Burial practice and its effect on groundwater pollution in Maiduguri, Nigeria

Cemeteries in Nigeria have never been perceived as having a significant potential contamination to the environment and are often located within residential setups. This work presents a study of special interest, because up till now, there are no known publications in the north-eastern states of Nigeria that investigated the relationship between cemeteries and the natural environment. The objective was to investigate whether burial practices affect the groundwater within the vicinity of an active municipal cemetery in the Gwange area of the Maiduguri metropolis, Borno State, Nigeria. Groundwater quality measurement from boreholes located at varying radial distances from the cemetery was also conducted. The result was compared with that of WHO and showed evidence of attenuation with distance. The method of burial is a chemical-free method and dictated by local culture in the area. The site is underlain by a sedimentary rock of the Chad Formation and is characterized by coarse-grained soils of high permeability coefficient (1.04 × 10^-4-2.38 × 10^-4 cm/s). The soil sample was composed of 3.2 to 8.4% fines which fall beneath the standard of 30% that is considered adequate for natural attenuation of contaminants. The soils were poorly graded and exhibit non-plastic properties. The grave invert, being predominantly higher than 1 m, seems to have significantly influenced the low levels or the absence of contaminants especially cations in the groundwater sample. The high levels of pH (9.5), EC (1874 μs/cm), NO₃ (67.4 mg/l), NO₂ (0.92 mg/l), PO₄ (344.5 mg/l), and NH₄ (1.03 mg/l) in groundwater samples (especially the cemetery borehole) are an indication that higher interment density over time presents a significant threat to groundwater quality.