Local authority environmental health officer perspective on the standard of land contamination reports submitted through the planning system

This is the first part of a two-part series developed by the SiLC Professional & Technical Panel (PTP) regarding the standard of land contamination reports submitted through the planning system. Here David Carr, who represents CIEH on the PTP, presents a local authority environmental health officer (EHO) perspective, with a follow-up article to be provided by SiLCs on the PTP representing the consultancy sector.

Article contributed by: David Carr, Lead Scientific Officer, Environmental and Community Protection, Dacorum Borough Council

This article is based on the author’s experiences and discussions with colleagues in other local authorities.

Local authority Environmental Health Departments in England are consulted on dozens of planning applications a month, which need to be screened to determine whether land contamination conditions will be warranted if permission is granted. Some, but unfortunately not many, of these applications will be accompanied by a Stage 1 Preliminary Risk Assessment (PRA), where land contamination is suspected, or the proposed end use would be vulnerable to the presence of land contamination.  In addition to those planning applications asking for permission to be granted, other consultations are received for the discharge of land contamination conditions that were placed on conditional permitted developments.

A local authority Environmental Health Practitioner or Environmental Protection Officer, in any month, will be reviewing numerous land contamination reports ranging from  PRAs, through site investigations and quantitative risk assessments (generic or detailed), to options appraisals, remediation strategies/verification plans and remediation verification reports, as required by LCRM.

In the course of this work, there are common quality issues encountered with each of those types of report that mean it is not possible to discharge land contamination planning conditions at the first attempt. This can lead to costly and frustrating delays for the developer and the need for on-going liaison and discussion between the planning authority as advised by environmental health and the developer and their environmental consultant.

The following are some of the most common issues found at each stage of reporting that, if they could be overcome, would result in a much smoother progression through the planning process. It is important to recognise that regulation of sites affected by land contamination where controlled waters are a receptor of concern will be led by the Environment Agency, so the commonly observed issues in this article reflect the human health focus of local authority environmental health/ protection officers.

LCRM Stage 1 Preliminary Risk Assessments:

• Failure to take account of information on recent or historical land uses at a site available within the documentation submitted by the developer in support of their application that is not discernible from historical maps and aerial photographs.

• Failure to gain access to the buildings on the site and no acknowledgement of such as an area of uncertainty and no commitment to remedy the situation or update the report subsequently.

• Other considerations often overlooked are drainage features and associated infrastructure, such as interceptors and soakaways.

Intrusive Site Investigations and LCRM Stages 2 and 3 Risk Assessments:

• Failure to appropriately explain and justify the site investigation in terms of its scope and rationale, most usually but not exclusively, in relation to the locations of the chosen sampling points. For example, it is not unusual for features identified within the PRA report and uncertainties within the conceptual site model (CSM) not to be targeted by the subsequent site investigation.

Other issues often encountered with the site investigations are:

• significant areas of a site not being investigated, usually because of constraints such as buildings still being present, with no acknowledgement that this represents considerable uncertainty and with no commitment to undertake a supplementary investigation at a later date.

• a potential ground gas risk being identified at PRA which is not pursued during the site investigation, without any justification, or only investigated in a cursory manner by one or two gas monitoring boreholes with response zones chosen in a seemingly arbitrary manner.

• in cases where ground gas risk represented a potential risk and sufficient ground gas monitoring has been undertaken in line with expected good practice, it is rare to find an illustrative/ cross-section representation of the updated CSM reflecting the monitoring findings

• sampling locations not being overlain on historical or present site plans, or on proposed layout plans.

• failure to consider larger sites as different zones, depending on conditions encountered, different land use histories and, in some circumstances, end uses proposed.

• Risk assessments rarely progress past the Stage 2 generic quantitative risk assessment. On sites where the GQRA finds low risk this will typically result in the report being deemed sufficient but can result in unnecessary remediation work being recommended.

• LCRM Stage 3 detailed quantitative risk assessments are encountered infrequently but where they are, issues encountered tend to provide insufficient information about the nature of the soils, wrongly apply statistical assessments or do not sufficiently measure or assess the risk of vapour for particular contaminants.

Options Appraisals and Remediation Strategies, including verification plans:

• Options appraisals on more complicated sites tend to include minimal details and assessment of the pros and cons for the options not chosen, compared to those that are chosen.

• Issues commonly encountered with remediation strategies:

• • Incomplete strategies/ design reports for gas protection measures because gas membrane and foundation specifications have yet to be finalised at the time of the submission of the strategy.

  • Incomplete strategies because the approach to materials management, including pollution prevention practices during earthworks are being left for the yet-to-be-appointed ground works contractor to decide.

  • No discussion about the decommissioning of monitoring wells, which can represent an important pathway for gas migration from depth.

• Verification Plans and Verification reports are generally without problem provided sufficient testing and record keeping is agreed and that the work is carried out by an environmental consultant rather than the developer or their groundwork contractor. On a positive note a significant improvement had been noticed over the past few years in understanding the need to have ground gas protection measures installed and verified by independent and suitably qualified contractors.

Summary

Overall, following the guidance in LCRM and specifically the reporting suggestions would result in a quicker process through the planning system and be more likely to result in first-time discharge of conditions.