1                                            Introduction

1.1                                      Preamble

The Drainage Services Department (DSD) has commissioned ERM - Hong Kong, Ltd, (ERM) to prepare a Contamination Assessment Plan (CAP) as part of the Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage 1 Sewers, Rising Mains and Ancillary Pumping Stations EIA and Traffic Impact Assessment (the “Project”) (Agreement No. CE 31/99).  The CAP sets out the requirements for a baseline contamination assessment of the Study Area.

 

The Environmental Impact Assessment Study Brief issued by the Environmental Protection Department (EPD) for this Project requires the DSD to give consideration to historical land uses in relation to possible land contamination along the proposed sewer alignment.  The types of land uses made reference to are identified in the Section 3.1 of Annex 19 Technical Memorandum on Environmental Impact Assessment Process  (EIA-TM), and include:

 

(i)         oil installations including oil depots and petrol filling stations;

(ii)        gas works;

(iii)       power plants;

(iv)       shipyards/boatyards;

(v)        chemical manufacturing/processing plants;

(vi)       steel mills/metal workshops;

(vii)      car repairing  and dismantling work shops; and

(viii)     dumping ground and landfill.

 

Where the above potentially contaminating land uses have been identified within the Project area, the Study Brief requires that a Contamination Assessment Plan (CAP) be developed and endorsed by the EPD. Following 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), before disturbing the ground of the concerned sites. If land contamination is confirmed, a Remediation Action Plan (RAP) shall be prepared, and both the CAR and the RAP shall be submitted as a combined report to the EPD for approval before disturbing the ground of the concerned sites. If applicable and required in consultation with the EPD, the contaminated site(s) shall be remediated in accordance with the approved CAR/RAP.

 

1.2                                      Background

As part of the Project, a preliminary desk top assessment and field based site appraisal was conducted by ERM in August 2000.  The preliminary assessment included:

 

·       contacting the relevant Government Authorities for background information on reported incidents, including chemical spills or leaks;

·       undertaking a historical review of the Study Area using aerial photographs;

·       Lands Department’s “Blackspot” information; and

·       survey maps.

 

The information obtained from the preliminary assessment, combined with visual evidence obtained during the initial site appraisal, identified 32 sites as potential sources of contamination.  The specific land uses identified include:

 

·       vehicle repair and maintenance yards;

·       car junk yards;

·       trailer storage yards;

·       scrap yards and metal recycling facilities;

·       concrete batching plants;

·       metal workshops;

·       saw mills;

·       construction material and open storage areas; and

·       uncontrolled dumping.

 

Specific details of the sites and land uses are provided in Table A1.  In order to determine those activities which pose the highest potential for contamination, a contamination rating was determined based on visual evidence only, and so thus comprises only a qualitative evaluation of the potential contamination of the site. The EPD’s Guidance Notes for Investigation and Remediation of Contaminated Sites of Petrol Filling Stations, Boatyards and Car Repair/Dismantling Workshops (Report Number EPD/TRI/99) has been used as the basis to determining those activities which pose the highest potential for contamination as well as specific guidelines for petrol filling stations, boatyards and car repair/dismantling yards.  The rating categories used in the preliminary site evaluation are as follows:

 

·       “A” rating indicates a high potential for land contamination, with strong visual evidence to suggest the potential for soil and groundwater contamination (i.e. spillage/leakage of oils and/or chemicals, burn pits, areas of uncontrolled dumping );

 

·       “B” rating indicates a medium potential for land contamination, with some visual evidence to suggest the potential for soil and groundwater contamination; and

 

·       “C” rating indicates a low potential for land contamination, with no major concerns observed during the site appraisal.

 

It should be noted that all ratings are based on visual inspection (i.e. conducted from the entrance and/or boundary of the site) and available historical records such as aerial photos. At this stage, this type of visual inspection was deemed sufficient to determine a general rating of the potential for land contamination. However, once site access is available, further work will be required to confirm the visual findings and the presence of any “hot spots”, in order to determine the requirements for intrusive site investigation activities.

 

The overall contamination concerns are considered to be low, as the various properties identified in the site appraisal are fairly small in size and no large chemical spills or storage facilities were identified. Any contamination that may occur is expected to be localised for each property.  ERM proposed that intrusive site investigations be carried out on sites identified with a potential contamination rating of either “A” and “B”, and where access is available.  It is considered that relatively large volumes of contaminant would have to be either spilt or released at the sites for any contaminants to migrate off site and cause a significant negative impact to the Project area.

 

The identification of any contamination during the investigations may result in the following implications for the Project:

 

·       additional costs and time associated with the disposal of potentially contaminated soils, from excavation works.

 

·       potential health risks to site construction workers during any development works.

 

·       potential health risks to future site users.

 

 

1.3                                      Objectives

The main objective of this CAP is to identify contamination at specific sites within the Study Area which may have a potential impact on the Project.

 

At this stage, property access for site specific investigation work has not been obtained.  Therefore, information on the potential land contamination within the identified sites, provided in this CAP, was based upon the visual site appraisal, described in Section 1.2, in August 2000.  However, as specific soil sampling and analysis has not been carried out on the potentially contaminated sites, no quantitative information regarding the level and extent of the contamination is available at this stage.  Specific soil sampling and analysis will therefore be dependent upon the availability of access to the Project area boundary.  

 

 

1.4                                      Environmental Legislation and Non-statutory Guidelines

Assessment of land contamination sources and the potential impacts to particular development projects are investigated under the EPD's direction and oversight in accordance with the Practice Note for Professional Persons (ProPECC PN 3/94), Contaminated Land Assessment and Remediation and the 1997 Technical Memorandum on Environmental Impact Assessment Process (EIA Ordinance, Cap. 499, S.16) (EIAO TM) and EPD’s Guidance Notes for Investigation and Remediation of Contaminated Sites of: Petrol Filling Stations, Boatyards and Car Repair/Dismantling Workshops (1999).

 

ProPECC PN 3/94 defines the objectives of a land contamination assessment study and criteria and guidance for evaluating different levels of impact.

 

There are currently no enforceable standards in Hong Kong for land contamination.  In ProPECC PN 3/94, the Dutch Ministry of Public Housing, Land-Use and Environment Guidelines (the Dutch Guidelines) (1994) are used as reference criteria by the EPD.  In the Netherlands, the Dutch Guidelines were developed for the specific case where the drinking water supply is sourced entirely from groundwater.  Hence, the Dutch Standards are very strict in regard to some specific contaminants, but must be viewed in the context of the site specific Hong Kong situation.

 

Under the Annex 19 of the EIAOTM, Guidelines for Assessment of Impact On Sites of Cultural Heritage and Other Impacts, consideration shall be given to a number of potentially contaminating historical land uses, including metal workshops, car repair and dismantling workshops and dumping grounds, as having the potential to cause or have caused land contamination.  As all of these land uses have been identified either adjacent to, or within, the Project area boundary during the site appraisal, this CAP has been prepared to set out the requirements for a baseline contamination evaluation of the proposed sewer alignment.  A Contamination Assessment Report (CAR), will be prepared following site investigation activities.  If significant contamination is identified in the CAR, a Remediation Action Plan (RAP) will be developed to deal with these areas during excavation works for the laying of the sewers. The RAP should follow the contents requirements as specified in the EPD’s Guidance Notes for Investigation and Remediation of Contaminated Sites.

2                                            Scope and Methodology of the Assessment

2.1                                      Scope

The following scope of work is proposed for those sites, along the proposed sewer alignment, which were identified as possible sources of contamination in the previous ERM report (August 2000):

 

·       39 soil borings or test pits to a depth of three metres at the locations identified on Figures 2.2a to 2.2e are proposed for this assessment.  The actual locations and number of borings will be subject to accessibility (determined by relevant Government Departments, eg District Lands Office) and site conditions.  This will be agreed with the EPD prior to any investigation works.

 

·       Collection of 3 soil and 1 groundwater (if applicable) samples per borehole will be collected at each of the drill holes or trial pit locations, unless rock is encountered, i.e. at various depths 0.5 m, 1.0 m and 3m, or at three depths determined by the on-site geologist.

 

·       Screening of soil samples from boreholes at one metre intervals for volatile organic compounds (VOCs)  using a photoionisation detector (PID). Where servicing and painting activities are identified, at least one sample from each site should be taken for analysis of VOCs/SVOCs;

 

·       Depending on the location and site activities, soil samples will be analysed.  The scope of the analysis will be determined based on Tables 3.1 and 3.2 in the Guidance Notes for Investigation and Remediation of Contaminated Sites of: Petrol Filling Stations, Boatyards and Car Repair / Dismantling Workshops.  The range of contaminants for each of the identified land uses, may include Total Petroleum Hydrocarbons (TPH), and simple aromatics (e.g.  benzene, toluene, ethyl benzene, and xylene) (BTEX) for oily sludges and fuel/lubricating oils; and selected heavy metals.  Selected samples will also be analysed for: VOCs to detect organic paints, primers or  solvents/ thinners;  semivolatile organic compounds (SVOCs); and the Toxicity Characteristic Leaching Procedure (TCLP)[1];  and

 

·       Collation and review of soil results into a CAR suitable for presentation to the EPD.

 

 

2.2                                      Methodology

2.2.1                                Non-Intrusive Investigations

Prior to undertaking the intrusive investigations, a further review should be undertaken to ensure that all available information on the current and historical land use and operations at the suspected sites within the Project area boundary have been identified.  In particular, information should be collected, where available, on the local subsurface geology, hydrogeology and hydrological conditions in the immediate vicinity of the site and will be presented in the CAR.

 

2.2.2                                Intrusive Site Investigation

Where access is permitted, it is proposed that a detailed site investigation will be carried out to confirm the status of any soil contamination.  As many of the potentially contaminated sites identified during the preliminary visual assessment were outside the Project area boundary and are private properties, it is expected that access will not be available at these sites.  Therefore, detailed investigation work will be undertaken within, or as close as possible to, the Project area boundary adjacent to these sites to provide initial information  about the potential of contamination within the Project area boundary.

 

Figures 2.2a to 2.2e detail the locations of the subject sites and the indicative locations of the proposed boreholes.  The borehole locations have been determined based upon the EPD’s Practice Note for Professional Persons (ProPECC PN 3/94), Contaminated Land Assessment and Remediation using a linear distribution pattern along the sewer alignment.  The precise location of the soil borings will be influenced by accessibility and on-site conditions.  The locations will be subject to agreement with EPD.

 

During onsite activities, field staff will also record evidence of any areas of :

 

·       open burning;

·       areas of dead or stressed vegetation;

·       areas of stained soil;

·       recent soil disturbances;

·       on site disposal of municipal or hazardous wastes;

·       oil slicks or discoloration on surface waters;

·       storage of chemicals and other materials;

·       abnormal odours;

·       indications of presence of septic tanks; or

·       on site wells.

 

Drilling or Trenching

Following access arrangements being granted and clearance to drill, the boreholes will be drilled using a mobile drill rig, backhoe, hand auger or suitable sampling tool, as appropriate.  Prior to drilling, the drill equipment will be cleaned with a non-phosphate soap solution and water, with a distilled water rinse. This procedure will be repeated after use at each borehole or trial pit to avoid potential cross contamination between boreholes/trial pits, and during sampling to ensure that any contamination from the surface does not affect deeper substrata or the groundwater.

 

During the drilling/trenching process, the lithology will be recorded by the on-site geologist.  The final borehole depth is intended to be three metres but will be dependent upon the site conditions and at the discretion of the on-site geologist.  If significant contamination is identified, the borehole will be extended to 5 metres or groundwater, whichever is encountered first. Any free product floating on the top of the groundwater and the thickness should be recorded. The floating layer should be removed/recovered and analysed. Furthermore, drilling should be extended to at least 1-2 metres below the bottom of any nearby underground storage tank even if it is below groundwater level.

 

Table 2.2a presents details of the parameters to be tested for those boreholes located outside the potentially contaminated sites.  Table 2.2b presents a summary of the possible pollutants and monitoring parameters for each of the different types of potentially contaminating activities.

Table 2.2a      Sampling Parameters

Activities/ Potential Source of Contamination

Test methods (USEPA Method) (for soil or groundwater samples)

For those boreholes within close proximity to potentially contaminating sites with a rating of “A” or “B”, in order to determine the potential for migration of pollutants to areas where construction and excavation works are planned.

TPH by US EPA* 8015M

VOCs by US EPA 8260

SVOCs by US EPA 8270

*Dutch List Metals by AA/ICPMS

TCLP by US EPA 1311

* United States Environmental Protection Agency (USEPA)

 

**Dutch List Metals include Pb, Cr, Zn, Cu, Sb, As, Be, Cd, Hg, Ni, Se, Ag, and Tl

 

 

Table 2.2b      Generic Approach and Monitoring Parameters based upon Site Activities

Site Number

Type of Activities Based upon August 2000 Site Appraisal.

Potential Source of Contamination

Possible Pollutants

Test Methods (US EPA Method) (for soil or groundwater)

1

Vehicle repair and maintenance yards

vehicle maintenance, scrap vehicle parts, fuels and lubricants storage.

heavy metals, hydrocarbons (fuels, oils, lubricants), solvents or degreasers, paint, battery acid, and mineral fibres.

TPH by US EPA method 8015M;

VOC/SVOC by US EPA method 8260/8270;

Dutch List Metals by ICPMS,AA;

TCLP by US EPA 1311; Asbestos

 

2

Car dumps

vehicle maintenance, scrap vehicle parts, fuels and lubricants storage.

heavy metals, hydrocarbons (fuels, oils, lubricants), solvents or degreasers, paint,  battery acid.

TPH by US EPA method 8015M;

VOC/SVOC by US EPA method 8260/8270;

Dutch List Metals by ICPMS,AA;

TCLP by US EPA 1311, Asbestos

 

3

Trailer parks

vehicle maintenance, scrap vehicle parts, fuels and lubricants storage.

heavy metals, hydrocarbons (fuels, oils, lubricants), solvents or degreasers, paint.

TPH by US EPA method 8015M;

VOC/SVOC by US EPA method 8260/8270;

Dutch List Metals by ICPMS and AA;

TCLP by US EPA 1311, Asbestos

 

4

Scrap Yards/metal recycling facilities

mechanical machinery, scrap metals and debris storage, maintenance activities.

heavy metals, hydrocarbons (fuels, oils, lubricants) and solvents or degreasers, mineral fibres.

TPH by US EPA method 8015M;

VOC/SVOC by US EPA method 8260/8270;

Dutch List Metals by ICPMS and AA;

TCLP by US EPA 1311, Asbestos, PCB

 

5

Concrete batching plants 

mechanical machinery, maintenance activities, fuel and lubricants storage.

hydrocarbons (fuels, oils, lubricants) and solvents or degreasers.

TPH by US EPA method 8015M;

VOC/SVOC by US EPA method 8260/8270;

Dutch List Metals by ICPMS and AA;

TCLP by US EPA 1311

 

6

Metal workshops

mechanical machinery, foundry metal works, scrap metals and debris storage, fuel and lubricants storage.

heavy metals, hydrocarbons (fuels, oils, lubricants-cutting and coating oils), solvents and degreasers, paints.

TPH by US EPA method 8015M;

VOC/SVOC by US EPA method 8260/8270;

Dutch List Metals by ICPMS and AA;

TCLP by US EPA 1311

 

7

Saw mills

timber cutting and shaping activities, mechanical machinery, fuels and lubricants storage.

wood treatment chemical, hydrocarbons (fuels, oils, lubricants-cutting and coating oils), metals.

TPH by US EPA method 8015M;

VOC/SVOC by US EPA method 8260/8270;

TCLP by US EPA 1311;

 

8

Food Processing

mechanical machinery, cleaning,

solvents and degreasers, lubricants (cutting and coating oils).

TPH by US EPA method 8015M;

VOC/SVOC by US EPA method 8260/8270;

Dutch List Metals by ICPMS and AA

 

9

Areas of uncontrolled dumping or burning (burn pits)

general construction waste, vehicle and machinery parts, paints, fuels, oils, metals, batteries,

heavy metals, hydrocarbons (fuels, oils, lubricants-cutting and coating oils), paints, organic solvents, acids, lubricants and unidentified contaminants.

TPH by US EPA method 8015M;

VOC/SVOC by US EPA method 8260/8270;

 Dutch List Metals by ICPMS and AA;

TCLP by US EPA 1311, PCB and dioxins;

2.2.3                                Sampling Programme

The sampling programme will be undertaken with strict adherence to appropriate protocols so as to minimise the potential for cross-contamination between sampling locations.  The soil sampling methodologies are based on methods developed by the US EPA, adapted to Asian standards of operation and practice, as appropriate.  These methods include decontamination procedures, sample collection, preparation and preservation, and chain-of-custody documentation, as outlined below.

 

Decontamination Procedures

Sampling equipment used during the course of the future site investigation programme will be decontaminated by washing and scrubbing the equipment with suitable non-phosphate detergents.  Where available, a steam cleaner or pressure washer will be used.

 

During sampling and decontamination activities, disposable latex/nitrile gloves will be worn to prevent transfer of contaminants from other sources.  Any disposable equipment will be disposed as general waste after each use.  Provisions will be made to containerise any decontamination fluids, although the volume of fluids to be produced is expected to be low.

 

Soil Sample Collection

Soil samples will be placed into appropriate clean glass bottles or sampling containers (provided by the laboratory) immediately after collection.  They will then be transferred to an ice box or cooler container.  Samples will be kept as cool as possible, by regularly replacing the icepacks.  All samples will be collected under chain of custody protocols as described below.

 

Soil samples will be collected for head space analysis using a Photo Ionisation Detector (PID), to assist in the selection of any samples for laboratory analysis of volatile or semivolatile organic compounds.  The meter will be calibrated before use to a known calibration standard of isobutylene gas.

 

2.2.4                                Sampling Management

The fieldwork and sampling should be performed by a qualified geologist and/or contaminated land specialist. All samples collected will be placed in a cooler with ice and kept at less than 4 degrees Celsius.  Samples will be dispatched to an approved laboratory for analysis as soon as possible.  All samples will be handled under chain of custody protocols and relinquished to the laboratory representative at the drill site or at a location specified by the laboratory.

 

 

2.3                                      Analytical Programme

Potential contaminants as identified in the Guidance Notes for Investigation and Remediation of Contaminated Sites of: Petrol Filling Stations, Boatyards and Car Repair / Dismantling Workshops will be identified using various analytical test methods.  The selected soil samples submitted from each of the borings will be analysed for:

 

·       total petroleum hydrocarbons (TPH) by USEPA Method 8015; 

·       priority pollutant or Dutch List metals by ICPMS /Atomic Absorption (AA);

·       volatile organic compounds (VOCs) by USEPA Method 8240;

·       semivolatile organic compounds (SVOCs) by USEPA Method 8270; and as per the 1999 Guidance Notes, samples will be tested for the Toxicity Characteristic Leaching Procedure (TCLP) by USEPA 1311/6010/7000 Series Methods, in order to determine contaminant quality for disposal to landfill (if that remedial measure is selected).

 

2.3.1                                Quality Control and Quality Assurance (QA/QC)

Samples should be representative of field conditions.  At each sampling location, soil samples shall be collected using pre-cleaned sampling equipment.  All sample containers shall be provided by the contracted laboratory who guarantee their sterilisation and preservative contents. 

 

One duplicate sample will be collected for every ten samples for quality control and quality assurance (QA/QC) during the field investigation.

 

Precision will be calculated as the relative percent difference (RPD) between the original sample and the blind duplicate. 

 

2.3.2                                Analytical Laboratory

Analysis of samples will be carried out by an appropriate, HOKLAS-certified analytical laboratory located in Hong Kong or another qualified overseas laboratory.  The laboratory shall maintain high standards of analytical and technical services for the detection of trace organic contaminants.  All analysis will be conducted according to standard procedures set by the US EPA, along with internal QA/QC procedures.

 

 

2.4                                      Generic Remediation Measures

The selection of an appropriate treatment method(s) is dependant upon a number of factors and so should be considered on a case by case basis, these include:

 

·       degree and extent of the contamination;

·       anticipated future use of the site;

·       nature of the contaminants;

·       soil characteristics; and

·       time allowable for remediation.

 

As no quantitative information is currently available on the level and extent of potential contamination at the identified sites, a review of the more widely used remediation options has been provided to assist in the determination of an appropriate treatment technology, once the characteristics of a site have been established. It is important to note that before remediation work is allowed to commence, approval of the Contamination Assessment Report (CAR) and Remediation Action Plan (RAP) should be obtained from the EPD.  Remediation work should also be overseen by an experienced professional with experience in soil and groundwater treatment technologies.

 

The following remediation methods, as outlined in Table 2.4a, are based upon the EPD’s Guidance Notes for Investigation and Remediation of Contaminated Sites of: Petrol Filling Stations, Boatyards and Car Repair / Dismantling Workshops and Practice Note for Professional Persons (ProPECC PN 3/94), Contaminated Land Assessment and Remediation. As many of the sites are relatively small in nature, the potential for extensive contamination is considered to be low, with the following methods providing the most practical options to remediating contaminated sites of this type.

Table 2.4a       Comparison of Remediation Methods

Method

Principal Use

Equipment

Expertise Required

Soil Venting (in-situ)

·       Removal of volatile to semi-volatile organics from unsaturated zone in soil.

·       often used in conjunction with other remediation methods (charcoal filter or catalytic oxidation units) to remove contaminants before discharge.

 

Soil venting/air sparging system

High

Air Sparging (in-situ)

·       Considered an extension onto soil venting, removing volatile organics (BTEX) and chlorinated solvents from groundwater.

·       also removes volatile chemicals and promotes bioremediation.

 

Soil venting/air sparging system

High

Biotreatment

(in-situ)

·       Anaerobic or aerobic biodegradation, with the addition of oxygen and nutrients to shorten the treatment time.

·       Degradation of petroleum products, phenols and PCB’s.

 

 

High

Immobilisation

(in-situ)

·       Remediation of heavy metals.

·       Application of stabilising or immobilising reagents so that heavy metals present will be bound/chelated by chemical reaction or fixed/trapped by physical reaction.

 

Molecular sieves, chelating exchange resins, hydrated limes

High

Recovery Trenches or Wells

(in-situ)

·       Removal of leaked oil (Petroleum hydrocarbons) from groundwater.

·       often used in conjunction with other remediation methods (activated carbon) to remove contaminants before groundwater is discharge.

Skimmer pumps &

Dual pumps systems.

Moderate

Excavation/

Disposal

(ex-situ)

·       Shallow contamination, one-off excavation and contaminant removal, addresses all contaminants.

·       Pre-treatment of excavated soil prior to disposal may be required.

Excavator

Low

Note: The ProPECC PN3/94 and EPDs Guidance Notes provide further details on the above mentioned remediation measures.

 

 

 

 

It is recommended that in-situ remediation methods are adopted wherever possible, in order to save valuable landfill space. Excavation and disposal to landfill should be considered as the last resort and should only be used when:

 

·       in-situ remediation is proved to be not feasible; and

·       there is very localised contamination and the quantity of contaminated soil for landfilling is small.

 

Acceptance of contaminated material for landfill disposal is dependant on the excavated material meeting the accepted criteria, which is set primarily in terms of Toxicity Characteristics Leaching Procedure (TCLP), as shown in Table 2.4b. If excavated material contains other contaminants in addition to those mentioned below, approval for disposal will have to be obtained from EPD and assessed on a case by case basis.

Table 2.4b       Landfill Disposal Criteria for Contaminated Soil

Parameter

TCLP Limit (ppm)*

 

Cadmium

10

 

Chromium

50

 

Copper

250

 

Nickel

250

 

Lead

50

 

Zinc

250

 

Mercury

1

 

Tin

250

 

Silver

50

 

Antimony

150

 

Arsenic

50

 

Beryllium

10

 

Thallium

50

 

Vanadium

250

 

Selenium

1

 

Barium

1000

 

Note: Soil samples should be stored at 0-4 °C. This allowable storage time for mercury in soil samples is 8 days while the storage time for the rest of the parameters (above) in soil samples can be up to 6 months. Soil samples, if stored beyond the allowable storage time, are not considered representative of the actual site conditions (ASTM-E1391-90).

 

*Reference to EPDs Guidance Notes for Investigation and Remediation of Contaminated Sites of : Petrol Filling Stations, Boatyards, Car Repair/Dismantling workshops  

 

 

 

2.5                                      Programme Schedule

The assessment will comprise the following activities:

 

·       required revisions and endorsement of the CAP by EPD (this task includes meetings, and if required, additional site appraisals) based on the finalisation of the detailed design of the study;

 

·       mobilisation of the investigation contractor (pending access arrangements and equipment availability) and contracting analytical laboratory [five working days];

 

·       field sampling programme (number of days in field depends on number of sites and sampling locations to be employed) [one working day per borehole depending on ground conditions];

 

·       analytical programme/laboratory turnaround (normal turnaround time is expected 10 days to two weeks depending upon the number of samples); and

 

·       assessment and reporting of results in a draft contamination assessment report (CAR), including, if required, development of a remedial action plan (RAP)(estimate minimum of three weeks).

 

The analytical programme may be expedited, if necessary, depending upon project timing. A typical turn around time for laboratory analyses is 10 working days to 2 weeks; however, a priority analysis programme may be instituted in order to obtain faster return on laboratory data and entails an additional cost.

 

 

2.6                                      Assessment and Reporting

Following the completion of field investigations a Contamination Assessment Report (CAR) will be developed.  The report will present the findings of the contamination assessment programme and include the methodology used during the soil sampling work, and details of field observations such as visual observations made during the investigation programme, and results of field screening.  The CAR will also include borehole logs, and figures showing soil sample locations. 

 

As there are currently no legislative standards for the clean up of soil and groundwater contamination in Hong Kong, the analytical results will be compared against international standards for soil contamination (Dutch Standards).  Arising from the on-site observations and the quantitative sampling results received, professional judgement will be provided regarding soil and ground water contamination, and the necessity of appropriate mitigation measures. 

 

The CAR  produced under this Project will be prepared in draft format and submitted for review to EPD and DSD.  Upon receipt of comments from DSD and EPD, the CAR will be finalised.

 

If required, a detailed Remedial Action Plan (RAP) will be prepared in consultation with the DSD and EPD.  Any proposed remedial options will examine the relevant issues of soil and groundwater treatment versus disposal, proposed future land uses of the Project, and potential risks based upon the soil and groundwater contamination type and concentrations.

 

The results of the sampling programme, the report, and the objectives of the RAP shall be reviewed with EPD prior to finalisation.  It should be noted that no estimate of the time frame for any remediation is presented at this time.

 

 

Table A1           Potentially Contaminated Sites in Project Area

Site

No.

Current Land use

Observed Evidence of Contamination

General Project Location

Blackspot  Reference (if any)

1

Small Scrap and Storage Yard, with construction materials and equipment

Metal scrap, minor vehicle repairs (in one service bay), unpaved areas with fuel storage

P2

1

2

Vehicle/Motor Components, with some trailer storage

Observed scrap motor bikes, vehicle parts; unpaved areas

P2

2

666

Cosmo Way Enterprises Trailer Storage

Trailer storage; paved, appears to be well kept; minor vehicle maintenance

S5

--

666a

Kon Chueng Food Processing Factory

Dumping area behind factory; small burn pits noted (suspected for burning of trash); storage of full and empty chemical containers; site maintains one Cat. 5 underground storage tank

S5

--

666b

Vacant Land area along dirt road

Uncontrolled dumping: fresh dirt and debris piles; some oil based product or oily residues dumped; paint cans

S5

--

3

Scrap Yard

large scrap metal piles; unpaved areas with metal storage, scrap shredding, vehicle dumping

S4

3

3a

Scrap and Construction Material Storage

Observed scrap metal piles, at least 100 drums (suspected empty), scrap vehicles;  steel pilings and construction materials stored; area unpaved

S4

--

3b

Car Dump

Observed scrap vehicles, scrap metal

S4

--

3c

Temporary Concrete Batching Plant

Typical concrete batching activities; suspected fuel tanks present; sand and gravel piles; detailed inspection not allowed

S4

--

4

San Tin Vehicle Maintenance

Observed four vehicle service bays; much of property vacant, unpaved

S4

4

6

Vacant land; some storage

Mostly vacant; has some construction materials and scrap

P1, S4

6

6a

Scrap Metal Storage

Miscellaneous scrap storage, metal and vehicles

S4

--

6b

Equipment and Materials Storage

miscellaneous materials in open unpaved area; observed six empty portable storage tanks

S4

--

7

Jaguar, Tai Hing Motor Companies

Vehicle/motor components; used cars and scrap cars; minor vehicle maintenance;  no access to site

P1

7

12

Car Storage

New and used cars; no apparent maintenance

P1, S2

12

23

Vehicle Repair/Scrap Yard

Vehicle and motor components; observed spillages on ground, which is only partially paved; fuel storage

P5, S1

23

24

Kam Luem Motor Vehicle Repair

Vehicle repair activities; no access allowed to site

S1

24

26

Ya Luen Storage

Storage of construction materials and equipment; no access allowed to site

S1

26

26a

Hop Wo Construction Materials

Scrap materials and scrap vehicles; metal parts; stacked drums, old heavy construction equipment and materials

S1

--

26b

Construction Material Storage

Storage of metal scaffolding and parts; some drums observed; no access allowed to site.

S1

--

26c

Yau Fai Factory

Apparent small steel factory and metal plating works; storage of construction materials, crane and lift parts

S1

--

27

Excellence Engineering Company

Warehouse and Timber operation; minor vehicle maintenance observed; no access allowed to site.

S1

27

28

Unidentified Factory Building

Old slaughterhouse? Observed large concrete tank (water?), storage of bags of seeds

S1

28

29

Construction Materials and Equipment

Civil engineering company storage; observed some above ground storage tanks and storage of oil drums (without secondary containment)

S1

29

79

Vacant Lot; Former Vehicle storage

Vacant; paved; former storage activities

S1

79

80

Fai Wong Junk Yard and Vehicle Repair Workshop

Observed old vehicles and parts; general construction materials; partially paved, with staining of soil; no access allowed to site

S1, P4

80

81

Jitwing Motor Components

Vehicle repair and maintenance activities; scrap cars, junk yard; site is paved, but oil staining observed; no access allowed to site

S1, P4

81

82

Wah Sing Vehicle Machine Trading

Vehicle repair and maintenance activities; vehicle and machine parts observed; drum storage, with staining noted on concrete; site partially paved; no access allowed

S1, P4

82

83

Fungs World Industrial Limited

Machinery and motor maintenance activities; various parts and components stored; generally looked in good condition; paved

S1, P4

83

84

Chuen Yip Vehicle Repair

Vehicle repair and maintenance, motor components and scrap parts; area unpaved, and heavy staining observed; painting activities note; no access allowed to site

S1, P4

84

85

Hop Yik Generator Company

Motor maintenance activities, generator components; site generally clean

S1, P4

85

86

Vacant lot

Vacant; suspect trailer storage

P4

86

Note: Refer to Figure 7.4a in the EIA(DE) Report for locations.

 

 

 

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 (1) Testing parameters of TCLP test include, Cadmium, Chromium, Copper, Nickel, Lead, Zinc, Mercury, Tin, Silver, Antimony, Arsenic, Beryllium, Thallium, Vanadium, Selenium, and Barium.