6 LAND CONTAMINATION

6.1 Introduction

6.1.1 The EIA report identified several potential sites of land contamination and recommended that further investigation was required to address the land contamination impact while the concerned land was available to DBL after land resumption. The land contamination work shall follow the guidelines as stated in "Guideiance Notes for Investigation and Remediation of Contaminated Sites of Petrol Filling Stations, Boatyards, and Car Repair/Dismantling Workshops" and the ProPECC PN3/94 Contaminated Land Assessment and Remediation. The scope of work is outlined in this chapter.

6.2 Review Potential Contaminated Sites Identified in the EIA

6.2.1 The potential contamination sites along the DBL alignment as identified in the EIA are presented in Figure 6.1, and the details are summarized in Table 6.1. The ET shall carry out supplementary site apprasials for the following sites with reference to the findings of the EIA:

(i) Area C1 near proposed helipad
(ii) Area C3 near propose road to helipad
(iii) Area D near Ha Tsuen Interchange
(iv) Area F under the alignment of DBL south to San Wai Sewage Treatment Works
(v) Area G under the alignment of DBL south to San Wai Sewage Treatment Work
(vi) Area J under the alignment of DBL along Fuk Hang Tsuen Road
(vii) Area L at Lam Tei Interchange
(viii) Area M at Lam Tei Interchange
(ix) Area K at Lam Tei Intechange
(x) Area B near the proposed helipad

6.3 Preparation of the Contamination Assessment Plan

6.3.1 The ET shall base on the findings of EIA and the supplementary site apprasials to prepare Contamination Assessment Plans (CAPs) before the construction stage (probably immediately after the land is made available to DBL).

6.3.2 Table 6.1 lists the parameters that should be analysed, and the number of samples to be taken at each identified area (according to EPD's Guidance Notes for Investigation and Remediation of Contaminated Sites) for reference. All the information given in Table 6.1 (including the number and location of sampling points and testing parameters) should be reviewed during the preparation of Contamination Asessment Plan.

6.3.3 The Contamination Assessment Plan (CAP) shall be prepared and submitted to EPD for endorsement prior to conducting the site investigation. A Contamination Assessment Report (CAR) shall be prepared based on results obtained from site investigation and submitted to EPD.

6.3.4 Upon receipt of the EPD's approval, the CAP will be implemented and the findings of the investigations will be reported in the Contamination Assessment Report (CAR).

6.3.5 The results of the sampling exercise would determine whether contaminated land is, in fact, an issue that needs to be addressed further. If results from sample analysis indicate the presence of potential contaminants, then it may be necessary to update or amend the current CAP in light of the findings. If land contamination is confirmed, a Remediation Assessment Plan (RAP) shall be prepared, and both the CAR and the RAP shall be submitted as a combined report to the EPD for approval prior to the implementation of any remedial technology. If applicable and required in consultation with the EPD, the contaminated site shall be remediated in accordance with the approved CAR/RAP.

6.3.6 Implementation of the RAP can begin once the CAR and RAP submission are approved by the EPD. The essential steps involved in remedial programme are detailed in the EPD's Guidance Notes document. In all cases, contaminated soil remediation, treatment or disposal of it must be managed in an environmentally sound manner, including compliance with all relevant legislation and Government requirements.

6.4 Programme for Land Contamination Investigation

6.4.1 The CAP together with the sampling and testing work shall be planned to start after the land is available to DBL through early negotiations or resumption and the subsequent CAR and RAP shall be approved by the EPD before commencement of any construction work which may disturb the ground of the concerned sites. Contaminated soil should be remediated before construction work could be started on the concerned sites.

6.5 Mitigation Measures During Construction Phase

6.5.1 As a precaution, it is recommended that standard good practice shall be implemented during the construction phase to minimise any potential exposure to contaminated soils or groundwater. These measures include:

• The use of bulk earth-moving excavator equipment will minimise construction workers’ potential contact with contaminated materials
• Exposure to any contaminated materials may be minimised by the wearing of appropriate clothing and personal protective equipment such as gloves (when interacting directly with suspected contaminated material), providing adequate hygiene and washing facilities and preventing smoking and eating during such activities
• Vehicles containing any excavated materials should be suitably covered to limit potential dust emissions or contaminated wastewater run-off, and truck bodies and tailgates should be sealed to prevent any discharge during transport or during wet conditions
• Only licensed waste haulers should be used to collect and transport any contaminated material to an appropriate disposal site and procedures should be developed to ensure that illegal disposal of waste does not occur
• The necessary waste disposal permits should be obtained, as required, from the appropriate authorities, in accordance with the Waste Disposal Ordinance (Cap 354), Waste Disposal (Chemical Waste) (General) Regulation (Cap 35), as required
• Records of the quantities of wastes generated and disposed of should be maintained

6.5.2 In accordance with good construction practice, silt traps should be used to reduce the impact to drainage caused by suspended solids arising from disturbed ground, or any construction materials such as cement and gravel. Groundwater should be disposed of in accordance with the WPCO.