Environmental Geology & Geological Consultants Ltd. have been retained by a prospective purchaser of the former Clariant chemical Manufacturing Site at Nook Lane, Oswaldtwistle, to liaise with the regulatory authorities and to review and summarise findings relating to land contamination at the site.
Findings indicated that site is clearly contaminated with a variety of chemical substances. However, at present, the level of contamination has not been shown to be sufficient to warrant the classification of the site as Contaminated Land under Part IIA of the Environmental Protection Act 1990. In particular:
Pollution of the underlying coal measures secondary aquifer and glacial till unproductive strata was identified as potentially representing significant contaminant linkages. However, in light of revisions made to the Statutory Guidance, in particular the broad objectives, linkages relating to these receptors were not ultimately deemed to be significant and on this basis the site does not meet the criteria to be classified as Contaminated Land under Part IIA of the Environmental Protection Act 1990 due to pollution of these strata.
With respect to Lottice Brook, an assessment of the frequency and magnitude of observed contamination, and taking into account data uncertainty and upstream water quality, it is considered by the Environment Agency that the level of impact falls under ‘Category 3’ as described in the Statutory Guidance. Category 3 includes land where the Environment Agency considers that it is very unlikely that serious pollution would occur; or that there is a low likelihood that less serious types of significant pollution might occur. This means that significant pollution of controlled waters has not been demonstrated for the principal contaminants identified, and thus, that the site does not meet the criteria to be classified as Contaminated Land under Part IIA of the Environmental Protection Act 1990 on the basis of pollution of this watercourse.
With respect to Human Health criteria, the final decision to not classify the site as Contaminated Land under Part IIA of the Environmental Protection Act 1990, was made with reference to the exposure criteria associated with ‘Commercial’ land use and the ‘Public use of open spaces / recreational’ land use. These criteria are considerably less stringent than the ‘Residential’ land use, criteria and even though the Residential land use has been modelled without demonstrating a great deal of exceedance of those criteria, those are the criteria that would need to be met in future if a residential land use was to be agreed by the regulatory authorities.
A change of land use such is likely to trigger a review of existing data and the requirement to obtain more data. The Environment Agency have suggested that, if any development were to occur on site then they would like to see some treatment of the unconsented discharge to Lottice Brook that is thought to drain the Manufacturing Site. In this context it should be noted that it is possible that further sampling and site investigation could lead to the categorisation of the site as Contaminated Land under Part IIA on the basis of ongoing impact to Lottice Brook.
Furthermore, it is clear that the existing data and HHRA provide insufficient information upon which to base a final decision regarding use of the site for residential purposes, and that the level of remediation that may be required to satisfy those criteria would not be known until such a time as a more comprehensive site investigation and HHRA has been undertaken. No estimation of remediation costs can be made until these figures are known.
It is recommended that, as a next step, a preliminary planning permission enquiry form be submitted to Hyndburn Borough Council, to establish whether or not they would be willing to allow the site to be used for the proposed purpose. If Hyndburn Borough Council is satisfied with the proposed use, and that it fits with their overall planning strategy for the Borough, it would then be appropriate to consider the next steps with regard to additional site investigation and Human Health and Controlled Waters Risk Assessment.