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Framework for Addressing Uncertainty and Variability in Pesticide Risk Assessment
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Reports of research projects on which WEBFRAM is based

Most ecotoxicological pesticide risk assessments are deterministic, i.e. they use fixed values for toxicity and exposure and produce a single estimate of the risk. This estimate is then compared to an assessment factor, uncertainty factor or trigger value agreed across the EU. If the assessment factor is breached then a higher tier assessment is carried out. However due to the fact that deterministic methods cannot incorporate variability or uncertainty directly, refinement is dealt with in a subjective manner. In light of this, CRD decided in 2003 to sponsor a suite of projects aimed at trying to incorporate the issues of uncertainty and variability into the risk assessment process.

Click on the project numbers below to download pdf copies of the project reports.

Webfram 1: Web-integrated framework for addressing uncertainty and variability in pesticide risk assessment – this developed the statistical methodology and the website.
Webfram 2: Modelling the effects of pesticides on non-target aquatic organisms to improve risk assessment. This module developed landscape based scenarios that enables the risk to aquatic life from both drainflow and spray-drift to be assessed.
Webfram 3: Addressing uncertainty and variability in pesticide risks assessments for birds and mammals. This module dealt with developing risk assessment models for birds and mammals that followed current guidance as well as incorporating the issues of uncertainty and variability.

Webfram 4: Methods of addressing variability and uncertainty for improved pesticide risk assessments for above ground non-target invertebrates. This project investigated the issues of uncertainty and variability for non-target arthropods.
Webfram 5: This project investigated the issues of uncertainty and variability for below ground soil organisms.
Webfram 6: Acceptability of pesticide effects on non-target species – this project explored the issue of acceptability.
Webfram 7: This project explored the issues associated with assessing the long-term risk to birds and mammals. This work is published as a special issue of the journal Ecotoxicology (2005, Volume 14, Number 8).

PS2331: This follow-up project developed the threshold approach for aquatic and bird/mammal risk assessments (now implemented on the website) and carried out a validation study using data from field studies on birds.