Sustainability and Remediation - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 896

also more intellectually accessible to a wider range of stakeholders than a complex
set of calculations that convert all factors into a limited set of quantitative metrics.
So there appears to be a dilemma between using decision criteria that are strictly
rational, measurable and comparable, and using criteria that are “rich” in their
coverage of impacts and may possibly lead to apparent duplication. The way out
of this dilemma is that where possible a richer and more accessible set of indicators
should be used, but with explanation and transparency, where there may be possi-
ble overlapping considerations, or points of cross-reference. For example, one set
of indicators might be direct emissions of NOx and SOx of the remediation pro-
cess, but with a cross reference to state that this assessment specifically excludes
impacts associated with emissions from HGV transport, as HGV miles are covered
by a separate indicator.

20.2.2 Risk Management

20.2.2.1 Risk Management Principles

Risk Management involves taking practical steps to mitigate identified risks so that
they are eliminated or at least reduced to an acceptable level. In land contamination
remediation terms it involves demonstrably breaking the source-pathway-receptor
contaminant linkage (Nathanail et al. 2007 ), as shown in Fig. 20.4 . Breaking the
contaminant can involve removing or otherwise modifying the source, interrupt-
ing the pathway or modifying the behaviour of the receptor, or relocating the
receptor. Source management can involve contaminant destruction, detoxification,
immobilisation, transfer or reduction in concentration. Pathway interruption can
involve isolation (e.g. encapsulation) or plume treatment (e.g. monitored Natural
Attenuation or permeable reactive barriers). Receptor management can include
relocation of sensitive species or in a work place scenario provision of personal
protective equipment, restricting access or minimising exposure duration.
Risk Management options for soil and groundwater contamination can
be grouped into civil engineering, biological, chemical, physical, solidifica-
tion/stabilisation, thermal or institutional categories (Nathanail and Bardos 2004 ).
Civil engineering approaches either relocate the contaminant (soil vapour extraction
or off site disposal) or physically isolate it from receptors of concern (e.g. vertical
hydraulic barriers or capping layers). Biological agents (e.g. microbes or plants)

Pathway

Source

Receptor

Fig. 20.4 Risk Management
interventions by breaking the
source-pathway-receptor
contaminant linkage

Source
“Control”

Pathway
Management

Protection