Portable X-Ray Fluorescence (pXRF) Analysis of Heavy Metal Contamination in Graveyards with Contrasting Soil Types

Abstract

Human remains have been interred in burial grounds since historic times. Although the re-use of graveyards differs from one country, region or time-period to another, over time graveyard soil may become contaminated or enriched with heavy metal elements. This paper aims to present heavy metal element soil analysis from two UK church graveyard study sites with contrasting necrosols, but similar burial densities and known burial ages dating back to the 16th Century and some possibly older than 1,000 years. Portable X-Ray Fluorescence (pXRF) element analyses were undertaken, both in-situ on surface locations and laboratory-based on surface and near-surface soil pellets. Results show elevated levels of Pb, Mn, Cr, Cu, Zn and Ca in both necrosols when compared to background values. Element concentration anomalies remained consistently higher than background samples down to 2 m bgl, where sampled, but reduced away from church buildings which may reflect burial densities. Element concentration anomalies were higher in the clay-rich necrosol than in sandy necrosol. Field-based rapid measurements gave similar relative concentration values to laboratory-based soil pellet measurements, although laboratory-based analyses were more precise. Study results implications suggest that long-used necrosols are likely to be more contaminated with heavy-metal elements than similar soil outside graveyards with implications for burial grounds management, adjacent populations and where burial grounds have been deconsecrated and turned to residential dwellings.