section 9

1. INTRODUCTION

1.1 Contamination can be defined as “the introduction by man into the environment of substances or energy liable to cause hazards to human health, harm to living resources and ecological systems, damage to structures or amenity, or interference with legitimate uses of the environment” (Holdgate 1979, and adopted by the RCEP, 1984). The soil is a primary recipient, intended or otherwise, of many waste products and chemicals used in modern society.

1.2 The Spur Line passes across a range of landuses, including agricultural, residential, container storage, industrial and fish farming areas. While there are no extensive areas of contaminated land such as landfills, chemical stores, etc. across which the Spur Line passes, there is potential for the presence of small industries or storage sites to create an impact in the construction and operation of the Spur Line. This Contaminated Land Assessment Plan (CAP) has been written for the contaminated land assessment of Agreement No. EA990008, Sheung Shui to Lok Ma Chau Spur Line (Spur Line) in accordance with EPD Practice Note for Professional Persons Concerning ProPECC PN 3/94 - Contaminated Land Assessment and Remediation and the EPD Guidance Notes for Investigation and Remediation of Contaminated Sites of: Petrol Filling Stations, Boatyards or Car Repair/Dismantling Workshops. The CAP is prepared to fulfil the requirement of section 3.11.2 of the EIA Study Brief.

2. METHODOLOGY

2.1 This contaminated land assessment includes the following steps:

(i) A desktop study on the history of landuse along the Spur Line alignment (the Desktop Study) which provides a clear and detailed account of the relevant past land history and the present land uses along the alignment. This identifies areas of potential land contamination.

(ii) Identification of works associated with Spur Line construction that may impact contaminated sites.

(iii) A site survey in order to identify all potentially contaminated areas and pollutants for the land contamination assessment.

(iv) Recommendations for a schedule of 2 stage sampling, initially at potentially contaminated areas identified in the Desktop Study and during the site survey followed by further sampling to determine the extent of contaminated areas if contamination is confirmed, and the laboratory analysis of essential parameters. This should be carried out at the site investigation stage of works to confirm the presence or absence of contamination.

(v) Recommendations on appropriate remedial action for several scenarios based on the range of different types of contaminants which may be found during site investigations. Any remedial action proposed will be beneficial not only in terms of preparing the land for construction but will also alleviate potential impacts on groundwater, water quality in river courses and the ecology of the area.

(vi) The application of the recommended sampling, analysis and remediation programme to specific locations along the alignment to facilitate the implementation of the Contamination Assessment Plan during the site investigation stage.

3. STUDY AREA

3.1 The Study Area includes the immediate track and tunnel alignment and the engineering works boundary (Figure 2.1). Three temporary works areas have been earmarked at Lok Ma Chau, Kwu Tung and at the Sheung Shui Temporary Housing Area. In the Lok Ma Chau area, fishponds will require temporary draining and stabilisation with partial or complete infilling to create a base for pier and station foundation works.

3.2 4.3 km of the alignment passes through a tunnel under rural areas dominated by agriculture. Within this predominantly tunnelled section, a range of ground surface works will be undertaken, some in locations where there is potential for contaminated land to be impacted. These surface works include: the TBM launching shaft at Sheung Shui, the recovery shaft at Chau Tau, Emergency Access Points (EAPs) and ventilation buildings, the locations where surface jet grouting is required for the construction of cross passages and the Kwu Tung station box. The most significant areas where potential impacts may occur are the Kwu Tung station box where a number of small industries and storage areas are located, at the scrap metal yards in Sheung Shui around the launching shaft and around the recovery shaft at Chau Tau, where a number of container storage yards may contribute to land contamination.

3.3 Figures 10.1, 10.2, 10.3, 10.4 show the alignment and future surface structures which may have impacts on contaminated land.

3.4 Construction methods will include excavation works for surface structures, for the cut and cover tunnel sections, launching and reception shafts and the Kwu Tung station box, bored piling works for the viaduct supports and for Lok Ma Chau station construction, and excavation of material from the tunnel. The tunnel is sufficiently deep that it is unlikely to impact any contaminated areas. The extent of surface impacts, and the type of remediation to be proposed will depend on whether the works is extensive, such as the TBM launching and recovery shaft excavation, or minimal, as in the viaduct pier supports.

4. RISKS TO HEALTH

4.1 A contamination assessment is important because of the health risks posed to site workers on exposure to contaminated soil or sediments, and contamination of groundwater during earth moving operations, excavation or piling works. Workers could become exposed to contaminants either directly e.g. skin contact during the work by inhalation of dust or vapours, or through ingestion whilst eating or smoking on site.

4.2 If remediation is found to be necessary at any point of the alignment it should be carried out to a suitable level so as not to pose any future health risks to users of the site. As long as there is no direct human - soil interface, it is likely that in many places the sediments could remain in-situ or be remediated to a level sufficient for its future use.

4.3 Contaminants of particular concern due to their potential health risks include inorganics such as cyanides and heavy metals, organics such as mineral oils, halogenated solvents, polycyclic aromatic hydrocarbons and volatile aromatic hydrocarbons and minerals such as asbestos.

4.4 Contaminants may also pose a fire hazard or explosion risk if volatile gasses or flammable contaminants are found.

5. DESKTOP STUDY

Industries having the Potential to Cause Land Contamination

5.1 Historically there is evidence that the New Territories was the location for various light industries and other landuses which change frequently but often have a potential to contaminate the land. These include car repair yards, container storage areas, livestock farms, paint and dye factories and other small scale industries. Many of these small industries still operate today, although the density of factories has reduced over recent years. In addition there are dumping grounds, refuse collection points and illegal dumping areas which are likely to result in some ground contamination. Many of these landuses fall within the areas of the proposed alignment and, if unmitigated, give rise to concern for their future landuse.

5.2 A number of industries have been identified in ProPECC PN 3/94 as having the potential to cause land contamination. These include:

· oil installations (e.g. oil depots, oil filling stations);

· gas works;

· power plants;

· shipyards/boatyards;

· chemical manufacturing/processing plants;

· steel mills/metal workshops; and

· car repairing/dismantling workshops.

5.3 This list is not exhaustive and judgement is needed to determine if contamination is likely from other land uses or industries.

Land Ownership

5.4 There is a variety of ownership along the alignment of the Spur Line. Across Long Valley there are many agricultural lots, whilst in Kwu Tung many owner occupied small houses typical of the New Territories are found. Significant areas of land along the alignment are Government Land, particularly in the Lok Ma Chau and Sheung Shui areas.

Landuse History

5.5 In order to assess potential land contamination, the past landuse history and the present landuse of the areas which will fall under the Spur Line alignment have been reviewed. Aerial photographs have been used and landuse information has been obtained from the District Land Offices in Yuen Long (DLO Yuen Long) and Fanling (DLO North).

6. SITE SURVEY

Objectives and Methodology

6.1 The objectives of a site survey for the land contamination assessment are to confirm any land-uses found in the DLO records and to identify any other uses which may be illegal and not recorded. The Study Area has been taken to be the gazetted area of the Spur Line, although large portions of this gazetted alignment will not be directly affected except via the underground tunnel. The site survey has also been used to gather information on other activities such as storage and management of hazardous substances.

6.2 Initial site inspections were carried out on 17 May, 27 July 1999 and 17 September 2001. No advance notice was given to land users in order to obtain as authentic information as possible. A number of sites along the alignment were disregarded due to information obtained during the desktop study and site visits which indicated no likelihood of contamination. The findings of the site survey are evaluated to identify all potentially contaminated areas and parameters for further investigation in a sampling and analysis programme.

6.3 Ground conditions were also observed during the site surveys, to determine the ease of infiltration and potential for underground dispersion of pollutants.

Results of Desktop Study and Site Visits

6.4 A full listing of the desktop study results and the findings of site visits to each site are provided in Appendix A. As some sites cover more than one lot, each site listed has been assigned a letter. The sites are described from west to east along the alignment and their locations identified in Figures 10.1, 10.2, 10.3, 10.4. The nature of the land in each lot, and the activities being carried out which may potentially contaminate the ground, are shown in Plates 10.1 to 10.5, 10.6 to 10.10, 10.11 to 10.15, 10.16 to 10.19, 10.20 to 10.24, 10.25 to 10.29. Not all lots could be photographed, however, a description of each lot is given in the following tables. Table 6.1 lists lot numbers, their assigned letter and the type of works which may impact the area (viaduct, EAP, launching shaft, etc).

Table 6.1

Lot Numbers, Assigned Letters and Section

Letter	Lot Number	Section	Letter	Lot Number	Section
A	DD99/372 S.D RP	Ramp and Viaduct	G	DD95/ 786, 791, 792, 772 (part)	Kwu Tung Station Box
B	DD99/ 470 - 483, 486 – 493, 527, 545 - 548	Recovery Shaft	H	DD96/ 772 (part)	Kwu Tung Station Box
C	DD96/352, 353, 354, 355, 423	Miscellaneous Storage Area (TBC)	I	DD95/ 803 S.A. ss.	Kwu Tung Station Box (TBC)
D	DD96/ 428	Miscellaneous Storage Area/Cross Passage	J	DD95/ 803 S.B.	Kwu Tung Station Box (TBC)
E	DD 96/645 – sections	Cross Passage	K	DD95/ 43 - 45, 53 - 59, 65 - 67, 70 - 74	Cross Passage
F	DD 96/717, 718, 721	Cross Passage	L	Sheung Shui Government Land	Launching Shaft

TBC: To be confirmed. These sites may fall outside of the above ground works areas and therefore may be removed from the contamination assessment at a later date if it is found that they will not be impacted by works.

6.5 Table 6.2 summarises the results of the desktop study and site visits. The table lists the registered landuse of the site and the likely potential and extent of contamination. CAP Appendix A includes any permit numbers or Short Term Tenancy Agreements (STT) or Short Term Waivers (STW) which cover the lots.

Table 6.2

Findings of Desktop Study & Site Visits and the likely Potential for Contamination

Site and Lot No.	Figure No. / Plate No	DLO Registered Landuse	Site Inspection	Potential for Land Contamination
A DD99/372	F:10.1 P:10.1 – 10.5	Container vehicle park, open storage	Confirmed landuse. Some petrol pumps, chemical waste area	Likely, rough surface, cracked concrete, storage of chemical and hydrocarbons on site
B DD99/470-483, 486-493, 527, 545-548	F:10.1 P:10.6 – 10.10	NA*	Containers, open storage, storage of chemicals, oils and solvents	Likely, gravel and cracked surface and storage of potential contaminants and scrap metals
C DD96/352, 353, 354, 355, 423	F:10.1 P:10.11 – 10.15	NA*	Sign stated car repairs. Previous storage of many chemical drums, most marked harmful. Site now cleared (Sept 2001).	Likely, evidence of spillage on ground. Concrete cracked (Works area TBC)
D DD96/428	F:10.2 P:10.16	NA*	Disused/abandoned pig farm with chemical storage	Likely, cracked surface and spillage evident
E DD96/645	F:10.2 P:10.17	NA*	Farm buildings, chemical storage, livestock waste drums, site generally littered with waste	Inventory of chemicals and pesticides used required. Rough surface may have allowed some infiltration
F DD96/717, 718, 721	F:10.2 P: -	NA*	Container storage area, some parked vehicles and drum storage	Possible, some containers are very old, and battered, spillages could have occurred.
G DD95/786, 791, 792, 722	F:10.3 P:10.18 & 10.19	Illegal container storage	Container and storage area with temporary structures. Surface rough and some chemicals stored	Possible - depending on whether any spillages have occurred.
H DD96/772	F:10.3 P:10.20 & 10.21	No registered landuse	Metal recycling company. Many parked vehicles, rough gravel surface.	Possible - depending on whether spillages have occurred
I DD95/803	F:10.3 P: -	NA*	Storage area for adjacent factory.	Possible from historic contamination as this was a leather goods factory
J DD95/803	F:10.3 P:10.22	NA*	Car repairs/dismantling yard. Ground concreted and vegetated	Likely due to infiltration through cracked concrete and vegetation
K DD95/43-45, 53-59, 65-67, 70-74	F:10.3 P:10.23 & 10.24	NA*	Access denied but site is fenced and appears to be used as a repairs and maintenance site for Paul Y ITC	Likely but activities carried out here must be clarified. Site access not possible.
L Government Land in Sheung Shui	F:10.4 P:10.25 – 10.29	NA*	Access denied but scrap metal yard in operation observed. Some storage of chemical drums and metal waste	Likely but exact locations must be determined.

Note NA* - No information available from DLO

6.6 The main areas for concern are container storage areas, particularly those in DD99 close to Lok Ma Chau (A and B), the car repair/dismantling yards at Kwu Tung (J) and the scrap metal yards in Sheung Shui (L).

6.7 The main contaminants are likely to be oils, organic solvents and heavy metals. Some chemicals known to be hazardous were found. These included methylene chloride, listed as a hazardous air pollutant (under the US Clean Air Act, 1991). Many chloro alkanes are designated as priority pollutants (Clean Water Act) and are on the Superfund Hazardous substances list, as is chloroform which was found close to site F. In addition to specific named substances and chemicals there was much evidence of oil and petrol spillage, piles of scrap metals and storage of unspecified chemicals.

Site Appraisal

6.8 From the desktop study and site visit information collected, it is possible to determine whether a contaminated land site investigation is needed. This information was used to check against the set of criteria described in Table 6.3 which is taken from the EPD Guidance Notes for Investigation and Remediation of Contaminated Sites of: Petrol Filling Stations, Boatyards or Car Repair/Dismantling Workshops. For this set of landuses if the answer to any of the criteria is ‘No’, a full scale site investigation is recommended. A positive answer to all criteria indicates that simplified site investigation may be sufficient. The criteria can be used as guidelines or indicators for different potentially contaminating landuses.

Table 6.3

Criteria for Adoption of Full-scale or Simplified Site Investigation

Criteria	Yes/No
1. Length of operation of the site is less than 5 years.
2. There is a practice of recording spill incidents or monitoring chemical storage.
3. Waste disposal is carried out in accordance with Government requirements
4. Absence of underground storage tank on site
5. Absence of surface contamination indicators which include: a) stained areas b) uncontrolled chemical drum storage c) cracked concrete near storage of chemical drums d) unnatural colours and odours; and e) abandoned piping/mechanical components or cans.

6.9 In the case of Spur Line, no site along the alignment is known to have an underground storage tank. At several sites where chemicals are stored, a negative answer is likely to criteria 2 and 3 as most sites landuse is illegal and no DLO records are available. At many of the sites there is evidence of spillage of chemicals, uncontrolled chemical drum storage, cracked concrete or rough gravel surfaces, all of which are criteria for full scale site investigations. On the basis of this information, a Land Contamination Assessment Plan (CAP) is recommended. The following section describes the CAP for the Spurline Project.

7. LAND CONTAMINATION ASSESSMENT PLAN (CAP)

7.1 This section summarises the results of the desktop study and site inspection and proposes a sampling and analysis programme based on the data collected. The sampling programme should be carried out during the site investigation stage.

Site Investigations

7.2 A site investigation should be approached in a systematic way bearing in mind the purpose and the level of detail which is required. The main topics, as defined by EPD (1999) are:

· Physical site conditions, including geology, topography, soil type and physical properties, drainage and groundwater.

· Likely contaminants - previous site use.

· Extent and severity of contamination, the concentrations, depth, spatial distribution of contamination in both soils and groundwater.

· Effects on users, including the nature and level of contamination with regard to future use.

· Potential environmental harm.

· Hazards during construction.

7.3 The subsurface geology and groundwater flow are important as petroleum hydrocarbons in particular can float and migrate some distance. This could impact other drainage waters around the Spur Line alignment and cause modification of BOD₅, SS and other important parameters. Many of the areas where potential contamination sites were identified, are located on flat, low-lying land, not far above the water table. There is therefore potential for contaminants to enter the groundwater in these areas.

7.4 Table 7.1 below lists the site numbers and the main activities at each site identified. Likely contaminants associated with different site activities are listed in Table 7.2. The level of contamination and the extent of contamination need to be determined through a formal sampling and analysis programme and the most suitable methods for clean up of the site determined.

Table 7.1

Lots along the Spur Line and Potential Contaminating Landuses

Site	Fuelling Areas	Servicing/Parking Areas	Paint Shop	Fitting out/ repairs	Coating/ steel treatment	Vehicle Breaking	Chemicals or waste storage	Drainage and soakaway systems	Agricultural Activities
A	√	√	√	√	√	√	√	√
B	√	√	√	√	√	√	√
C							√
D							√		√
E	√				√		√
F							√
G		√	√	√		√	√
H		√					√
I							√
J		√	√	√			√
K	√	√	√	√	√	√	√
L	√	√		√	√	√	√	√

Table 7.2

Activities found along the Spur Line and their likely associated contaminants

Contaminant	Fuelling Areas	Servicing/Parking Areas	Paint Shop	Fitting out/ repairs	Coating/ steel treatment	Vehicle Breaking	Chemicalsor waste storage	Drainage and soakaway systems	Others
Metals (all)	√	√	√	√	√	√	√	√	√
Lead	√	√	√
Chromium		√
Zinc	√		√
Copper	√	√
Cyanides				√	√		√	√	√
Organic Contaminants		√	√	√	√		√	√	√
Simple aromatics	√	√		√	√	√	√		√
Organic solvents	√	√	√	√	√		√		√
Polyaromatic hydrocarbons		√			√	√	√		√
Fuels/oils	√	√		√		√	√	√	√
Biocides				√	√	√	√	√	√
Oily sludges		√		√	√	√	√	√	√
Microbacteriological							√	√	√
Acids				√	√	√	√	√

NOTE:

Simple aromatics includes benzene, toluene, ethylbenzene, xylene etc

Organic solvents includes non-halogenated and halogenated solvents

Fuels/oils includes Total Petroleum Hydrocarbons

Acids includes sulphuric and hydrochloric

SOURCE: EPD (1999)

Voelcker Science (1999)

Methodology for Evaluation of Contaminated Land

Selection of sampling locations

7.5 From the desktop study and site visit information collected, the need for a contaminated land site investigation was determined. This information was used to identify areas of potentially contaminated land. The approach taken in selecting suitable locations for sampling and analysis took into account the following factors.

· The extent to which the potentially contaminated land site overlapped with the KCRC Scheme boundary.

· The form of the railway alignment at the location of each site (viaduct, cut and cover, ramp or tunnel).

· The location of boreholes conducted for the Site Investigation (S.I.).

7.6 The sections of each potentially contaminated land site which fall within the Spur Line Scheme Boundary and may potentially be impacted by above ground activities are shown on Figures 10.1, 10.2, 10.3, 10.4 and tabulated in Table 7.3. The figures also show the limits of the viaduct, cut and cover and tunnel sections along the alignment. The locations of those boreholes that are within potentially contaminated sites and will be used for sampling and analysis under the Contamination Assessment Plan (Stage 1) are highlighted in Figures 10.6, 10.7, 10.8, 10.9. These boreholes have been located, to coincide (as far as possible), with the locations of identified potentially contaminated areas during site visits. These potentially contaminated areas are generally locations where staining has been noted from vehicles, chemical storage areas, or spillage.

7.7 Figures 10.10, 10.11, 10.12, 10.13, 10.14, 10.15, 10.16, 10.17, 10.18 show detailed site layout and monitoring locations for the CAP investigation.

7.8 Where no boreholes are available for sampling close to the potentially contaminated site, a trial pit will be dug at the potentially contaminated area. The section on sampling methodology outlines sampling procedures, including appropriate depths.

7.9 In some cases, access could not be gained during the site visits and the location of the trial pit will need to be defined when the land has been resumed. At this stage a Supplementary CAP will be submitted to EPD for approval of the reviewed sampling locations. If access to the site confirms an absence of potentially contaminating activities no sampling will be proposed. In this case the CAP will recommend no further action. It however, contamination is suspected, the contractor will carry out sampling after approval of the Supplementary CAP and the results will be provided in a Supplementary CAR, leading to a Supplementary RAP if necessary.

7.10 Table 7.3 details the locations of each borehole/trial pit to be sampled at Stage 1 and parameters chosen for testing at each site, and whether access is currently possible.

Table 7.3

Chosen Sampling Locations and Parameters

Site	DH/TP No.	Chosen Sampling Locations	Chosen Parameters for Testing
A	DH/084	Adjacent to chemical waste point and vehicle repairs area (plate 10.2) concrete is cracked and infiltration may have occurred.	Metals, CN, TPH and organics have been chosen due to the varying vehicle maintenance activities and storage of unknown chemical wastes in the vicinity.
A	DH/085	Adjacent to chemical stores and with visible spillage of potential contaminants on ground. The vehicle repair area at the east side of the site is unlikely to be affected by construction works.	Metals, CN, TPH and organics chosen due to unknown nature of contaminants.
A	A-TP1 – A-TP3	Locations will be specified after resumption of land when access is gained. One GP likely to be close to vehicle washing area (plate 10.3) and oil drums (plate 10.4)	Metals, CN, TPH and organics
B	DH/071	Located adjacent to and slightly below a vehicle repair workshop. This is an area to which runoff is lively to have occurred and is above a stream contaminated with similar runoff.	Metals, TPH, CN and organics chosen because of the nature of vehicle repair activities.
B	DH/076	Located inside a vehicle repair workshop where drums of chemicals / petrol are stored (plate 10.8). There is evidence of spills on the floors.	Metals, TPH, CN and organics due to the nature of vehicle repair activities and uncertain nature of stored chemicals.
B	B-TP1 - B-TP3	Inside vehicle repair workshop as DH/071	As DH/071
C	C-TP1	At the KCRC site boundary closest point to the adjacent chemical store (Plate 10.13). Chemicals have been spilt and may have dispersed this far.	Metals, TPH and organics due to the variety of contaminants which could be associated with the chemical store.
D	D-TP1	Hotspot located adjacent to stored drums and where evidence of chemical / petroleum spillage can be seen (Plate 10.16). The indoor drum storage area has a concrete floor and spills would have washed to the location of D-TP1.	Metals, TPH and organics will all be tested for due to the unknown contaminants which could have been spilt at this site.
E	DH/051	Hotspot located adjacent to stored petrochemical drums and where some oil spillage was noted (Plate 10.17).	Metals and TPH chosen based on evidence of activities occurring at this site.
F	DH/043	Located where spills of oils are visible.	Metals and TPH chosen as basic indicative parameters. Methylene chloride & Chloroalkanes will be tested for.
G	DH/034 and G-TP1 & 2	Hotspot located adjacent to waste drums (Plate 10.18) where chemical spills noted.	Metals and TPH chosen as representative of contaminants likely to be found due to the nature of container storage activities.
H	H-TP1 & 2	Hotspot will be located where visual inspections show possible metal contamination of land may have occurred(plate 10.20 & 21).	Metals and TPH chosen as these are likely to have been used in on site activities.
I	I-TP1	Located next to workshop area.	Metals and TPH chosen as basic indicative parameters. Total Sulphur will be tested for due to leather treating activities at adjacent site.
J	J-TP1	Inside vehicle repair workshop. Located where there is evidence of spillages.	Metals, CN, organics and TPH chosen to test for contamination from vehicle maintenance activities.
K	K-TP1 – 3	Adjacent to the suspected more contaminated areas (to which access can not be gained). In an area where containers are stored and maintained. Decision made on contamination testing after resumption of land	Metals and TPH
L	L-TP1 - 4	Adjacent to suspected contaminated areas where chemicals are stored or scrap metal piled. Decision to be made after resumption of land	Metals and TPH

Sampling Methodology

7.11 Prior to a borehole being constructed, it is usual practice to dig an inspection pit up to 3 m deep to verify the presence or absence of utilities. An environmental scientist with experience in contaminated land assessment should be on site to monitor the first few boreholes to confirm that the samples are being taken at the right locations and in the correct manner. A visual inspection of the trial pits will also enable the environmental scientist to make a visual assessment of the likelihood of severe contamination.

7.12 It is preferable that samples are taken from the trial pit as a visual assessment of the ground material can be made more readily than a borehole and the exact sample depth can be verified. If contamination is suspected at the base of the trial pit, samples will be taken at greater depth from the borehole.

7.13 The approach to sampling will be dependent on the section of the alignment and construction methods to be used. In most sections, Stage 1 boreholes will be sampled to 3 m depth. This is considered sufficient as excavation will be to around 2 m depth. Any trial pits in the vicinity of future landscaped areas will be sampled at 0.5 m as works will only affect the surface layers.

7.14 Trial pits and boreholes should be sampled at three depths each. These are 0.0 – 0.5m depth, 1.0 – 1.5m depth and 2.5 – 3.0m depth, unless otherwise specified.

7.15 Table 7.4 describes the locations and number of boreholes and trial pits to be sampled, the number of samples to take and the parameters to be tested. In all cases, Total Petroleum Hydrocarbons (TPHs) will be analysed. In selected samples, metals, cyanide and organics (chlorinated and non-chlorinated solvents, aromatics and polyaromatic hydrocarbons (PAHs)) will be included in Stage 1 sampling. In sites such as container yards, organics are unlikely to be a problem and are therefore not included in the parameter list. Some sites will require organics testing. The results of these analyses will help to fine tune the testing required for Stage 2 sampling and analysis.

7.16 At sites where access has not been possible a rapid on-site assessment must be made once land is resumed. This will confirm the likely extent of contamination expected and propose the number of trial pits necessary. At present the number of trial pits proposed is based purely on the area of likely contamination and how many trial pits are proposed according to EPDs guidelines. Likewise, the parameters for sampling will be confirmed and agreed with EPD, as current proposed parameters are based on assumptions without having gained access to he land. Locations within each such site will be finalised at this time dependant on the activities causing potential contamination. This rapid assessment and agreement with EPD will be particularly necessary at Site L, where the TBM launching shaft is located.

7.17 In addition, some sites have been included at this stage prior to final confirmation of the above ground works. Some sites may be dropped from this assessment at a later stage if no above ground works affect them , e.g. C, I and J.

Site & Lot No.	Section	Potentially Contaminated land directly impacted by engineering works (m²)	Sampling Number (Boreholes)	Sampling Number (Trial Pits)	Depth of Sampling	Total number of samples to be analysed	Analysis Parameter For each sample
A DD99/372S.D.RP	Open Ramp Section	5,000	DH/085 DH/084	A-TP1 A-TP2 A-TP3	DH-3.0 m TP-3.0 m	15	Metals, CN, TPH and Organics
B DD99/471-483, 486-493,527, 545-548	Recovery Shaft and Cut and Cover section	5,000	DH/076 DH/071	B-TP1 B-TP2 B-TP3	DH-3.0 m TP-3.0 m	15	Metals, TPH, CN and Organics
C DD96/351-355, 425	Temporary Works (TBC)	TBC	-	C-TP1	0.5 m	1	Metals, TPH and Organics
D DD96/428	Temporary Works and Cross Passage	100	-	D-TP1	3.0 m	3	Metals, TPH and Organics
E DD96/645	Cross Passage	250	DH/051	-	3.0 m	3	Metals and TPH
F DD 96/717, 718, 721	Cross Passage	100	DH/043	-	3.0 m	3	Metals and TPH Selected organics
G DD95/ 786, 791, 792, 772 (part)	Kwu Tung Station Box	1500	DH/034	G-TP1 G-TP2	DH-3.0 m TP-3.0 m	9	Metals and TPH
H DD96/ 772 (part)	Kwu Tung Station Box	600	-	H-TP1 H-TP2	3.0 m	6	Metals and TPH
I DD95/ 803 S.A. ss.	Kwu Tung Station Box (TBC)	TBC	-	I-TP1	3.0 m	3	Metals and TPH Total Sulphur
J DD95/ 803 S.B.	Kwu Tung Station Box (TBC)	TBC	-	J-TP1	3.0 m	3	Metals, CN and TPH Organics
K DD95/ 43 - 45, 53 – 59, 65 - 67, 70 – 74, 29	Cross Passage	800	-	K-TP1 K-TP2 K-TP3	3.0m	9	Metals and TPH
L Government Land at Sheung Shui	Launching Shaft	5,000 TBC		5 trial pits likely	TP – 3.0 m	15	Metals and TPH

7.18 At Stage 2, the aim will be to determine the extent of the contamination at sites where contaminants have been detected. Where contaminants have been identified an estimation of the depth and extent of contamination will be made based on results obtained at Stage 1.

7.19 A 5m diameter will be assumed around each borehole/trial pit at which Dutch B levels have been exceeded and this area will be excavated. A minimum of 5 samples, comprising 4 from around the boundary and 1 from the centre of the base of excavation will be taken. Excavated material should be stockpiled and bunded using appropriate measures while the 5 samples are tested. If Dutch B levels are still exceeded excavation will be extended outwards in 0.5m increments and further samples tested until levels below Dutch B standards are reached.

7.20 Samples will be tested for limited parameters dependent on previous exceedances of Dutch B at the original Stage 1 location. Testing for TCLP will also be carried out in the case of heavy metals if it has not been previously carried out. This will determine the potential for disposal to landfill. To speed at works where the programme is very tight (e.g. Site L) TCLP tests can be included in the Stage 1 testing.

7.21 In addition, the depth of testing may be limited if construction works will not be carried out at that particular area. For example, where any sites clearance works will be carried out it may only be necessary to handle the upper 0.5 to 1 m of soil. This will be decided by the Environmental Manager on Site. All further sampling parameters and depths will be in accordance with this CAP.

7.22 The proposed analysis programme is summarised below:

Two Stage Analysis Programme

Stage 1

Sampling of all

potentially contaminated areas

General Examination of TPH, Heavy Metals (and Organics and CN for selected sites)

Evaluation of Analytical Results

Not Contaminated Contaminated

Proceed with Project without Stage 2

any Remediation Measures

Sampling to determine

extent of contamination

Examination of Form of Heavy Metals

PAH, BTEX if not previously determined

(TCLP)

Evaluation

Not Contaminated Contaminated

Remediation Remediation Remediation

Measures Measures Measures

for non hazardous for hazardous for heavy

organics organics metals

Sampling Methods

7.23 There are several methods that can be used to obtain samples of potentially contaminated material within the ground. These are listed below:

· Hand methods - usually for depths up to 0.5 m by manual excavation or up to 5 m with a hand auger. This usually produces only small, disturbed samples.

· Trial pits - can be used up to about 3 m depth. Allows easy collection of large samples.

· Light cable percussion boreholes - traditional method for geotechnical soil investigations. Can penetrate to 50 m depth and allow easy water monitoring or gas wells to be inserted.

· Power auger drilling - very quick method, however samples are limited to around 6 m depth and are disturbed.

7.24 Trial pits are the most widely used technique, especially when sampling is required to depths of less than 3 m. Care should be taken to avoid underground services. It is likely that a combination of boreholes and trial pits can be used for the Spurline Investigations.

7.25 For borehole sampling, samples will be collected from the top, middle and bottom (above rockhead) of the borehole as recommended in BSI DD175. The depth of the samples will depend on the field sampling data. For trial pit sampling, samples will be taken at three depths (e.g. 0.5 m, 1.5 m and 3 m). If contamination is evident at 3 m depth, additional samples at greater depths should be collected. Where groundwater is encountered, groundwater samples should also be taken and records kept of the ground water level in the trial pit. Photographic records should be kept of each borehole and trial pit to show the gradient of pollution into the ground and the appearance of each sample. The presence of 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.

7.26 All soil samples should weigh not less than 0.5 kg and must be representative of the location at which they are taken. Samples should be handled in an appropriate manner so as to avoid cross contamination, and should be stored between 0 - 4ºC. Cooling of samples containing volatile contaminants is especially important. All samples should be properly labelled and any excess sample kept for further testing if necessary. Sample containers should be thoroughly cleaned between sampling of individual samples. It is important for the sampling person to avoid direct or indirect contact with potentially contaminated materials.

7.27 All samples should be well contained, sealed, properly labelled and any excess sample kept for further testing if necessary.

Parameters to be Tested for Contamination

7.28 The parameters to be tested at each proposed sampling location are based on the expected contaminants related to the land use. Prior to sampling, an examination of the site should be made by an environmental scientist responsible for the sampling, to confirm whether additional or alternative analyses are required apart from those listed in Table 7.

7.29 Waste automotive oils which may be detected at container sites are composed of an organic base with additives to increase performance. Additional compounds such as chlorinated solvents may be present in the waste oils due to blending of used oils during storage. The presence of such suspected carcinogens and mutagens is the basis of concern about waste oils in the environment. The sampling programme recommends that in Step 1 only total petroleum hydrocarbons (TPH) are tested for, and organics and CN at certain specified sites. If necessary, Polyaromatic hydrocarbons (PAHs) and Benzene, Toluene, Ethylbenzene and Xylene (BTEX) will be required to be determined if Step 2 of the analysis programme is to be implemented.

7.30 For the inorganic analysis heavy metals according to the Dutch List (including Cd, Cr, Cu, Hg, Ni, Pb, Zn etc) should be determined in addition to cyanides where electroplating activities may have taken place.

Analytical Laboratory and Methodology

7.31 The laboratory for chemical analysis for the land contamination assessment should achieve HOKLAS accreditation for environmental testing of sediment trace metals: Cd, Cr, Cu, Ni, Pb, Zn and Hg and preferably for TPH, and organics including PAHs and BTEX.

7.32 The methodology should be compatible with international standard methods. Detection limits should be to standards listed in Table 7.5.

Table 7.25

Detection Limits of Parameters to be analysed in Soil

Parameter

Detection Limit (mg/kg dry soil)

Metals:

Cd,

0.1

1.0

0.1

1.0

Total Petroleum Hydrocarbons (TPH)

Simple Aromatics:

Benzene

Toluene

Ethylbenzene

Xylene

1.0

Polyaromatic Hydrocarbons (PAH):

Acenaphthene

Acenaphthylene

Anthracene

Chrysene

Pyrene

Fluorene

Naphthalene

1, 2 benzo-pyrene

0.1

0.2

0.1

0.4

Cyanide

Halogenated Solvents:

Dichloromethane

Carbon tetra-chloride

Chloroform

Trichloroethylene

1,1,1, Trichloroethane

Tetrachloroethylene

Dichloroethane

Dibromoethane

Dichlorobenzene

1.0

Non-Halogenated Solvents:

Heptane

Nonane

Dimethyl Pentane

Methyl Hexane

Methyl Heptane

Trimethyl Pentane

Octane

1.0

Evaluation of Potential Impacts

7.33 The interpretation of analytical results should be considered by comparing the data with the Dutch Indicative List which is recommended by EPD in ProPECC PN 3/94 for interpretation of the analytical results.

7.34 The soils, geology, groundwater and climate of Hong Kong are different to those of the Netherlands. The reference values have been developed for use under these specific conditions. The adsorption of pollutants to soil colloids may be different under such conditions and therefore pose a different toxicity risk.

7.35 Appendix A contains the Dutch list which should be considered carefully in terms of application to the Hong Kong environment. It can be used as an indicative measure of levels of contamination, qualitatively based on like groups of contaminants, known landuses and possible pollutants.

Timing of Sampling and Analysis

7.36 Where possible all sampling should take place as soon as possible after the approval of this CAP by EPD. Borehole and trial pit sampling can both be incorporated into the Geotechnical Site Investigation Contracts. Following the SI, analysis should be carried out immediately, before deterioration of samples occurs. The CAR and RAP can then be prepared for those sites.

7.37 Where access can not be gained to the sites sampling locations will be identified after land resumption. The procedure is outlined in the Section on Selection of Sampling Locations. It is expected that after resumption of the land, sampling and analysis followed by the write up of CAR and RAP, and approval of these reports by EPD would take a minimum of 3 months.

8. REMEDIATION MEASURES TO BE CONSIDERED IN THE REMEDIATION ACTION PLAN (RAP)

8.1 Following approval of the CAP by EPD and completion of the sampling and analysis programme, a Contamination Assessment Report (CAR) will be produced. The CAR will detail the results of the implementation of the CAP and evaluate the extent of the potential contamination on the site. Suitable means of minimising the environmental impact from these areas of contamination should be defined. If remediation of the land is required, the type of remediation should be identified in a Remediation Action Plan (RAP).

8.2 The selection of an appropriate remediation technique for a site is dependent on a number of factors including:

(i) the type of contamination;

(ii) the extent of contamination;

(iii) the time available and speed of each technique;

(iv) cost effectiveness;

(v) the future use of the site;

(vi) availability of expertise and equipment.

8.3 There are a range of options available for treating contaminated land sites and new techniques are constantly being developed. The main methods in use are:

· Retention and isolation of material on-site using an appropriate form of cover, barrier or encapsulation system.

· Physical, chemical or biological treatment to eliminate or immobilise the contaminants.

· Removal of material from the site for disposal elsewhere.

8.4 ProPECC Note PN 3/94 also includes recovery trenches or wells for removal of leaked oil and soil venting for volatile organic compounds (VOCs). It suggests that “wherever possible, in-situ remedial measures should be adopted”. This policy should be followed as far as possible in order to prevent increasing the pressure on landfills.

8.5 Table 8.1 describes several techniques which would be applicable to contamination expected within the works of the Spur Line.

Table 8.1

Remediation techniques which could be used at sites along the Spur Line

Type of Contamination	Technique
Oil – surface layers	Bioremediation - in-situ or on site degradation of organic pollutants to harmless CO₂ & waterusing microbes. Ranked 1 by Haiges (1989). Other bioremediation techniques include adding cotton which absorbs the oils. Bacteria which occur naturally in the cotton then degrades the oils before decomposing the cotton into the soil and enriching it. Soil washing/flushing – addition of a surfactant/solvent and flushing in-situ or washing excavated soil. The oils and fluids separate out and the oily waste can then be bioremediated.
Oil – above groundwater or at depth in the soil.	Recovery trenches or wells – used to constrain groundwater flow so that oils settle and can be skimmed off. A dual pump system uses a deep pump in the groundwater to create a depression cone into which the free floating product will migrate. This can then be pumped off. The dual pump system is ranked I by Haiges. Other techniques include simpler pumps which extract both oils and water which can then be separated at the surface..
Heavy hydrocarbons and oily sludges	Thermal treatment - soil is excavated, sorted and fed into a rotary kiln thermal unit and heated until combustion occurs. The clean soil is then cooled and moistened and can be replaced.
Cyanides	Incineration – similar thermal heating and combustion as for heavy hydrocarbons. Care must be taken to ensure that air emissions achieve required standards.
Heavy Metals	Soil washing – soil is passed through sieves and scrubbers using water or oxidising chemicals which leach the contaminants out. The sludge residue can then be disposed of at a chemical waste treatment plant. Discharge of washed water must comply with WPCO standards. Stabilisation – contamination can be permanently isolated using lime, cement, thermoplastic or soluble silicate reagents to chelate metal ions to soil colloids. The soil is excavated, sorted and injected with the reagent before replacing and compacting to high density.
Volatile Compounds	Soil Venting – contaminant are removed through extraction wells using a vacuum which enhances chemical movement from soil particles to air pockets. Air Sparging – mainly used to remove volatiles from groundwater by injecting air into the saturated zone and transferring the contaminants to the vadose zone from which they can be vented.
Microbiological	Incineration – to eliminate any toxic micro-organisms or bacterias, such as anthrax spores, the only consistently dependable method is incineration.
Broad spectrum of contaminants	Excavation and Landfilling – best used for shallow contaminants and one off excavations. Because of limits on contaminants that can be disposed of in landfills (based on TCLP)* pre treatment may be required by another method (e.g. bioremediation) prior to disposal.

NOTE:

Haiges (1989) rated techniques from 1 (best) to 8 (worst) for treatment of oil contaminated soils on the basis of technical feasibility, achievable treatment levels, adverse impacts, cost and time taken.

* TCLP - Toxicity Characteristic Leaching Procedure Limits - as outlined in the Guidance notes issued by EPD (1999).

9. APPLICATION OF CONTAMINATION ACTION PLAN TO SPUR LINE

9.1 From the desktop study, site survey and generic methodology for sampling and analysing pollutants from potentially contaminated sites, a number of sites along the Spur Line alignment have been identified as being potentially contaminated.

9.2 An estimate has been made of the quantity of contaminated land which may be present at each site (Table 9.1). This is based on site visits, the extent of the area used at each site, and the assumption that the contamination has penetrated to a depth of approximately 1 m from the ground surface. Where cross passages are located, it is assumed that only the surface area around location of jet grouting will be impacted during construction. Where quantities of material are too small to make physico-chemical or biological treatment cost-effective, disposal of the material may be considered. In this case, if heavy metals are found present, TCLP testes must be carried out.

9.3 The total quantity of contaminated land is estimated at this stage of the assessment, to be up to 18,300 m³. This volume needs to be confirmed through implementation of the CAP and the sampling and analysis programme during site investigation, at which time the quantities requiring remediation or disposal will be more accurately defined.

9.4 Where volumes are relatively small and/or contaminant level is low, disposal may be a preferable option. Where volumes are large and/or contaminant levels are high, remediation techniques should be considered as a cost effective and environmentally favourable option.

Table 9.1

Main Activities at Each Site, Contaminants Likely to be

Present and Maximum Possible Extent of Contamination

Site	Main Activities	Structure or Works Impacting Area	Estimated Maximum quantity (m³)	Main Contaminants Likely to be present
A	Container Storage	Ramp and Viaduct	5,000	Metals, fuels/oils, acids, cyanides
B	Container Storage	Recovery Shaft	5,000	Metals, fuels/oils, acids, cyanides
C	Chemical Store	Miscellaneous Storage Area (TBC)	TBC	Organics, oils, metals, solvents
D	Pig Farm	Cross Passage	100	Metals, microbacteriological
E	Farm Buildings	Cross Passage	250	Metals, microbiological
F	Chemical Storage	Cross Passage	100	Organics, solvents, metals, oils
G	Container Storage	Kwu Tung Station Box	1,500	Metals, fuels/oils, acids, cyanides
H	Metal Recycling	Kwu Tung Station Box	600	Metals, TPH
I	Storage	Kwu Tung Station Box (TBC)	TBC	Organics, solvents, metals, oils
J	Car Repairs/ Dismantling	Kwu Tung Station Box (TBC)	TBC	Metals, cyanides, organics, fuels/oils, acids
K	Vehicle Maintenance	Cross Passage	800	Metals, cyanides, organics, fuels/oils, acids
L	Scrap Metal Yard	Launching Shaft	5,000 TBC	Metals, fuels/oils
Total volume (m³)			18,350 m³

Precautionary Measures to be Taken during Construction

9.5 The following measures should be implemented to minimise risks to workers during remediation works, excavation of soil, construction of viaducts, jet grouting for cross passages, piling works or excavation of Kwu Tung station and construction of the EAPs. These measures will also mitigate against transferring contamination to groundwater, to surface water courses or to the air.

· Site workers should wear gloves, masks, and other protective clothing where exposure to vapours or contaminated soil may be encountered.

· Contaminated materials should be moved with bulk earth movers to prevent human contact.

· Adequate washing facilities should be provided and smoking/eating should be prohibited in the area.

· Contaminated sediments which have been stockpiled or are being transported should be covered with tarpaulin.

· Leakage of pollutants or leaching from excavated soil should be prevented by storing on an impermeable surface.

Temporary Works Areas

9.6 Temporary works areas are proposed in the Sheung Shui area which have previously been used as container parking areas. The site inspection showed that, as is typical of such landuses there has been some leakage of oils and lubricants. However, these sites should not pose a health risk during their use in the construction phase provided there are no earth moving activities at the sites. The leaked oil can be covered with a layer of gravel or sawdust to soak up the leaks, and the materials disposed of appropriately. However, if earth movement is carried out, the precautionary measures detailed above should be followed.

10. OTHER PROJECTS IN THE STUDY AREA

10.1 The recently publicised Kwu Tung NDA under the NENT Planning Study also has the potential to be impacted by contaminated land. The findings and recommendations of the Spur Line EIA should be taken into account in the EIA for the NDA, and in the development of a CAP for the NDA. In this way, the information available about areas which overlap the two projects will be maximised and potential environmental impacts minimised.

11. SUMMARY

11.1 This contaminated land assessment includes a desktop study on relevant past and present landuses, a site survey, an assessment on the findings and recommendations on a schedule of sampling / analysis of essential parameters and appropriate remediation measures. Application of the sampling/analysis programme to specific sites identified to have potential contamination along the Spur Line alignment is included.

11.2 No underground storage tanks or extensive areas of contaminated land have been identified in this assessment within the works area of the alignment. The main areas for concern are container storage areas, particularly those in DD99 close to Lok Ma Chau (A and B), and any car repair/dismantling yards (e.g. J). The main contaminants are likely to be oils, organic solvents and heavy metals.

11.3 A Contamination Assessment Plan is presented which outlines the methods for sampling and analysis of the identified potentially contaminated sites, and criteria for evaluation.

11.4 Remediation measures for different types of potentially contaminated land are recommended, however, the small quantities which have been identified for several sections of the alignment make remediation too costly to be effective, and disposal should be considered. It is estimated that the maximum quantity of material in areas of potential contamination, which may require treatment or disposal is approximately 18,350 m³. These quantities and the degree of contamination need to be confirmed at the site investigation stage when analytical results are available for production of the CAR.

REFERENCES

Holdgate, M.W., (1979) A Perspective of Environmental Pollution, University Press, Cambridge.

Royal Commission on Environmental Pollution (RCEP), (1984), 10th Report: Tackling Pollution - Experience and Prospects, Cmnd 9194, HMSO, London.

LaGrega M.D., Buckingham P.L & Evans J.C. (1994), Hazardous Waste Management, McGraw-Hill, Singapore.

Cairney T (ed) (1993), Contaminated Land: Problems and Solutions, Chapman & Hall, London.

EPD (1999), Guidance Notes for Investigation and Remediation of Contaminated Sites of: Petrol Filling Stations, Boatyards or Car Repair/Dismantling Workshops. Report EPD/TR1/99

Voelcker Science (1999) Guide to Contamination Packages

HSE (1998), Protection of Workers and the General Public during Development of Contaminated Land.

http://www.ContaminatedLAND.co.uk/ - Pages on Past Industrial uses, Causes of Contamination, Standards and Guidelines, Remediation Techniques

British Standards Institution (1988), Draft for Development DD175: 1988 Code of Practice for the Identification of Potentially Contaminated Land and its Investigation, BSI, London.

Kelly R.T. (1980) Site Investigation and Material Problems, in: Reclamation of Contaminated Land, B21-B2-13, Society of Chemical Industry.

Haiges L et al. (1989) Evaluation of underground fuel spill clean-up technologies, in Haztech International Conference, San Francisco.

ProPECC PN 3/94. Environmental Protection Department. Practice Note for Professional Persons: Contaminated Land Assessment and Remediation.

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