7 Geology, Soils and Land Affected by Contamination

7.1 Objective

7.1.1 To take reasonable precautions in carrying out the works to prevent, contain, or limit adverse environmental impacts and health and safety risks arising from construction on or adjacent to land affected by contamination or disturbance of contaminated soils during construction activities, including limiting adverse impacts on designated geological features.

7.2 Geology, Land Contamination and Waste Management Plan

7.2.1 As explained in Section 1.7 of this CoCP, the contractor’s EMP will include a Geology, Land Contamination and Waste Management Plan which will describe the procedures and measures to be implemented to manage construction works, including the following:

works that may affect mine workings or designated geological sites;
construction activities on land which may be contaminated;
the handling, storage, transfer and disposal of waste materials and contaminated materials (see Section 8 of this CoCP);
the reuse or recycling of waste material (see Section 8 of this CoCP); and
works that may affect private water supplies.

7.3 Mitigation of Potential Impacts on or due to Works in Geology and Soils

7.3.1 Construction of the Project may affect the Ferry Hills Site of Special Scientific Interest (SSSI), which is of geological interest. The Geology, Land Contamination and Waste Management Plan will set out procedures agreed in consultation with SNH for any works which may affect the SSSI, which may include procedures for the appropriate recording of geological formations, inspections and complementary rock mapping of the rock face. Consent for SSSI works described in the Environmental Statement will be deemed as part of the Parliamentary Bill process.

7.3.2 There is potential for construction works to be undertaken over abandoned mine workings. The Geology, Land Contamination and Waste Management Plan will set out the measures to be implemented, including consultations with the Coal Authority and SEPA, as appropriate, in relation to undertaking works over abandoned mine workings. If necessary, the contractor will undertake a detailed assessment and risk assessment of the potential impact of drilling and grouting to consolidate abandoned mine workings on groundwater and ground gas migration and ground movements to identify appropriate measures required to mitigate potential environmental impacts and health and safety risks. Matters relating to dust and air quality due to drilling and grouting activities are covered in Section 6 of this CoCP.

7.3.3 The Geology, Land Contamination and Waste Management Plan will set out the measures to be implemented to assess and control the risks to workers in excavations where the presence of ground gas may lead to confined space risks, or due to works associated with mine workings where risks associated with ground gas may be present. This will include compliance with CIRIA Report C665. If significant ground gas issues are identified, appropriate monitoring will be undertaken and/or appropriate ground gas protection measures provided by the contractor.

7.3.4 The Geology, Land Contamination and Waste Management Plan will set out the measures to be implemented by the contractor, including, as appropriate, undertaking a risk assessment, monitoring groundwater levels and undertaking structural or dilapidation survey of buildings or structures adjacent to the works where there may be potential settlement risks or a risk of lateral ground movements which may damage structures.

7.3.5 Approaches and mitigation measures relevant to construction activities and handling of soils relating to works which may affect agricultural interests and reuse of soils within the landscape works are covered in Sections 11 and 13 of this CoCP respectively. An assessment of soils to be reused will be undertaken by the contractor to identify any potential risks posed to the water environment from reused soils to be used in embankments.

7.4 Construction on or adjacent to Land Affected by Contamination

7.4.1 Where land affected by contamination is identified a management plan will be prepared by the contractor to facilitate compliance with relevant handling and disposal legislation. Disposal of waste and contaminated materials is covered in Section 8 of this CoCP.

7.4.2 The section of the Geology, Land Contamination and Waste Management Plan dealing with land affected by contamination will set out the control measures to be implemented by the contractor for construction activities on or adjacent to the land. This will include the following, as appropriate:

Procedures to be followed, including appropriate watching briefs, to identify areas within the Project where land contamination may be encountered.
Information relating to historical site research.
Carrying out appropriate site investigations to determine the extent and type of contaminants present.
Identification of potential sources of contamination, pathways connecting contamination sources and receptors capable of being harmed, and assessment of the risk of harm to receptors.
Sealing of existing pathways through services (e.g. land drains) affected during construction.
Lining of drainage trenches to prevent the ingress of contaminated groundwater or lateral migration through granular backfill.
Consultation with the relevant local authorities and SEPA regarding control or protection measures to be implemented to deal with identified risks, including appropriate techniques for excavating contaminated material and the control of contaminants and discharges in their insitu or mobilised form, for solids, liquids, gas and leachate; and appropriate health and safety and precautionary measures.

7.4.3 Asbestos has been identified during site investigations adjacent to St Margaret’s Marsh. The control measures set out in the Geology, Land Contamination and Waste Management Plan will include procedures appropriate for construction works associated with asbestos. The contractor will observe the exposure limits and measurement methods for asbestos, set out in HSE Guidance Note EH 10 1988 and will comply with HSE Guidance Note MS13 Asbestos 1988, the Health and Safety Commission Approved Code of Practice and Guidance Note Work with Asbestos Insulation and Asbestos Coating 1983 insofar as these are applicable to the construction works.

7.4.4 Appropriate control measures relevant to mitigating risks associated with asbestos dust in accordance with the above guidelines will be included in the Dust and Air Quality Management Plan referred to in Section 6 of this CoCP.

7.4.5 Waste materials, known to contain some heavy metals and possibly other contaminants, have been identified during investigations in St Margaret’s Marsh. Appropriate procedures and control measures will be developed by the contractor, including procedures for any site investigations required as set out in Section 7.5 of this CoCP, and methods appropriate for construction activities on or adjacent to potentially radioactive contamination.

7.4.6 Any remedial action undertaken in relation to land affected by contamination will be carried out under the appropriate remediation licensing.

7.4.7 Where piling works are undertaken in areas of land affected by contamination, the contractor will adhere to appropriate guidance including the Piling and Penetrative Ground Improvement Methods on Land Affected by Contamination: Guidance on Pollution Prevention, National Groundwater and Contaminated Land Centre Report NC/99/77.

7.4.8 The measures set out in the Geology, Land Contamination and Waste Management Plan will apply equally to land used for the construction and land used temporarily, for example for site offices and works compounds.

7.5 Site Investigation

7.5.1 The contractor will use adequate site investigation data to enable an assessment of the possible adverse effects arising due to land affected by contamination, development of appropriate construction methods and design of appropriate mitigation to be undertaken. The contractor will undertake additional site investigation work if necessary and this will cover the following, as appropriate:

Historical and current land uses.
Historical and current activities, processes and waste products.
Geological and hydrogeological setting.
Soils and groundwater sampling.

7.5.2 Site investigations will be undertaken in accordance with the following, as appropriate:

Planning Advice Note 33 [PAN 33] Development of Contaminated Land.
Protection of Workers and the General Public During the Development of Contaminated Land.
BS 10175 Investigation of Potentially Contaminated Sites.
BS 5930 Code of Practice for Site Investigations.
the Site Investigation Steering Group publication, Guidelines for the safe investigation by drilling of landfills and contaminated land.

7.5.3 The contractor will also consult with the relevant local authorities and SEPA regarding site investigations for areas of land affected by contamination and, where appropriate, the risk to ground and surface water resources, processes and abstractions will be assessed.

7.6 Private Water Supplies

7.6.1 The contractor will undertake a risk assessment associated with excavation or blasting work impacts on aquifers and private water supplies. Where required, the contractor will use low explosive loading densities for any blasting works following relevant British Standards including BS5228 Code of Practice for Noise and Vibration Control on Construction and Open Sites (Part 2- Vibration), and the Scottish Development Department Planning Advice Note 50 [PAN 50] Annex D ‘The Control of Blasting at Surface Mineral Workings’.

7.6.2 The contractor will repair or replace any water supply pipes damaged during construction.

7.7 Monitoring

7.7.1 The contractor will prepare and implement a gas monitoring procedure as appropriate due to the presence of areas of landfill, made ground, industry sites, quarries and naturally occurring gassing strata.

7.7.2 The Geology, Land Contamination and Waste Management Plan will set out appropriate controls to support adherence to the procedures relating to working on or adjacent to land affected by contamination.

7.8 References

Asbestos: Exposure limits and measurement of airborne dust concentrations, Guidance Note EH 10 1988, Health and Safety Executive
Asbestos: Medical Guidance Note Guideline Note MS13 Asbestos 2005, Health and Safety Executive
BS 5228: 2009 Noise and Vibration Control on Construction and Open Sites, British Standards Institution
BS 5930:1999 Code of practice for site investigations, British Standards Institution
BS 8485:2007 Code of practice for the characterization and remediation from ground gas in affected developments, British Standards Institution
BS 10175:2001 Investigation of potentially contaminated sites, British Standards Institution
CIRIA C665 Assessing risks posed by hazardous ground gases to buildings (revised), 2007
CIRIA Special Publication 32 Construction Over Abandoned Mine Workings, 1984
Control of Asbestos at Work Regulations 2002
Environmental Protection Act 1990, as amended
Ferry Hills SSSI citation (available on SNH SiteLink at http://www.snh.org.uk/snhi/ )
Health and Safety Commission Approved Code of Practice and Guidance: Work with Asbestos Insulation, Asbestos Coating and Asbestos Insulating Board
Piling and Penetrative Ground Improvement Methods on Land Affected by Contamination: Guidance on Pollution Prevention, National Groundwater and Contaminated Land Centre Report NC/99/77, 2001
Planning Advice Note 33 [PAN 33]: Development of contaminated land
Planning Advice Note 50 [PAN 50] Annex D ‘The Control of Blasting at Surface Mineral Workings’
Protection of Workers and the General Public During the Development of Contaminated Land, Health and Safety Executive, 1991
Site Investigation Steering Group: Guidelines for the safe investigation by drilling of landfills and contaminated land, 1994
The Confined Spaces Regulations 1997
The Control of Substances Hazardous to Health Regulations 2002, as amended