Memorandum by the Environment Agency (CEM
56)
GROUNDWATER POLLUTION POTENTIAL OF CEMETERIES
BACKGROUND
The Agency welcomes the Select Committee's inquiry
into cemeteries.
The Agency recognises that new cemetery developments
or extensions to existing cemeteries can be emotive subjects with
local residents. Of particular concern is the impact such developments
may have on the environment. However, these worries are often
disproportionate to the real environmental risks. Though less
emotive, pet cemeteries raise similar issues.
Under current legislation, the Local Planning
Authority is the principal body controlling new cemetery developments
under the Town and Country Planning Act 1990 and the Planning
and Compensation Act, 1991. The Agency is a statutory consultee
within the planning process for applications for new and extended
cemetery developments. Planning consent is not required for the
burial of individuals on their own land.
REVIEW OF
POLLUTION POTENTIAL
In order to provide guidance on the risks to
groundwater from the burial of humans or animal carcasses, the
Environment Agency commissioned a study of the pollution potential
of cemeteries. This study concluded that UK cemeteries generally
present no significant pollution threat, although local factors,
such as geology, can increase the potential risk. Potential chemical
contaminants that will be present include:
dissolved organic carbon;
alkali earth metals such as sodium.
The use of arsenic as an embalming agent was
banned in 1951. Current embalming chemicals appear to pose little
threat. Formaldehyde, the chemical commonly used, degrades rapidly
in the subsurface under typical environmental conditions. The
potential for migration away from the site is therefore minimal.
There is also a potential risk from microbiological
contaminants including viruses, bacteria and pathogens. The potential
for contamination by these agents is determined by their ability
to survive in the subsurface, the size of the pores or fissures
through which they may migrate and the depth of the water table.
Shallow groundwater protected by only a thin unsaturated zone
and composed of coarse grained or fissured materials is potentially
vulnerable to contamination. In contrast, groundwater in finer-grained
non-fissured material with a deep water table is better protected.
In principle, because of their smaller size, viruses should be
more easily transmitted through to the water table than the larger
bacteria and protozoa.
Sites with the greatest potential risk are large
sites, with more than 200 burials per year, that are located in
freely draining soils with a shallow water table. The risks from
microbiological contaminants are believed to be minimal because
these organisms generally have short lifespans and/or are filtered
by soil or aquifer material. However, the presence of preferential
pathways, such as fissures, may increase the risks.
Where large cemetery sites are proposed, the
Agency believes that a formal risk assessment should be conducted
that takes into account the hydrogeological and geological conditions,
proximity of receptors, such as water supply boreholes and springs,
as well as other environmental factors. We do not believe this
action is necessary for smaller burial sites (10 or less burials
per year), including "green burials", unless there are
boreholes and springs close to the site. The minimum distance
to any borehole or spring should be 50 metres.
The issue of "green burials" is an
emerging one which has only been with us for a few years. Green
burials differ from normal burials as a result of differences
in the materials used for enclosing the body, commonly a cardboard
container or a shroud instead of a coffin, the absence of embalming
and the use of shallower burial depths, around 1.3 metres deep
compared with typical1y 1.8 metres for a normal burial. In principle,
the rate of decay from a green burial is relatively rapid due
to the readily degradeable nature of the materials used.
SITE-SPECIFIC
STUDIES
There are few specific UK studies on the impact
of cemeteries on groundwater quality. The Agency therefore, in
collaboration with the British Geological Survey, has been investigating
groundwater quality at two cemeteries; an old cemetery and an
active site.
The old cemetery was used between 1813 and 1875
and is believed to have contained in excess of 1,100 bodies. The
study has concluded that it does not present a source of contamination.
Preliminary results from the operating cemetery,
which has been operational for 25 years, show evidence of bacterial
contaminants in groundwater derived from corpses. Some of the
boreholes outside the perimeter of the burial site showed evidence
of contamination suggesting migration of contaminants in the groundwater.
No viruses were detected. The measured concentrations were low
indicating that the loading to the groundwater is relatively small
or that degradation or attenuation is occurring. The results indicate
that the potential risks to groundwater in general are minimal.
LEGAL POWERS
TO PREVENT
WATER POLLUTION
A permit is not required for human cemeteries
under water pollution or waste management legislation. However,
if a cemetery were to cause pollution of groundwater, or other
controlled waters, it is possible that action could be undertaken
under the Groundwater Regulations 1998 or the Anti-pollution Works
Notices Regulations 1999. The Agency would, however, only use
these powers as a last resort where the pollution was significant
and where other measures had failed.
GROUNDWATER PROTECTION
PRACTICE
The Agency's Policy and Practice for the Protection
of Groundwater and supporting tools such as the Groundwater Vulnerability
and Source Protection Zone maps can form the basis of an initial
risk screening exercise. These are a starting point for a risk
assessment and can identify areas where groundwater is inherently
more sensitive to pollution from surface activities and where
major potable abstractions may be at risk from such activities.
The Agency would be opposed to large graveyards and animal burial
sites within Zone 1 Groundwater Source Protection Zones. Guidance
on animal burial sites is given in the MAFF Code of Good Agricultural
Practice.
The above points have not yet been incorporated
into the Agency's policy. The Agency's groundwater protection
policy and guidelines are currently under review and we are considering
the incorporation of the following guidance in the revision of
the policy document:
no burials within Zone 1 Groundwater
Source Protection Zones around a spring, well and borehole;
a minimum distance of 250 metres
from graves to wells, boreholes or springs used for water supply;
a minimum distance of 30 metres from
graves to other springs or watercourses;
a minimum distance of 10 metres from
graves to field drains;
no burial into standing water and
the base of the grave should be above the local water table.
Adoption of these practices should avoid the
need for site-specific assessments for the lower risk proposals
(low burial rates and low groundwater vulnerability). Site-specific
risk assessments are needed for higher burial rates and in areas
where groundwater is inherently more vulnerable, in addition to
the good practice measures noted above.
December 2000
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