Chemical risk assessment – ecosystem services

Environmental Sciences Manager Malyka Galay Burgos

Administrative Assistant Sonia Pulinckx

Background

Assessing the risks of chemicals to man and the environment is based on the concept of comparing exposure to chemicals with their respective hazardous properties. However, there are differences in the criteria for deciding whether the level of exposure represents an acceptable or unacceptable risk. For man, decision criteria are focused on protecting the individual and regulations are applied relatively consistently around the globe. For the environment, protection goals are less clearly defined and not applied consistently in regional regulations. Regional environmental policies seem to take a cost-benefit approach to environmental impacts. There are two possible extremes for doing this: i) a precautionary approach aiming for zero release of chemicals into the environment; ii) uncontrolled release with no effective management to mitigate impacts. Most environmental regulatory schemes adopt an approach somewhere between these extremes. For example, some effects on individuals may be accepted if the population is unaffected or if it recovers from episodic exposure. For this approach to make sense, protection goals need to be suitably defined. Reviews of current regulations indicate that protection goals are only generally defined leaving a lack of clarity on how to achieve such protection.

Discussion of current chemical regulation schemes has led to calls for changes in the way environmental toxicity thresholds are derived. The use of limited species toxicity tests and application factors is tenuously linked to protection goals and could be over-protective in some cases or under-protective in others. Given that there are relatively few examples of major impacts e.g. TBT, DDT, from the thousands of chemicals in commerce, it may be that the current approach tends to be over-protective. This could be restricting the societal benefits of chemicals. On the other hand the uncertainties in the approach may underestimate effects, for example, in potentially sensitive ecosystems such as coastal marine reefs or in assessing endocrine disruption of chemical mixtures.

In addition to discussions for changes in current risk assessment schemes, there are policy discussions ongoing on the use of ecosystem services in setting protection goals. Examples include the Millennium Ecosystem Assessment, the European Commission strategy on biodiversity and ecosystem services, the UK National Ecosystem Assessment (UK NEA), the EFSA Guidance on a harmonised framework for pesticide risk assessment and the identification and evaluation of pesticide risk management options. This growing interest in using ecosystem services to help define and communicate protection goals will inevitably influence chemical regulation. Therefore, it is timely for the chemical industry to engage in this topic in order to determine and influence developments.

The TF should investigate a new risk assessment paradigm based on a structured framework for identifying which ecosystem services might be affected by chemicals, setting protection goals and then assessing relevant risk assessment schemes. We propose to follow and expand the recently published EFSA framework applied to pesticides (1).

The expected duration is 1 year and will involve 3 phases:

Phase 1 - Develop a Framework for the chemical industry applicable to all sectors by considering the following:

Description of key exposure scenarios and ecosystems including continuous and intermittent exposures, seasonality in receiving environments, spatial differences and scales.

Identification of the main stressors driving ecological status.

Establishment of current and potential uses of the environment in terms of ecosystem services. What does the local society use?

Definition of spatially explicit protection goals. Use case examples to exemplify, e.g. direct discharge of untreated sewage and no-impact scenarios for down the drain chemicals in different regions. Prioritise/select case examples for phase 2.

Identification of key service providing units. What are their attributes/dimensions?

Phase 2 - Case studies to show how the framework would be used:

Receiving environments to include freshwater, marine, soil.

Exposure scenarios to include down the drain (pharmaceuticals, home and personal care products representing constant exposure), episodic exposure in terrestrial and aquatic environments (pesticides), intermediate exposure scenarios (biocides?), multiple sources of exposure from industry value chains (e.g. oil and/or mining companies).

Also consider multiple stressors to explore relative contributions of chemicals to overall ecosystem stress.

Phase 3 “ Recommendations on how Risk Assessments Schemes need to be evolved:

There is scope to incorporate greater ecological relevance in risk assessment in order to achieve protection goals, e.g. population metrics, community structure. If the ecotoxicological community is about to develop more ecologically relevant paradigms for chemical risk assessment, we should combine the approach with consideration of the ecosystem services we wish to protect.