Environmental risk assessment is a tiered process used to evaluate and prioritise the risks posed by chemical substances to an environmental system or receptor. This is achieved using scientific techniques to analyse the hazards, potential for exposure and adverse effects caused by particular contaminants. Each of these factors is influenced to some degree by the properties of the chemical elements or compounds themselves, and of the media in which they are present.
Environmental risk assessments are used for many purposes and within a range of regulatory regimes. Although the specific methodology may differ in line with applicable legislation, the underlying principles remain largely the same.
Adeptus undertakes a range of environmental risk assessments which meet the requirements of regulatory regimes concerned with the actual or potential release of chemicals into the environment.
Our tiered or iterative approach to risk assessment ensures that cases where a simple screening assessment provides the necessary degree of confidence, no unnecessary work is undertaken. In the case of ‘borderline’ risks, the initial screening assessment may not be sufficient to enable a decision. Here, further assessment may be undertaken to fully characterise risk, or alternatively to derive a threshold concentration below which risks are acceptable.
Objectives of Environmental Risk Assessment
There is growing recognition of the need to ensure that natural ecosystems are not impaired by chemical exposure. This is due to both the importance of ecosystem function, and the ability for ecosystems to act as early indicators for possible impacts on human health. Increased public awareness of ‘man-made’ chemicals can also lead to concern that the mere presence of such substances equates a risk to human health or the environment.
In the case of existing soil contamination or groundwater contamination, risk assessment provides a basis for setting remedial objectives or clean-up standards, as well as for enforcement action by the regulators. Risk assessment is also crucial in predicting the future environmental distribution, persistence and toxicity of substances such as industrial effluents, petroleum products, gaseous emissions and mine tailings. The potential future risks from newly developed chemicals, or those being produced/discharged in increasing quantities is also routinely assessed by environmental distribution and toxicity modelling.
Equally, naturally occurring chemicals may be present at elevated concentrations due to the effects of human activity. At sufficiently high doses, either can be capable of causing toxic effects in organisms, ecosystems and humans. Impacts on human health can occur via direct environmental exposure, or indirectly via the food web.
Under specific circumstances, products designed for application to land may also present excess risk of environmental damage. Misapplication of fertilizers as well as pesticides can lead to pollution of waterways, with adverse impacts including damage to fish stocks, algal bloom and eutrophication.
Environmental Risk Assessment Methods
An environmental risk assessment generally comprises following stages. Each of these may be relatively simple and straightforward, very detailed, or somewhere in between; the degree of complexity will depend on the specifics of the situation under evaluation.
Typically, the nature and quantities of chemicals of concern must first be established, and the occurrences that could lead to harm identified. This enables an understanding of the consequences that are likely to result if the hazard were to be realised. The probability and magnitude (or severity) of the the adverse effects that might result from the hazard(s) are then factored into the risk assessment.
Contaminant concentrations may be available from laboratory analysis of contaminated media samples, allowing for relatively simple risk screening against predetermined standards. Where final or equilibrium contaminant concentrations are not known, contaminant physical chemical properties are used the to assess partitioning between air, water, soils, sediments and biota. This allows calculation of residence times, persistence and a predicted environmental concentration (PEC).
Various toxicity data are analysed and statistical procedures may be utilised to evaluate the relationship between any ‘dose’ of a substance and the toxic response or harm caused. This is referred as the dose-response relationship. The outcome of this stage is either an estimation of toxicity at the PEC derived from the exposure assessment, or a predicted no [toxic] effect concentration (PNEC).
In the final step, the above factors are considered together. Assessment of likelihood and severity of any adverse effects will allow risk to be characterized quantitatively, qualitatively or both. Ultimately, the degree of risk that can be deemed acceptable will depend on the sensitivity and importance of the situation or receptor in question and the regulatory regime under which it falls.
Broadly, where risks are deemed low enough that no reduction measures are necessary, periodic monitoring may be the only requirement to ensure this remains the case. Where the magnitude or probability of hazard result in an unacceptable risks (such as those affecting human health), risk reduction measures and/or a remediation strategy may be required.
Further detailed risk assessment may become necessary where either a) screening suggests unacceptable risks that must be quantified; b)
In some cases the answer may not be as clear cut as above. In such cases, detailed toxicological risk assessment may be required.
As environmental risk assessment consultants we have extensive training and experience in the application of scientific data and principles to real world situations. We works with many organisations and stakeholders to deliver pragmatic, commercially aware environmental risk management and reduction solutions.
Please contact us via the form beneath this page, or on 0161 667 1292 to discuss your requirements with a risk assessment consultant.