Document Title - Torfaen County Borough Council · Web viewBaseline desk study data obtained and reported within the Phase 1 Geo-environmental Assessment [Ref: 9.1] extends up to

9 Soils, Geology and Contaminated Land

9.1 INTRODUCTION9.1.1 This chapter assesses the effect of the Proposed Development on Soils, Geology and Contaminated Land. In particular it considers the potential effects of contamination on ground conditions and human health during the construction and operational phases of the development.

9.1.2 This chapter (and its associated figures and appendices) is not intended to be read as a standalone assessment and reference should be made to the Front End of this ES (Chapters 1 to 5).

9.1.3 The chapter describes the legislative and policy background, the methods used to determine potential effects, the baseline conditions currently existing on the proposed Application Site; likely significant effects of the Proposed Development, the mitigation measures required to prevent, reduce or offset any significant adverse effects and the likely residual effects after these measures have been employed.

9.1.4 In addition, the assessment also draws on the findings of the following documents:

Phase I Geo-environmental Assessment for the Llanfrechfa site undertaken by WSP Environmental Ltd in December 2006 and updated December 2007 [Ref. 9.1];

Phase II Geotechnical and Geo-environmental Assessment completed by WSP Environmental Ltd in June 2008 [Ref: 9.2];

Phase II Geotechnical and Geo-environmental Supplemental Assessment completed by WSP Environmental Ltd in August 2008 [Ref: 9.3]; and

Phase II Geotechnical and Geo-environmental Assessment completed by WSP Environmental Ltd in April 2012 [Ref: 9.4].

A copy of the April 2012 Phase II Geotechnical and Geo-environmental Assessment includes a summary of the earlier ground investigation reports and is provided in Appendix 9.1.

9.2 LEGISLATION, POLICY AND GUIDANCELegislative Framework9.2.1 The applicable legislative framework is summarised as follows:

Part IIA of the Environmental Protection Act 1990 [Ref: 9.5];

Environment Act 1995 [Ref: 9.6];

The Contaminated Land (Wales) (Amendment) Regulations 2012 [Ref: 9.7];

Welsh Government The Contaminated Land Statutory Guidance for Wales 2012 [Ref: 9.8;]

Construction (Design & Management) Regulations 2007 [Ref: 9.9]; and,

Control of Asbestos Regulations 2012 [Ref: 9.10].

Planning Policy9.2.2 Strategic level planning policy at the national, regional and local level is discussed in Chapter 5 Policy Context. The relevant planning policy to this assessment has been considered from the following sources:

People, Places, Futures – The Wales Spatial Plan, 2008 Update [Ref: 9.11];

Planning Policy Wales 2011 [Ref: 9.12];

The Gwent Structure Plan 1996 [Ref: 9.13];

Adopted Local Plan for the County Borough of Torfaen 2000 [Ref: 9.14]; and

Chapter 9 Soils, Geology & Contaminated LandWSP

00018930.00Specialist and Critical Care Centre EIA

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Torfaen County Borough Council Deposit Local Development Plan (to 2021) 2011 [Ref: 9.15].

9.2.3 The following planning policies are considered relevant to this assessment:

People, Places, Futures – The Wales Spatial Plan 2008 Update

Chapter 12 - Valuing the Environment

Planning Policy Wales 2011

Chapter 13, Minimising and Managing Environmental Risks and Pollution

Adopted Local Plan for the County Borough of Torfaen

Policy E13 Proposals for development on or in close proximity to land which is known or suspected to be contaminated and / or unstable will only be permitted subject to other relevant policies in this local plan and the developer demonstrating to the County Borough Council that the contamination and / or instability can be removed or reduced to an acceptable level in respect of:-

A The health, safety and amenity of people on or near the site;

B The flora and fauna on the site; and

C The quality of the local air and water.

Policy G1B The impact of the proposal upon the environment. In particular, the following factors will be considered:-

ii) The design for the site ensures that the proposal does not pollute the environment.

Torfaen County Borough Council Local Deposit Plan (to 2021) 2011

Policy B Natural Environmenti) The proposal does not result in unacceptable adverse effects in respect of land contamination, instability or subsidence; air, heat, noise or light pollution; landfill gas; water pollution; or flooding, from or to the proposal. The Gwent Structure Plan 1996

Policy ENV4 Development which creates atmospheric, water and/or noise pollution which will have an unacceptable effect on communities or the environment will not normally be permitted.

9.2.4 The preparation of a Phase I and Phase II Geo-environmental and Geotechnical Assessments at the Application Site comply with current legislation and the planning policy as they allow for detailed consideration of land quality and are a means of identifying unacceptable risks to human health and the wider environment. The results of the investigation have enabled, where necessary, the design of mitigation measures deemed appropriate to ensure that contamination does not result in ‘significant harm or significant possibility of harm’ to human health and the wider environment.

Guidance

9.2.5 The following guidance has been used within this assessment:

Environment Agency (2004) Model Procedures for the Management of Contaminated Land (CLR11) [Ref: 9.16];

Health and Safety Executive (HSE), Guidance Note HS (G) 66, ‘Protection of Workers and the General Public during the Development of Contaminated Land’, 1991[Ref: 9.17];

British Standards Institution (2011), BS10175 Investigation of Potentially Contaminated Sites – Code of Practice, BSI [Ref: 9.18];

Environment Agency and NHBC (2000) Guidance for the safe development of housing on land affected by contamination, EA R&D Publication 66 [Ref: 9.19];

Environment Agency (2000) Technical Aspects of Site Investigation (2 volumes) R&D Technical Report P5-065 [Ref: 9.20];



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Environment Agency (2000) Secondary Model Procedures for the Development of Appropriate Soil Sampling Strategies for Land Contamination, R&D Technical Report P5-066 [Ref: 9.21];

Environment Agency 'Piling and Penetrative Ground Improvement Methods on Land Affected by Contamination: Guidance on Pollution Prevention (NC/99/73) [Ref: 9.22];

CIRIA C665 (2007) ‘Assessing risks posed by hazardous ground gases to buildings’ [Ref: 9.23]; and

HSE, INDG258, ‘Safe Work in Confined Spaces’, 2006 [Ref: 9.24].

9.3 ASSESSMENT METHODOLOGY AND SIGNIFICANCE CRITERIAScope of the Assessment9.3.1 The ES chapter for Soils, Geology and Contaminated Land consists of a phased approach to the baseline assessment, comprising a Phase I and Phase 2 Geo-environmental and Geotechnical Assessment of the current Application Site, including a review of available baseline information on the site setting. This approach follows the requirements of Planning Policy Wales and the Environment Agency Guidance on Requirements for Land Contamination Reports, as recommended in the consultation response from TCBC.

9.3.2 The scope for the preparation of the baseline study contains the following elements:

Site inspections to obtain an appreciation of site features, site setting and potential environmental risk;

Review and comment on existing information and / or reports on the sites, where available;

Review of previous edition Ordnance Survey maps and any other available plans to assess the historical usage of the sites (former contaminative uses);

Review of desk-based information pertaining to the soils, geology and land contamination at the site and surrounding area to assess ground conditions and presence of sensitive environmental receptors;

Liaison with relevant authorities including the EA (Planning Liaison Officer) and TCBC (Environmental Health and Building Control);

Undertake a targeted intrusive site investigation to determine potential sources of contamination;

Assess likelihood of potential sources of land contamination in order to provide a generic quantitative assessment of whether contaminated land poses a significant risk, i.e. through the identification of potential contamination source-pathway-receptor relationships; and

Where necessary, identify potential techniques for the remediation of possible contamination.

Extent of the Study Area9.3.3 Baseline desk study data obtained and reported within the Phase 1 Geo-environmental Assessment [Ref: 9.1] extends up to 1km from the Application Site for potential off-site contamination sources and sensitive receptors.

9.3.4 An original walkover survey was undertaken on 7th November 2006 and included an external inspection of buildings and site features within the boundaries of the Application Site. An updated walkover survey was completed on the 5th March 2012. Land uses of the land adjacent to the north, east, south and west of the Application Site were also noted at the time of the walkover survey.

Consultation9.3.5 The following statutory and non-statutory consultees were contacted or online databases were searched as part of the Phase 1 Geo-environmental Assessment [Ref: 9.1] and their responses have been incorporated in to this chapter:

EA;

TCBC Contaminated Land officer;



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British Geological Survey (BGS); and

Health Protection Agency (HPA).

9.3.6 Full consultee requests and responses are either presented at the front end of this Environmental Statement in Chapter 2 or within the Phase 1 Geo-environmental Assessment [Ref: 9.1]. Where online databases were searched, full details are presented in the Phase 1 Geo-environmental Assessment [Ref: 9.1].

Method of Baseline Data Collation Desk Study

9.3.7 A number of primary sources of information were utilised to inform the baseline conditions at the Application Site, and these are presented in more detail in the Phase I Geo-environmental Assessment [Ref: 9.1], but include:

Historical Ordnance Survey Maps;

British Geological Society (BGS) Geology Map 249, Newport, North London, Scale 1:50,000; and,

Envirocheck Report (2006).

Site Visit

9.3.8 A photographic record of the reconnaissance was obtained and is presented in the Phase I Geo-environmental assessment [Ref: 9.1].

Phase II Geotechnical and Geo-environmental Assessment

9.3.9 A detailed intrusive site investigation has been completed across the Application Site during April and May 2008 and in December 2011, and was designed to enable characterisation of the ground conditions beneath the Application Site, the nature and extent of the potential contamination sources and ground gas regime beneath the Application Site. The investigative works included the advancement of a combination of window sampler holes, trial pits, cable percussive boreholes and rotary boreholes which provided general coverage of the Applications Site, together with targeting potential areas of concern identified within the Phase 1 Geo-environmental Assessment. Groundwater sampling and ground gas monitoring was completed in available boreholes in 2008 and 2011.

Significance Criteria9.3.10 The provisions for dealing with contaminated land are made under Part IIA of the Environmental Protection Act 1990 and the Environment Act 1995. Under these Acts, the presence of contaminated land is generally only of concern if there exists an actual or potentially unacceptable risk. Within the context of current UK Legislation, the interpretation of a “significant risk” is termed to be one where:

9.3.11 Significant harm is being caused or there is a significant possibility of such harm being caused, (harm is defined as: harm to health of living organisms or other interference with the ecological systems of which they form a part and, in the case of man, includes harm to his property); or

9.3.12 Significant pollution of controlled waters is being caused or there is a significant possibility of such pollution being caused.

9.3.13 Current guidance on the assessment of contamination risk advocates the use of a conceptual risk assessment model in an attempt to establish connecting links between a hazardous source and a sensitive receptor via an exposure pathway.

9.3.14 The fundamental concept behind this approach is that, without each of the three elements (source, pathway and receptor) there can be no significant risk from the contamination. Thus, the presence of a contamination hazard at a particular site does not necessarily imply the existence of associated risks. The source-pathway-receptor model is illustrated as follows:

SOURCE → PATHWAY → RECEPTOR



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e.g. Fuel Spill e.g. Direct Contact e.g. Human

9.3.15 There are no known published standard criteria for assessing the significance of the potential effects that may arise from land contamination. However, where appropriate, the significance of the effect (where a contamination risk has been identified) has been determined from criteria developed from best practice techniques and professional judgement, utilising published guidance and legislation, e.g. EA R&D Publication CLR 11 (2004) ‘Model Procedures for the Management of Land Contamination’ [Ref: 9.17], in order to determine soil and contamination related issues that have the potential to cause harm. Measures of the magnitude or scale of effect and the importance or sensitivity of the resource affected has also been used.

Valuation of the Receptor

9.3.16 The following criteria have been used for the Valuation of Receptors.

Table 9.1: Criteria for Assessing Valuation of Receptors

Value Criteria Example Receptors

High Generally, but not exclusively, sites of international and national importance and resource/features which are unique and if lost cannot be replaced or relocated. Receptors of greatest sensitivity.

Human Health, including, construction and maintenance workers, future site users/occupants and third party neighbours.

Medium Features of important consideration at a regional or district scale.

Mineral Resources

Low Features important at a local scale. Soils

Negligible Features of negligible importance/sensitivity. -

Effect Magnitude (the extent of change i.e. deviation from the baseline)

9.3.17 Contamination has been assessed by the identified presence of specific potential sources of contamination, pathways and sensitive receptors. The categories below are used in assessing the effect magnitude.

Table 9.2: Criteria for Assessing Effect Magnitude

Magnitude Criteria

High Significant, long term deterioration/improvement in local conditions or circumstances, i.e.:

Construction phase release of contaminants which causes a significant effect on identified receptors;

Elimination and/or mitigation of existing large scale effects upon identified receptors during the operational phase.

Medium Readily apparent change in conditions or circumstances, including long term effects, i.e.:

Minor release of contaminants during the construction phase;

Elimination and/or mitigation of limited existing effects upon identified receptors during the operational phase.

Low Perceptible change in conditions or circumstances, generally in the short term, i.e.



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Limited, temporary contaminant release associated with construction phase;

Temporary creation/elimination of pollution pathways during the construction phase.

Negligible Negligible change in conditions or circumstances affecting identified receptors.

Significance of Effects

9.3.18 The assessment of potential effects, as a result of the Proposed Development, has taken into account both the construction and operational phases.

9.3.19 The overall significance of an effect has been assessed by considering the magnitude of the residual effect against the following:

The number and type of activities of the population affected, e.g. residential users and site workers;

The type and sensitivity of the receptor, e.g. human health, flora, geological resources and controlled waters;

The type of effect / benefit; and

The significance of the residual effect has been defined using the terms below.

9.3.20 The following terms have been used to define the significance of the effects identified:

Major effect: where the Proposed Development could be expected to have a very significant effect (either positive or negative) on the existing environment or human health (e.g. high to moderate sensitivity land uses, ecosystems and water resources resulting in human exposure to hazards). Where there is a pathway to release/mobilise/expose the contamination to humans (e.g. potable water supplies) and/or ecosystem (e.g. fish kills). Where there is the potential for moderate and major changes to very sensitive systems (e.g. acute/chronic effects to human health or major fish kills and severely effected biodiversity). Alternatively, where the removal of a source of contamination would result in a significant improvement to very sensitive systems;

Moderate effect: where the Proposed Development could be expected to have a noticeable effect (either positive or negative) on the existing environment e.g. low sensitivity land uses, water receptors and ecosystems resulting in little or no human exposure. Where a pathway may exist and there is the potential for minor changes to ecosystems e.g. minor fish kills and reduced biodiversity value, or where the partial or complete removal of a source of contamination could result in a noticeable improvement to ecosystems;

Minor effect: where the Proposed Development could be expected to result in a small, barely noticeable effect (either positive or negative) on the existing environment e.g. low sensitivity land uses, water receptors and ecosystems exposed to contaminants resulting in no human exposure with the potential for minor changes to ecosystems. High/moderately sensitive receptors exposed to contaminants found in relatively low concentrations that pose no significant risk to humans, animals or plants or where the partial or complete removal of a source of contamination found in relatively low concentrations could result in a small improvement to ecosystems; and

Negligible: where no discernible effect is expected as a result of the Proposed Development on humans, animals or plants.



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9.4 BASELINE CONDITIONS9.4.1 The Application Site currently comprises the northern half of Llanfrechfa Grange Hospital which includes the works and estates department (with adjacent maintenance yard), administration units, hospital dining room and a laundry facility. The remainder of the Application Site comprises three agricultural fields, currently tenanted and utilised for cattle/sheep grazing.

9.4.2 The ground cover within the existing hospital section of the Application Site typically comprises a mixture of tarmac roads and car parking, concrete hardstanding in the areas of maintenance and laundry, paving slabs along walkways and landscaped grounds.

9.4.3 The Application Site is located at the edge of the village of Llanfrechfa, approximately 4 miles north of Newport. The Application Site is surrounded to the north, east and south by agricultural land and to the west by a residential area.

Site reconnaissance9.4.4 The following potential sources of contamination and geotechnical constraints were noted during the site walkover as part of the Phase 1 Geo-environmental Assessment:

The existing laundry building, which is reported to be located on the former boiler house and associated Above-ground Storage Tanks (ASTs);

Numerous ASTs and Intermediate Bulk Containers (IBCs) located adjacent to the laundry building containing laundry solvents and diesel;

A large waste compound with gravel ground cover containing a number of steel containers (of unknown contents), medical waste bins and disused fridges were located within the north-eastern section of the hospital area of the Application Site. This is believed to be the location of a former refuse tip / landfill;

A maintenance area located within a central eastern part of the hospital area which comprises brick built buildings including a vehicle maintenance room, containing batteries for recharging small forklift trucks. In addition, chemicals including resins, tar and disinfectant were observed within this area;

Garages and general storage areas located within the southern section of the Application Site;

An electricity substation located immediately to the west of the laundry building, which is surrounded by gravel hardcore within a small locked compound; and

Potential Asbestos Containing Materials (ACMs) associated with lagging on the pipe work for the ASTs to the west of the laundry building and the roofing materials associated with the building adjoining the maintenance yard.

9.4.5 The following potential geotechnical constraints were noted during the site walkover:

Changes in topographical levels across the Application Site.

Historical land uses9.4.6 Historical maps indicate that Llanfrechfa Grange, a Grade II Listed Building beyond the Application Site to the south, was built circa 1848, along with the historically important (but unlisted) walled garden. A further building, White Hall, was also shown present in the northwest of the site in 1882.

9.4.7 Llanfrechfa Grange Hospital is understood to have been built in the late 1950’s / early 1960’s around Llanfrechfa Grange. White Hall had been demolished by 1972.

9.4.8 Llanfrechfa Grange Hospital was built with residential blocks and communal leisure and medical facilities. The configuration of the hospital appears to have remained largely the same since it was built with the addition of the laundry building prior to 1993 in the eastern section of the Application Site, on the site of former boiler house buildings and former above ground oil storage tanks.



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9.4.9 In the late 1980’s / early 1990’s an office block appears to have been added which was subsequently extended by 1999. Further extensions to the existing communal buildings were noted in the late 1990’s and up to 2004.

9.4.10 A refuse tip in the east of the site, located to the north of the laundry building is recorded as being on-site prior to 1969 until pre 1993.

9.4.11 Historical maps indicate that Ysgubornewydd Farm has been present to the north of Llanfrechfa Grange since before 1886 and has remained as agricultural land until the present day. Residential areas approximately 250m to the west of the Grange Site were developed in the late 1960’s and the A4042 dual carriageway being noted prior to 1999.

Geology and Hydrogeology9.4.12 Geological Map Sheet No. 249, Newport, 1:50,000, Solid and Drift edition, indicates that the Application Site is underlain by the Raglan Marl (mudstones) part of the Downton series of the Lower Old Red Sandstone.

9.4.13 The published geological information also indicates the presence of sandstone bands running in a general north to south direction through the Application Site. Glacial Drift deposits of Sand and Gravel are identified to be present within the south-western section of the agricultural fields and within close proximity to the Llanfrechfa Grange Hospital section of the Application Site.

9.4.14 A series of intrusive ground investigation techniques, including rotary boreholes, cable percussive boreholes, cone penetration tests, window sampler holes and trial pits, have been utilised across the Application Site to provide general coverage to characterise ground conditions and to target potential sources of contamination identified within the Phase 1 Geo-environmental Assessment [Ref: 9.1]. Figure 9.1 shows the locations of exploratory holes completed as part of the Phase II Geotechnical and Geo environmental Assessment 2012 [Ref: 9.4].

9.4.15 Ground investigation data obtained as part of the Phase II Geotechnical and Geo-environmental Assessment 2012 [Ref: 9.4] within the Application Site generally concurs with the published information. The ground conditions generally comprised topsoil overlying Raglan Marl. Glacial Till was present in the north-western section of the Application Site above the Raglan Marl; however, the investigation also indicates the presence of Glacial Sand and Gravel within the southwest of the Llanfrechfa Grange Hospital site. The site investigation also indicates the presence of Made Ground associated with the former refuse area and in the vicinity of the laundry and maintenance yard. Additionally, Made Ground, comprising reworked natural material with gravel, including china, clay pipe and concrete, was encountered in two exploratory holes within the agricultural fields within the east and north eastern section of the Application Site.

9.4.16 A summary of the ground investigation data is presented below:

Very soft to soft friable sandy clay topsoil was encountered within the majority of exploratory holes to maximum recorded depth of 0.65m with an average depth of approximately 0.30m below ground level;

Made Ground was encountered in a number of exploratory holes in the Llanfrechfa Grange section of the Application Site. The average thickness was 1.4m although the maximum recorded thickness of Made Ground was 3.2m in the vicinity of the laundry building. The Made Ground typically comprised a combination of hardcore, brick, clinker and sandstone with occasional glass and tile, together with re-worked clay or Marl. In addition, Made Ground comprising reworked natural sandy clay was encountered in two exploratory holes within the northern section of the Application Site to a depth of 1.15m;

Glacial Till was encountered locally in the west of the Application Site and typically comprised orange brown, very sandy, very gravelly clay becoming sandy, clayey gravel with depth. The thickness of the Glacial Till was not proven;

Weathered Raglan Marl was encountered in all exploratory holes and varied significantly in weathering grade, generally improving in competency with depth. This material generally comprised red brown,



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locally light grey, slightly sandy, slightly gravelly clay. The more competent Raglan Marl comprised interbedded very weak to weak sandstone and mudstone, as encountered within the shallower cable percussive boreholes, which increased in strength with depth, as proven in the Cone Penetration Testing and the rotary cored boreholes. The maximum proven depth of the Raglan Marl was 15mbgl;

The Raglan Marl is classified as a Secondary A Aquifer by the Environment Agency;

No EA licensed groundwater abstractions have been identified within a 1km radius of the Application Site and it is not located within an EA designated Groundwater Source Protection Zone.

Groundwater monitoring undertaken across the Application Site indicates the presence of a relatively shallow ground water; and

Further details relating to hydrogeology (i.e. groundwater abstractions, depth to groundwater etc) are discussed further within Chapter 13 (Water Quality, Water Resources, Flood Risk and Drainage).

Contamination9.4.17 Visual and olfactory evidence of contamination during the site investigation works included:

A slight hydrocarbon odour within one exploratory hole (WS08) located adjacent to the laundry building from 0.9m to 1.50mbgl;

Metal grates, pipes, glass, masonry, plastic and paper encountered within one exploratory hole (TP13) within the former refuse tip / landfill; and

A small proportion of clinker within the Made Ground across the Application Site.

9.4.18 The Phase I Geo-environmental Assessment [Ref: 9.1] and Phase II Geotechnical and Geo environmental Assessment [Ref: 9.4] included a reviewed of a Jacob Gibbs (2001) Phase II Intrusive Investigation of the Grange Site. However, this previous investigation did not cover the entire area of the current Application Site. The findings of this review are provided below:

The possible former landfill located within the large waste compound was confirmed in the north east of the Grange Site, to the north of the laundry, covering an approximate area of 1,025m2 and extending to a depth of up to 3.6mbgl (the volume of landfill being calculated as 7,500m2, based upon a mean thickness of 2.5m);

Contamination across the site, with exception of the former refuse area and laundry, was limited to hotspots of elevated arsenic and Polycyclic Aromatic Hydrocarbons (PAHs) within Made Ground in the maintenance area of the site;

Elevated levels of cadmium, copper, lead, mercury, zinc and the presence of asbestos (chrysotile and amosite) was recorded within the former refuse area of the site;

Elevated concentrations of Tetrachloroethene (PCE) were identified between the former refuse area and the laundry building. It was also noted that elevated levels of copper, nickel, selenium and PCE were recorded within the groundwater. A soil source of the PCE was not identified, although, dry cleaning laundry operations are a typical source of PCE contamination; and

No significant levels of ground gas were identified within the site.

9.4.19 For the purpose of the Phase II Geo-Environmental Assessment 2012 [Ref: 9.4], to enable the appropriate assessment of risks posed to previously identified receptors, the Application Site was separated into three areas (refer to Figure 9.1). The areas are predominately based upon their historical use and have been identified as follows:

Zone A - the eastern area of the Grange Site (south-eastern section of the Application Site), includes the laundry, maintenance yard, stores, dining room and a former refuse tip;

Zone B - comprises the west of the Grange Site (south-western section of the Application Site), including landscaped grounds, a number of office blocks and associated infrastructure and parking;



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Zone C - currently comprising the agricultural land immediately north of the hospital (north of the Application Site).

9.4.20 The following summarises the findings of the assessment:

Elevated concentrations of Total Petroleum Hydrocarbons (TPH) C21 to C40 fraction were recorded in within the Made Ground in Zone A, although not at concentrations in excess of the respective soil screening values for a commercial/industrial end use. The highest concentrations were encountered in the vicinity of the former refuse area and boiler house (WS08) which were noted to exceed the residential without plant uptake screening criteria;

No concentrations of metals, polycyclic aromatic hydrocarbons or Volatile Organic Compounds (VOCs) were identified to exceed the screening criteria for a commercial/industrial end use. Locally, elevated metal (barium, nickel, lead and vanadium) and PAH concentrations within the Made Ground from Zone A were noted to exceed the criteria for a residential without plant uptake scenario.

Free fibre asbestos was identified within the former refuse area in the east of the Application Site (Zone A).

Elevated chromium and barium was recorded within the groundwater to exceed the applied screening criteria in locations across the site.

TPH concentrations in groundwater that were found to exceed the applied screening criteria were identified in Zone B and Zone C, typically of carbon factions aromatic C21-C35 and total TPH C21-C40. In addition, selected PAH determinands and elevated bis(2-ethylhexylphthalate) were identified to exceed the appropriate screening criteria in the groundwater underlying the former refuse tip and in the corner of the adjacent field.

No VOCs were recorded in the groundwater to exceed the appropriate screening criteria, although local trace concentrations of toluene and chloroform were identified within the groundwater adjacent to the north of the laundry building.

No elevated concentrations of inorganic or organic contaminants were recorded to be present within the surface water of Sirhowy Brook.

Hazardous Ground Gases9.4.21 Elevated concentrations of Carbon Dioxide have been recorded within Zone A with maximum concentrations within WS03 and WS08 of 22% v/v and 12%v/v, respectively. WS03 and WS08 are located within close proximity to the existing laundry building in the Zone A situated in the south eastern section of the Application Site. In addition, a maximum Methane concentration of 36.6%v/v was recorded for WS03. Based on a maximum flow rate of 1.6l/hr, Zone A has been classified as CIRIA Characteristic Situation 2 (CIRIA C665 [Ref: 9.22]).

9.4.22 An elevated concentration of Carbon Dioxide was recorded in RH04 of 6% v/v located in Zone B within the south western section of the Application Site with concentrations of 3.6 – 4.7%v/v also recorded in RH02 and BH05, respectively. Methane concentrations were recorded to be 0.2%v/v or less. The maximum recorded flow rate was 1.3 l/hr, as such Zone B has also been classed as CIRIA Characteristic Situation 2.

9.4.23 In Zone C, a maximum concentration of Carbon Dioxide (5.1%v/v) was recorded within RH01-2011 and a maximum flow rate of 25l/hr were recorded. Based on CIRIA 665 [Ref: 9.22] this would classed as CIRIA Characteristic Situation 3; however, this flow rate was only recorded on one occasion and the levels were not consistent. Therefore, based on the low recorded concentrations of gas (typically <5%v/v carbon dioxide and 0.2%v/v methane) and no apparent source of gas generation within the DEIN site, CIRIA Characteristic Situation 3 is considered to be a conservative classification and CIRIA Characteristic Situation 2 may be deemed more appropriate for the DEIN site.

Consultations



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9.4.24 Consultations were undertaken as part of the Phase 1 Geo-environmental Assessment [Ref: 9.1] and EIA Scoping Report and pertinent responses are provided below:

The Contaminated Land Officer at TCBC indicated that there are known issues of contamination at the Application Site;

The HPA data did not identify a significant risk with respect to radon gas;

BGS data indicates that the Application Ste is located within an area where there is a low to very low risk of landslip subsidence hazards; and no to a very low risk of running sand ground stability hazards;

Coal Authority data indicates that the Application Site is not located within an area that is considered to be affected by coal mining;

The EA commented that ‘if the existing buildings are to be demolished to make way for the new buildings, we may require site investigations to determine the potential for contamination of the soil and groundwater from the previous land use activities. If this is the case we will request conditions to be imposed on any planning permission granted’.

TCBC confirmed the methodology and approach to the assessment of contaminated land was acceptable, and no specific additional comments relevant to the Soils, Geology and Contaminated Land assessment were made.

Potential Contamination Sources9.4.25 Based on the findings of the Phase I Geo-environmental Assessment and Phase II Geotechnical and Geo-environmental Assessment the potential sources of on-site contamination are considered to be:

Heavy metal and organic contamination identified within the vicinity of the laundry building and former refuse tip;

Localised contamination hotspots of metal, PAH and hydrocarbons in Zone A;

Asbestos containing materials associated with the existing pipework / building fabric and asbestos containing material within the former refuse tip;

Contaminants identified within the groundwater principally comprising metals (chromium and barium) and locally elevated hydrocarbons (Zone B and Zone C), PAH and VOCs (Zone A); and

Elevated concentrations of Carbon Dioxide and Methane recorded within monitoring wells in the southern half of the Application Site.

Potential Geotechnical Risks9.4.26 Based on the findings of the Phase I Assessment and Phase II Geotechnical and Geo-Environmental Assessment, the potential on-site geotechnical constraints are considered to comprise:

Below ground obstructions associated with former development;

Groundwater softening of development levels; and,

Slope stability issues associated with potential cut and fill operations across the Application Site.

Potential Receptors9.4.27 The following sensitive receptors have been identified in the context of the Proposed Development in relation to effects from contaminated land and geotechnical issues:

Demolition and construction workers – these potential receptors are considered to be of high sensitivity due the possible severity that an effect could have on human health if the potential contamination and geotechnical risks are not appropriately managed;



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Future site occupants – these potential receptors are considered to be of high sensitivity due the possible severity that an effect could have on human health if the potential contamination and geotechnical risks are not appropriately managed;

Third party land – the majority of the immediate surrounding area comprises agricultural land, however, residential properties are located within close proximity to the west and at the farm to the north, where human exposure to contaminants is possible and/or slope stability issues have the potential to effect on public highways. On this basis this potential receptor is considered to be of high sensitivity; and,

On-site soils – if potential contamination sources (i.e. asbestos containing materials) and identified sources of contamination are not appropriately managed during the construction process the potential to effect on-site soils exists. No soil contamination has been identified within the agricultural fields to the north of the Application Site; however, Made Ground including elevated concentrations of contaminants has been identified across the southern section of the Application Site. As such, this receptor is considered to be of low sensitivity within the southern section of the Application Site and of medium sensitivity within the northern section of the Application Site.

9.4.28 Controlled water receptors have been considered in Chapter 13 (Water Quality, Water Resources, Flood Risk and Drainage).

Significant Risks9.4.29 Based on the available baseline data presented above, it is considered that the following significant risks are present:

The potential for heavy metal and organic contamination across the Application Site to effect human health and on-site soils;

The potential for asbestos containing materials to effect human health, on-site soils and third party land;

The potential for hazardous ground gases to effect human health and third party land; and

The potential for slope stability issues associated with cut and fill operations to effect human health and third party land.

9.4.30 Potential risks to controlled water receptors from contamination have been considered in Chapter 13 (Water Quality, Water Resources, Flood Risk and Drainage).

Future Baseline9.4.31 Should the Proposed Development not proceed it is considered that the future baseline conditions in relation to contaminated land are likely to remain similar in relation to the current baseline conditions.

9.5 ASSESSMENT OF EFFECTS, MITIGATION AND RESIDUAL EFFECTSDemolition and Construction

Effect of contaminated soils and materials on the health of demolition and construction workers and the general public

9.5.1 Potential asbestos containing materials within the fabric of on-site buildings could effect the health of demolition and construction workers and the general public during demolition of the on-site buildings. Free fibre asbestos within the refuse area could affect the health of construction and maintenance workers undertaking groundworks in the vicinity of the landfill area (and Zone A). In addition, elevated concentrations of heavy metals and organic contamination have been identified within the south-eastern section of the Application Site (Zone A) generally associated with Made Ground. All of the above could potentially effect the health of demolition and construction workers and the general public during demolition and construction activities.



12

9.5.2 Disturbance of asbestos containing materials during demolition activities and the excavation of potentially contaminated soils (including asbestos) can pose a health risk to site workers through dermal contact (i.e. direct skin contact with contaminated soils), ingestion (i.e. via the transfer of contaminated soils from unwashed hands during eating) and / or inhalation (i.e. breathing in contaminated dusts, fibres and particulate matter generated by demolition / excavation activities).

9.5.3 Disturbance of asbestos containing materials during demolition and the excavation of potentially contaminated soils (including asbestos) can also pose a health risk to the general public in the immediate vicinity of the Application Site, through inhalation of contaminated dusts and particulate matter generated by demolition / excavation activities.

9.5.4 The sensitivity of demolition and construction workers and the general public is high and the magnitude of change, prior to mitigation, is medium to high. Therefore, there is likely to be a direct, temporary to permanent, medium to long-term effect on demolition and construction workers and the general public of moderate to major negative significance prior to the implementation of mitigation measures.

Mitigation

9.5.5 Prior to the commencement of demolition and construction activities, all available asbestos registers / survey documentation for the Application Site will be obtained and reviewed to identify the presence or absence of asbestos containing materials within on-site buildings. In the absence of sufficient information, a demolition asbestos survey will be undertaken. In the event that asbestos containing materials are identified they will be removed in accordance with the Control of Asbestos Regulations 2012 [Ref: 9.9] to ensure the potential risks are appropriately managed.

9.5.6 Effects to the health of construction workers and the general public from contaminated soils and materials identified within south eastern section of the Application Site will be controlled under the Construction (Design & Management) Regulations 2007 [Ref: 9.8] and a risk assessment will be prepared to ensure the protection of workers and the general public during the demolition and construction phases, which will specify appropriate safe working practices. In areas of the Application Site where contaminated soils / materials have been identified specific personal protective equipment (PPE) and if necessary, respiratory protective equipment (RPE), will be utilised, particularly during ground works. Generic safe working practices include, but are not limited to:

use of appropriately qualified persons for the intended task;

use of PPE;

provision of on-site washing facilities;

washing of hands at the end of every work period (including forearms, face etc if become dirty);

no eating rule on-site and confining of smoking areas away from work site, and only after decontamination;

reporting of any ill health; and

the damping down of exposed surfaces during periods of dry / windy weather.

9.5.7 Asbestos control measures would be required in Zone A during redevelopment to ensure adequate protection of construction works and third party neighbours in accordance with the Control of Asbestos Regulations 2012 [Ref: 9.10]. These measures, as outlined within an asbestos management strategy / remediation strategy, may include (not limited to),

A watching brief by an asbestos specialist;

Airborne fibre monitoring/filtering;

Dust suppression;

Provision of appropriate RPE; and



13

Controlled methods of stockpiling and segregation of materials.

9.5.8 All site works and ground works will be undertaken in accordance with the Considerate Constructers Scheme to help ensure a well-managed operation which minimises environmental risks.

9.5.9 All of the above measures and other relevant good site practices to avoid/minimise the likely significant effects at source, will be included within the Construction Environmental Management Plan (CEMP) and enforced throughout the construction phase.

9.5.10 Further delineation assessments and potential remediation / mitigation works may be required to address identified soil and shallow groundwater contamination especially in the vicinity for the laundry and former refuse area. Should such works be deemed necessary then a remediation strategy will be developed.

9.5.11 In addition, all persons engaged in site redevelopment will be made aware of the findings of the intrusive investigation and the sources of contamination identified within the Application Site. The associated hazards of handling potentially contaminated materials will be conveyed to all site workers and all works will be conducted in accordance with Model Procedures for the Management of Contaminated Land (CLR11), 2004 [Ref: 9.16] and the Health and Safety Executive publication entitled ’Protection of Workers and the General Public during the Development of Contaminated Land‘, 1991 [Ref: 9.17].

Residual Effects

9.5.12 The sensitivity of demolition and construction workers and the general public is high and the magnitude of change, following mitigation, is negligible. Therefore, there is likely to be a negligible effect on demolition and construction workers and the general public following the successful implementation and maintenance of the mitigation measures outlined above.

Effect of the disturbance / mobilisation of contaminated materials on soils and neighbouring sites

9.5.13 The Phase 1 Geo-environmental Assessment [Ref:9.1] and Phase II Geotechnical and Geo-environmental Assessment 2012[Ref: 9.4] has identified the potential for asbestos containing materials to be present within the fabric of on-site buildings, and confirmed the presence of contamination sources (including free fibre asbestos) principally associated with the Made Ground encountered across the south-eastern section of the Application Site.

9.5.14 Demolition and construction activities, including for example the demolition of buildings, excavation of soils and movement of vehicles, can potentially lead to the disturbance and mobilisation of contaminants within on-site soils and/or the building fabric.

9.5.15 The operation of vehicles and general activities associated with demolition and construction activities have the potential to give rise to the potential for spillages/leakages of fuel oils/other hazardous materials/chemicals from site vehicles or stores. Such spillages/leakages, should they arise, may cause a direct effect to on-site soils.

9.5.16 Wind-blown dusts and contaminants (i.e. asbestos fibres, heavy metals etc) generated by the demolition of buildings and excavation of soils also have a potential to directly effect neighbouring sites, particularly during periods of dry, windy weather.

9.5.17 The sensitivity of on-site soils is low and the magnitude of change, prior to mitigation, is low to medium. Therefore, there is likely to be a direct, temporary, medium-term effect on soils of negligible to minor negative significance prior to the implementation of appropriate mitigation measures.

9.5.18 The sensitivity of neighbouring sites is high and the magnitude of change, prior to mitigation, is low to medium. Therefore, there is likely to be a direct, temporary, medium-term effect on neighbouring sites of minor to major negative significance prior to the implementation of mitigation measures.

Mitigation

9.5.19 Prior to the commencement of demolition and construction activities, all available asbestos registers / survey documentation for the Application Site will be obtained and reviewed to identify the presence or absence of asbestos containing materials within on-site buildings. In the absence of sufficient



14

information a demolition asbestos survey will be undertaken. In the event that asbestos containing materials are identified they will be removed prior to demolition in accordance with the Control of Asbestos Regulations 2012 to ensure the potential risks are appropriately managed [Ref: 9.10].

9.5.20 All identified ASTs identified within the Phase 1 Geo-environmental Assessment [Ref: 9.1] will be decommissioned in accordance with EA guidance document PPG2 ‘Above Ground Oil Storage Tanks’ [Ref: 9.26].

9.5.21 The Phase II Geotechnical and Geo-environmental Assessment [Ref; 9.4] was completed and targeted at the potential sources of contamination identified within the Phase 1 Geo-Environmental Assessment [Ref: 9.1]. Metal and organic contamination as well as free fibre asbestos was identified within the south-eastern section of the Application Site (Zone A). Based on the masterplan the proposed buildings and areas of hardstanding will cover a large proportion of the southern and central eastern section of the Application Site, as such the need to excavate and disturb contaminated materials is likely to be reduced.

9.5.22 However, where contaminated soils are to be disturbed (i.e. cut and fill activities, foundation construction, service trenches etc.) appropriate mitigation measures will be utilised to protect on-site soils and neighbouring properties. These measures are likely to include, but are not be limited to:

The suppression of contaminated dusts and potential free fibre asbestos during excavation by damping down of soils, particularly during dry periods;

The remediation of contamination hotspots, where required;

The segregation of contaminated waste types for appropriate off-site disposal;

The use of wheel washes and covered wagons to reduce the potential for migration of contaminants off site;

A variety of good environmental site practices will be implemented in order to avoid or minimise effects at the source. Such measures include, but are not limited to, the following:

Working areas shall be clearly defined to ensure minimal disturbance of soils;

Controlled methods of stockpiling and segregation of materials.

Haul routes and accesses shall be clearly defined to minimise the risk of accidents. Construction vehicles will be regularly maintained to reduce the risk of hydrocarbon contamination associated with leaks and spillage and will only be active when required.

Designated areas for the storage of hazardous materials, fuels and chemicals. All designated areas will be appropriately bunded (110% the volume of the vessel) and all filler points/valves will be located within the extent of bund or appropriate drip trays provided;

Implementation of a temporary drainage network to prevent surface water runoff (silts, muds, hydrocarbons) from leaving the Application Site or entering surface water drains. Measures may include the cleaning of vehicle wheels prior to leaving Application Site;

Controlled, and covered, waste storage areas;

Provision of fuel emergency spill kits, located at strategic points;

Provision of environmental awareness training for site workers;

Adopting the Environment Agency Pollution Prevention Guidelines (outlined below); and

The position and extent of working areas shall reflect surrounding areas and works being carried out. The contractor shall appraise the suitability of such working areas in this respect as part of working method statements. The contractor will operate a “permit to dig” procedure as part of its working practices on site.

9.5.23 All site works will be undertaken in accordance with the Environment Agency’s Pollution Prevention Guidelines, in particular;



15

PPG1 ‘General Guide on the Prevention of Pollution’ [Ref: 9.25];

PPG2 ‘Above Ground Oil Storage Tanks’ [Ref: 9.26];

PPG6 ‘Working at Construction and Demolition Sites’ [Ref: 9.27];

PPG8 ‘Safe storage and disposal of used oils’ [Ref: 9.28];

PPG21 ‘Pollution Incident Response Planning’ [Ref: 9.29]; and

PPG26 ‘Storage and Handling of Drums and Intermediate Bulk Containers [Ref: 9.30].

9.5.24 Ground workers will also be made aware of the findings of the intrusive site investigation via the “permit to dig” procedure and provided with environmental awareness training.

9.5.25 All measures, such as those described above, shall be included within the CEMP for the Application Site.

Residual Effects

9.5.26 The sensitivity of on-site soils is low and the magnitude of change, following mitigation, is negligible. Therefore, there is likely to be a negligible effect on soils following the implementation of mitigation measures.

9.5.27 The sensitivity of neighbouring sites is high and the magnitude of change, following mitigation, is negligible. Therefore, there is likely to be a negligible effect on neighbouring sites following the implementation of the above mitigation measures.

Effect of hazardous ground gases on the health of construction workers

9.5.28 Ground gas monitoring data indicates the presence of elevated concentrations of Carbon Dioxide (and locally Methane) across the southern and north-eastern section of the Application Site. Excavations formed as part of the construction phase could result in construction workers being exposed to these hazardous ground gases.

9.5.29 The sensitivity of the construction workers is high and the magnitude of change, prior to mitigation, is high. Therefore, there is likely to be a direct, temporary to permanent, short to long-term effect on construction workers of major negative significance prior to the implementation of mitigation measures.

Mitigation

9.5.30 Where entry into confined spaces and / or excavations is required by construction workers a combination of suitably qualified personnel, appropriate PPE (including RPE), monitoring equipment and safe entry procedures will be utilised to mitigate any potential risk of exposure to hazardous gases / vapours.

9.5.31 All works will be conducted in accordance with the Health and Safety Executive publication entitled ‘Safe Work in Confined Spaces’, INDG258, 2006 [Ref: 9.23].

Residual Effects

9.5.32 The sensitivity of construction workers is high and the magnitude of change, following mitigation, is negligible. Therefore, there is likely to be a negligible effect on construction workers following the successful implementation and maintenance of mitigation measures.

Effect of slope / excavation instability on the health of construction workers

9.5.33 Due to the topography on the Application Site earthworks will be required to address level changes. Earthworks will also be required in the creation of a proposed lake. On this basis, unless appropriately managed, earth working and any necessary cut and fill operations could result in slope instability / failure potentially resulting in physical injury to construction workers.

9.5.34 The sensitivity of construction workers is high and the magnitude of change, prior to mitigation, is high. Therefore, there is likely to be an indirect, temporary to permanent, medium to long-term effect on construction workers of major negative significance prior to the implementation of mitigation measures.



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Mitigation

9.5.35 Prior to the commencement of earthworks across the Application Site, a strategy for safe working will be developed to ensure that effects to constructions workers are appropriately mitigated. This strategy will be developed further as the design progresses as the nature and extent of cut and fill activities will be fundamentally influenced by development plateau levels. A cut and fill modelling exercise will be undertaken to evaluate the necessity and design of retaining structures.

9.5.36 Effects to the health of construction workers from slope instability associated with cut and fill operations will be controlled under the CDM 2007 [Ref:9.9] and risk assessments will be prepared to ensure the protection of workers, which will specify appropriate safe working practices.

Residual Effects

9.5.37 The sensitivity of construction workers is high and the magnitude of change, following mitigation, is negligible. Therefore, there is likely to be a negligible effect on construction workers following the successful implementation and maintenance of the above mitigation measures.

Effect of Below Ground Obstructions and Slope Stability on Proposed Building Stability and End Users

9.5.38 Below ground obstructions (i.e. former foundations) are likely to be present across areas of the Application Site that have previously been developed. These features require appropriate investigation and suitable assessment as proposed foundations are constructed on these obstructions could lead to possible instability of future on-site buildings and infrastructure.

9.5.39 In addition, due to the existing topography at the Application Site cut and fill operations will be undertaken to create level development platforms. If not appropriately engineered, it could result in differential settlement / slope instability which in turn could effect on proposed structure stability and future end users.

9.5.40 The sensitivity of the proposed structures is medium and the magnitude of change, prior to mitigation, is medium. Therefore, there is likely to be a direct, permanent, long-term effect on proposed structures of moderate negative significance prior to the implementation of mitigation measures.

Mitigation

9.5.41 Below ground sub-structures will be removed during the groundworks and demolition phases.

9.5.42 A cut and fill modelling exercise will be undertaken to evaluate the necessity and design of retaining structures. Where necessary, slope stability assessments will be undertaken during detailed design phase to determine appropriate mitigation measures to mitigate potential slope stability effects; this may include but not be limited to:

slope re-shaping/grading;

slope stabilisation through an appropriate vegetation planting scheme; and

construction of appropriate retaining structures.

9.5.43 In addition, proposed structures will be located a suitable distance away from the crest of slopes and appropriate foundation solutions will be developed to maintain the stability of slopes.

Residual Effects

9.5.44 The sensitivity of proposed structures is medium and the magnitude of change, following mitigation, is negligible. Therefore, there is likely to be a negligible effect on proposed buildings following the implementation of the above mitigation measures.



17

Operation

9.5.45 The potential effects considered below assume the mitigation measures as set out in the construction phase have been implemented.

Effect of contaminated soils and materials on the health of future site occupants and maintenance workers

9.5.46 The potential effects after completion of the development are primarily focused on potential future contamination sources, including for example leaks / spillages from above ground fuel storage tanks, which may result during the lifetime of the development. However, it is noted that potential effects from previously identified contamination may remain (depending on the level of remedial works undertaken) which may still effect on identified receptors should works be undertaken which breach installed / implemented mitigation measures (e.g. excavation beyond capping layers or installation of foundations) and where possible these potential effects have also been considered.

9.5.47 The development of the site will cap the site through the provision of hardstanding and built cover removing the risk of direct exposure to contamination for future site occupants.

9.5.48 The previous assessment works also identified localised contamination (including asbestos) within soils and groundwater which may pose a risk to human health receptors during disturbance/excavation of made ground (i.e. should maintenance of the development be required during its lifetime that requires the disturbance of the ground).

9.5.49 Should the maintenance work involve the excavation of ground at the application site, there is a risk that potentially contaminated soil (including asbestos) and groundwater could pose a direct health risk to workers through direct skin contact with, or ingestion or inhalation of contaminated materials

9.5.50 The sensitivity of future occupants and maintenance workers is high and the magnitude of change, prior to mitigation, is medium to high. Therefore, there is likely to be a direct, permanent, long-term effect on future occupants and maintenance workers of moderate to major negative significance prior to the implementation of mitigation measures.

Mitigation

9.5.51 The mitigation measures detailed below predominantly address potential risks arising from future contamination sources, such as leaks for above ground storage tanks associated with the laundry and new development. It is considered that remedial measures implemented as part of the construction phase will mitigate against the potential risks from currently identified contamination. However, it is noted that further works and /or mitigation measures may be required should works be undertaken which may breach such measures, such as excavation beyond clean capping layer which may require further monitoring to demonstrate that the mitigation measures (membranes etc.) are robust. Should such works be anticipated it is considered that good general working practices and mitigation measures identified as part of the construction phase above, would be sufficient to mitigate potential risks.

9.5.52 As good practice a land quality statement (in form of a validation report) should be prepared following completion of the remediation works and development of the site to provide any occupant with an understanding of the potential risks posed by residual contamination remaining following completion of the construction phase to ensure protection of future site workers and the surrounding environment. This should detail any sources of residual contamination, where the contamination is located, summarise the potential risks such contamination may cause, along with details of mitigation works undertaken (e.g. installation of cover layer) and provide recommendation for mitigation against such risks in the future.

9.5.53 The mitigation measures specified to be implemented during the construction phase will have been undertaken prior to the operational stage of the proposed development. Such measures may include the incorporation of a clean cover layer in areas of landscaping or hard-standing.

9.5.54 Subject to finalisation of the remediation strategy, contaminants in shallow soil and perched groundwater in the vicinity of the laundry may also require remediation to reduce the risks associated with vapour inhalation.



18

9.5.55 Maintenance workers will be potentially at risk of exposure to contamination via direct contact and via inhalation of free fibre asbestos where they are involved in below ground excavations.

9.5.56 Mitigation of these effects can be achieved through the adoption of safe working practices, which should be held within the site’s health and safety file, and through the design and use of clean service corridors and marker layers.

9.5.57 Furthermore, the use of ‘clean’ service trenches will be adopted within those areas where contamination has been identified thereby mitigating the potential effect to future maintenance workers.

Residual Effects

9.5.58 The sensitivity of future occupants and maintenance workers is high and the magnitude of change, following mitigation, is negligible. Therefore, there is likely to be a negligible effect on future occupants and maintenance workers following the successful implementation and maintenance of the above mitigation measures and the remediation of any identified on-site contamination.

Effect of hazardous ground gases on the health of future site occupants and maintenance workers

9.5.59 Ground gas monitoring data indicates the presence of elevated concentrations of Carbon Dioxide (and locally Methane) across the Application Site. The southern section of the Application Site has been identified as Characteristic Situation 2 in accordance with guidance document CIRIA 665 ‘Assessing risks posed by hazardous ground gases to buildings’ [Ref: 9.23]. The northern section of the Application Site was classified as Characteristic Situation 3, although this is deemed to be a conservative classification. The construction of buildings without the incorporation of appropriate gas protection measures could result in future site occupants being exposed to hazardous ground gases.

9.5.60 The sensitivity of the future site occupants and maintenance workers is high and the magnitude of change, prior to mitigation, is high. Therefore, there is likely to be a direct, permanent, long-term effect on future site occupants of major negative significance prior to the implementation of mitigation measures.

Mitigation

9.5.61 All buildings constructed within those areas identified within the Phase II Geotechnical and Geo environmental Assessment 2012[Ref: 9.4] as being Characteristic Situation 2 or 3 will include mitigation measures in accordance with CIRIA 665 ‘Assessing risks posed by hazardous ground gases to buildings’ [Ref: 9.23]. The protection measures for Characteristic Situation 2 and 3 are ultimately the same and therefore where required gas protection measures will include:

Well-constructed in-situ (reinforced) concrete ground slab (at least 1200g DPM) or a pre-cast concrete ground slab with gas resistant membrane (2000g DPM) and;

A passively ventilated or positively pressurised underfloor subspace. The passively vented layer could include a suitable thickness of appropriate granular material as well as more specialist void former material.

Additionally, where basements or under-croft car parking are proposed then the need for specific protection measures may be negated, although this will be determined as the detailed design progresses.

Detailed design of gas protection measures required within buildings across the Application Site will be developed further as the detailed design progresses and will be agreed with Torfaen County Borough Council prior to construction.

9.5.62 Maintenance workers will be potentially at risk of exposure to ground gas where they are involved in below ground excavations. Mitigation of these effects can be achieved through the adoption of safe working practices, which should be held within the site’s health and safety file, and through the design and use of clean service corridors and marker layers.

Residual Effects



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9.5.63 The sensitivity of future site occupants is high and the magnitude of change, following mitigation, is negligible. Therefore, there is likely to be a negligible effect on future site occupants following the successful implementation and maintenance of the above mitigation measures.

Effect of accidental leaks and spillages on underlying soils

9.5.64 Accidental leaks and spillages as a result of site operations and from the laundry could potentially effect on the underlying soils. The illustrative masterplan shows a goods yard and storage facility located within the eastern section of the Application Site and the laundry is to be retained in its current location. A number of chemicals and fuels are stored in above ground storage tanks outside the laundry. At this stage the nature and amount of potentially hazardous substances to be stored within Proposed Development is not known; although, due to the nature of the Proposed Development, for the purpose of this assessment, it has been assumed that some potentially hazardous substances (i.e. fuel oils) will be stored on-site.

9.5.65 The sensitivity of on-site soils is low and the magnitude of change, prior to mitigation, is low / medium. Therefore there is likely to be a direct, temporary to permanent, medium-term effect on soils of negligible to minor negative significance prior to the implementation of appropriate mitigation measures.

Mitigation

9.5.66 Hard surfacing will be constructed within the goods yard and storage facility to prevent direct effect to underlying soils from potential accidental spillages and leaks. An audit of the current laundry environmental managements systems will be undertaken and an upgrade to the site, including the presence of suitable bunds and appropriate tanks, undertaken if required.

9.5.67 Consideration will be given to EA Pollution Prevention Guidelines to mitigate at source the potential effects from the storage and use of hazardous chemicals and materials on-site, in particular:

PPG 1: General guide to the prevention of pollution [Ref: 9.25] ;

PPG 2: Above ground oil storage tanks [Ref: 9.26];

PPG 8: Safe storage and disposal of used oil [Ref: 9.27];

PPG 18: Managing fire water and major spillages [Ref: 9.28];

PPG 21: Pollution incidence response planning [Ref: 9.29];

PPG 26: Storage and Handling of Drums and Intermediate Bulk Containers [Ref: 9.30]; and

PPG 25: Hospital and Health Care Establishments [Ref: 9.31].

9.5.68 Emergency plans and procedures in place at the Gwent SCCC will include provisions to effectively minimise and control leakages or spills of contaminative substances on the Application Site. The appropriate staff will be trained in the handling of contaminative substances and regular checks will be made to ensure that storage containers and tanks are secure and in good condition.

Residual Effects

9.5.69 The sensitivity of on-site soils is low and the magnitude of change, following mitigation, is negligible. Therefore, there is likely to be a negligible effect on on-site soils following the implementation of the above mitigation measures.

Monitoring and Follow Up9.5.70 A Construction Environmental Management Plan (CEMP) for control and management of potential risks at the Application Site will be developed and implemented by the Principal Contractor for the preparatory and construction phases of the development. The CEMP will incorporate the mitigation measures recommended above to reduce the significance and, where possible, eliminate the identified effects.

9.5.71 The CEMP will be a live document setting out the management system to be adopted on-site. Detailed risk assessments will be prepared for all operations from which a safe system of work shall be



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developed. The Principal Contractor will be required to monitor this process and develop assessments and working methods appropriate to changes in work activities.

9.5.72 In line with CDM 2007 [Ref: 9.9], the principal contractor's role is to plan, manage and co-ordinate health and safety while construction work is being undertaken and will also be a live document.

Limitations and Assumptions 9.5.73 Due to the age of several of the structures on-site it has been assumed that asbestos containing materials may be present within the building fabric. Proposed mitigation measures have been developed based on these assumptions which are considered to represent a worst case scenario. A review of the available asbestos registers will be undertaken for on-site buildings, however, if information relating to asbestos within the building fabric is deemed to be insufficient, a demolition asbestos survey will be undertaken to ensure appropriate mitigation measures can be developed in accordance with the Control of Asbestos Regulations 2012 [Ref: 9.10]. On completion of these investigations the findings will be incorporated in to the CEMP to ensure that an appropriate level of mitigation is provided.

9.6 CUMULATIVE EFFECTS9.6.1 Where possible, consideration of the ground conditions for the following developments has been summarised below:

Residential development at Llanfrechfa Grange (south) comprising 400 residential dwellings and associated access. A planning application has not been submitted although it is anticipated that the development would have commenced by 2013.

103 residential dwellings on Llantarnam Rd (which has received planning consent). This site has previously been used as sports fields for the employee’s the Burtons Factory. Ground Conditions and contamination have not been considered within the case officers report, as such it is assumed that it was not considered to be a significant issue;

42 residential flats adjacent to 329 Llantarnam Road (which has received planning consent) This site relates to a small vacant unmaintained grass area adjacent to the Burtons Factory, as mentioned above ground conditions and contamination do not appear to have not been considered within the case officers report, as such it is considered that it was not assumed to be a significant issue;

Residential development at South Sebastopol. The case officers conclusions with respect to ground conditions states that the site exhibits a low level of known and potential contamination that can be dealt with by recognised techniques and in view of the EA’s comments, conditions are attached to the recommendation requiring further survey work to cover contamination and pollution issues. The relevant condition relates to completing a detailed scheme for investigation and the preparation and approval remediation techniques to be adopted;

Malthouse Lane Development in Llantarnam. The outline consent is for industrial purposes within Use Classes B1 (business), B2 (general industrial) and B8 (storage and distribution). The application has been recommended for approval with conditions relating to the protection of controlled waters including the preparation of a desk top study, site investigation and remediation method statement, if required; and

Development at County Hall comprising residential housing in excess of 100 units. No planning application has been submitted although it is anticipated that development would commence circa 2012/2013.

9.6.2 Whilst it is considered possible that potential contaminants may also exist at the other developments within the locality and the potential for cumulative effects and interactions to human health and the wider environment may be possible, the mitigation techniques outlined in Chapter 9 Soils, Geology and Contaminated Land will serve to reduce this potential effect within the study area to a minimum, resulting in a negligible effect.



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9.6.3 In addition, assuming other developments within the immediate vicinity adopt similar techniques which are typically used to mitigate potential effects during the redevelopment of brownfield land, the cumulative effects and interactions are predicted to be of negligible significance.



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Table 9.2: Summary of Effects Table for Soils, Geology and Contaminated Land

Description of Likely Significant Effects


Summary of Mitigation / Enhancement Measures

Significance of Residual Effects

Relevant Policy

Relevant Legislation

(Major, Moderate, Minor, Negligible)

Positive / Negative

(P/T) (D/I)ST/MT/LT)


Positive / Negative

(P/T)(D/I)

ST/MT/LT)

Demolition / Construction

Effect on human health from contaminated soils and materials

Moderate to Major

Negative T - P D MT - LT

Demoltion asbestos survey, if required.

Mitigation measures to be developed in line with published guidance and best practice, if require and outlined in CEMP.

Use of generic safe working practices.

Use of asbetsos control measures.

Negligible N/A - - -

PPW – Chap 13

TCBC ALP - E13 G1 (Bii)

GSP - ENV4

Part IIA of the EPA 1990;

EA 1995; 0

Contaminated Land (Wales) (Amendment)Regs 2012;

Contaminated Land Statutory Guidance for Wales 2012

Control of Asbestos Regs 2012

CDM Regs 2007

Effect on soils from disturbance/mobilisation of contaminated soils and materials

Minor Negative T D MT Mitigation measures to be developed in line with published

Negligible N/A - - - PPW – Chap 13

TCBC ALP -


EA 1995;



23





Relevant Policy



Positive / Negative



Positive / Negative

(P/T)(D/I)

ST/MT/LT)

guidance and best practice, if required and outlined in CEMP and SWMP.

Consideration of the relevant EA Pollution Prevention Guidance notes.

Demolition asbestos survey, if required.

Use of asbetsos control measures.

E13 G1 (Bii)

GSP - ENV4

TCBC LDP DP – B (i)




Effect on neighbouring sites from disturbance/mobilisation of contaminated soils and materials

Minor to Major

Negative T D MT Negligible N/A - - -

Effect on human health from hazardous ground gases.

Major Negative T - P D ST - LT Mitigation measures to be developed in line with HSE guidance document INDG258.



GSP -


EA 1995;




24





Relevant Policy



Positive / Negative



Positive / Negative

(P/T)(D/I)

ST/MT/LT)

ENV4


CDM Regs 2007

Effect of slope and excavation stability on human health

Major Negative T - P I MT - LT

Development of a strategy for safe working.

Cut and fill modelling exercise.

Slope stability assessments, if required.

Negligible N/A - - - - -

Effect of below ground obstructions and slope stability on building stability and end users.

Moderate Negative P D LT Below ground sub-structures will be removed during demo phase.

Cut and fill modelling exercise to be prepared pre-construction.

Negligible N/A - - - - -



25





Relevant Policy



Positive / Negative



Positive / Negative

(P/T)(D/I)

ST/MT/LT)

Slope stability assessments, if required.

Appropriate retaining structures where required.

Operation

Effect on human health from contaminated soils and materials

Modertae to Major

Negative P D LT Construction of hardstanding (i.e. buildings / car parking)

Inclusion of ‘clean’ soil cover layers within soft landscaped areas or removal of indeified source (i.e. Made Ground)

Asbestos surveys undertaken prior to demolition, if required. If necessary, removal will be



GSP - ENV4


EA 1995;






26





Relevant Policy



Positive / Negative



Positive / Negative

(P/T)(D/I)

ST/MT/LT)

undertaken prior to demolition.

Effect on human health from hazardous ground gases.

Negligible -Major

Negative P D LT

Mitigation measures to be developed in line with CIRIA guidance document CIRIA C665.


PPW – Chap 13


GSP - ENV4


EA 1995;



Effect of accidental leaks and spillages on soils.

Minor Negative T - P D MT

Appropriate storage of hazardous materials / chemicals.

Consideration of the relevant EA Pollution Prevention Guidance notes.


PPW – Chap 13


GSP - ENV4)

TCBC LDP DP – B (i)


EA 1995;





27

Key to table:

P/T = Permanent or Temporary, D/I = Direct or Indirect, ST/MT/LT = Short Term, Medium Term or Long Term

N/A = Not Applicable



28

REFERENCES Ref 9.1: WSP Environmental (WSPE) (2007), ‘Phase 1 Geo-environmental Assessment, Proposed

Development of The Site at Llanfrechfa’ (Ref: 12061286-001), UK, WSPE.

Ref 9.2 WSPE (2008), ‘Phase II Geotechnical and Geo-environmental Assessment, Llanfrechfa Grange and DEIN Site’ (Ref: 12061286-004), UK, WSPE.

Ref 9.3 WSPE (2008), ‘Phase II Geotechnical and Geo-environmental Supplementary Assessment, Llanfrechfa Grange and DEIN Site’ (Ref: 12061286-004), UK, WSPE.

Ref 9.4 WSPE (2012), ‘Phase II Geotechnical and Geo-environmental Assessment, SCCC, Gwent, (Ref: 18236.0001), UK, WSPE.

Ref 9.5 HMSO (1990), Environmental Protection Act: Part 2A, Contaminated Land’, UK, HMSO.

Ref 9.6 HMSO (1995), Environment Act 1995, UK, HMSO.

Ref 9.7 Welsh Government (WG) (2006), ‘The Contaminated Land (Wales) (Amendment) Regulations 2012’, UK, Welsh Statutory Instruments.

Ref 9.8 WG (2012), ‘The Contaminated Land Statutory Guidance for Wales, UK, WG.

Ref 9.9 HMSO (2007), ‘Construction (Design & Management) Regulations 2007’, UK, HMSO.

Ref 9.10 HMSO (2012), ‘The Control of Asbestos Regulations’, UK, HMSO.

Ref 9.11 WG (2008), ‘People, Places, Futures – The Wales Spatial Plan, 2008 Update’, WG.

Ref 9.12 WG (2011), ‘Planning Policy Wales’, WG.

Ref 9.13 Gwent County Council (1996), ‘The Gwent Structure Plan’, UK, Gwent Council.

Ref 9.14 Torfaen Borough Council (2000), ‘Adopted Local Plan for the County Borough of Torfaen‘, UK, Torfaen County Borough Council (TCBC).

Ref 9.15 TCBC (20011), ‘Torfaen County Borough Council Local Deposit Plan (to 2021) Deposit Plan 2011’ UK, TCBC.

Ref 9.16 Environment Agency (EA) (2004), ‘Model Procedures for the Management of Contaminated Land (CLR11)’, UK, EA.

Ref 9.17 Health and Safety Executive (HSE) (1991), Guidance Note HS (G) 66, ‘Protection of Workers and the General Public during the Development of Contaminated Land’, UK, HSE.

Ref 9.18 British Standards Institute (BSI) (2001), BS10175:2001, ‘Investigation of Potentially Contaminated Sites – Code of Practice’, UK, BSI.

Ref 9.19 EA and National House Building Council (NHBC) (2000), ‘Guidance for Safe Development of Housing on Land Affected by Contamination’, EA R&D Publication 66, UK, EA/NHBC.

Ref 9.20 EA (2000), ‘Technical Aspects of Site Investigation (2 Volumes)’, R&D Technical Report P5-065, UK, EA.

Ref 9.21 EA (2000), ‘Secondary Model Procedures for the Development of Appropriate Soil Sampling Strategies for Contaminated Land’, R&D Technical Report P5-066, UK, EA.

Ref 9.22 Environment Agency (EA) (2001), ‘Piling and Penetrative Ground Improvement methods on Land Affect by Contamination: Guidance on Pollution Prevention (NC/99/73)’, UK, EA.

Ref 9.23 Wilson, S; Oliver, S; Mallet, H; Hutchings, H; Card, G (2007), ‘CIRIA C665 – Assessing Risks Posed by Hazardous Ground Gases to Buildings’, UK, CIRIA.

Ref 9.24 HSE (2006), INDG258, ‘Safe Work in Confined Spaces’, UK, HSE.

Ref 9.25 EA, PPG1 ‘General Guide on the Prevention of Pollution’, UK, EA.

Ref 9.26 EA (2004), PPG2 ‘Above Ground Oil Storage Tanks’, UK, EA.



29

Ref 9.27 EA, PPG6 ‘Working at Construction and Demolition Sites’ UK, EA.

Ref 9.28 EA (2004), PPG8 ‘Safe storage and disposal of used oils’, UK, EA.

Ref 9.29 EA (2004), PPG21 ‘Pollution Incident Response Planning’, UK, EA.

Ref 9.30 EA (2004), PPG26 ‘Storage and Handling of Drums and Intermediate Bulk Containers’, UK, EA.

Ref 9.31 EA (2004), PPG25 ‘Hospital and Health Care Establishments’, UK, EA

12264272 – Llanfrechfa Grange – Environmental Impact AssessmentEIA: Volume 1 Environmental Statement – Chapter 9: Soils, Geology & Contaminated Land

Gwent Healthcare NHS TrustWSP Environmental

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Document Title - Torfaen County Borough Council · Web viewBaseline desk study data obtained and reported within the Phase 1 Geo-environmental Assessment [Ref: 9.1] extends up to

Documents