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Risk Assessment

Risk assessment adds an important contribution to advancing sustainability. In a risk assessment, risk is understood to be the possibility of adverse consequences from an event or activity. A risk assessment, therefore, is a process for evaluating the likelihood and/or magnitude of such consequences. Risk assessment should be viewed as a tool for evaluating the relative merits of various options for managing risk.[226] This includes carefully posing the risk management questions and evaluating the options available to manage the environmental problems at hand. There are a number of context-specific types of risk assessment that can be useful in understanding aspects of sustainability in complex, real-world situations. Four of these are described below. [227-230]

Human Health Risk Assessment                                                           
Human health risk assessment (HHRA) is the process used to estimate the nature and probability of adverse health effects for humans who may be exposed to environmental stressors (chemical, non-chemical, or both), now or in the future. HHRA can help inform solutions to a broad range of problems related to human health risk.
HHRA may help answer questions such as:

Risk Assessment
  • What types of health problems may be caused by environmental stressors such as chemicals and radiation?
  • What is the chance that people will experience health problems when exposed to different levels of environmental stressors?
  • Is there a level below which some chemicals don't pose a human health risk?
  • What environmental stressors are people being exposed to and at what levels and for how long?
  • Are some people more likely to be susceptible to environmental stressors because of factors such as age, genetics, pre-existing health conditions, ethnic practices, gender, and socioeconomic status?
  • Are some people more likely to be exposed to environmental stressors because of factors such as where they work, where they play, what they like to eat?

Children’s Environmental Health Assessment
Children are a subpopulation that may be more susceptible to harm caused by environmental stressors because of various physiological and behavioral factors:[231]

  • their bodily systems are still developing;
  • they eat more, drink more, and breathe more in proportion to their body size; and,
  • their behavior such as crawling on the ground and hand-to-mouth activity can higher exposures to chemicals and organisms.

Because children have different exposure circumstances and physiological characteristics than adults, EPA has developed an action development guidance entitled Guide to Considering Children's Health When Developing EPA Actions: Implementing Executive Order 13045 and EPA's Policy on Evaluating Health Risks to Children (PDF) (42 pp, 727K). This Guide is designed to help Agency staff involved in developing regulatory actions determine whether Executive Order 13045 Protection of Children from Environmental Health Risks and Safety Risks and/or EPA's Policy on Evaluating Risk to Children applies to an Agency action and, if so, how to implement the Executive Order and/or EPA's Policy. EPA has developed several guidance documents devoted to assessing children’s environmental health risks. These can be found at EPA’s risk assessment portal and include:

Many important EPA regulatory decisions have their basis in protecting children against environmental threats. Examples include:

Cumulative Risk Assessment
There are multiple definitions of cumulative risk assessments. The Food Quality Protection Act (FQPA) defines cumulative risk as the risk from the total exposure to multiple stressors (usually chemical) that cause one or more common toxic effects to human health by the same, or similar, sequence of major biochemical events. The EPA’s Cumulative Risk Framework provides a considerably broader definition that includes combined risks from aggregate exposures to multiple agents or stressors, where agents or stressors may be chemical, biological, social, or physical (e.g. noise, nutritional status).[233] EPA’s cumulative risk assessment process focuses on populations and consideration of population variability; it has been used in many of the EPA’s programs, including: Research and Development, Superfund, Air, Water, and cross-program endeavors like the Community Action for a Renewed Environment program.

With this type of assessment, stakeholder input is crucial. Various statutes require assessments of cumulative risk: the 1996 FQPA requires assessments based on multiple pesticides with a common mode of action; whereas NEPA of 1970 requires broader based cumulative assessments that consider multiple chemical and nonchemical stressors.

The 2009 National Research Council (NRC) report Science and Decisions: Advancing Risk Assessment [226] encourages EPA to implement cumulative risk assessment. EPA is in the process of developing a human health risk assessment framework that takes into account the NRC recommendations, and highlights the important roles of planning, scoping, and problem formulation in designing risk assessments that emphasize the importance of scientific review and public, stakeholder and community involvement. [234]

Ecological Risk Assessment
An ecological risk assessment[235] is the process for evaluating how likely it is that the environment may be impacted as a result of exposure to one or more environmental stressors such as chemicals, land change, disease, invasive species and climate change. Ecological risk assessments can be used to predict the likelihood of future effects (prospective) or evaluate the likelihood that effects are caused by past exposure to stressors (retrospective). Information from ecological risk assessment is then used by risk managers for follow-up such as communicating to interested parties and the general public, limiting activities related to the ecological stressor, limiting use of a given chemical, or developing a monitoring plan to determine if risks have been reduced or whether an ecosystem is recovering.

An ecological risk assessment helps answer questions about potential risks such as impacts on the aesthetic value of a place due to physical alterations, effects of pollution on endangered species, or the consequences of long-term release of contaminants to an ecosystem. Examples of specific questions that can be addressed with an ecological risk assessment include:

  • How would the construction of a dam impact fish populations in nearby water bodies?
  • Can the residential or agricultural application of an insecticide end up harming an endangered bird species?
  • Do contaminants in the environment from an abandoned industrial or mining facility significantly reduce the use of the site and to nearby areas?
  • What is the risk of introducing a non-native oyster to an estuary?
  • How does fertilizer runoff reduce oxygen levels in water bodies such as bays?
  • Are some plants or animals more likely to be susceptible to environmental stressors because of factors such as age, genetics, body size, or differences among species?

How can Risk Assessment contribute to sustainability?

An important consideration in any sustainability assessment is whether environmental or human health will be better or worse off if an action is taken, both near term and for future generations. Therefore, risk assessment is a key component of sustainability assessment.[192]

By its very nature, cumulative risk assessment strives to account for the full range of chemical and non-chemical stressors, such as psychosocial stressors.[233] Such characterizations of risk are well aligned with the broad scope of sustainability because they consider not only human health, but also lifestyle and socioeconomic factors that may affect health. NexGen--ORD’s Chemical Safety and Sustainability Program--and other emerging risk assessment activities, can help facilitate the development of more sustainable chemicals through improving high- throughput chemical testing and exposure assessment.

Assessing risks to and protecting the health of infants and children is a crucial role for risk assessment in the context of sustainability. This is particularly the case when infants and children are more sensitive or more highly exposed to environmental hazards.[236] EPA has established a Policy on Evaluating Risk to Children to ensure that environmental health risks of children are explicitly and consistently evaluated as part of EPA's risk assessments and that all standards set by EPA are protective of any heightened risks faced by children.[237]

What are the main steps in a Risk Assessment?        

Although the NRC reports focused on human health risk assessment for chemical exposures, the same basic process has been adapted for evaluating many other types of risk, including ecological risks. Risk assessment processes have been extensively reviewed, commented upon, and endorsed by both the EPA Science Advisory Board and the NRC and many external groups including academia and industry, and risk assessment has been used as a decision-making tool in every major EPA program.[226, 238, 239]
EPA has developed a large number of guidance documents for conducting all aspects of risk assessment. The classic four-step process of hazard identification, dose-response assessment, exposure assessment, and risk characterization were formally established with NRC’s publication of “Risk Assessment in the Federal Government: Managing the Process” in 1983, often referred to as the “Red Book”:

  • Step 1Hazard Identification: identify hazards and the type of effects potentially caused by the environmental exposure;
  • Step 2Dose-Response Assessment: assess the level of exposure (either a dose or exposure concentration) relative to the level of adverse effect;
  • Step 3Exposure Assessment: characterize the elements of the exposure (e.g., intensity, frequency, and duration); and,
  • Step 4Risk Characterization: combine the dose response and exposure assessments to describe the risk for the adverse effects determined through hazard identification. This step also involves characterizing the uncertainty in risk of effects along with the variability of the effects in the individuals exposed.
  • Other forms of risk assessment, notably ecological risk assessment, follow different steps, but the overall paradigm for these assessments is similar in that they evaluate the likelihood that adverse effects may occur or are occurring as a result of exposure to one or more stressors.
    For example, EPA’s guidance on ecological risk assessment identifies the following steps:[235]

  • Step 1—articulate the purpose for the assessment, define the problem, and develop a plan for analyzing and characterizing risk, if determined;
  • Step 2—evaluate available data to determine how exposure to stressors is likely to occur and, given this exposure, the potential and type of ecological effects that can be expected. This step is similar to the dose response and exposure assessment steps in the traditional [human health] risk assessment process; and,
  • Step 3—describe risks by integrating the exposure and stressor-responses profiles. Similar to human health risk assessment, risk characterization for ecological risk includes a summary of assumptions, scientific uncertainties, and strengths and limitations of the analyses.

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What are the strengths and limits of Risk Assessment in a sustainability context?

Risk assessment has moved beyond the chemical-by-chemical approach and made significant strides in addressing the combined effects of multiple exposures through cumulative risk assessment. In addition, cumulative risk assessment techniques are being developed to incorporate other non-chemical stressors (e.g., health conditions and psychosocial stress) into the overall assessment of risks for populations. [240] However, there is still great uncertainty in the approaches and the data for understanding exposures and health outcomes for cumulative risks.

Decision-makers face considerable limitations in being able to apply risk assessment in the case of compounds or conditions for which scientists lack strong data on effects. While NexGen and Tox 21 may help alleviate some of this limitation for chemical compounds, emerging substances (e.g., nanomaterials) and other sources of uncertainty such as stress or behavioral factors, are only beginning to be studied as to their role on health and the environment.

A wide range of information is needed to conduct risk assessments, including data on the nature and extent of contamination, fate and transport processes, the magnitude and frequency of human and ecological exposure, and the inherent toxicity of chemicals. In practice, information is usually limited in one or more of these key areas, which leads risk assessors to make estimates and use judgment when performing risk calculations; consequently all risk estimates are uncertain to some degree. To account for this, risk assessments should include a fair and transparent presentation of the uncertainties in the calculations and a characterization of how reliable (or how unreliable) the resulting risk estimates are. [241]

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How are Risk Assessments used to support EPA decision-making?

The importance of risk assessment at EPA is highlighted in the Agency’s Risk Assessment Portal , which provides basic information and links to EPA guidance and tools for analyzing risks in human health, ecological health, and many other fields. Risk assessment at EPA has evolved considerably since it was first introduced to evaluate cancer risk in 1976.[242] Today, risk assessments are important inputs into the process of developing environmental regulations, cleanup levels, and industrial permits.[192] Risk assessments may be used as a means of evaluating risk reduction associated with specific actions in any of these core EPA activities. EPA uses risk assessment to characterize the nature and magnitude of health risks to humans (e.g., residents, workers, recreational visitors) and ecological receptors (e.g., birds, fish, wildlife) from chemical contaminants and other stressors that may be present in the environment. Risk managers use this information to help them decide how to protect humans and the environment from stressors or contaminants.

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Where can I find more about Risk Assessment?

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Illustrative Approaches Applying Risk Assessment

  • EPA Design for the Environment

    Source: EPA Office of Chemical Safety and Pollution Prevention[257]
    Suite of sustainability tools: chemical alternative assessment; green chemistry; collaborative problem-solving; life-cycle assessment; risk assessment
    EPA’s Design for the Environment (DfE) Partnership Program helps consumers, businesses, and institutional buyers identify products that perform well and are cost-effective, but are safer for human health and the environment.[257] This program promotes sustainability by working with small businesses and consumers to identify risks involved with chemicals used in products or manufacturing processes. Chemical Alternatives Assessment is a key analytic tool for the implementation of DfE. It is a tool for evaluating chemicals of potential concern by comparing alternative chemicals within the same functional-use group across a consistent and comprehensive set of hazard endpoints. Other analytic tools that are instrumental for the conduct of this program include risk assessment and life-cycle assessment. Through the DfE, EPA collaborates with industry, environmental groups and universities to decrease health and environmental risk by encouraging green design and reformulation of a wide range of products while maintaining their effectiveness. As more consumers seek sustainable products that are designed to have minimal impact on the environment and their health, an environmental “seal of approval” could help consumers select products that match their values.[258

    DfE offers that “seal of approval” by awarding use of the logo on products that meet environmental design criteria. The logo assures consumers that the DfE scientific review team has screened each ingredient for potential human health and environmental effects and that—based on currently available information, EPA predictive models, and expert judgment—the product contains only those ingredients that pose the least concern among chemicals in their class. Products are also expected to meet effectiveness criteria, i.e., glass cleaners must meet criteria for effective glass cleaning. To obtain the DfE recognition, ingredients in the formulation must be publically disclosed (with the exception of specific allowances for trade secret ingredients). EPA also offers the DfE label to partnering companies that design or reformulate high-performance and cost-effective products using the safest ingredients.[258]

    The screening process (PDF) (43 pp, 726K) for the DfE logo is detailed and comprehensive. DfE scrutinizes ingredients, starting with known toxicity information and performing an inherent property analysis when toxicity information is not available. With inherent property analysis, scientists estimate toxicity for a chemical ingredient without toxicity information using available toxicity information for a chemical with similar structure. Strong structural similarities to a chemical with high environmental or health toxicity would be a flag for concern.

    DfE sets specific standards for chemicals of known toxicity. For example, DfE will not recognize products that contain any pollutants on the Hazardous Air Pollutants list. Furthermore, DfE will not recognize products that contain chemicals on the EPA Toxics Release Inventory chemical list unless they meet stringent DfE criteria.

    This program fosters sustainability in a cost-effective way that benefits companies, consumers, and environmental and public health. Through such partnerships and education, EPA is helping businesses and consumers select safer chemicals and technologies, thereby reducing the number of potentially hazardous chemicals in use.

  • The Future of Radiation Protection: 2025

    Source: EPA Office of Air and Radiation[255]
    Suite of sustainability tools: futures methods; green accounting; risk assessment; exposure assessment; collaborative problem-solving
    The Future of Radiation Protection: 2025 (PDF) (81 pp, 901K) is a report on challenges the radiation protection community will confront over the generation ahead. It is also a handbook with exercises that people in the field of radiation protection can use to develop better responses to those challenges. It is a product of a project carried out by the Institute for Alternative Futures with support from the US EPA. The project involved hundreds of people inside and outside the radiation protection community during a three-year period between late 1999 and early 2002.

    The project reached conclusions that are themselves challenging. The bottom line is that the challenges ahead are so numerous and serious that they cannot be dealt with successfully through business as usual. A major shift in perspective and approach is needed:

  • From To

    Exclusive focus on current issues, programs, budgets

    Greater attention to the full range of radiation-related challenges facing society, leading to major changes in current priorities

    Tacit assumption that the future will be much like the present

    Realization that the future is likely to be much worse than the present if business-as-usual continues

    Radiation protection defined primarily by a focus on “Legacy” issues

    Assessment that Legacy issues will decline in importance and that future needs center primarily around developing more preventative approaches to 4 Key Sectors: Energy, National Security, Industrial & Consumer, and Health

    Radiological attacks and other terrorist acts viewed as possible but not given a high priority

    Radiological attacks and other terrorist acts considered highly credible and on a high priority

    Reactive responses to problems after they become serious

    More anticipatory, preventative approaches to problems

    Conflicts between deeply entrenched positions

    Emphasis on good science and shared principles for working toward better positions

    Limited emphasis on public information and involvement due to habits of secrecy from the Cold War era

    Primacy of transparency and public right-to-know; emphasis on public education and as much access as feasible to credible, usable information

    Radiation protection as a community onto itself

    Integration of radiation and environmental protection through shared principles for guiding action, combined databases, and risk harmonization

  • Next Generation of Risk Assessment (NexGen)

    Source: EPA Office of Research and Development[269]
    Suite of sustainability tools: risk assessment; green chemistry
    EPA’s ORD is heading a multi-Agency program to bring the new biological testing described in the 2007 NRC report Toxicity Testing in the 21st Century: A Vision and a Strategy to EPA’s risk assessment program. The results of this effort will not only benefit EPA and partnering agencies’ risk assessors to incorporate molecular systems biology data into risk assessments, but also support industrial green chemistry efforts by providing a rapid way to make more sustainable choices in selecting industrial chemicals and evaluating their life-cycle.

    The program, called NexGen (for Next Generation of Risk Assessment), began in early 2008 as an effort to modernize the risk assessments being done by the Agency for IRIS and other purposes. A multi- Agency work group was established to analyze the vast quantity of molecular biology data being generated on various chemicals and discover ways to incorporate this new knowledge into the risk assessment process. The work group focused on three representative cases as proof of concept. They selected three well-studied cases for which there was not only an abundance of new molecular biology data, but also existing conventional risk assessments: benzene, ozone, and polycyclic aromatic hydrocarbons. In each case study, the work group attempted to “reverse-engineer” the processes described by the molecular biology results to discover if they might produce similar results to those seen in conventional risk assessment. After developing these three draft prototype cases, a group of experts from both inside and outside government was established to discuss the prototypes at a workshop held in November 2010. Experts from that workshop presented the concepts and the case studies at a Public Dialogue Conference in February 2011 to explain the program to a wide audience drawn from industry/trade associations, environmental/public health organizations, academia, media, citizens, international agencies, and other government agencies.

    The NexGen framework projects that, in the future, there will be three tiers of assessment. The first tier, which will be used for screening and ranking, will use high-throughput molecular biology methods as well as structure-activity analysis to examine tens of thousands of chemicals with potential exposure to seek information on hazards. (This approach can also be used in industrial green chemical selection). The second tier will focus on thousands of potential problem chemicals identified in tier 1 and include limited risk assessments based on science-based defaults and upper confidence limits. This may lead to hundreds of chemicals entering tier 3, where extensive analysis and risk assessment may lead to major regulatory decision-making.

  • EPA’s Healthy Schools Program

    Sources: EPA Office of Children’s Health Protection[270]
    Suite of sustainability tools: risk assessment; segmentation analysis
    Healthy schools are essential for ensuring a sustainable future for America’s children. More than 53 million children and about 6 million adults spend a significant portion of their days in more than 120,000 public and private school buildings. Many of these buildings are old and in poor condition, and may contain environmental conditions that inhibit learning and pose increased risks to the health of children and staff. Unhealthy school environments can affect attendance, concentration and performance, as well as lead to expensive, time consuming cleanup and remediation activities. EPA has developed a variety of tools to help prevent and resolve environmental issues and improve sustainable practices in schools, including the three examples outlined below.

    Voluntary Guidelines for Selecting Safe School Locations
    On October 3, 2011, EPA released the final School Siting Guidelines. These guidelines can be used by communities to help protect the health of students and staff from environmental threats when selecting new locations for schools. The new voluntary guidelines will help local communities consider environmental health issues in establishing school site selection criteria and in conducting effective environmental reviews of prospective school sites. The guidelines recommend involving the public throughout the site selection process to help ensure community support for these decisions.

    EPA developed the guidelines in consultation with other Federal agencies, states, school districts, community organizations, health care professionals, teachers, as well as environmental justice, children’s health and environmental groups, among others.

    By following the recommendations in the guidelines, communities, tribes, territories and states can help provide a safe, healthy, and sustainable environment for children, teachers and staff.

    Indoor Air Quality (IAQ) Tools for Schools Action Kit
    TheIAQ Tools for Schools Action Kit shows schools how to carry out a practical plan to improve indoor air problems at little- or no-cost using straightforward activities and in-house staff. The Kit provides best practices, industry guidelines, sample policies, and a sample IAQ management plan. This initiative is co-sponsored by the National Parent Teacher Association, National Education Association, Association of School Business Officials, American Federation of Teachers, and the American Lung Association.

    Healthy School Environments Assessment Tool
    HealthySEAT is a free, completely customizable software tool to help school districts establish and manage comprehensive facility self-assessment programs. Examples of school environmental hazards include chemical releases, pesticide exposures, flaking lead paint, mold and other indoor air quality problems, and damaged asbestos-containing building materials.

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