2                                            Land Contamination Issues

2.1                                      Introduction

Two above ground oil storage tanks (No. 4 and No. 5 Light Oil Tanks) with associated pipelines and one oil separation sump are to be demolished to provide space for installation of the FGD plants.  A land contamination assessment was carried out at these areas to comply with the EIA study brief's requirements.  This section briefly describes the land contamination assessment and makes a reference to the Contamination Assessment Plan (CAP), Contamination Assessment Report (CAR) and Remediation Action Plan (RAP) documents that were prepared under this EIA Study.

2.2                                      Land Contamination Assessment

The land contamination assessment was carried out following the methodology and procedures prescribed in the contamination assessment plan (CAP) which made reference to EPD’s Practice Note for Professional Persons (ProPECC PN 3/94) and Guidance Notes for Investigation and Remediation Contaminated Site of Petrol Filling Stations, Boatyard and Car Repair/Dismantling Workshops.  The CAP was approved by the EPD in November 2005.  A copy of CAP is included as Annex A of this report.

The land contamination assessment included soil and groundwater sampling, laboratory analyses for target parameters, preparation of contamination assessment report (CAR) and preparation of remediation action plan (RAP).  A copy of the RAP, which also includes CAR as an appendix, is provided in Annex B of this report.

The Site Investigation (SI) for the land contamination assessment was conducted in the area adjacent to the tanks and oil separation sump between 14 to 19 November 2005.  The SI consisted of drilling of six bore holes, soil sampling, installation of six groundwater sampling wells at drilling locations, groundwater sampling, and laboratory analyses for target parameters.  The SI programmed also incorporated a field and laboratory QA/QC programme to ensure adequate sample results' quality.  A total of 15 soil samples and six groundwater samples (exclusive of QA/QC samples) were collected from the Site areas for laboratory analysis of total petroleum hydrocarbons (TPHs), polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethyl benzene and xylene.

2.3                                      Results and Recommendations

Total petroleum hydrocarbon (TPH) was detected in one out of 15 soil samples and five out of six groundwater samples at concentration exceeding the EPD Dutch B values for mineral oil and implied a TPH contamination at the Site.  Remediation measures and procedures for TPH contamination were recommended for the Site for the demolition operation, and the details are provided in the RAP.

The excavated contaminated soil will be remediated in accordance with the EPD’s Guidance Notes for Investigation and Remediation of Contaminated Sites of Petrol Filling Stations Boatyards, and Car/Repair/Dismantling Workshops, May 1999.  The remediation actions could involve excavation, testing, on-site treatment (ie soil venting/biopiling) and on-site reuse.

As groundwater is not used for either domestic or industrial purposes at the Site and in the adjacent areas and taking into consideration the absence of free-floating products and the relatively low concentrations of TPH detected in the groundwater, remediation of TPH in the groundwater of the Site is not considered necessary.  Groundwater extraction is not anticipated during the demolition and/or construction programmes as the proposed excavations are at levels well above the site groundwater table.  However, if groundwater is encountered during the demolition and/or construction programmes and groundwater dewatering from the work areas is required, the extracted groundwater will be collected, appropriately stored on-site and recharged back to the underlying ground.

With the implementation of the remedial measures in the RAP, the hazard and environmental impacts associated with the potential land contamination and handling and treatment of the contaminated soil and ground water are considered acceptable.