Graduated index of self-cleaning degree of cemetery soils: development methodology and practical application

Introduction. The existing system of sanitary and epidemiological control does not fully reflect the specifics of cemetery pollution and does not allow an objective assessing the degree of completion of the processes of mineralization of cadaveric material, which creates legal uncertainty when deciding on reburial.

The aim of the study is to develop and validate a graded indicator of the degree of self-purification (DSP) of cemetery soils for an integral assessment of their condition.

Materials and methods. The study was based on five hundred forty soil samples collected from 12 cemeteries in 5 regions of the Russian Federation with graves of varying ages (from 1 year to 50 years). Chemical (ptomains, NH₄/NO₃ ratio), microbiological (sanitary indicator microorganisms index, pathogenic enterobacteria, eggs of geohelminths), physical and chemical (redox potential, activity of proteolytic enzymes) and biotest (phyto-toxicity, acute toxicity for daphnia) indicators were determined. The work used standard methods of statistical data analysis.

Results. To develop an integral indicator, indicators of the soil condition of necrosems were analyzed, each of which was assigned a weighting factor in the range of 10–15%. Individual 4-point scales were developed for each of them, on the basis of which a formula for calculating the self-purification index (PSA) was derived. This allowed identifying four successive stages of self–purification: fresh contamination (PSC 1.0–1.9), active decomposition (2.0–2.6), completion of mineralization (2.7–3.3) and conditionally clean soil (3.4–4.0). When checking the relationship of the PSS with the prescription of burial, a high correlation was obtained (r = 0.82; p < 0,001). The sensitivity of the method was 94%, the specificity was 91%. Based on these data, a practical algorithm for applying the indicator in the framework of sanitary and epidemiological surveillance is proposed.

Limitations.The work studies not all types of soils and only traditional ground burials.

Conclusion. The developed indicator allows an objective assessing the mineralization stage, forecasting the trend in self-purification processes, and making informed decisions about the possibility of repeated burial.

Compliance with ethical standards. The study does not require submission of a biomedical ethics committee report or other documents.

Contribution:
Ushakova O.V. – research concept and design, data collection and processing, text writing, and editing;
Rakhmanin Yu.A. – research concept and editing;
Evseeva I.S. – research concept and design, data collection and processing, and editing.
All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version

Conflict of interest. The authors declare no conflict of interest.

Funding. The study had no sponsorship.

Received: April 24, 2026 / Accepted: June 18, 2026 / Published: July 31, 2026

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