Oral Bioavailability - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 309

mineralised soils in Devon and Cornwall in the south-west of England, it is
practically impossible to remediate in any sensible fashion. The lines of evi-
dence approach, which includes bioaccessibility testing and contaminant solid
phase distribution determination with associated data interpretation, may be a
pragmatic way forward (Palumbo-Roe and Klinck 2007 ).

• Is there an adverse environmental risk associated with remediation?

◦ Remediation can involve a large amount of heavy machinery and transport

(plant), which will have a significant effect on the quality of life to the
surrounding population and adverse health effects through dust inhalation;

•

Is the number of contaminants driving the risk three or fewer?
◦

If the site is contaminated with a wide variety of contaminants, considera-
tion must be given to which contaminant is driving the risk calculation. As a
rule of thumb, if three or less contaminants are causing a potential risk then
bioaccessibility will probably decrease the estimates of risk.

• Is there in-vivo validation data associated with the in-vitro method under

consideration?
◦

The criteria associated with validation of a bioaccessibility test are discussed
in detail under Section 7.1.3 .

• Does the local regulator accept in-vitro bioaccessibility in Human Health Risk

Assessment?
◦

The regulators responsible for a given site should be contacted prior to a site
investigation in order to determine whether bioaccessibility testing is accepted.
This will ensure that financial resources are not wasted by unnecessary testing,
in the case of that bioaccessibility data is not acceptable, and natural resources
such as soil is not unnecessarily remediated, if the opposite is true.

• Is the land use likely to change in the future?

◦ The application of bioaccessibility data needs to be considered in terms of

the land use at the time of the assessment and any proposed future land
use. Because of soil ageing and weathering etc. (see Section 7.2.5 )itis
considered that naturally occurring contaminants in soil will have a lower
bioaccessibility/bioavailability than those found in made ground. In addition
the bioaccessibility of contaminants may be altered (increased or decreased)
by land practices such as the liming of soil to raise the pH or the addition of
organic matter (Wragg 2005 ).

7.4 Examples of Bioaccessibility Studies

Bioaccessibility research is a rapidly developing scientific area, as such there are
many examples of its application in the scientific literature. It is beyond the scope
of this chapter to give a comprehensive review, however the following section gives
examples of bioaccessibility related studies for a variety of contaminants arising
from geogenic sources and anthropogenic influences. Other examples of where