formation known as the ex-alluvial cone of the Danube of the Sarmatia Sea. Based on the chrome in the waterof this geological structure, a direct relationship between the content in heavy metals (especially Cr) of thewater used in the current supply of some families is hypothesized to explain the prevalence of BEN. A databasecontaining the nephropathy cases registered from 1958 until present per localities was created and cases weremapped. By questionnaires and interviews with the affected persons, the water sources used for a long periodof time (over 10 years) were localised. Water samples were gathered from 15 localities where people have beenaffected by BEN and who are presently on dialysis. Two probes were sampled from each water source (the firstafter a long rainy period and the second after a long dry period) and the concentration of heavy metalsanalysed. In three localities, more detailed studies were done focusing on the people affected by BEN againstthe potable water sources used over 30 years. The analysis of water samples supports the hypothesis that heavymetals with a higher concentration than the accepted limit (in 41 of 42 sampling points, Cr values exceeded themaximum permissible concentration) have an important role in the appearance and development of BEN. Theindepth study of three localities and the water sources used for long periods of time also supported thehypothesis.The results obtained support the idea of reconsidering the causes which contribute to BEN’sappearance and development. The overlapping of localities of sick and deceased people with the extension ofthe ex- alluvial cone of the Danube of the Sarmatia Sea cannot be considered coincidental.