EcoRA
The ecological risk assessment is a rather complex process, resulting finally into the assessment of stress factor influence on ecosystems or on their components. At present, these methods represent the most suitable and an increasingly employed tool which is used both in the Czech Republic and abroad to assess an existing or potential risk and the negative impact of anthropogenic and non-anthropogenic activities on the ecosystems structure and function.
This text provides a basic introduction of methodology and gives an overview of tools facilitating the risk assessment. A case study is also provided, giving an example of applying individual stages of EcoRA procedure on real data.
This tutorial has been created at the RECETOX research centre, cooperating with the Institute of Biostatistics and Analyses of MUs Faculty of Medicine and Faculty of Science.
The main information source for this tutorial was Methodology of Ecological Risk Assessment published in 2002 as a final report of the project IDRIS II (VAV 340/1/00) by TOCOEN, s.r.o., which is a complete methodology for EcoRA process together with the core publications in this field.
The conception of ecological risk assessment is based on several essential parts (stages). This structure is more or less followed in all available methodical procedures. The basic conception thus involves problem formulation, exposure assessment, effects assessment, and risk characterization.
Basic definition of Ecological Risk Assessment
The Ecological Risk Assessment (EcoRA) provides tools to assess negative impacts of natural disasters, human activities and pollutants on organisms or on entire ecosystems.
Problem formulation - more
The problem formulation involves the identification of objectives and assessed endpoints, the preparation of conceptual model and the establishment of analyses plan. In this stage, the core of the problem is characterized; potential stressors are described, as well as their sources, the region of interest and potential risks. A rich informational background must be established in this stage, in order to facilitate the decision process in the subsequent stages, and to make our work easier then.
Exposure assessment
The exposure assessment is one of two analytical stages of the process. The aim of this stage is to make the best possible description of ways how the monitored parameters can be exposed to specific stressors and how to quantify this exposure. The input data can be, for example, real environmental concentrations in a specific matrix, or data from contaminants determination in organisms tissues. Various exposition models can be very useful.
Effects assessment
The effects assessment is another analytical stage. Its objective is to characterize the relationship between the exposure to the stressor and the stressors influence on the assessed organism. The effects assessment might be based on epidemiological studies; in most cases, however, the information from toxicity testing is used. The values obtained in this stage will be employed in the subsequent risk assessment.
Risk characterization
The risk characterization is a summary output of risk assessment, resulting from the data integration from previous stages. The effects of stressor exposure - with the objective to describe the risk - can be defined as the surface of a four-dimensional space. The individual dimensions are concentration of stressor to which the receptor is exposed, time of exposure, receptors properties and form of effect. In addition, the risk characterization involves the uncertainty assessment as well as the consideration of available evidences before giving a final output.
Risk description
Risk description provides important information to interpret the risk results and identifies a threshold for adverse effects on the assessment endpoints. When evaluating ecological risks and the potential for response alternatives to achieve acceptable levels of protection, risk managers should characterize risk in terms of magnitude, severity, distribution, and the possibility of recovery for the affected receptors.
Risk management
The ecological risk assessment should find out whether a risk is present and to define a magnitude of that risk. With this information, risk managers have to integrate the risk assessment results with other considerations to make and justify risk management decisions. Other considerations in making risk management decisions include existing background levels of contamination, available cleanup technologies, and costs of alternative actions and remedy selections.
Risk communication
It is the process of informing people about the hazards of monitored site. The purpose of this step is to help residents of affected communities to understand risk assessment and risk management, form scientifically valid perceptions of the likely hazards and participate in making decisions about how risk should be managed.The process of informing people about site hazards is a two-way conversation in which the site team informs and is informed by affected community members.
Main information sources for EcoRA methodology
- EPA (1992) Guidelines for exposure assessment. U.S. Environmental Protection Agency, Risk Assessment Forum, Washington, DC, 600Z-92/001.
- EPA (1998): Guidelines for ecological risk assessment. U.S. Environmental Protection Agency, Risk Assessment Forum, Washington, DC, EPA/630/R095/002F, 1998.
- EPA (2003): Ecological Assessment Endpoints (GEAEs) for Ecological Risk Assessment. U.S. Environmental Protection Agency, Risk Assessment Forum, Washington, DC. EPA/630/P-02/004F.
- European Commission (2002): Report on a harmonised approach to the Ecological Risk Assessment of Chemicals, preliminary report, discucced by the scientific steering committee at its meeting of 7-8 November 2002.
- Holoubek, I., Dušek, L., Bláha, L., Anděl, P., Maršálek, B. Hofman, J., Šmíd, R., Klimeš, D., Jarkovský, J., Čupr, P., Škarek, M., Kohoutek, J., Holoubková, I., Šnábl, I., Kukleta, P. (2002): Region specifický přístup v analýze ekologických rizik - metodika hodnocení ve vztahu k přírodním katastrofám. Závěrečná zpráva projektu VaV/340/1/00. TOCOEN, s.r.o., Brno. TOCOEN REPORT No. 225.Brno, listopad 2002.
- Holoubek, I., Hofman, J., Doležal, L., Dušek, L. (2000): Shrnutí experimentálních výsledků z případové studie Zlín prováděné v rámci projektu VaV 340/1/96: Vliv povodní v roce 1997. Pro MŽP ČR vypracoval TOCOEN s.r.o., Brno. TOCOEN REPORT No. 180. Brno, listopad 2000. 62 stran + přílohy.
- Suter, G. W II (1993): Ecological risk assessment. Lewis Publ., Boca Raton, Florida, 538 p.
- Suter, G. W. II, Efroymson, R. A. Sample, B. E and Jones, D. S (2000): Ecological Risk Assessment of Contaminated Sites. Lewis Publ., Boca Raton, Forida, 438 p.
