Geochemistry of Bulgarian soils in villages affected and not affected by Balkan endemic nephropathy: a pilot study

Balkan endemic nephropathy (BEN) is a chronic tubulointerstitial disease whose mosaic-like distribution throughout the Balkans has not changed significantly since its initial description. In this study, we explored the hypothesis that the occurrence of BEN is linked with the environmental geochemistry of villages. Soil samples were collected from BEN and non-BEN villages in the Vratza region of Bulgaria. Samples were digested in nitric acid and analyzed for 22 elements by hexapole, inductively coupled plasma, and mass spectrometry. Selected results are that: 1) absolute concentrations from both types of villages were not enriched above "background" concentrations; and 2) copper, molybdenum, lead, and cadmium concentrations were higher in BEN than in non-BEN soils, while selenium concentrations were lower. Although geochemical differences between BEN and non-BEN villages were found, not all differences were statistically significant, in part due to a limited number of samples.