Cumulative Assessment Group Methodology for Pesticides
The European Food Safety Authority (EFSA) has developed a new approach for grouping pesticides that paves the way for the implementation of cumulative risk assessment - a sophisticated technique to assess the risk posed by exposure to multiple pesticide residues. The general methodology for classifying pesticides into so-called cumulative assessment groups (CAGs) is based on identifying compounds that exhibit similar toxicological properties in a specific organ or system. As a first step the Authority's Panel on Plant Protection Products and their Residues (PPR) has applied this methodology to define groups of pesticides which are toxic to the thyroid and central nervous systems.
Identifying pesticides to be included in these groups is a major step forward in EFSA's ongoing work to implement cumulative risk assessment as required by European law[i]. This approach will be gradually introduced in regulating the use of pesticides in the European Union. EFSA highlighted that the cumulative assessment group methodology applies to pesticides only and does not include other types of chemicals potentially present in food.
Broad criteria for consumer protection
The methodology developed by the PPR Panel uses broad criteria for inclusion of pesticides in groups to maximise consumer protection. This follows on from the formal consultation of the European Commission on general recommendations regarding the desired level of protection to be achieved.
Groups are formed by identifying pesticides that produce similar toxic effects in a specific organ or system. The methodology consists of four stages:
- Identifying specific and unambiguous toxic effects that adversely affect an organ or system - known as hazard identification (e.g. imbalance of the thyroid system).
- Hazard characterisation that describes the precise nature of this adverse effect to specific organs or systems (e.g. identifying the most appropriate indicator for the specific effect, for instance, a hormone).
- Data collection - gathering data on the indicators (e.g. changes in hormone levels at the dose where the advesre effect occurs) that point to a specific toxic effect (e.g. imbalance of the thyroid system) in an organ/system.
- Grouping of pesticides that exhibit a similar toxicological effect into cumulative assessment groups by organ or system (e.g. thyroid).
This approach requires expert scientific judgment as it involves the analysis and interpretation of large volumes of complex data. In addition to identifying pesticides that affect the thyroid and nervous systems, the PPR Panel has carried out a large body of preliminary work for the development of groups for effects on other organs/organ systems such as the reproductive system, the liver, eye and adrenals.
EFSA will now begin the gradual implementation of cumulative risk assessment in its work on pesticides and, in dialogue with the European Commission, will set future priorities to develop the methodology further. The Authority is also due to hold an 'Information Session' for stakeholders in 2014 on implementing cumulative risk assessment.
EFSA's work in cumulative risk assessment of pesticides is just one area where it is actively engaged in evaluating the risk to human health and the environment from exposure to chemical mixtures. The Authority's Science Strategy highlights the need to develop a harmonised and consistent approach for the risk assessment of chemical mixtures in food.