Kelmarsh Petroleum Storage Depot
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Land Quality Assessment: Combined Phase 1 and 2: Final GPSS Portfolio: Kelmarsh Petroleum Storage Depot Defence Infrastructure Organisation Land Quality Assessment Combined Phase 1 & Phase 2 GPSS Portfolio: Kelmarsh Petroleum Storage Depot Final July 2013 Contract Number: FTS3/ELMG/101 Land Quality Assessment Combined Phase 1 And 2 GPSS Portfolio: Kelmarsh Petroleum Storage Depot Final Defence Infrastructure Organisation Prepared by Atkins Limited for Estates Management Central The Ministry of Defence Kingston Road Defence Infrastructure Organisation Sutton Coldfield under contract number B75 7RL FTS3/ELMG/101 This document and its contents have been prepared and are intended solely for the Defence Infrastructure Organisation’s information and use in relation to the Combined Phase 1 and 2 Land Quality Assessment for the GPSS Portfolio: Kelmarsh Petroleum Storage Depot. Document History Job number: 5106238 Document ref: Kelmarsh PSD Combined Phase 1/2 LQA Revision Purpose description Originated Checked Reviewed Authorised Date Rev 2.0 Final M L NW E July 2013 TASK OFFICER --------------------------------- PROJECT SPONSOR ---------------------------------- Land Quality Assessment: Combined Phase 1 and 2: Final GPSS Portfolio: Kelmarsh Petroleum Storage Depot Table of Contents Chapter Pages Land Quality Statement i 1. Introduction 1 1.1. Terms of Reference 1 1.2. Objectives 1 1.3. Methodology 1 1.4. Scope of Work and Sources of Information 2 1.5. Structure of this Report 3 2. Site Description and Setting 4 2.1. Site Location 4 2.2. Surrounding Area 4 2.3. Site Description 4 2.4. Site History 6 2.5. Environmental Setting 7 2.6. Site Sensitivity 8 3. Preliminary Conceptual Site Model 9 3.1. Potential Sources of Contamination 9 3.2. Potential Receptors 9 3.3. Preliminary Phase 1 Environmental Risk Assessment 11 3.4. Preliminary Conceptual Site Model for Investigation 11 4. Site Investigation 14 4.1. Objectives 14 4.2. Methodology 14 4.3. Investigation Findings 16 5. Assessment of Risks 19 5.1. Introduction 19 5.2. Tier 2 Generic Quantitative Risk Assessment 19 5.3. Risk Assessment Summary 22 6. Conclusions 24 6.1. Overall Land Quality 24 6.2. Environmental Risks 24 6.3. Suitability of Investigated Areas for Continued Use 25 Figures Figure 1 – Site Location Plan (Drawing 5106238-DWG-021) Figure 2 – Site Layout Plan & Potential Sources of Contamination (Drawing 5106238-DWG-022) Figure 3 – Preliminary Conceptual Site Model for Site Investigation (Drawing 5106238-DWG-023) Figure 4 – Exploratory Hole Location Plan (Drawing 5106238-DWG-024) Figure 5 – Revised Conceptual Site Model (Drawing 5106238-DWG-025) Appendices Appendix A - Envirocheck Appendix B – Historical Maps 3 Land Quality Assessment: Combined Phase 1 and 2: Final GPSS Portfolio: Kelmarsh Petroleum Storage Depot Appendix C – Environmental Risk Assessment Classification Tables Appendix D - Site Investigation Factual Report Appendix E – Laboratory Results 4 Land Quality Assessment: Combined Phase 1 and 2: Final GPSS Portfolio: Kelmarsh Petroleum Storage Depot Land Quality Statement Introduction and Terms of Reference Atkins Limited (Atkins) was instructed by the Defence Infrastructure Organisation (DIO) branch of the Ministry of Defence (MOD) to carry out a Combined Phase 1 and 2 Land Quality Assessment (LQA) of the Government Pipelines and Storage System (GPSS) Portfolio: Kelmarsh Petroleum Storage Depot (PSD), (the Site) under contract FTS3/ELMG/101 between Atkins and DIO. This Combined Phase 1 and 2 LQA is required to assess the environmental quality of the Site and evaluate potential environmental liabilities from contamination associated with the Site. Site Location and Surrounding Land Use This Site is located approximately 1.5km to the northeast of the village of Kelmarsh and 1.2km to the southwest of the village of Arthingworth in Northamptonshire. The approximate Ordnance Survey National Grid Reference for the Site is 474541 280680. Surrounding land is predominantly open fields and woodlands Site Description Kelmarsh PSD occupies approximately 6.57 hectares and is an irregular shaped parcel of land comprising approximately 95% grassland and 5% hardstanding. Most of the buildings are located in the south part of the Site by the entrance off Kelmarsh Road and underground and aboveground storage tanks are located in the centre and north. The Site was used as a PSD with hydrocarbons pumped to the Site. The hydrocarbons were directed to a series of underground storage tanks (USTs) and then transported off the Site to the various end users, including RAF and military bases in Northamptonshire, by road and rail and later by pipeline. Atkins understands that the hydrocarbons stored included aviation fuel, kerosene and diesel. Records indicate that the Site was decommissioned sometime in the 1990s. Currently, the only Site activities are an active pipeline which runs in and out of the Site in the south by the Site entrance, together with the pipeline inspection gauge. The Site is now on ‘care and maintenance’. Site History The Site was developed as a PSD in the 1940s and hydrocarbons supplied to the Site by pipeline and stored on-site in seven USTs. Distribution was by rail until the 1960s when the rail sidings were demolished. Road loading was in use until mothballing of the Site in the early 1990s when Site operations ceased. Environmental Setting Published information shows the Site is underlain by Superficial Deposits (in the northeast) and Whitby Mudstone formation. Site-specific information from the Phase 2 Site Investigation indicates Made Ground is present in isolated areas to depths ranging from 0.70 to 1.90m below ground level (bgl) resting on natural strata comprising stiff clay and sand, possibly Superficial Deposits and/or totally weathered bedrock. Superficial Deposits are a Secondary Aquifer and bedrock is Unproductive Strata. Groundwater has been detected at the Site at depths ranging from 0.7 to 2.49mbgl with a possible flow towards the southeast. Site Sensitivity Receptors Sensitivity Summary Description Groundwater Moderate Shallow groundwater is present in the Superficial Secondary Aquifer/or Bedrock. Surface Waters Moderate River Ise is within 250m Low Ecological sensitivity is considered low because no designated ecological receptors Flora/Fauna have been identified within 1km of the Site i Land Quality Assessment: Combined Phase 1 and 2: Final GPSS Portfolio: Kelmarsh Petroleum Storage Depot Potential Sources of Contamination Atkins Phase 1 LQA identified a number of historic, on-site potentially contaminative activities from past operations including potential leaks/spills of hydrocarbons from tanks, pipework, loading areas, drums storage, workshops, generators, substations, interceptors and in Made Ground itself, although there was no documentary information or physical evidence to confirm that contamination was present from these potential sources. In addition, it was practice in the past to bury sediment from tank cleaning in pits, often called ‘graves’ and four are present on the Site. On- and off-site humans, controlled waters and property (buildings and infrastructure) were identified as potential receptors to the sources of contamination listed above. Potential contaminant linkages (PCLs) were identified and subject to a preliminary qualitative environmental risk assessment. Phase 2 Site Investigation PCLs related directly to past/current Site operations and considered to pose a potential moderate or high risk were investigated as part of the Phase 2 LQA. This comprised the advancing of ten window samples installed with combined groundwater/ground gas monitoring installations. Samples of soil and groundwater were analysed for Total Petroleum Hydrocarbons (TPH), Polycyclic Aromatic Hydrocarbons (PAHs), benzene, toluene, ethyl benzene, xylenes (BTEX), MTBE, tetraethyl and tetramethyl lead and asbestos. A generic quantitative risk assessment (GQRA) for human, controlled waters and property receptors was carried out by comparison of soil and water concentration data with generic assessment criteria (GAC) for human receptors and controlled waters receptors assessed by comparison of groundwater concentration data with drinking water standards (DWS) for the groundwater receptor, and environmental quality standards (EQS) for the surface water receptor. Ground gas results were assessed for human and property receptors. No asbestos was identified in the soil samples analysed. Visual and olfactory evidence of contamination, comprising hydrocarbon type odours, were observed in soil in AWS005 and AWS004, but contaminants in the soil samples analysed were either below the laboratory method detection limit (MDL) or the commercial/industrial land-use GAC. Contaminants in groundwater samples were all reported below laboratory method detection limits. The Characteristic Situation (CS) for carbon dioxide and methane was CS2 because of concentrations detected in AWS005. Phase 2 Environmental Risk Assessment The environmental risk assessment is summarised below: • a moderate risk has been identified to current/future construction/maintenance workers from contaminants in soil and groundwater even if they do not exceed the GAC because they may be in direct contact with contaminants when they are required to excavate and handle soil. However, this will be reduce to low risk if robust risk assessments are carried out to identify appropriate personnel protective equipment and suitable working methods to protect these receptors, in accordance with current guidance and