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Extra sessions to begin Tuesday. Thank you. Risk Assessment. Yes, I do want you to do the readings. What are the basic concepts applicable to all environmental risk assessments - human health risk assessments - ecological risk assessment - industrial applications of risk assessments.
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Extra sessions to begin Tuesday Thank you
Risk Assessment Yes, I do want you to do the readings
What are the basic concepts applicable to all environmental risk assessments • - human health risk assessments • - ecological risk assessment • - industrial applications of risk assessments
What are the unifying concepts? • What are their currently used methodologies? • How are they applied?
Risk assessment concepts • Hazard • Risk • Risk assessment • Risk management • Risk perception • Risk communication
The technique of risk assessment is used in a wide range of professions and academic subjects Risk assessment has become a commonly used approach in examining environmental problems. For instance, the approach is used to assess the environmental risks posed by Genetically Modified Organisms (GMOs), chemicals, ionising radiation and specific industrial plants. Definitions in risk assessment are all-important because of the wide range of uses of the approach, and different meanings of terms used by different groups of experts and practitioners.
Hazard • “the potential to cause harm” • Can be defined as “a property or situation that in particular could lead to harm” • Risk • A more difficult concept to define • Used to mean “chance of disaster” • In the process of risk assessment, most commonly means: ‘the combination of the probability, or frequency, of occurrence of a defined hazard and the magnitude of the consequences of the occurrence.” • Risk = Severity x Likelihood • Risk assessment • the evaluation of the degree of harm or danger from some condition such as exposure to a toxic chemical - either quantitatively or quanlitatively • The process of determining an expected annual mortality • Carried out to examine the effects of an agent on: • Humans (health risk assessment) • Ecosystems (ecological risk assessment)
Environmental risk assessment (ERA) • examination of risks resulting from technology that threaten ecosystems, animals and people. • Includes • human health risk assessments, • ecological or • ecotoxicological risk assessments, • and specific industrial applications of risk assessment that examine end-points in people, biota or ecosystems. • Many organisations are now actively involved in ERA, developing methodologies and techniques to improve this environmental management tool. • OECD (organization for economic cooperation and development) • WHO (world health organization) One of the major is the availability and certainty of data
Risk perception • What do the risks mean to those effected? • Depends on how the risk is perceived • depend heavily on how the risk is perceived. Risk perception involves people's beliefs, attitudes, judgements and feelings, as well as the wider social or cultural values that people adopt towards hazards and their benefits. • Risk perception will be a major determinant in whether a risk is deemed to be "acceptable" and whether the risk management measures imposed are seen to resolve the problem. • Risk Management • the decision-making process through which choices can be made between a range of options which achieve the "required outcome” – i.e. reduction of risks to an "acceptable" level within the constraints of the available resources. • Managed how? • Eliminated (total ban on the use or marketing of a hazardous chemical) (but what about the substitute?) • Transferred (risk transferred to insurance companies, eg) • Retained (more often retained w/o knowledge) • Reduced (most common approach; regulation, voluntary industry agreements
As Lois Gills of Love Canal stated ‘From a community’s perspective, risk assessments are ‘the risks that someone else has chosen for you to take.’ What is a life worth … but equally important is whose life”’ Is risk a technical matter that is determined objectively or a social construction that emerges from communication among experts, affected parties, and public agencies?
Risk communication • Simplest form: any public or private communication that informs individuals about the existence, nature, form, severity, or acceptability of risks • An increasingly important area of risk management • The way in which information relating to risks is communicated • Closely linked to risk perception Can be: one-way transmission of information two-way exchange of views on the risk
Role of risk assessment in environmental management • Can be used in the design of regulation • Targets for regulation can be selected (risks > benefits?) • Societally ‘acceptable’ risk levels can be determined (ALARP) • Decisions can be made on the appropriate level of risk reduction • Can provide a basis for site-specific decisions, for instance in land-use planning or siting of hazardous installations (eg: risk posed by contaminated land sites in relation to the land’s proposed use and remediation measures) • To prioritize environmental risks, for instance in the determination of which chemicals to regulate first – within context • To compare risks; for instance to enable comparisons to be made between the resources being allocated to the control of different types of risk, or to allow risk substitution decisions to be made.
What risk assessment and management can and cannot do • Good points • A technique which can weigh-up information that is basically in different "languages” (provides a bridge between the scientific and the social) • A mechanism to aid decision-making (aid) • As a means of comparison between risks to determine whether there is equity of action or that the action is proportionate to the risk • A basis for effective risk communication (but there are limitations – need to address the value issues that underlie the perception of risk) • A method for highlighting and prioritising research needs • Pitfalls • Possible over-reliance and over confidence in results (uncertainties) • Narrow focus on parts of a problem rather than the whole (parts, not the whole) • Awkward relationship between risk assessment and the precautionary principle
A typology of risk assessment and management methods • Human health risk assessment • Ecological risk assessment The former have a differing historical development and regulatory and policy imperatives • Applied industrial risk assessment (more engineering risk assessment) • Methodology least developed for ecological risk assessment
Overview of risk assessment methods • What are the steps required in all types of risk assessment? • Number of hazards that can be examined through ERA is vast • Techniques have also evolved differently due to the institutional basis of the risk assessor and the intended use of the risk assessment
Nat’l Academy of Sciences model • Hazard Identification • Dose-Response Assessment • Exposure Assessment • Risk Characterisation • Developed for human health risk assessment; formed the basis of ecological models of risk assessment used in the US • But does not encompass all the types of ERA in use
ERA unifying steps • Problem Formulation: • Hazard Identification • Release Assessment • Exposure Assessment • Consequence Assessment • Risk Estimation • Risk Evaluation
Health Risk Assessment • Methodologies and techniques firmly established • Physical Risks - Ionising Radiation • Chemical Risks • Food Safety Risk Assessment
Chemical Risk Assessment • Legislation • The procedures, methods and techniques for regulatory risk assessment of chemicals in the EU is described in both legislation and supporting Technical Guidance Documents. Implementation is supported by the European Chemicals Bureau, part of the Joint Research Centre, in Ispra. • Same with the US. • What about Lebanon? • International Organisations such as OECD, IPCS and ECETOC and many National Organisations are conducting programmes on human health and ecological risk assessment. The work contributes both to the shaping of regulation and the response to regulation.
CRA • Human Health Risk Assessment for Chemicals • Based on the NAS model. Remember that? • Difference in methodology is due to difference in class of chemical and toxicological end-point being assessed • All human health risk assessments of chemicals include hazard identification, dose-response assessment, exposure assessment and risk estimation/characterisation. • Hazard Identification is defined as "the identification of the adverse effects which a substance has an inherent capacity to cause" (CEC, 1993). This involves consultation of any toxicological and epidemiological data.
CRA: Human Health Risk – chemical risk • Dose-Response Assessment • Dose-response assessment is the "estimation of the relationship between dose, or level of exposure to a substance, and the incidence and severity of an effect" (CEC, 1993). • The dose-response relationship is gotten from epidemiological and toxicological data • The principle of the assessment is to compare the [ ] of a substance to which a pop is exposed w/ the [ ] of a at which no adverse effects are expected to occur • Risk reduction measures • Raising awareness on the safe handling of substance • Use of emission permits with set limits • Marketing restrictions • Total ban of a substance or activity
CRA: Human Health Risk Assessment for Chemicals • Exposure Assessment • Typically based on the NAS model • The "determination of the emissions, pathways and rates of movement of a substance and its transformation and degradation in order to estimate the concentration/doses to which human populations or environmental compartments are or may be exposed” • Environmental exposure to chemicals can be direct - as a result of emission to the environment (air, land, water) of a substance through industrial manufacture, use or disposal, • or indirect - through drinking water or the food chain.
Reminder: NAS model • Hazard Identification • Objective is to identify the substance(s) that could injure humans exposed to them and thus to reduce injury • A relation exists between the dose of agent received and the response produced. Experiments conducted. Use of epidemiological data (mainly based on observational approaches) • Dose-response assessment • Estimation of the relationship between dose, or level of exposure to a substance, and the incidence and severity of an effect. Typically –direct human data is lacking • Exposure assessment • Determination of the emissions, pathways and rates of movement of a substance and its transformation and degradation to estimate the [ ] / doses to which human populations or environmental compartments are or may be exposed • Via lungs, via digestive tract, and via skin • A range of exposure values should be estimated • Risk characterisation • Estimation of the incidence and severity of the adverse effects likely to occur in a human population or environmental compartment due to actual or predicted exposure to a substance; may include ‘risk estimation’ (quantification of likelihood); summary of data in risk assessment process + uncertainties
Different typologies of health risk assessment • * Neurotoxic (examples of lead and pesticides) • * Immunotoxic (example of allergenic substances) • * Developmental (example of thalidomide) • * Reproductive (example of phthalates) • * Carcinogenic (example of dioxins)
HRA – biological risks • those risks associated with biological agents of concern to public health such as pathogenic strains of bacteria, which are of particular concern as food-borne hazards, • and those risks associated with the introduction of genetically engineered organisms into the environment or the food chain. • The World Health Organization has adopted risk assessment as the main way to scientifically justify food safety standards (FAO/WHO, 1995). • However, significant problems exist when applying quantitative risk assessment techniques to microbial hazards, such as the difficulties in obtaining dose-response data and elaborating appropriate dose-response relationships in humans
Ecological risk assessment • Ecological Risk Assessment (EcoRA) involves the assessment of the risks posed by the presence of substances released to the environment by man, in theory, on all living organisms in the variety of ecosystems which make up the environment. • EcoRAs tend to focus: • risks from chemicals and Genetically Modified Organisms (GMOs) • physical risks such as temperature rises caused by cooling water releases from industry.
Ecological Risk Assessment • EcoRA methodology has been developed from that already established for human health. • The general principles are widely agreed upon but the application of the process still provokes considerable argument. • The Health Risk Assessment (HRA) approach lends itself well in many respects to EcoRA but, due to the complex nature of the potential target(s) or receptor(s), several problems have presented themselves to practitioners. • HRA is concerned with individuals and morbidity and mortality, • EcoRA -- populations and communities and the effects of substances on mortality and fecundity. • Thus…
EcoRA • EcoRA has to deal with a multitude of organisms, all with varying sensitivities to chemicals and various groups have distinct exposure scenarios • Because of the difficulty in obtaining toxicity data on all organisms in an ecosystem, • the recognised practice is to test selected representatives of major taxonomic groups and use these as surrogates for the whole system. • But: This method is questionable • It may not protect the most sensitive species exposed in the environment. • Failure to identify the effects of an agent on a potential receptor can result in widespread damage to organisms and ecosystems.
The Risk Assessment Process for Chemicals • The method for ERA as used by the EU • Four steps used in Health Risk Assessment • Effects Assessment involves the identification of the hazard based on its physico-chemical properties, ecotoxicity and intended use, and the estimation of a Predicted No Effect Concentration (PNEC), derived from ecotoxicity data and the application of assessment factors; • Exposure Assessment involves the calculation of a Predicted Environmental Concentration (PEC). This is derived using monitoring data, realistic worst cases scenarios and predictive modelling techniques. It is a complex task and should consider release, degradation, and transport and fate mechanisms. Local relevant emission and distribution routes are shown in Figure 6.3. • Risk Characterisation involves the calculation of a quotient - the PEC/PNEC ratio. If the ratio is less than 1 the substance is considered to present no risk to the environment in a given scenario.
Exposure assessment: Local relevant emission and distribution routes
ERA • a developing field • Many problems which need resolving such as; • Determining the effects at population and community levels • Selection of end-points; • Selection of indicative species; • The selection of field, laboratory, mesocosm and microcosm tests • The incorporation of resilience and recovery factors of the ecosystem. • Many organisations are actively involved in the development of ecological risk assessment methodology, they include the US EPA, the US NRC, OECD, SETAC and ECETOC.
Evaluation of risk and risk management • Complex process of determining the significance or value of the identified hazards and estimated risks to those concerned, or affected • The evaluation of risk is concerned with issues relating to how those affected by risks perceive them, the value issues underlying the perceived problem and the trade-off between the perceived risks and benefits. • Let’s look at the factors involved in risk perception and risk acceptance. • We will also examine the advantages and disadvantages of the major approaches used in making risk management decisions - bootstrapping, formalised methods such as cost-risk-benefit analysis, and professional judgement.
The importance of risk evaluation and perception • Risk evaluation attempts to define what the estimated risk actually means to people concerned with or affected by the risk. • A large part of this evaluation will be the consideration of how people perceive risks. • We will provide an overview of the psychometric and cultural approaches underpinning risk perception, offering an insight into the reasons why risks are perceived in different ways.
How safe is safe enough? • ? = how safe is safe enough? • An ERA will characterise the risk posed by a situation and then the process of risk management will eventually lead to a choice of action that will achieve the desired level of "safety". • The determination of this "acceptable" or "tolerable" level of risk may have been prescribed before the risk assessment process begins - through societally determined acceptable levels of risk in the form of legislative environmental quality standards for instance, or industry derived "norms". • In this case, risk management attempts to analyse which options for action based on the results of the risk assessment will produce these pre-determined risk levels.
… the risk management process will attempt to derive ‘acceptable’ or tolerable risk on a case-by-case basis • Thus • Acceptable to whom? • When risk assessment and management procedures are carried out by regulators or government, the aim is to produce societally acceptable risk levels. • When an individual company carries out a risk assessment, in the absence of societally determined standards, risk levels will be determined which are acceptable to the company. These may have reference to societally acceptable levels or may be based on a formal risk-cost-benefit approach as advocated by some software packages on risk reduction.
Decision making to determine "acceptable" or "tolerable" risk uses a number of approaches. The three major approaches to acceptable risk decisions -- are professional judgement where technical experts devise solutions, -- bootstrapping where historical precedent guides decision making -- formal analyses where theory-based procedures for modelling problems and calculating the best decision are used. These approaches are explained in detail in the readings.
Risk management action • Environmental risk can be: • transferred to another body such as an insurance company, • retained by a company or nation, • eliminated by removal of the risk agent, • reduced. In most environmental risk management conducted by nations on behalf of society, risk reduction will be the risk management option chosen. For individuals or companies, risk transfer is a common approach. This may be required by legislation, especially for infrequent catastrophic events. Risk elimination is often very difficult because of all the social and economic effects the removal of an agent can create.
Risk reduction? • substitution • Can the agent be substituted by another, less risky agent? For instance, can a chemical pesticide be substituted by a biological method? What are the risks of the new agent being introduced into the scenario? Is the new agent as effective? • information • Providing information about the safe use and disposal of agents will try to ensure that the risks assessed are the same as what actually occur in practice. • information • Education and information may also allow the public and users to choose lower risk options and force the manufacturers into the production of less risky agents. • --> marketing • Limit the availability of the agent by marketing bans or limits on the production or importation of the agent. Such a risk reduction technique has severe implications politically and economically and can often be controversial. Such decisions are taken at a national or regional level and at an international level such agreements are difficult to obtain.
New directions • Risk Assessment: • Harmonisation of risk assessment methods • Data deficiencies and gaps • Harmonisation of test protocols for chemicals • Understanding of mixtures or multiple stressors • Improvement of exposure assessment • Internationally harmonised assessment factors • Speeding up risk assessments
New Directions • Risk Management: • Development of explicit methodologies for risk management • Increased transparency of decision-making • Peer review of risk management assessments • Increased participation in risk management
Risk Communication • Reminder: Risk communication is defined in its simplest form as “any public or private communication that informs individuals about the existence, nature, form, severity, or acceptability of risks” • As we’ll see, it actually involves more than that! • From a technical perspective, • risk assessment = the evaluation of the degree of harm or danger from some condition such as exposure to a toxic chemical, • while risk management = the implementation of steps to reduce the danger to the public and the environment
Risk assessment - again • Risk = Severity x Likelihood • a technical, four-step procedure: • Hazard identification. What is the potential source of danger? For example, does a waste incinerator emit highly toxic dioxins or other hazardous chemicals? • Assessment of human exposure. Are any human populations exposed to this hazard? If so, can the various routes or pathways of the hazardous substance to specific organs or tissues of human bodies be traced? Finally, how much (what dosage) of this substance enters these human bodies? • Modeling of the dose responses. What is the relationship between the dosage that is received and harmful responses or illnesses in the exposed population? • Characterization of the overall risk. What are the overall implications of the dose responses for the health of the exposed population? • Technical models of risk assessment use the resulting numerical value as the basis for judgments of what is an “acceptable risk. This judgment involves values.
Limitations of technical model • exceedingly difficult to trace the “pathway • need to show direct correlation between particular chemicals and the specific illnesses • Cultural-Experiential Model of Risk • technical models conflate numerical risk (expected annual mortality) with judgments about the experience of those forced to live with imposed or involuntary risks • big difference between those who take risks and those who are victimized by risks others take
‘hazard’ versus ‘outrage’ • experts often make assumptions about environmental risks that are quite removed from the experience of those affected by these risks • the context in which a risk is embedded raises a number of questions that may affect one’s judgment of whether a risk is acceptable or not: • Is the risk imposed by distant or unknown officials? • Is it engaged in voluntarily? • Is it reversible?
Sandman’s proposal • Risk = hazard + outrage • Hazard is what experts mean by risk (expected annual mortality) • Outrage should refer collectively to those factors that the public considers in assessing whether their exposure to a hazard is acceptable • Voluntariness • Control • Fairness • Process • Diffusion in time & space