WREXHAM COUNTY BOROUGH COUNCIL
GUIDANCE ON THE DEVELOPMENT OF SITES WITH POTENTIAL LAND
CONTAMINATION
1st Edition, October 2002
Prepared by the:
Public Protection Department (Environmental Services Directorate)
The information in this leaflet has been provided in good faith, it should be borne in mind that the status of information may
change, become out of date and that new working practices may develop. Ultimately it is the responsibility of the
person/company involved in the development and assessment of potentially contaminated land to apply up to date working
practices in assessing the contamination status of a site and in determining the remediation requirements.
CONTENTS
Section
Subject
Page
1.
Introduction
1
2.
Assessing Contamination for the Development
of Sites with Potential Land Contamination
2
3.
Potentially Contaminated Sites
3
4.
Summary of Procedures for Assessing
Potential Land Contamination for Development
Purposes
5
5.
Phase 1 – A Desk Study
6
6.
Phases 2 & 3 – Further Site Investigation
8
7.
Phase 4 – A Remediation Strategy
9
8.
Wrexham CBC’s Viewpoint
10
9.
Contacts
11
10.
Sources of Further Information
12
FURTHER COPIES OF THIS LEAFLET ARE AVAILABLE TO DOWN LOAD ON WREXHAM
COUNTY BOROUGH COUNCIL’S WEB-SITE: www.wrexham.gov.uk
1. INTRODUCTION
This leaflet has been prepared by Wrexham County Borough Council (Wrexham CBC) to provide
information which may assist in the preparation of planning applications and/or building regulations
applications concerning the development of potentially contaminated land.
Land can be affected by contamination in the form of chemicals or gases in the soil and/or water,
buildings, or other material on a site. Such sites are likely to be brownfield sites i.e. those which have
been previously developed, often for commercial or industrial use.
As a result of the requirements to develop brownfield sites it is possible that some developments will
take place on potentially contaminated sites. It is essential to ensure that potential contamination is
adequately dealt with upon a change of land use, thereby ensuring the land is made suitable for its new
use and presents no danger to the health and safety of people who come into contact with it. In some
cases certain types of development (which are likely to be the most sensitive types e.g. housing) may
not be suitable for sites with a certain type of contamination. In such cases the site may be better
developed for another type of use, e.g. commercial or industrial. It is hoped that this leaflet, together
with the Local Planning Guidance Note No 22 – Development of Sites with Land Contamination will
go some way to ensuring that developed land remains safe.
This leaflet highlights the type and extent of investigations that need to be undertaken to ensure
Wrexham CBC fulfils its statutory obligations under planning, building and environmental health
legislation. In addition, this leaflet briefly explains the ‘link’ between the planning regime and the new
contaminated land regime under Part IIA of the Environmental Protection Act, 1990 and Contaminated
Land (Wales) Regulations, 2001.
1
2. ASSESSING CONTAMINATION FOR THE DEVELOPMENT OF SITES WITH
POTENTIAL LAND CONTAMINATION
Wrexham CBC aims to ensure that the development of brownfield sites will be carried out in an
appropriate way. During development control procedures the planning department will require that
prospective developers give appropriate consideration to any potential contamination issues at their
sites.
Once potential contamination issues are thought to exist at a site, the assessment of the site will be to at
least the level of that required under Part IIA (see below). Therefore, no further assessment of
contamination issues on the site would be required under Part IIA provided that at a later date, (after
the development) there is no subsequent change in the environment/development situation on and in
the vicinity of the site.
Part IIA
Part IIA provides a framework for Council’s to manage potential contamination issues on sites where
development is not taking place (i.e. not under the planning regime) with the object of ensuring that:
‘by reason of substances in, on or under the land:
-significant harm is being, or is likely, to be caused;
-or pollution of controlled waters is being or is likely to be caused’.
The meaning of ‘substances’ and ‘significant harm’ should be in accordance with the statutory
guidance provided by the National Assembly for Wales for the Part IIA regime.
This means that where land is identified as contaminated (under the strict definition detailed in Part
IIA) Council’s are required to ensure that remediation takes place to return the land to a state that is
suitable for its current use i.e. significant harm is not being caused or likely to be caused and it is not
and will not cause pollution of controlled waters. Therefore, where contamination has not been
addressed under the planning regime, sites will be assessed under Part IIA.
With regard to contamination site investigations and remediation of contaminated land,
Wrexham CBC will consult and have regard to comments made by other statutory bodies,
principally the Environment Agency.
2
3. POTENTIALLY CONTAMINATED SITES
There are many former land uses that are potentially contaminating and some sites may have had a
number of potentially contaminating uses, occurring either all at one time or at separate times. The
(former) Department of Environment identified a number of such uses, see List 1. For each type of
use, a profile is available which describes the:
 type of activities which may have taken place on the site;
 potential contaminants and locations where they may be found;
 factors that may affect the contamination; and
 migration and persistence of contamination.
In addition, the Construction Industry Research and Information Association (CIRIA) RP440 guidance
lists potentially contaminative uses, as detailed in List 2.
Additional industries that the Council recognise may be contaminative are detailed in List 3. However,
none of these lists are complete, but the information which is available is useful in designing site
investigations, assessment of risk and remediation requirements.
List 1 - Department of Environment Industry Profiles
1.
2.
3.
4.
5–18
19
20–24
26
27-31
32
33
34
35
36
37
38
39
40-41
42
43
44
45
46
49
Airports
Animal and animal products processing works
Asbestos manufacturing works
Ceramics, cement and asphalt manufacturing works
Chemical works of various types
Dockyards and dockland
Engineering works: of various types
Gas works, coke works and other coal carbonisation plants
Metal manufacturing works of various types
Oil refineries and bulk storage of crude oil and petroleum products
Power stations (excluding nuclear power stations)
Pulp and paper manufacturing works
Railway land
Road vehicle fuelling, service and repair: garages and filling stations
Road vehicle fuelling, service and repair: transport and haulage centres
Sewage works and sewage farms
Textile works and dye works
Timber products manufacturing works and Timber treatment works
Waste recycling, treatment and disposal sites: drum and tank cleaning and recycling plants
Waste recycling, treatment and disposal sites: hazardous waste treatment plants
Waste recycling, treatment and disposal sites: landfills and other waste treatment or waste disposal sites
Waste recycling, treatment and disposal sites: metal recycling sites
Waste recycling, treatment and disposal sites: solvent recovery works
Profile of miscellaneous industries incorporating:
Charcoal works
Dry-cleaners
Fibreglass and fibreglass resins manufacturing works
Glass manufacturing works
Photographic processing industry
Printing and bookbinding works
3
List 2 - CIRIA RP440 Industry/Site Profiles
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
Iron and steel industry
Metal processing industry
Mining and extractive industries
Non-ferrous metal smelting and refining
Power stations (Gas/Oil/Coal)
Shipbuilding sites
Animal processing works
Asbestos works
Gas works
Paper Manufacture
Printing industry
Textile industry
Wood treatment works
Chemical plants
Garages/Petrol stations
Oil refineries/Storage sites
Biocide production plants
Incineration facilities
Landfill sites
Sewage works and farms
Dockland sites
Ministry of Defence land (munitions manufacture)
Railway land
Scrap yards
List 3 - Additional potentially contaminative uses not listed above:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Brickworks;
Food processing industry;
Laboratories for educational or research purposes;
Premises housing dry cleaning operations;
Intensively cultivated agricultural land or buildings used for the storage of agro-chemicals;
Canal basins and wharves;
Waste heaps (including colliery spoil, lagoons, metalliferous waste etc…);
Electricity supply industries;
Industries using radioactive substances; and
Demolition of buildings, plant or equipment used for any of the activities listed in Appendix A.
There are normally a series of 3 to 4 phases involved in assessing potential contamination issues at a
site:
Phase 1 – Desk Study
Phase 2 – Further site investigation works
Phase 3 – Further more detailed site investigation works
Phase 4 – Remediation works
It may be that the findings of a Phase 1 investigation show that a Phase 2 assessment is not needed. Or
following a Phase 2 investigation, Phases 3 and/or 4 are not needed.
IT IS IMPORTANT TO NOTE THAT ALL CONTAMINATION INVESTIGATIONS SHOULD BE CARRIED OUT
ON A ‘SITE SPECIFIC’ BASIS SINCE NO ONE SITE IS THE SAME AS ANY OTHER.
4
4. SUMMARY OF PROCEDURES FOR ASSESSING POTENTIAL LAND
CONTAMINATION FOR DEVELOPMENT PURPOSES
Attempt to determine the past history
of the site and surrounding area.

Does the site or area within influencing distance have an
industrial history (see p3-4)?
Are there any known or suspected hazards at or within
influencing distance of the site?
Does Wrexham CBC have any information on the site?
YES
NO
Carry out a Phase 1 contamination
investigation (see p6)


Do the findings of the Phase 1
investigation require a further site
investigation works (Phase 2)?
YES

No contamination investigation is
required at this stage. However, if
during site works evidence of
contamination is uncovered, or further
information comes to light, then
Wrexham CBC should be contacted
for advice since a Phase 1
investigation may now be needed.
NO 
Carry out a Phase 2
contamination investigation
(see p8)
No further contamination
investigation works (i.e. Phase 2)
are required.

YES
Do the findings of the Phase 2
investigation require further site
investigation works?
Carry out a Phase 3
contamination investigation.

NO
YES
Do the findings of the Phase 2
investigation show that
remediation is required.
Do the findings of the Phase 3
investigation show that remediation
is required?
YES
NO
Carry out
remediation.
No further works are required.
5
NO
No further
works are
required.
5. PHASE 1 – A DESK STUDY
A desk study investigation of the site and land within influencing distance of the site should be
undertaken by a suitable person. The desk study should comprise a report which assesses at least the
following information in terms of potential contamination on or within influencing distance of the site:





Current and former uses of the site and the surrounding area, identifying in particular potential contamination
hazards, potential receptors and pathways;
Geology (superficial deposits and solid (rock));
Hydrology (surface water);
Hydrogeology (groundwater); and
Pollution incidents on and within influencing distance of the site.
The information to be assessed can typically be obtained from the following sources:








Local history information e.g. historical maps (Ordnance Survey maps. often dating from the late 1800’s
onwards), trade directories, books – found in libraries, county records offices, Landmark Information Group,
museums and other local history sources;
Groundwater, surface water, pollution incidents, authorised processes and landfill site information can be
provided by the Environment Agency;
Wrexham CBC can provide information on planning and environmental health issues;
A mining report can be obtained from the Coal Authority which will detail, past, current and proposed mining
activities;
The British Geological Survey may have maps and other information such as borehole logs for the site and
surrounding area and soil survey data;
Aerial photographs;
Information from the current site owner and/or vendor of the site; and
A walkover survey.
A walkover survey of the site and the surrounding area should be undertaken by a suitable person. The
inspection should identify:







Indications of potential contamination, for example: signs of chemical containers, tanks, odour, signs of
spillages, made ground;
Topography and associated features;
Soil type and condition;
Surface water features and their condition (e.g. dis-colouration), including ponding, waterlogged ground,
water loving plants (e.g. reeds);
Vegetation and its condition e.g. sparse, dead, stunted growth, species;
Structures and site access, including evidence of services (e.g. overhead cables), signs of
movement/instability; and
Historical features e.g. road names, local knowledge.
6
Upon assessment of the above information, a conceptual model should be developed indicating
potential pollutant linkages.
A Pollutant Linkage will comprise:
Source

(a substance or group
substances with the potential
to cause significant harm)
Pathway

(a route by which a
source could reach a
receptor e.g. direct skin contact)
Receptor
(that which could be
significantly harmed by
the source e.g. a person)
The final desk study report should at least include: dated site plans showing the current, previous and
proposed uses of the site; the sources of information investigated; the conceptual model; and the
conclusions of the assessment. The following documents: 1, 2, 5, 11, 12 13, 15, 18 and 23 listed in
Section 10 – Sources of Further Information, provide recognised best practice guidance on desk study
investigations.
Failure to demonstrate familiarity with a sites former uses and land within influencing distance
of the site and thus the potential for contamination to exist on the site will be regarded as
insufficient information. The Planning Department will usually expect a Desk Study report to
accompany a planning application for a potentially contaminated site. If such a report is not
provided, the department may request the information before considering the application
further, or alternatively a condition requiring an investigation may go on the planning
permission.
‘SUITABLE PERSONS’, ‘CONSULTANTS’ AND ‘SPECIALISTS’
A suitable person, consultant and/or specialist would require the following skills and knowledge to
competently carry out any level of contamination investigation:






have extensive experience in land contamination issues and possibly a suitable qualification (e.g.
environmental degree);
have an understanding of the contaminated land regime (Part IIA) and its associated concepts;
have experience in identifying the types of hazards that may affect a development;
have experience in carrying out a desk study investigation, including a walkover survey and reporting the
findings of the study;
be able to determine when further investigation is required i.e. Phase 2 investigation, and/or specialist advice
is required; and
have experience in carrying out intrusive investigation works, risk assessments and report on the findings of
such works.
The person/company carrying out the contamination investigation works should have:
 appropriate professional indemnity insurance;
 an appropriate quality management system in place;
 use accredited laboratories; and
 an awareness of all occupational hygiene issues and health and safety legislation.
For further advice on this matter see Section 9.
7
6. PHASES 2 & 3 – FURTHER SITE INVESTIGATION
If the desk study indicates that contamination has occurred or is suspected, the developer should
commission further site investigation works. Phase 2 works are generally intrusive however generally
new methods, such as geophysical investigations, are becoming increasingly popular to give an initial
indication of ground conditions.
In order to ensure that potential contamination issues at a site have been adequately addressed,
Wrexham CBC will normally require that the objectives, scope and execution of the Phase 2
investigation is agreed prior to the works commencing. The report on the findings should then be
provided to Wrexham CBC for consideration.
The design, methods and procedures available for Phase 2 works are numerous and should be entirely
site specific, therefore, only a brief indication of what may be expected is detailed in this leaflet. It is
advisable for the developer and person carrying out the investigation works (i.e. consultant) to consult
the relevant best practice documents, most of which are listed in Section 10 – Sources of Further
Information.
Generally Phase 2 works involve the collection of soil, leachate and/or water samples for analysis and
long term gas and water monitoring (and sample collection) may also be carried out. These works can
be done by various means and to varying degrees and cost. Where extensive and heavy contamination
is suspected the further investigation works may be limited with a view to a more detailed and specific
investigation subsequently being carried out (Phase 3) once the Phase 2 works have provided a general
overview of the contamination. Typical Phase 2 works are:
Trial pits


4 - 5m deep holes often excavated by a digger in superficial deposits i.e. not rock.
Useful to visually inspect ground conditions and collect soil and water samples.
Boreholes



Boreholes can be drilled to almost any depth in any material, there are various drilling methods to suit most
types of ground, including rock.
Can be designed for the long-term monitoring of water and gas.
Soil samples for analysis can also be collected, although a reliable indication of ground conditions may be
difficult to determine (due to limited visibility) unless a large number of boreholes are drilled. In addition,
there can be difficulties in determining the depth a soil sample has been collected from, although this is likely
to be dependant on the type of drilling method employed.
The design of the investigation should take into account the findings of the desk study, services
(e.g. underground electricity and gas facilities) etc… Samples should be collected based on good
practice working methods and laboratory analysis should be conducted according to accredited
methods.
8
The results of the site investigation should be detailed in a report and the following information should
be included:







Plan of sample locations (to scale);
Site investigation methodology (e.g. reasons for type of investigation, design of the investigation, sample
locations and depths, sample collection, storage and analysis procedures, field measurements and instruments
used, laboratory used, rationale for choice of chemical analysis)
Ground conditions e.g. trial pit, borehole logs and an interpretation of the data;
Results of any monitoring and laboratory tests;
Significance of the results, including standards used for the assessment of the results and any risk assessment
procedures;
Conclusions – including uncertainties; and
Recommendations – including remediation proposals (if necessary).
The conclusions and recommendations of the report may indicate that further detailed site investigation
works (Phase 3) are required. For example, it may not have been possible for the Phase 2 works to
quantify/show the extent of the contamination or provide sufficient data to research/assess possible
remediation works.
An inappropriate/incomplete assessment that fails to show the degree, extent of contamination,
and/or the remediation (if any), that is required to ensure that:
‘by reason of substances in, on or under the land:
- significant harm is being, or is likely, to be caused;
- or pollution of controlled waters is being or is likely to be caused’
will be deemed as inadequate. As a result the Planning Department is likely to request further
information before determination of an application for a proposed development, alternatively a
condition may be set on the planning permission.
7. PHASE 4 – A REMEDIATION STRATEGY
Following Phase 1 (and possibly Phases 2 & 3) contamination investigation works Wrexham CBC
may agree that the proposed use for the site is suitable but subject to remediation works.
Wrexham CBC will require that any remediation works are carried out by a suitably qualified company
and that the details of the works are approved prior to their commencement. Written quality assurance
and a detailed written record of the remediation works carried out will be required by Wrexham CBC
and we will expect these records (which are a means for demonstrating compliance) to be agreed in
advance.
Failure to demonstrate that the remediation works have been carried out to the agreed standard will be
regarded as insufficient and the site may be investigated under Part IIA at a later date – this may mean
the site is designated as ‘contaminated land’ and further remediation works required as a result.
Communication between the developer, Planning Department and Public Protection Department should
prevent this occurring.
9
8. WREXHAM CBC’S VIEWPOINT
At the pre-application stage or on receipt of a planning application, Wrexham CBC will have regard to
the following issues:
1.
Has the site or the surrounding land been statutorily classified as contaminated land by Wrexham
CBC (Public Protection Department) under Part IIA of the EPA, 1990?
2.
Is the site or the surrounding land recognised by Wrexham CBC (Public Protection Department) as
potential contaminated land under Part IIA of the EPA, 1990?
3.
As a result of current or previous land uses, or land uses within influencing distance of the site, is
the site known or suspected to have contaminated ground?
4.
Has the developer carried out a suitable contamination investigation of the site or are they in
possession of information on contamination issues on or within influencing distance of the site?
5.
Does the site require investigation prior to the determination of the planning application?
6.
Does the site require remediation to ensure that by reason of substances in, on or under the land:
- significant harm is being, or is likely, to be caused;
- or pollution of controlled waters is being or is likely to be caused?
7.
Has the developer carried out suitable remediation of the site or prepared suitable remediation
proposals for the site?
On completion of works required by a planning condition and prior to development of the site,
Wrexham CBC will have regard to the following issues:
1.
Were the site investigation works suitable and complete?
2.
Did the site investigation works identify the need for remediation works?
3.
Were the remediation works suitable and carried out in accordance to the approved standard
required – has the developer demonstrated compliance with the required standards?
4.
Have any post monitoring works been completed in accordance with the approved requirements?
10
9. CONTACTS
For further information or advice regarding planning issues please contact the Development Control
section in the Planning Department at:

Lambpit Street
PO Box 1290
WREXHAM
LL11 1WL

bob.dewey@wrexham.gov.uk

01978 292470
For further information or advice regarding contamination issues, including a list of environmental
consultants (the list is not a comprehensive list and other sources of contact are suggested, nor is it an
‘approved list’ and clients should undertake their own checks to verify the suitability of a consultant)
please contact the Scientific Officer in the Environmental Protection section of the Public Protection
Department at:

Crown Buildings
Chester Road
WREXHAM
LL13 8ZE


angela.thompson@wrexham.gov.uk
toni.slater@wrexham.gov.uk
01978 297041
OR
OR look for ‘land contamination’ on the web-site: www.wrexham.gov.uk
For further information or advice regarding funding issues please contact the Welsh Development
Agency (WDA) at:

Jeff Porter MRICS
Environment Manager
Welsh Development Agency
Unit 7, St Asaph Buisness Park
St Asaph
Denbighshire
LL17 0LJ

jeff.porter@wda.co.uk

01745 586239
Sites designated as Contaminated Land under Part IIA are not eligible for WDA funding.
11
10. SOURCES OF FURTHER INFORMATION
The following documents should be referred to where necessary, it should be noted that other
documents exist and some are currently in preparation which are not listed here and may also be useful
references.
1.
British Standards Institution (BSI) ‘Code of Practice for Site Investigations: BS5930’, 1999
2.
British Standards Institution (BSI) ‘Code of Practice for the Investigation of Potentially Contaminated Sites:
BS10175: 2001’, 2001
3.
Building Research Establishment (BRE) ‘BRE Report – Measurement of gas emissions from contaminated land’,
1987
4.
Building Research Establishment (BRE) ‘BRE Report – Construction of new buildings on gas contaminated land’,
1991
5.
Construction Industry Research and Information Association (CIRIA) ‘Special Publication 103 – Remedial Treatment
for Contaminated Land – Volume III: Site investigation and assessment’, 1995
6.
Construction Industry Research and Information Association (CIRIA) ‘Report 149 – Protecting development from
methane’, 1995
7.
Construction Industry Research and Information Association (CIRIA) ‘Report 150 – Methane investigation
strategies’, 1995
8.
Construction Industry Research and Information Association (CIRIA) ‘Report 151 – Interpreting measurements of gas
in the ground’, 1995
9.
Construction Industry Research and Information Association (CIRIA) ‘Report 152 – Risk assessment for methane and
other gases from the ground’, 1995
10.
Department of the Environment ‘Waste Management Paper No.27 – Landfill Gas’: 2nd Edition’, 1991
11.
Department of the Environment ‘Contaminated Land Research Report – CLR No. 1 Volumes 1 & 2 - A framework
for assessing the impact of contaminated land on groundwater and surface water’, 1994
12.
Department of the Environment ‘Contaminated Land Research Report – CLR No. 2 Volumes 1 & 2 – Guidance on
preliminary site inspection of contaminated land’, 1994
13.
Department of the Environment ‘Contaminated Land Research Report – CLR No. 3 – Documentary research on
industrial sites’, 1994
14.
Department of the Environment ‘Contaminated Land Research Report – CLR No. 4 – Sampling Strategies for
Contaminated Land’, 1994
15.
Department of the Environment ‘Industry Profiles’ various titles, 1995
12
16.
Department of the Environment and The Welsh Office ‘The Building Regulations 1991 – Site Preparation and
resistance to moisture, Approved Document C, 1992 Edition
17.
Environment Agency National Groundwater and Contaminated Land Centre ‘Decommissioning Redundant Boreholes
and Wells’
18.
Environment Agency ‘Technical Aspects of Site Investigation: Volumes I and II – Research and Development
Technical Report P5-065/TR’, 2000
19.
Environment Agency ‘Secondary Model Procedure for the Development of Appropriate Soil Sampling Strategies for
Land Contamination – Research and Development Technical Report P5-066/TR’, 2000
20.
Environment Agency ‘Guidance on the Disposal of “Contaminated Soils”’, Version 3, April 2001
21.
Environment Agency ‘Technical advice to third parties on pollution of controlled waters for Part IIA of the
Environmental Protection Act’, 2002
22.
Environment Agency ‘Contaminated Land Research Reports 7-10 and the CLEA Model’, 2002
23.
Environment Agency/National House Builders Corporation (NHBC) ‘Guidance for the Safe Development of Housing
on Land Affected by Contamination’, 2000
24.
Environment Agency/Building Research Establishment (BRE) ‘Protective Measures for housing on gas-contaminated
land’, 2001
25.
Interdepartmental Committee on the Redevelopment of Contaminated Land (ICRCL) ‘Guidance on the assessment
and redevelopment of contaminated land: ICRCL 59/83, 2nd Edition’, July 1987
26.
National Assembly for Wales ‘Statutory Instruments 2001 No. 2197 (W.157) Environmental Protection, Wales – The
Contaminated Land (Wales) Regulations, 2001
27.
National Assembly for Wales ‘Remediation of Contaminated Land – National Assembly for Wales guidance to
enforcing authorities under Part IIA of the Environmental Protection Act 1990’, November 2001
28.
Statutory Instrument 1989 No. 1147 & 2000 No. 3184 ‘The Water Supply (Water Quality) Regulations, 1989 and
2000
29.
Statutory Instrument 1996 No. 3001 ‘The Surface Waters (Abstraction for Drinking Water) (Classification)
Regulations, 1996
30.
Statutory Instrument 1998 No. 2746 ‘The Groundwater Regulations, 1998
13