Towards a multi-faceted Vadose Zone Assessment Protocol : cemetery guidelines and application to a burial site located near a seasonal wetland (Pretoria, South Africa)

Abstract

Cemeteries are generally considered low-risk landfills and are, therefore, not adequately governed in terms of minimum requirements for engineering geological and hydrogeological investigations. With the decay of human bodies, bulk of the contaminant load typically is present within one year of burial and decreases over time. Further controls include adsorption of pathogens and particulates to soil in the vadose zone and eventual breakdown in changing aerobic and anaerobic subsurface environments. A case study is presented where a cemetery has been active for decades and contains in excess of 18 000 human bodies. With recent expansion, water seepage was identified into newly excavated burial pits and all further development has ceased. Trial pitting and detailed soil profile descriptions are used to infer hydrological interaction at the site and to address possible contamination pathways. Future work is recommended with respect to water quality, although valuable insight is provided to the consequences of improper ground investigation prior to development. Final comments are made regarding provisional guidelines in the forms of a Cost-Effort-Risk Screen and a multi-faceted Vadose Zone Assessment Protocol.