Environmental Risk Assessment

Background

Environmental Risk Assessment (ERA) of chemicals is a systematic, scientific process used to evaluate the potential risks that chemical substances pose to the environment and its various components. Whilst different chemical types are governed by their own legislations and have specific requirements, they have similar overarching objectives for protecting the environment.

The main objectives of ERAs include:

Identifying and quantifying hazards – ERA determines what environmental threats exist from chemicals and estimates the likelihood and magnitude of potential harm.

Protecting ecosystems – The process helps safeguard natural habitats, wildlife populations, and ecological processes from degradation or destruction by setting protection goals.

Informing decision-making – ERA provides scientific evidence that regulators, policymakers, and project managers use to make informed choices about whether to approve activities, what conditions to impose, or what alternatives to consider.

Guiding risk management – By identifying where risks are unacceptable, ERA helps determine what mitigation measures, monitoring programs, or safety protocols are needed to reduce environmental harm to acceptable levels.

Ensuring regulatory compliance – Many jurisdictions require ERAs before approving new chemicals helping ensure activities meet environmental protection standards.

Balancing development and conservation – ERAs help society weigh the benefits of economic activities against potential environmental costs, supporting more sustainable development practices.

The ERA process follows a structured approach with four main components:

1. Hazard Identification – Determines the inherent hazardous properties of the chemical (i.e. toxicity evaluation)

2. Exposure Assessment – Evaluates how and how much of the chemical enters the environment (i.e. chemical fate and transport evaluation)

3. Effects Assessment – Determines what harm the chemical can cause (i.e. determines the relationship between the level of exposure to a chemical and the severity or probability of adverse effects on living organisms)

4. Risk Characterization – Combines information/data on hazard, effects, and exposure to determine if the risk is acceptable (i.e. calculating risk/hazard quotients)

Comprehensive ERAs should also consider:

• Chemical physical-chemical properties affecting environmental behaviour

• Relevant environmental compartments (e.g. freshwater, marine, terrestrial, sediment)

• Relevant organism groups (e.g. fish, invertebrates, algae, plants, birds, mammals, soil organisms)

• Bioavailability

• Indirect effects on habitats, food webs, and ecosystem services

• Recovery potential after exposure cessation

Chemical entering the environmental in the UK/EU are governed by a number of regulatory frameworks including:

• Regulation EC 1107/2009 for Pesticides

• Regulation 528/2012 for Biocides

• EMA Guidelines 2024 for Pharmaceuticals

• Regulation EU 2019/6 for Veterinary Medicines

• REACH Regulation EC 1907/2006 for General Chemicals

While current chemical regulations and requirements can be complex and expensive, future regulations will likely become even more stringent and complex. For example, while we know that organisms are not exposed to single chemicals in the environment but to a mixture of chemicals, most environmental and chemical regulations do not adequately address chemical mixtures. This is most often due to regulatory inertia and resource constraints.   

Recorded lecture

Key Reading

KEMI (2020) Hazard and Risk Assessment of Chemicals: An Introduction 

SETAC (2018) Environmental Risk Assessment of Chemicals