Oral Bioavailability - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 312

In a study of and abandoned copper-arsenic mine in Devon, in the South-west of
England in the UK (Devon Great Consols (DGC)) Palumbo-Roe and Klinck ( 2007 )
investigated the mineralogical factors that control the bioaccessibility of arsenic in
soils influenced by the past mining operation in the area. Bioaccessibility (deter-
mined using a physiologically based extraction test, as described by Cave et al.
( 2003 )) was related to the solid phase distribution of arsenic present in the test soils
(determined by the CISEDmethod (Cave et al. 2004 )). The results of this study show
that the mine soils from DGC have higher arsenic bioaccessibility (median 15%)
than those not affected by mining activities and other background soils collected
from the sampling area (the Tamar catchment), with a median bioaccessibility of
9%. Determination of the solid phase distribution of the arsenic present indicated
that the arsenic present in the test soils was mainly hosted by an iron oxyhy-
droxide component, whose partial dissolution was responsible for the bioaccessible
arsenic fraction. The degree of crystallinity of this component was thought to be an
important control on the arsenic bioaccessibility.
Caboche et al. ( 2008 ) investigated the bioaccessibility at sites influenced by dif-
ferent sources of historical contamination: a former lead-zinc mining site and a
site in which soils were contaminated by atmospheric deposits of lead containing
particles. The total concentrations ranged from 48 to 247 mg

kg dw − 1

· for arsenic

kg dw − 1 for lead, with the most contaminated soils
representing the mining site. Bioaccessibility data for the two contaminant sources
showed that for the mining soils arsenic and lead bioaccessibility was lower (ranging
from 2.7 to 8% for arsenic and 13.2 to 35.5% for lead) compared to 10 to 52% for the
soils contaminated by atmospheric deposition. The results of this study underline the
importance of bioaccessibility data when comparing the exposure to contaminants
present at contaminated sites.

and from 1,462 to 16,267 mg ·

7.5 The BARGE Network

The Bioaccessibility Research Group of Europe (BARGE) is a network of European
institutes and research groups, formed in 1999/2000, to 'study human bioaccessibil-
ity of priority contaminants in soils' ( www.bgs.ac.uk/barge ). A priority objective of
the network is the provision of oral bioaccessibility/bioavailability data for Human
Health Risk Assessments and policy making that is both robust and defensible.
A key driver for the inception of the network, identified by representatives of
the 16 Member States of the concerted action CLARINET (Contaminated Land
Rehabilitation Network for Environmental Technologies), was a European wide
urgency for more realistic oral bioavailability factors that could be used in site
specific Risk Assessment and policy making. Initial collaborative efforts, finan-
cially supported by the Dutch Ministry of Housing, Spatial Planning and the
Environment (VROM) and the participating institutes, allowed for the bringing
together of a multi-disciplinary team of research scientists (with a diverse range
knowledge base in pharmaco-kinetics, physiology, geochemistry and analytical
measurement techniques), policy makers and Risk Assessment practitioners, all key
in the decision making process.