SUMMARY GUIDANCE ON
CONTAINMENT OF LEAD MATERIAL
Version 1.1 - January 2014
CONTAINMENT OF LEAD MATERIAL
This guidance addresses the appropriate use and the key design elements of onsite
engineered containment systems, where this is an option for lead-bearing material
collected during the process of remediating lead contaminated sites.
KEY POINTS
a. Many lead remediation projects have faced serious challenges in achieving an acceptable long
term solution for disposal of contaminated material which cannot be recycled. Agreement on
the final disposal solution is often the most long drawn out aspect of the process.
b. For material which cannot be reprocessed, reused or managed adequately in-situ, secure
containment is normally the preferred option. Containment involves engineered structures
which isolate the waste securely and reduce risk to an acceptable level over the long term.
Containment may be in an purpose built facility or may involve transport to an existing
engineered landfill or hazardous waste facility, if feasible.
c. The primary objective of containment is to prevent direct contact with or distribution across the
environment of the lead material. Protection of ground water is a key priority.
d. The waste material is broadly homogeneous because lead is the main contaminant and this
allows the material to be managed in a “mono-landfill” designed specifically for this waste or in
a similar “mono-cell” within a larger landfill. Regulations in the USA and the UK, among other
countries, allow for and even encourage this approach.
e. A key issue is the selection of the site for the containment, with the most important aspects
usually being local acceptance and protection of groundwater. On-site containment should
always be considered and has an inherent attraction by linking the containment to the local
problem.
f.
A plausible long-term use for land where lead waste is buried under a secure cap is playing
fields or similar public open space. This is consistent with the increasing use of closed
municipal landfills for such purposes. In some cases, sites may be developed for commercial or
industrial uses, such as parking areas.
g. There are a number of key practical design details that should be taken into account. This
Guidance sets out some of these but does not address them in detail: qualified technical advice
should be sought.
h. The level of effort and cost put into the remediation project should be proportional to the overall
objectives of the remediation and to the levels of risk reduction to be achieved by carrying it
out. Determination of remediation clean-up targets and selection of options must be carried out
by experienced and competent personnel, in consultation with the local community and the
appropriate regulatory authorities.
GAHP Guidance Notes provide information on international good practices and regulations in remediation.
They are prepared to assist GAHP members in dealing with practical problems of remediation of polluted sites
and are intended to assist readers to identify key points that should be taken into account in reviewing or
approving any proposal. Guidance notes reflect the views of individual GAHP specialists and of invited outside
experts and do not necessarily represent the views of any specific government or agency. Additional
background and material may be found on the GAPH website.
CONTAINMENT OF LEAD MATERIAL
Version 1.1 - January 2014
REMEDIATION OF CONTAMINATED SITES
1. The Global Alliance on Health and Pollution (GAHP) is a collaborative body which coordinates resources
and activities on chemicals, wastes and toxic pollution in low- and middle-income countries. A key
component of GAHP’s programme is support for the implementation of remediation projects in locations
where there is high risk and urgency.
2. The science and technology for successful remediation are well known in industrialised countries, after
many decades of learning to deal with problems through trial and testing, which has required the expenditure
of hundreds of millions of dollars, euros and other currencies. In other countries, the essential technical
expertise may exist but experience in practical implementation is limited; relevant resources are very scarce;
and there are many competing priorities. These Guidance Notes summarise some of the key lessons of
experience, in order to support effective remediation projects in those other countries.
3. The success of a remediation project depends heavily on commitment and support from those affected.
The local community and local officials must be actively involved in order to move forward in dealing with a
contaminated site. Early attention and effort must be applied to the institutional and social aspects of a
potential project and to putting in place structures for management, quality, and long term monitoring and
maintenance of the project.
4. Projects often require a balance to be found between urgent action to deal with immediate risks and the
need for a full process and achieving complete remediation. A priority project which reduces the immediate
risk from the site without achieving full remediation should include a clear statement of what risk reduction is
planned and should set out what further actions would be required to bring risks fully down to acceptable
levels.
CONTEXT AND SCOPE OF THIS GUIDANCE
5. Remediation projects which deal with sites containing lead waste or lead-contaminated material face
challenges in recycling or disposing of the material collected during the project. Lead, being an element,
cannot be chemical broken down into harmless compounds, as is possible with some chemical pollutants.
After recycling as much of the material as feasible, there often remains a quantity of lead-contaminated
material which must be secured safely for the long term. Secure disposal of lead materials requires physical
containment, usually by burial.
6. Many lead remediation projects have faced serious challenges in achieving an acceptable long term
solution to the challenge of disposal of the material collected.
Lead projects require educating local
communities and officials about the risks of lead exposure. Unfortunately, this process can in some cases
“demonise” lead to the point where it is very difficult to obtain local acceptance and/or regulatory approval for
disposal options. Experience on recent remediation projects has demonstrated that agreement on the final
disposal solution is often the most controversial and long drawn out aspect of the process. A particular issue
is the applicability of generic “Hazardous Waste” approaches and requirements, particularly where the local
jurisdiction does not have relevant legislation or experience.
7. Containment of the lead-contaminated waste as close as possible to the source would reduce handling
and transportation risks and costs and so controlled burial at or close to the original site is an option that
should be always be considered, if space is available. In this context, containment refers to a facility
designed specifically for this waste. Disposal at an existing controlled landfill or hazardous waste facility is
another containment option which should be examined wherever feasible. This Guidance addresses the key
elements of an engineered containment or encapsulation for lead wastes, where this is one option
considered in the process of preparing a remediation project.
GAHP Guidance Notes provide information on international good practices and regulations in remediation. They are prepared to assist
GAHP members in dealing with practical problems of remediation of polluted sites and are intended to assist readers to identify key
points that should be taken into account in reviewing or approving any proposal. Guidance notes reflect the views of individual GAHP
specialists and of invited outside experts and do not necessarily represent the views of any specific government or agency. Additional
background and material may be found on the GAPH website.
2 CONTAINMENT OF LEAD MATERIAL
Version 1.1 - January 2014
9. Remediation projects should only be undertaken where the source of contamination has been eliminated
or controlled, so that re-contamination will not occur. This may require upgrading of processes and facilities,
relocation, or complete cessation of all the polluting activities. Action will be required by industry and by the
i
regulatory authorities but this not addressed here .
10. The level of effort and cost put into the remediation process and project, including the selection and
design of the disposal system, should be proportional to the overall objectives of the remediation and to the
levels of risk reduction to be achieved by carrying it out.
LEAD AND ITS IMPACTS
11. Lead is a metal which has many productive uses because of its resistance to corrosion and the ease
with which it can be shaped, moulded and alloyed with other materials. One of the largest and most
important uses is in lead-acid batteries for automotive, industrial and energy activities worldwide. However,
lead can have serious impacts on human health if ingested and absorbedii. The main target for lead toxicity
is the nervous system and children are particularly susceptible to harmful effects.
12. Recycling of lead is taking place at a growing rate, particularly in the case of Used Lead Acid Batteries
(ULAB), and this reduces the need for mining and processing of new lead sources. Unfortunately, in some
countries badly managed recycling can result in serious local pollution. This typically occurs where batteries
are broken by hand to recover the lead plates and where crude smelting is carried out to process the metal.
Such activities are often in the informal sector and may be located in residential areas where large number of
people are exposed to contamination, mainly through lead bearing dust which can become widely spread
outside the working area.
13. Other industrial processes and products can also generate lead pollution and therefore result in sites
which require remediation and which may raise similar issues to those of ULAB sites. Data collection and
research supported by GAHP indicates that hundreds of thousands of people are at risk worldwide from
polluted sites which release leadiii.
14. Remediation of closed or abandoned lead contaminated sites results in the identification and collection
of materials containing different levels and types of lead, including some where lead levels are high enough
to be considered hazardous. Lead, because it is an elemental metal, cannot be destroyed or converted to a
non-toxic form, although it may be possible to convert some wastes to more stable and less accessible
forms. All wastes from lead remediation projects require careful handling and appropriate reprocessing or
disposal.
CHARACTERISING THE MATERIALS INVOLVED
15. Lead in these contaminated sites will vary in concentration across the site and can be present in a
number of different chemical and physical forms.
Understanding this variability is central to selecting
options for dealing with the wastes. Sampling and mapping of concentrations across a site is critical for
understanding the scale of the problem and the potential costs but the extent of the sampling needs to be
consistent with the scale of the problem and the resources availableiv. Use of a portable XRF analyserv can
be a simple and effective way to map contaminant contours but results need to be checked and confirmed by
laboratory analysis.
16. On seriously contaminated sites, lead can be found in concentrations ranging from perhaps 300,000ppm
(about 30% pure metal) at the core, down to levels in the thousands of ppm in areas where soil or other
surfaces have been contaminated by the transport of waste material, as dust or in other forms. As the basis
for a remediation plan, the site needs to be divided in terms of different materials and concentrations which
may require different remedial actionsvi. For lead, this would probably cover three main types: smelting
GAHP Guidance Notes provide information on international good practices and regulations in remediation. They are prepared to assist
GAHP members in dealing with practical problems of remediation of polluted sites and are intended to assist readers to identify key
points that should be taken into account in reviewing or approving any proposal. Guidance notes reflect the views of individual GAHP
specialists and of invited outside experts and do not necessarily represent the views of any specific government or agency. Additional
background and material may be found on the GAPH website.
3 CONTAINMENT OF LEAD MATERIAL
Version 1.1 - January 2014
wastes and slags (which can have the very high concentrations); battery breaking debris; and soil
contaminated with lead dust. The delineation of different areas for remediation action will depend on the
characteristics of the specific site and materials.
17. Determination of remediation clean-up options for each area will depend on the material, the risks
presented by that particular area, the costs associated with the different options available and the anticipated
use after clean-up of the property and any adjacent groundwater. This process must be carried out by
experienced and competent personnel, in consultation with the local community and the appropriate
regulatory authorities.
RANGE OF OPTIONS
18. The practical options which should be considered for dealing with material from a lead contaminated site
are the following.
Reprocessing
19. The preferred approach, where technically and financially feasible, is to transport the materials to a
licensed smelter for reprocessing. The major factors controlling this option are concentration, the quality and
form of the lead-bearing material and the distance/cost to the nearest suitability facility. In general, lead with
concentration over 20% in the waste or soil is a good candidate for reprocessing if suitable smelters are
available and the logistics are not cost-prohibitive. However, reprocessing of concentrations down to as low
as 5%, may be worth investigating, even though this may not viable on a purely commercial basis, because
the net cost may still be lower than that for other options for this material.
Reuse
20. Some lead material, particularly lead blast furnace slag, may be suitable for reuse in contained uses in
transportation or industrial settings but in practice, such reuse is realistically viable only for limited quantities
of lead waste or contaminated material with the requisite characteristics, because it requires that proper
testing and control be maintained in the construction or manufacturing processes. At the same time, small
quantities are often not of interest to the potential user, reducing the practical options.
Treatment
21. Lead, as an element, cannot be destroyed but treatment may reduce the toxicity, solubility or
bioavailability of the lead wastes. Pre-treatment to reduce solubility may be appropriate in the context of
containment, if the wastes contain soluble forms of lead. In-situ treatment may help to reduce the bioavailability of lead in soils that are not highly contaminated but site specific analysis is required of
effectiveness and long-term stability of this approach. Institutional controls on future use of land may be
required with in-situ management approaches.
Containment
22. For material which cannot be reprocessed, reused or managed adequately in-situ, secure containment is
normally the preferred option. This is designed to eliminate direct contact with lead contaminated material
on site and to prevent it spreading to neighbouring areas. Containment involves engineered structures
which isolate the waste securely in such a way as to reduce risk to an acceptable level over the long term.
Covering of contaminated soil with a layer of clean material can be considered as a type of in-situ
containment but should be used only after careful consideration and discussion of land use and institutional
controls.
LEAD CONTAINMENT SYSTEMS
23. The primary objective of containment is to prevent the waste being distributed across the environment,
either as air-borne dust or suspended in stormwater runoff or drainage. Direct contact with the lead material
must be prevented and long term risks minimised. Although the most common lead compounds are not
GAHP Guidance Notes provide information on international good practices and regulations in remediation. They are prepared to assist
GAHP members in dealing with practical problems of remediation of polluted sites and are intended to assist readers to identify key
points that should be taken into account in reviewing or approving any proposal. Guidance notes reflect the views of individual GAHP
specialists and of invited outside experts and do not necessarily represent the views of any specific government or agency. Additional
background and material may be found on the GAPH website.
4 CONTAINMENT OF LEAD MATERIAL
Version 1.1 - January 2014
highly soluble in water at normal acidity, protection of ground water is a concern because of the impacts and
costs if a productive aquifer is contaminated.
24. The waste material from lead site remediation is broadly homogeneous because lead is the main
contaminant of concern, although there may be small quantities of other metals and chemicals. This allows
the material to be managed in a “mono-landfill” designed specifically for this waste or in a similar “mono-cell”
within a larger landfill. Regulations in the USA and the UK, among other countries, allow for and even
encourage this approach because it is usually simpler and cheaper than using capacity in costly general
hazardous waste landfills.
25. The basic requirements are to contain the waste so that contact is prevented and to ensure that it is not
dispersed by wind or surface water. This can be achieved with well established and generally
straightforward engineering approaches. Key elements are a base layer which has low water permeability
and a cover layer which prevents interference or physical disturbance and resists entry of water.
26. A key issue is the selection of the site for the containment, with the most important aspects usually being
local acceptance and protection of groundwater. Local acceptance depends on many factors, especially the
current and future use of the site. Long term monitoring and management must be addressed in this
context.
27. If there is physical room on the site being remediated, then on-site containment should be considered.
This may have advantages in terms of land access and ownership and of elimination of difficulties and costs
associated with transportation. If the site is already designated for industrial uses, an on-site facility may be
more acceptable to local communities and regulators than would be a new site. On-site containment, where
technically feasible, has an inherent attraction by linking the containment to the local problem.
28. A plausible long-term use for land where lead is buried is for playing fields, parking areas or similar
public open space, provided that appropriate cover has been provided and that relevant institutional controls
are in place. This is consistent with the increasing use of closed municipal landfills for such purposes and
allowed under guidance from USEPAvii and other agencies. With careful controls and appropriate planning,
sites may be developed for commercial or industrial purposesviii.
TECHNICAL ASPECTS
29. Where development of a project specific lead containment system is required, the following practical
aspects should be addressed. There are numerous interconnections between these aspects and an iterative
approach must be adopted to locating, design and implementing the containment structure. This Guidance
does not address any of these aspects in detail: qualified technical advice should be sought locally.
Suitability of sites
30. The most critical and time-consuming issue for a lead containment system is the selection and
acceptance of an appropriate site. As with any remediation measure, the current and planned uses of any
site considered are key issues. The technical challenges are relatively straightforward although cost will
always be a concern and cost-effectiveness must underlie the chosen option. Protection of groundwater can
be best assured by selection of an appropriate location and careful detailing of the design.
31. Selection of a sites should address the following.
Land use
o
Identify industrial or mining areas where containment would be consistent with current or probable
future use. Avoid land in residential use or with particular ecological value.
o
Prioritise land in possession or under control of local or national government agencies, or owned by the
company responsible for the contaminated site.
o
Seek sites with good accessibility and minimise distance, in terms of transportation.
o
Understand local priorities and preferences.
GAHP Guidance Notes provide information on international good practices and regulations in remediation. They are prepared to assist
GAHP members in dealing with practical problems of remediation of polluted sites and are intended to assist readers to identify key
points that should be taken into account in reviewing or approving any proposal. Guidance notes reflect the views of individual GAHP
specialists and of invited outside experts and do not necessarily represent the views of any specific government or agency. Additional
background and material may be found on the GAPH website.
5 CONTAINMENT OF LEAD MATERIAL
Version 1.1 - January 2014
Hydrology and geology
o
Understand local and regional groundwater patterns and uses, and avoid sites where a significant
groundwater resource may be affected.
o
If possible, avoid areas with particularly heavy rainfall (microclimates) or pronounced drainage
o
Seek areas that are not up-gradient of wells used for drinking water supply, or at least where such
wells are an adequate distance away (site specific assessment may be required to determine if wells
might be affected).
Physical conditions
o
Avoid wet, water-logged or flood-prone areas and sites on rock.
o
Select land with gentle slopes and no strong drainage features and where excavation can be done
relatively easily by conventional construction equipment.
o
Seek sites which have many metres of clay or clay-mix soils.
Design elements
32. In preparing a specific design for a containment, the key elements to be addressed include the following.
Details of typical engineering and construction methods are not addressed here.
o
o
o
o
o
o
Identification and segregation on site of the material to be enclosed
Physical or chemical treatment required – if any
Size and shape of containment
Capping and soil cover
Liner system (and associated leachate collection)
Institutional controls
33. Where there is concern about the potential for impact on groundwater, testing for solubility can be done,
to inform choices. Solubility testing should be carefully matched to the circumstances. The most widely
known test is the TCLPix developed by the USEPA but this is not directly applicable to mono-disposal of lead
wastex. Alternatives could be a neutral pH version of TCLP or a more focused analytical approach such as
LEAFxi.
34. If the lead waste contains highly soluble forms then stabilization or solidification approaches may be
considered for that part of the waste, recognising that these add significant complication and cost. These
approaches use chemical or physical processes to reduce the hazard of wastes by changing the solubility or
mobilityxii. Stabilisation normally involves chemical treatment which changes the characteristics of the waste.
Solidification techniques contain the waste material in a solid matrix. Cements or similar materials are often
used. The possible use of these approaches should be justified by testing and trials.
35. A common point at issue in design is the value of an engineered low-permeability bottom liner required
in order to provide acceptable protection of groundwater. The key factors are to avoid the generation of
leachate by minimising water entry into the containment and ensuring low leachability of lead from the waste.
Entry of water is controlled by good design of the cover and the surface drainage. If testing shows that some
components of the waste have high leachability then treatment of this component should be considered. A
well constructed mono landfill for lead waste would not be expected to generate leachate, provided that the
quantities of organic material such as vegetation included with the waste are controlled to low levels to avoid
possible impacts on leachate generation.
36. The purpose of a liner is to reduce to a minimum the rate of any seepage of leachate into the ground.
The choice between natural materials and a synthetic liner for the mono landfill is a design decision which
depends on a number of factors, including the characteristics of the local materials (clay is the preferred
natural liner material), the availability and cost of synthetic liners, the rainfall and groundwater
characteristics, and the type and quantity of the waste.
37. In the best circumstances, where suitable clay material is available locally and there is a sufficient
separation from any groundwater of potential value, a liner layer of compacted clay may be adequate. In
other cases, a single synthetic liner may be required. A dedicated mono-containment for lead does not
GAHP Guidance Notes provide information on international good practices and regulations in remediation. They are prepared to assist
GAHP members in dealing with practical problems of remediation of polluted sites and are intended to assist readers to identify key
points that should be taken into account in reviewing or approving any proposal. Guidance notes reflect the views of individual GAHP
specialists and of invited outside experts and do not necessarily represent the views of any specific government or agency. Additional
background and material may be found on the GAPH website.
6 CONTAINMENT OF LEAD MATERIAL
Version 1.1 - January 2014
require the double artificial lining that would be provided in a hazardous waste facility accepting mixed
hazardous waste.
38. Municipal and hazardous waste facilities normally have leachate collection and treatment systems to
cope with the large volumes of leachate generated by their mixed wastes. By contrast, a mono-landfill for
lead and associated material is not expected to generate significant leachate and therefore a full leachate
collection and treatment system would not normally ne required. In order to monitor the performance of the
system, appropriate monitoring manholes and wells should be provided and a response plan should also be
prepared with concrete actions to be taken if the monitoring shows evidence of leachate accumulation in the
bottom of the containment.
Construction and maintenance
39. Care must be taken in preparation and implementation, in order to ensure that the objectives are
achieved without risk to workers and the community and within the time an budget agreed. A detailed
Project Implementation Plan should be prepared, in which the following aspects (at least) should be
addressed.
o
o
o
o
o
o
Contracting approach and process
Site management and quality assurance
Safety procedures and training
Community education and information
Transportation control (if required)
Closure, final approval and monitoring
Institutional Controls and community monitoring
40. Institutional controls are an important part of the long-term control of the site. Site selection and
approval are based on assumptions about long term uses and systems must be established to ensure that
these uses are maintained. The local community has a key role in monitoring both the performance of the
containment and any changes to land use. It is essential that institutional responsibilities and necessary
resources are clearly established. The project must address the following.
o
o
o
o
o
o
Specific responsibilities and resources
Planning procedures and controls
Monitoring and maintenance of records
Community roles
Contingency plans
Response procedures.
EXAMPLES OF PRACTICAL CASES OF REMEDIATION
A number of recent remediation projects carried out by GAHP partners had to address containment issues.
The approaches adopted can be summarised:
TSM, Dakar, Senegal
The contamination in this area of Dakar city came initially from battery breaking and then from subsequent
re-processing of waste. The collected material included waste, contaminated soil from the processing areas
and the waste from house cleaning.
The climate is tropical so rainfall and flooding were issues. The
wastes were excavated from the contaminated areas and homes and moved to a temporary location, well
removed from the surrounding communities, and stored under a cover until permanent disposal could be
arranged. Various disposal options were considered including solidification and disposal to an abandoned
mine. The solution eventually adopted was to construct a dedicated secure cell at a local municipal waste
site (not itself an engineered landfill). This is an example of a mono-cell system
Haina, Dominican Republic
GAHP Guidance Notes provide information on international good practices and regulations in remediation. They are prepared to assist
GAHP members in dealing with practical problems of remediation of polluted sites and are intended to assist readers to identify key
points that should be taken into account in reviewing or approving any proposal. Guidance notes reflect the views of individual GAHP
specialists and of invited outside experts and do not necessarily represent the views of any specific government or agency. Additional
background and material may be found on the GAPH website.
7 CONTAINMENT OF LEAD MATERIAL
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An abandoned smelter site had resulted in a wide range of lead wastes, both at the site itself and in nearby
areas. Several waste dumps were identified and excavated. The high level lead material was taken and
reprocessed at another (approved) smelter by the original operator. The low level waste was buried in
engineered containments on-site. The whole site was then covered with clean material and converted into a
park and baseball field.
Zamfara, Nigeria
In this remote area of the country, the contaminated material came from extracting gold from what was, in
essence, low grade lead ore. Processing of the ore included breaking, grinding and extraction of gold using
mercury, all of which was done in or adjacent to family compounds. Consequently, the lead
contaminated materials were spread throughout the compounds and the villages. These contaminated
materials were excavated from the compounds and public areas and bagged for transport to the disposal
sites. Possible locations for mono-landfills for disposal of the material were identified following advice from
local community leaders and with approval from the Zamfara Ministry of Environment. These sites were in
low-use community land with competent clay soils and deep groundwater, located well away from the
villages and any active water sources. A landfill was constructed using an excavator, filled with bagged
waste from the clean-up, compacted, covered with clean soil, then closed and marked. There was
subsequently a debate with auditors from the funders about lining systems in the landfills before it was
accepted that liners were unnecessary due to the good clay soils and insolubility of the lead, as well as being
impractical at these remote village locations.
GAHP Guidance Notes provide information on international good practices and regulations in remediation. They are prepared to assist
GAHP members in dealing with practical problems of remediation of polluted sites and are intended to assist readers to identify key
points that should be taken into account in reviewing or approving any proposal. Guidance notes reflect the views of individual GAHP
specialists and of invited outside experts and do not necessarily represent the views of any specific government or agency. Additional
background and material may be found on the GAPH website.
8 CONTAINMENT OF LEAD MATERIAL
Version 1.1 - January 2014
ENDNOTES
i
Regulatory effort is required to identify and control the sources of lead contamination. The lead industry, through the
International Lead Association (ILA), has prepared and is promoting good practices in ULAB recycling and in smelting.
[Ref to come] GAHP will support both strengthening of government capacity to deal with the issues and upgrading of
industry practices, especially where the informal sector is involved.
ii
A brief summary of lead and its health impacts is given in US Agency for Toxic Substances and Disease Registry
(ATSDR) Fact Sheet on Lead at http://www.atsdr.cdc.gov/tfacts13.pdf
iii
Publication in the peer-reviewed public health literature has begun. See, for example, Chatham-Stephens et al in
Environmental Health and Pollution (http://dx.doi.org/10.1289/ehp.1206127). Other papers will be made available on the
GAHP website.
iv
Design of sampling programmes is beyond the scope of this guidance. A simple approach is provided in Blacksmith
guidance for site screening (see Blacksmith website). For residential sites, more detail is provided by USEPA in Chapter
4 of www.epa.gov/superfund/lead/products/handbook.pdf
v
X-ray fluorescence analyser. Field Portable XRF analysers (FP-XRF) are expensive but can often be hired for short
periods. For detail design of a remediation project, the accuracy of the FP-XRF results should be checked against the
results from an analytical laboratory (see www.epa.gov/superfund/lead/products/xrffaqs.pdf).
vi
This is similar to the USEPA approach of defining “Principal Threat” and “Low Level Threat” materials. See
http://www.epa.gov/superfund/health/conmedia/gwdocs/pdfs/threat.pdf.
vii
“Reusing Superfund Sites: Recreational use of land above hazardous waste containment areas”. US EPA Report
540-K-01-002. March 2001. http://www.epa.gov/superfund/programs/recycle/pdf/recreuse.pdf
viii
ix
For potential commercial use of Superfund sites: http://www.epa.gov/superfund/programs/recycle/pdf/c_reuse.pdf
The Toxicity Characteristic Leaching Procedure.
x
The TCLP test is based on the assumption of uncontrolled mixing of potentially hazardous waste with municipal waste
and is not directly applicable to mono-disposal. The standard TCLP test uses a sample of the waste and an acid
leaching solution. After mixing, the solution is tested for hazardous constituent concentration.
xi
The Leaching Environmental Assessment Framework (LEAF) allows the testing to be matched to the circumstances
and has recently been accepted by the USEPA (see http://www.vanderbilt.edu/leaching/leaf/).
From the mining sector, approaches include the Synthetic Precipitation Leaching Procedure (SPLP) and the related Field
Leach Test (FLT). Technical advice should be taken in selecting the relevant and appropriate approach.
xii
For an overview: http://clu-in.org/techfocus/default.focus/sec/Solidification/cat/Overview/
GAHP Guidance Notes provide information on international good practices and regulations in remediation. They are prepared to assist
GAHP members in dealing with practical problems of remediation of polluted sites and are intended to assist readers to identify key
points that should be taken into account in reviewing or approving any proposal. Guidance notes reflect the views of individual GAHP
specialists and of invited outside experts and do not necessarily represent the views of any specific government or agency. Additional
background and material may be found on the GAPH website.
9