Environmental Engineering Reference
In-Depth Information
CHAPTER NINE
An ecological risk assessment framework
for assessing risks from contaminated
land in England and Wales
STEPHEN ROAST, TIM GANNICLIFFE, DANIELLE K.
ASHTON, RACHEL BENSTEAD, PAUL R. BRADFORD,
PAUL WHITEHOUSE AND DECLAN BARRACLOUGH
Introduction
An ecological risk assessment (ERA) may be described as 'a process that evalu-
ates the likelihood that adverse ecological effects may occur or are occurring
as a result of exposure to one or more stressors' (USEPA 1992, 1998). Arguably
the most common stressors are chemical contaminants, and regulatory author-
ities in many countries around the world use ERA schemes to determine
whether chemical contaminants are impacting on ecological systems. The
USA, the Netherlands, Canada, Australia, New Zealand and the UK have all
spent considerable resources developing ERAs for use under their respective
regulatory regimes. But, although each country has developed its ERA schemes
for its own specific regulatory needs, the approach taken is broadly similar for
all ERAs.
The largest programme of work to develop ERA frameworks is that of the
United States Environmental Protection Agency (USEPA), which started in
the mid 1980s. Typically, the USEPA ERA follows three basic steps: problem
formulation, analysis and risk characterization (USEPA 1998). The ERA process
has been further adapted for use at EPA Superfund sites, to include eight
specific steps, from screening level evaluations to full site investigations and
risk management (USEPA 1999). Marking ten years of use in the United States,
the USEPA has recently assessed how well the ERA guidelines have worked,
identifying strengths and weaknesses (see Dale et al.
2008
; Kapustka
2008
;Suter&
Cormier
2008
).
The USEPA ERA scheme is perhaps more general than those developed in
other countries, being aimed at identifying risks from a very broad range of
disturbances, for example, 'habitat loss' (i.e., not just chemical contamination).
