Level of analysis: Micro (on substances) and Macro (on policies)
Assessed aspects of sustainability: Environmental and social
Main purpose of the assessment: To assess either environmental or health risks (or both) from a product, process, project or policy in qualitative and/or quantitative ways to assist in decision-making for minimising those risks.
Description of the methodology: Risk assessment is most-commonly used in assessing the environmental, health and safety related risks posed by chemicals, harmful substances, industrial plants, etc. Methodologically, it is rooted in two analytical approaches: probability theory and methods for identifying causal links between adverse effects and different types of hazardous activities.
Risk assessment is used in wide range of professions to examine risks of different natures. It is most-commonly used in assessing the environmental, health and safety related risks posed by chemicals, harmful substances, industrial plants, etc. Environmental Risk Assessment (ERA) is usually used as an umbrella term covering Human Health Risk Assessment (HRA), Ecological (or eco-toxicological) Risk Assessment, and specific industrial applications of risk assessment that examine endpoints in people, biota or ecosystems (Calow, 1998). The risks examined in the assessment can be physical such as radiation, biological such as a genetically modified organism or pathogen, or chemical such as an immuno-toxic substance (Fairman et al., 1998). Although the foundations of environmental risk assessment methodologies have traditionally been based on the investigation of effects on human health, the methodologies have also been expanded to examine the threats to ecosystem (DEFRA, 2000).
Methodologically, RA is rooted in two analytical approaches: probability theory and methods for identifying causal links between adverse effects and different types of hazardous activities.
Depending on the characteristics of the problem under review and the availability and form of data required, the risk assessment approach could be qualitative, semi-quantitative or quantitative. Quantitative RA is the determination of the probability and consequences of potential losses in numerical terms. The assignment of probability values to the various events in the risk model provides for a quantitative assessment of risk. Quantitative RA is unambiguously defined as a “probability x consequence” and provides a more uniform understanding among different individuals than qualitative risk assessment. Although the bulk of the effort in developing methods of risk analysis has been addressed to quantitative methods, critical aspects of risk frequently require qualitative evaluation. Qualitative RA may use “expert” opinion to estimate probability (or frequency) and consequence (or impacts) in terms of expressions as ‘likely’, ‘may occur’, ‘not likely’ and ‘very unlikely’.
The analysis of risks can be approached in several ways, from very general and rough to very detailed (DEFRA, 2000). Depending on given circumstance, including the type of activities, the study area, potential gaps in data and/or models and the uncertainty issue of risk assessment, the different steps and methods to be used in RA will differ. In general, the Risk Assessment includes the following steps (Fairman et al., 1998):
- Problem Formulation: Like scoping in LCA, initially the problem has to be defined and certain issues such as, sources of risks to be assessed and their characteristics, type of hazards, receptors, regulatory requirements, etc. must be clarified before the risk assessment starts.
- Hazard Identification: The identification may involve the establishment of all of the relevant hazards that may cause harm and working backwards to identify how this harm could occur.
- Release Assessment: This step attempts to give a measure of the likelihood of a release or occurrence of a hazardous situation. In quantitative risk analysis, a quantitative estimation of the probability of occurrence can be approached either using direct statistical data on the system under investigation or using analytical or simulation techniques. Expert judgment can be used to estimate the likelihood or probability of occurrence of hazards.
- Exposure Assessment: It includes a description of the intensity, frequency and duration of exposure through the various exposure media (routes of exposure) and the nature of the population exposed.
- Consequence Assessment: A Consequence Assessment will examine the effect of the release or production of the hazards, to the specified population and the quantification of the relationship between specified exposures to the hazard and the consequences of those exposures.
- Risk Estimation: Risk estimation consists of integrating the results from the release assessment, exposure assessment and the consequence assessment to produce measures of environmental risks. This may include an estimate of the numbers of measures indicating environmental damage, and the uncertainty involved in these estimates.
- Risk Evaluation: Risk Evaluation is the examination of significance of the identified hazards and estimated risks in practice. This includes acknowledgement of the public perception of the risk and the influence that this will have on the acceptability of risk and risk decisions.
An important aspect of RA is the estimation of the associated uncertainty, which is inherent to all risk assessments. There are several potential sources of uncertainty, e.g., gaps in historic/recent data. The consequence and exposure steps are one of the most important areas in which completeness of data are problematic. Quantifying all sources of uncertainty is difficult (Chapman, 2006). Methods used for estimating the uncertainty in RA include statistical analysis (for uncertainty related to data and parameters and models), expert judgment (for uncertainty related to models) and sensitivity analysis (for uncertainty related to future trends).
Risk assessment and management techniques are used as decision-making tools in policies and regulations. The RA approach is fundamental in development of EU policies and regulations for chemical, radiological and microbiological food borne hazards (Cowell et al., 2002; Rogers, 2003). The range of applications is wide and includes (Fairman et al., 1998):
– The design of regulation, for instance determining societally “acceptable” risk levels which may form the basis of environmental standards;
– Providing a basis for site-specific decisions, for instance in land-use planning or siting of hazardous installations;
– Prioritisation of environmental risks, for instance in determinations of chemical to regulate first;
– Comparison of risks, for instance to enable comparisons to be made between the resourcesbeing allocated to the control of different type of risk.
Like LCA, it is an analytical tool, which is used as a support in decision making in environmental management. In practice LCA and RA can be applied in several different combinations: completely separated, RA as a subset of LCA, LCA as a subset of RA and as complementary tools to get the whole picture (Flemströ, et al., 2004). The most common approach of combining LCA and RA is to include ecotoxicological and toxicological parameters in life cycle impact assessment (LCIA) used in a LCA, which has been performed in a number of well known impact assessment methods. Data generated from RA are very useful in the assessment component of LCA, especially toxicity (Olsen et al., 2001). The difficulty with data availability is also common for the two methods.
Risk assessments, compared to LCAs, are prepared due to legal requirements and the results as well as data sources are reported to authorities. Since data sources are reported and data quality requirements are high, the data acquisition for a RA study could be more extensive and costly than the data acquisition for a LCA study. In addition, the following are the other key differences between LCA and RA (Cowell et al., 2002; Sleeswijk et al., 2003):
– RA focuses on a specific harmful endpoint arising from product, process or event and their occurrence in specified scenarios.
– Unlike LCA, the absolute magnitude of a product or activity is very important in RA.
– In RA site-specific impact modelling is feasible as it is concerned with objects located at one or limited number of sites.
– RA results are defined in time and hence provide information concerning the timing of impacts, which is not possible with LCA.
– RA does not cover all emissions from all processes involved in a specific technical system e.g. transports and energy production, it only covers a part of the environmental impacts caused by a product.
– Furthermore, RA is often performed as a ‘worst-case’ analysis to ensure a safety distance to unwanted effect.
In RA site-specific impact modelling is feasible as it is concerned with objects located at one or limited number of sites. It can assess local or regional effects on specific targets.
It facilitates the comparison of environmental risk with other more familiar risks.
RA results are defined in time and hence provide information concerning the timing of impacts, which is not possible with LCA.
The risk assessment in practice may include an evaluation of what the risk mean in practice to those affected. However, this will depend heavily on how the risk being assessed is perceived.
RA focuses on parts of a problem rather than the whole. The most commonly performed risk assessment concentrate on single chemicals. Site–specific risk assessment may examine a number of risks but each will be done in isolation as the scientific data are not available for looking at the mixtures of agents yet.
Quantitative RA requires data, much of which is not currently available, the costs and time involved in obtaining data are huge.
Because of multiple uncertainties, risk assessments could either grossly under estimate or over estimate risks.
The results of RA require specialist knowledge to understand and interpret in a decision making context.
Quantitative RA results give an illusion of certainty that may not reflect the uncertainties in the models used to produce the results.
Opportunities for broadening and deepening LCA
Data generated from RA are very useful in the assessment component of LCA. The integration of LCA and RA provides an opportunity for data exchange between LCA and RA to get a better picture. For instance, emission data for industrial processes can be used for risk assessment and in life cycle inventories. The same holds true for toxicity information usable in risk assessment and life cycle impact assessment. In this regard (Sleeswijk et al., 2003) suggest that RA and LCA to be incorporated into a common modelling tool, containing a common database. Such an overall modelling tool would deliver the risks of individual chemicals and the impact scores for all LCA impact categories as output.
ERA provides a perfect framework to industries for demonstrating compliance with regulatory policies.
The recently enforced European Community regulation on chemicals, REACH (Registration, Evaluation, Authorisation and Restriction of Chemical substances) requires that the hazard data are collated in the form of a Chemical Safety Assessment (CEU, 2006). This needs to include hazard data relating to physico-chemical data, human health and environment and conclude with classification and choice of hazard phrases. A full risk assessment to meet the requirements of Directive 93/67/EEC (as described in its associated technical guidance documents), is expected for new substances being notified or for high-volume high-risk ‘existing’ substances being reviewed under the existing chemicals regulations. However, REACH will lead to the need to perform a risk assessment on virtually all substances being supplied in the guise of a ‘Chemical Safety Report’ (CSR).
Threats for broadening and deepening LCA
RA approach and results are more prone to public distrust because of the complexity of the issues and potential of subjectivity of the assessor(s). This could have implications for public credibility of the assessment.
Calow, P. (1998) Handbook of Environmental Risk Assessment and Management, Blackwell publishing.
CEU (2006) Regulation Concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) (EC) No 1907/2006, Council of the European Union (CEU), Brussels.
Chapman, A. (2006) Regulating Chemicals—From Risks to Riskiness, Risk Analysis, 26(3): 603-616.
Cowell, S., Fairman, R. and Loftstedt, R. (2002) Use of Risk Assessment and Life Cycle Assessment in decision making: a Common policy research agenda, Risk Analysis 22 (5): 879-894.
DEFRA (Department of the Environment, Transport and the Regions) (2000) Guidelines for environmental risk assessment and management http://www.defra.gov.uk/environment/risk/eramguide/index.htm
Fairman, R., Williams, W. and Mead C. (1998) Environmental Risk Assessment: Approaches, Experiences and Information Sources, Environmental Issues Series No. 4, European Environment Agency, Copenhagen.
Flemströ, K., Carlson, R. and Erixon, M. (2004) Relationships between Life Cycle Assessment and Risk Assessment -Potentials and Obstacles, Naturvårdsverket Report 5379.
Olsen, S., Christensen, F., Hauschild, M., Pedersen, F., Larsen H. and Tørsløv, J. (2001) Life cycle impact assessment and risk assessment of chemicals — a methodological comparison, Environmental Impact Assessment Review, 21(4): 385-404.
Rogers, M. (2003) The European Commission’s White Paper “Strategy for a Future Chemicals Policy”: A Review, Risk Analysis, 23(2): 381-388.
Sleeswijk, A., Heijungs, R and. Erler, S. (2003) Risk Assessment and Life-cycle Assessment Fundamentally Different yet Reconcilable, Greener Management International, 41 (Spring): 77-87.