emission rates for planned general land use or zoning districts, the source model uses an emissions probability mass function that weights each incremental permitted land use activity by the likelihood of occurrence. We thus reduce the uncertainty involved in planning for development with no prior knowledge of the specific industries that may locate within the land use district. These air toxics emission factors can then be used to estimate pollutant atmospheric mass flux from land use zoning districts, which can then be input to air dispersion and human health risk assessment models to simulate the spatial pattern of air toxics exposure risk. The model database was constructed using the California Air Toxics Inventory, 1997 US Economic Census, and land assessment records from several California counties. The database contains information on more than 200 air toxics at the 2-digit Standard Industrial Classification (SIC) level. We present a case study to illustrate application of the model. LUAIRTOX, the interactive spreadsheet model that applies our methodology to the California data, is available at http://www2.bren.ucsb.edu/~mwillis/LUAIRTOX.htm.     

Perceptions of Risk Associated with Use of Farm Chemicals: Implications for Conservation Initiatives

/ Data were collected from 245 farmers within the Darby Creek hydrologic unit in central Ohio to assess perceptions of risk associated with use of farm chemicals. Farmers were asked to evaluate the level of risk associated with use of agricultural chemicals for water quality, food safety, food quality, health of applicator, health of farm animals, wildlife, beneficial plants, beneficial insects, and human health. Study findings revealed that respondents perceived use of farm chemicals posed little or no threat to any of the assessed items. A composite index was formulated from the responses to the nine items and was titled Perceived Risk. Variance in the Perceived Risk index was regressed against social learning variables. The findings revealed that approximately 32% of the variance was explained by the predictive variables included in the model. It was concluded that the theoretical perspective was somewhat useful for understanding perceptions held about agricultural chemical use at the farm level. The findings are discussed in the context of future conservation and educational-information programs within the study region.KEY WORDS: Risk perception; Risk assessment; Groundwater; Pesticide contamination; Food safety; Environmental quality     

Risk assessment for selected xenobiotics by bioassay methods with higher plants

Different bioassays with higher plants were approved for use in a bioassay procedure for testing of xenobiotics according to the German Chemicals Act. Selected environmental pollutants (atrazine, cadmium chloride, 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, thiourea), all from a list of reference chemicals, were tested with these methods. Dose-response curves for growth of oats and turnips were evaluated in soil and vermiculite (nonsorptive substrate), and availability to plants was calculated by comparing the EC₅₀ values for one chemical in both substrates. The most active chemical was atrazine, followed by 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, cadmium chloride, and thiourea. The least available compound to plants was pentachlorophenol, tested with turnips (Brassica rapa var.rapa). The strongest inhibition of germination, demonstrated in an in vitro assay with garden cress (Lepidium sativum), was found with 2,6-dichlorobenzonitrile, the lowest with atrazine. The effect of an extended exposure of the plants to the chemicals was evaluated in a long-term bioassay with oats (Avena sativa) in hydroponic culture. Several dose-response curves during the growing period were derived. It was found that the EC₅₀ values for atrazine and thiourea decreased markedly during the first four weeks; thereafter the changes were much smaller. As an overall conclusion, a bioassay procedure is proposed that can be included in the graduated plan recommended by the German Chemicals Act.     

Risk aversion and compliance in markets for pollution control

This paper examines the effects of risk aversion on compliance choices in markets for pollution control. A firm's decision to be compliant or not is independent of its manager's risk preference. However, non-compliant firms with risk-averse managers will have lower violations than otherwise identical firms with risk-neutral managers. The violations of non-compliant firms with risk-averse managers are independent of differences in their profit functions and their initial allocations of permits if and only if their managers' utility functions exhibit constant absolute risk aversion. However, firm-level characteristics do impact violation choices when managers have coefficients of absolute risk aversion that are increasing or decreasing in profit levels. Finally, in the equilibrium of a market for emissions rights with widespread non-compliance, risk aversion is associated with higher permit prices, better environmental quality, and lower aggregate violations.     

Assessing Uncertainty in Estimates of Nitrogen Loading to Estuaries for Research, Planning, and Risk Assessment

Parametric (propagation for normal error estimates) and nonparametric methods (bootstrap and enumeration of combinations) to assess the uncertainty in calculated rates of nitrogen loading were compared, based on the propagation of uncertainty observed in the variables used in the calculation. In addition, since such calculations are often based on literature surveys rather than random replicate measurements for the site in question, error propagation was also compared using the uncertainty of the sampled population (e.g., standard deviation) as well as the uncertainty of the mean (e.g., standard error of the mean). Calculations for the predicted nitrogen loading to a shallow estuary (Waquoit Bay, MA) were used as an example. The previously estimated mean loading from the watershed (5,400 ha) to Waquoit Bay (600 ha) was 23,000 kg N yr⁻¹. The mode of a nonparametric estimate of the probability distribution differed dramatically, equaling only 70% of this mean. Repeated observations were available for only 8 of the 16 variables used in our calculation. We estimated uncertainty in model predictions by treating these as sample replicates. Parametric and nonparametric estimates of the standard error of the mean loading rate were 12–14%. However, since the available data include site-to-site variability, as is often the case, standard error may be an inappropriate measure of confidence. The standard deviations were around 38% of the loading rate. Further, 95% confidence intervals differed between the nonparametric and parametric methods, with those of the nonparametric method arranged asymmetrically around the predicted loading rate. The disparity in magnitude and symmetry of calculated confidence limits argue for careful consideration of the nature of the uncertainty of variables used in chained calculations. This analysis also suggests that a nonparametric method of calculating loading rates using most frequently observed values for variables used in loading calculations may be more appropriate than using mean values. These findings reinforce the importance of including assessment of uncertainty when evaluating nutrient loading rates in research and planning. Risk assessment, which may need to consider relative probability of extreme events in worst-case scenarios, will be in serious error using normal estimates, or even the nonparametric bootstrap. A method such as our enumeration of combinations produces a more reliable distribution of risk.     

Risk Management of Sediment Stress: A Framework for Sediment Risk Management Research

Research related to the ecological risk management of sediment stress in watersheds is placed under a common conceptual framework in order to help promote the timely advance of decision support methods for aquatic resource managers and watershed-level planning. The proposed risk management research program relies heavily on model development and verification, and should be applied under an adaptive management approach. The framework is centered on using best management practices (BMPs), including eco-restoration. It is designed to encourage the development of numerical representations of the performance of these management options, the integration of this information into sediment transport simulation models that account for uncertainty in both input and output, and would use strategic environmental monitoring to guide sediment-related risk management decisions for mixed land use watersheds. The goal of this project was to provide a sound scientific framework based on recent state of the practice in sediment-related risk assessment and management for research and regulatory activities. As a result, shortcomings in the extant data and measurement and modeling tools were identified that can help determine future research direction. The compilation of information is beneficial to the coordination of related work being conducted within and across entities responsible for managing watershed-scale risks to aquatic ecosystems.     

Computerized Map of Risk to Manage Wildlife Species in Urban Areas

For the last 20 years, human–wildlife conflicts have been rapidly increasing in towns. Although people want “greener” cities, the expansion of disliked species causes problems that are difficult to manage and to reduce. The complexity of the numerous factors involved in these human–wildlife relations needs the development of a comprehensive tool for urban planners. Today, with the development of computers and geographical information systems, it is easier to analyze and combine different spatial data as methods used for the management of risks in studies of natural hazards. Here we present a method for assessing and mapping the risk in cases of human–wildlife conflict. An application to starling management in a town in western France will show the efficiency of our methods to combine information given by a network of experts and to highlight higher risk sites. The map of risk provides a spatial result useful for comprehension, communication between people and agencies, and public education.     

Evaluation of Flood and Landslide Risk to the Population of Italy

We have compiled a database of floods and landslides that occurred in Italy between AD 1279 and 2002 and caused deaths, missing persons, injuries, and homelessness. Analysis of the database indicates that more than 50,593 people died, went missing, or were injured in 2580 flood and landslide events. Harmful events were inventoried in 26.3% of the 8103 Italian municipalities. Fatal events were most frequent in the Alpine regions of northern Italy and were caused by both floods and landslides. In southern Italy, landslides were the principal agents of fatalities and were most numerous in the Campania region. Casualties were most frequent in the autumn. Fast-moving landslides, including rock falls, rockslides, rock avalanches, and debris flows, caused the largest number of deaths. In order to assess the overall risk posed by these processes, we merged the historical catalogs and identified 2682 “hydrogeomorphological” events that triggered single or multiple landslides and floods. We estimated individual risk through the calculation of mortality rates for both floods and landslides and compared these rates to the death rates for other natural, medical, and human-induced hazards in Italy. We used the frequency distribution of events with fatalities to ascertain the magnitude and frequency of the societal risks posed by floods and landslides. We quantified these risks in a Bayesian model that describes the probabilities of fatal flood and landslide events in Italy.     

Models to Assess the Risk of Snow and Wind Damage in Pine, Spruce, and Birch Forests in Sweden

3 are damaged annually by snow and wind, roughly corresponding to a value of US$150 million, and in Europe, the damage amounts to hundreds of millions of US dollars each year. To help to reduce these losses, tools for risk assessment within forest management have been developed. Predictions were developed of the risk of damage from snow and wind to Scots pine (Pinus sylvestris L.), Norway spruce [Picea abies (L.) Karst.] and Birch (Betula spp. L.) plots using tree, stand, and site characteristics. The data were obtained from 6756 permanent sample plots within the Swedish National Forest Inventory, which were inventoried twice at five-year intervals between 1983 and 1992. Input data for model development used measurements from the first inventory of tree characteristics for the largest sample tree, stand, and site data, and records of snow and wind damage from the second inventory. Models were developed for three different regions for pine- and spruce-dominated sites, while models for the whole country were developed for birch sites. In general the estimated proportion of damaged plots was highly overestimated (31.7%–56.2%), compared with the observed proportion of 3.4%–11.9%. The models for Norway spruce comprising tree, stand, and site data show the best predictability of damaged plots, with 60.6%–67.6% of plots correctly classified. It is concluded that the models developed can be used to detect sites with a high probability of damage from snow and wind, and thus be used as tools to reduce future damage and costs in practical forestry.     

Towards an Integrated Approach to Natural Hazards Risk Assessment Using GIS: With Reference to Bushfires

This paper develops a GIS-based integrated approach to risk assessment in natural hazards, with reference to bushfires. The challenges for undertaking this approach have three components: data integration, risk assessment tasks, and risk decision-making. First, data integration in GIS is a fundamental step for subsequent risk assessment tasks and risk decision-making. A series of spatial data integration issues within GIS such as geographical scales and data models are addressed. Particularly, the integration of both physical environmental data and socioeconomic data is examined with an example linking remotely sensed data and areal census data in GIS. Second, specific risk assessment tasks, such as hazard behavior simulation and vulnerability assessment, should be undertaken in order to understand complex hazard risks and provide support for risk decision-making. For risk assessment tasks involving heterogeneous data sources, the selection of spatial analysis units is important. Third, risk decision-making concerns spatial preferences and/or patterns, and a multicriteria evaluation (MCE)-GIS typology for risk decision-making is presented that incorporates three perspectives: spatial data types, data models, and methods development. Both conventional MCE methods and artificial intelligence-based methods with GIS are identified to facilitate spatial risk decision-making in a rational and interpretable way. Finally, the paper concludes that the integrated approach can be used to assist risk management of natural hazards, in theory and in practice.     

Ecological Risk Assessment and Problem Formulation for Lake Uluabat,a Ramsar State in Turkey

Unlike the United States and the European Union, developing countries do not have sufficiently structured legal and institutional systems to apply certain environmental management tools such as ecological risk assessment. However, it is important for countries with valuable environmental and ecological resources to have appropriate tools and to strengthen their environmental management capabilities and capacities for the sake of those resources. The case study described in this paper attempts to be a case study towards developing environmental management plans, especially in developing countries. The problem formulation step of Ecological Risk Assessment applied in this study contributed to the basic elements of an environmental management plan including the following: the partnership-building process, prioritization of the problems and issues of the ecosystem, and development of the action plan. Based on the information provided by participants from a series of workshops held to develop an environmental management plan for Uluabat Lake, ecosystem risks were ranked and an action plan was formed. The results obtained with the aid of fuzzy set theory provided a base for identification of the action steps by allowing scientific information to be included in the process. The degree to which Uluabat Lakes problem formulation fits into the existing legal framework of Turkey is also analyzed in this paper.     

Modeling Protected Species Habitat and Assigning Risk to Inform Regulatory Decisions

In the United States, environmental regulatory agencies are required to use “best available” scientific information when making decisions on a variety of issues. However, agencies are often hindered by coarse or incomplete data, particularly as it pertains to threatened and endangered species protection. Stakeholders often agree that more resolute and integrated processes for decision-making are desirable. We demonstrate a process that uses species occurrence data for a federally endangered insect (Karner blue butterfly), a readily available habitat modeling tool, and spatially explicit information about an important Michigan commodity (tart cherries). This case study has characteristics of many protected species regulatory decisions in that species occurrence data were sparse and unequally distributed; regulatory decisions (on pesticide use) were required with potentially significant impacts on a viable agricultural industry; and stakeholder relations were diverse, misinformed, and, in some situations, unjustly contentious. Results from our process include a large-scale, empirically derived habitat suitability map for the focal species and a risk ranking of tart cherry orchards with risk based on the likelihood that pesticide applications will influence the focal protected species. Although the majority (77%) of pesticide-influence zones overlapped Karner blue butterfly habitat, risk scores associated with each orchard were low. Through our process we demonstrated that spatially explicit models can help stakeholders visualize and quantify potential protected species effects. In addition, model outputs can serve to guide field activities (e.g., species surveys and implementation of pesticide buffer zones) that help minimize future effects.     

Reflecting on stakeholders’ perceptions in an Ecological Risk Assessment workshop: Lessons for practitioners

A new form of Ecological Risk Assessment aims to improve environmental decision-making through strong stakeholder engagement, often in workshop situations. This wider focus increases interaction between workshop practitioners and stakeholders for reflecting on, and learning from, each others perceptions. In this article, we analyse and discuss a one day workshop that was concerned with trialling this method of deriving an Ecological Risk Assessment. We found that stakeholders had issues with some elements of the workshop process. The decision problem was formulated prior to the workshop and without consultation among all the stakeholders. Consequently, the original decision problem was rejected for a mutually derived broader focus and this resulted in a loss of clarity and purpose. Stakeholders did not wholly concur with the prioritising of ecological values over social and economic values and some stakeholders objected to defining assessment endpoints, because it implies a reductionist approach that doesn’t capture significance and understanding of systems. Ecological Risk Assessment workshops are complex and require significant practitioner and stakeholder development to provide useful and mutually derived outcomes.     

Risk assessment for atmospheric environmental management: a case study in the Hunter Region of New South Wales,Australia

The theoretical framework of a risk assessment scheme is applied to air quality assessment in a developing region in Australia, the Hunter Valley in the state of New South Wales. It is found that the application of such a scheme high-lights a number of inadequacies in the air quality management. New modeling methodologies are found to be necessary to assess some air quality impacts, as existing knowledge is inadequate. The importance of extensive data bases is underlined as is the need for social surveys to supplement air pollution monitoring when gauging aesthetic effects of air pollutants.A visiting fellow on leave from the School of Australian Environmental Studies, Griffith University, Brisbane, Queensland, Australia.