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Durham University

Department of Mathematical Sciences

Academic Staff

Publication details for Peter Craig

Craig, Peter S. (2006). Uncertainty factors in ecotoxicological risk management. 4th Edinburgh Risk Conference, Edinburgh, UK.

Author(s) from Durham


Uncertainty factors (also known as extrapolation or safety factors)
are widely used in lower tier ecotoxicological risk management in
order to allow for sources of variability and uncertainty for which
there is only limited information. From the point of view of
probabilistic risk assessment, the rationale underlying both the use
of uncertainty factors and the specific values chosen is often
unclear. On the other hand, uncertainty factors are a convenient
approach to lower tier risk assessment.

This paper considers the problem of how to improve these lower tier
risk assessments without moving completely away from the use of
uncertainty factors towards complex probabilistic modelling which
often requires calculations using Monte Carlo. It is shown how
relatively simple statistical models lead to manageable procedures
for computing a single uncertainty factor for multiple sources of
uncertainty including inter-species variation, elaborating on ideas
and methodology presented in a recent European Food Safety Authority
scientific opinion in relation to aquatic risk assessment for