Agency researches risk to groundwater through water run-off from cemetaries

The siting of cemeteries, and their potential risk to groundwater, is a sensitive local planning issue that can cause a great deal of public concern. Whether this concern is warranted has been difficult to ascertain since the evidence that exists is somewhat patchy. In order to guide Environment Agency (EA) and local authority planning officers when considering applications to extend or build new human or animal burial grounds, the Agency commissioned consultant WRc to study the available evidence and report on appropriate measures to safeguard against pollution from cemeteries.

The reassuring conclusion of WRc’s report Pollution Potential Of Cemeteries, Draft Guidance (Environment Agency R & D Technical Report P223), which is based on verifiable technical information and risk assessment techniques, is that UK cemeteries present no significant pollution threat, although local factors, such as climate and geology, can increase the potential risk.

Using data from around the world, the WRc desk study demonstrates that the potential contaminants from cemeteries and burial grounds are those typically associated with anaerobic digestion, including: dissolved organic carbon; ammonia; chlorides; sulphates; and the alkali earth metals, such as sodium. Embalming chemicals appear to pose little threat. The use of arsenic was banned in the UK in 1951, and formalin, which is currently the chemical of choice, although detectable close to recent burials in wet conditions, breaks down quickly in the ground.

To calculate the potential risk to groundwater WRc considered three model burial grounds:

  • a large municipal cemetery, receiving several hundred burials per year
  • a small cemetery or country churchyard taking 10 or less burials per year; and
  • a green burial ground, handling 30 burials per year. (Green burial involves no embalming).
  • Local conditions

    The data shows that a warm, damp climate, shallow water table, and cramped burial conditions combine to present the greatest potential threat. This is borne out by the experience of countries where such conditions prevail, such as in parts of South America.

    No significant risk was found from bacteria and pathogens – largely because such organisms generally die with, or soon after, the host body, well before they would have a chance of leaching into groundwater. However, there is data from Australia, which shows one non-pathogenic strain of pseudomonas having a tendency to be found in the proximity of larger cemeteries; slightly elevated levels of ammonia and chlorides were also indicated by the Australian data.

    To safeguard against water pollution the report recommends that, where large cemetery sites are proposed, a formal risk assessment should be conducted taking account of the underlying geological and hydrogeological conditions and the proximity of water supply sources. This is not necessary for small sites, unless they are very close to a borehole or spring. There is little recorded experience or data on green burial grounds, which are currently rare in the UK. When more is known on the possible risks from this type of burial, it may be possible to make clear recommendations.

    The WRc study confirmed how little up to date information is available on the possible pollution threat from all types of burial ground, and highlighted the need for further research to provide definitive guidance on their siting. The Geological Survey is currently preparing a research programme to provide new field evidence.

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