Supporting documents - Renfrewshire Council

Goodson Associates
8.4 Pollutant Linkage Assessment
Proposed Store Development, Wallneuk Road, Paisley - 9692
Considering the previous and current land use, there is potential for a range of
contaminants relating to former industrial activities to be present in sub
surface soils, and potentially deeper aquiferous groundwater. The presence of
the former on site iron foundry and engineering works are the most significant
potential sources of contamination that is likely to have impacted the site.
The often heterogeneous nature of made ground deposits may also contain
an array of contaminants potentially deleterious to human health and sensitive
receptors. There is additionally the potential for ground gas generation and
volatilisation of organic solvents/compounds. The site has the potential to
present a Medium to identified receptors risk with regard to the potential for
deleterious concentrations and spatial distribution of contaminants that may
exist on the site.
Off site sources are likely to have a limited impact on the site, given the
tarmac covering the site, the regional dip of strata and the impermeable
underlying glacial till deposits preventing migration of aqueous phase
pollutants.
An important aspect in considering the risk(s) that the site may pose to
sensitive receptors is the concept of “suitability” for use. The site in its current
setting is laid as impermeable hardcore/tarmac surfacing and as such, limits
the exposure pathway to underlying deleterious contaminants. It is also likely
that during redevelopment of the site in the late 1980’s providing car parking,
warehousing and recreational bowling centres the soils were
improved/volumes of ash and slag removed reducing the present day risk of
gross contamination remaining within insitu soils.
The development proposal is anticipated to comprise a substantial area of
hard cover thus eliminating direct contact and wind dispersion of exposed
soils. This is also pertinent with regard to ON SITE migration of contaminants
from other factories surrounding the site (being largely covered in
hardstanding). Limited soft landscaping is proposed around the site boundary
and thus surface soils that present a phytotoxic risk to plants may require
remediation. Utilisation and implementation of adequate drainage and storm
water attenuation is likely to reduce surface run-off and infiltration to
underlying sub surface soils thus to an extent mitigating impacts on ground
water.
The process of deriving a suitable and appropriate CSM for a site also
involves the assessment of the perceived or potential risk that a complete,
viable pollutant linkage is likely to have a deleterious influence on the
Receptor. A methodology for categorising potential risk is outlined in CLR6 22
and is included as (Appendix 8.)
Presented in Table 3 and in graphical format as (Appendix 9) is a summary of
the components of the preliminary CSM and the potential risk assigned.
22 DOE (1995) Prioritisation & Categorisation Procedure for Sites Which May be Contaminated (CLR 6)
Page 14