Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Development of a web-based pesticide risk assessment module for below-ground invertebrates - PS2305

Pesticide risks to soil invertebrates are assessed under the EU risk assessment scheme by conducting ecotoxicological tests with earthworms and, possibly, also tests with other soil invertebrates such as springtails, enchytraeid worms or predatory mites. Single species are exposed to pesticide residues under standard laboratory test conditions. For earthworms, higher-tier mesocosm (terrestrial model ecosystem; TME) or field tests may also be carried out to provide assessments of effects under more realistic exposure conditions if lower-tier (conservative or worst-case) tests indicate potential risk. All tiers of the risk assessments contain elements of uncertainty and variability that are not included in the risk description. Safety factors are used to represent unknown variability and uncertainty, to ensure adequate environmental protection, but are based on untested assumptions. As a result, the relevance of the risk description to real ecological conditions may be questioned and the efficiency of the risk assessment impeded, for example if stringent safety factors lead to ‘false positive’ indication of risk and unnecessary further testing. It is now widely agreed that such problems could be reduced if variability and uncertainty could be incorporated into the risk description, for example using uncertainty analysis approaches such as species sensitivity distributions. The objective of the proposed work would be to develop a risk assessment module for below-ground invertebrates that would incorporate variability and uncertainty and enable stakeholders to perform both deterministic and probabilistic risk assessments for selected pesticide use scenarios, following the structure of the existing risk assessment scheme. Example case studies would be included, using actual data for selected pesticides; these would be used to evaluate the pros and cons of different methods of uncertainty analysis in risk assessment and verify the predictive power of lower-tier probabilistic approaches against semi-field and field data. The module for below-ground invertebrates would contribute, along with risk assessment modules for other non-target species, to an integrated internet-based risk assessment framework. The proposed work aims to address DEFRA’s requirement for the development of such a framework to improve the risk assessment for pesticides and thereby assist the UK Pesticides Safety Directorate and other regulatory authorities in their regulatory decision making. In addition, the project would addresses a number of key recommendations of the EU workshop on probabilistic risk assessment (EUPRA), which aim to improve the risk assessment for pesticides at an international level.
The overall objective of this project would be to test the hypothesis that the application of probabilistic methods of uncertainty analysis to existing data sets can improve the efficiency of the risk assessment for effects of pesticides on below-ground invertebrates. This would be achieved by applying both probabilistic and deterministic risk assessment procedures to the available data and comparing the outcomes. The overall objective would be realised in five stages, each of which effectively represents a separate project objective, as indicated below:

Objective 1 – Acquire data (months 1-6). ECT, Southampton and NERI to source, and collate in a database, ecotoxicological parameter distributions for pesticide risks to soil invertebrate species relevant to key pesticide usage scenarios.

Objective 2 – Identify scenarios, case studies and uncertainty analysis methods (months 5-6).

Objective 3 – Develop and refine first phase risk assessment scenario(s) and one or more case studies and submit for web enabling (months 7-12)

Objective 4 – Develop and refine second phase risk assessment scenario(s) and one or more case studies and submit for web enabling (months 12-18).

Objective 5 – Finalise web testing and disseminate findings (months 20-24)

Project Documents
• Final Report : Development of a web-based pesticide risk assessment module for below-ground invertebrates   (457k)
Time-Scale and Cost
From: 2002

To: 2005

Cost: £200,256
Contractor / Funded Organisations
University - Southampton
Environmental Protection              
Pesticide use              
Fields of Study
Pesticide Safety