Cumulative Exposure Assessment of Pesticides

July 10, 2016

The European Food Safety Authority (EFSA) has announced significant advances towards cumulative risk assessment methodology following the development of a software tool capable of assessing exposure to large groups of pesticides. Cumulative exposure assessment to pesticides involves the simultaneous estimation of exposure to a number of pesticides within common assessment groups (CAGs), i.e. pesticides with the same toxicological effect, and/or similar modes of action.

The requirement for cumulative risk assessment is stipulated in the legislation governing the approval of active substances (Regulation [EC] No 1107/2009) and in the setting of Maximum Residue Levels (MRLs) (Regulation [EC] No 396/2005). Therefore, decisions on approvals and MRLs should take into account cumulative effects of pesticides when the methods to assess such effects become available. The EFSA began its work in this area in 2006 and the EFSA Panel on Plant Protection Products and their Residues (PPR) has subsequently published several Scientific Opinions on cumulative risk assessment (CRA) methodology. In their first Opinion, the PPR Panel evaluated existing methodologies on CRA, and recommended a tiered approach for hazard and exposure assessments. The approach was then tested with a group of triazole pesticides and subsequently guidance for the use of probabilistic methods for estimating dietary exposure including cumulative exposures was developed. Other supporting opinions have considered general methodology and criteria specifically developed for establishment of CAGs for pesticides with similar and dissimilar modes of action.

Probabilistic exposure software known as the Monte Carlo Risk Assessment (MCRA) model, was originally created through a project funded by the European Commission that involved researchers, scientists and regulators from 14 countries and was overseen by the National Institute for Public Health and the Environment for the Netherlands (RIVM). The MCRA software was further developed through the EU Framework 7 funded project — ACROPOLIS, which began in 2010. The ACROPOLIS project achieved a web-based model, capable of performing cumulative risk assessments by probabilistic approaches according to the guidance developed by the EFSA. In 2015, EFSA funded further development of the MCRA tool to allow the processing of CAGs containing up to 100 active substances. This year EFSA will further support improvements to the tool regarding its accessibility by external users and data organization and formatting. The partnership between RIVM and the EFSA is directed to making the MCRA model accessible to all countries and stakeholders in the European Union that have to assess the safety of pesticides. This project is being closely coordinated with the European Commission, which has established a working group to ensure that the project meets the needs of risk managers.

Our Work

Exponent has extensive experience with pesticide risk assessments, and with dietary exposure to food chemicals. Our scientists are internationally recognized experts in the fields of pesticides and in exposure assessment and are available to help you with your regulatory and stewardship needs. Our staff have been involved with development of the European probabilistic models as part of the original MCRA team and also with the FP7 funded ACROPOLIS project which developed the MCRA software specifically in relation to conducting cumulative exposure assessments for pesticides. We can assist you in understanding your requirement for cumulative assessments, with gathering the data you may need for such assessments and conducting the exposure work on your behalf, through to stewarding the results and data with the respective regulatory authorities.