EXPLORING THE ELEMENTAL HYPOTHESIS FOR THE SPATIAL DISTRIBUTION OF BALKAN ENDEMIC NEPHROPATHY

Balkan Endemic Nephropathy (BEN) is a chronic tubulointerstitial nephritis whose mosaic like distribution throughout the Balkans has not changed significantly since its initial description in 1950. Hypotheses to explain the occurrences of BEN include, among others, genetic predisposition, calcium, magnesium, or selenium deficiency; and exposure to nitrate and selected metals. To test the hypothesis that the spatial distribution of BEN is related to the biogeochemistry (e.g., metals, nitrate) of the environment, soils (garden and “background”), water (tap, well, spring) and selected foods (potatoes, onions) were collected from BEN and non-BEN areas in the Vratza region of Northwestern Bulgaria. Field analyses included alkalinity, pH, temperature, and nitrogen species. Solid samples were digested in nitric acid. Water and leachates were analyzed for 28 elements by HEX-ICP-MS. Anions in water were analyzed by IC. Selected results include: 1) in general, concentrations of chemicals from both types of locations were not enriched above “background” concentrations; 2) arsenic concentrations were typically higher in BEN samples than non-BEN samples and selenium concentrations lower; 3) molybdenum and aluminum also showed patterns of higher concentration in BEN samples; 4) depending on the sample type other elemental differences were found between BEN and non-BEN locations; 4) nitrate- levels were higher in BEN than in non-Ben water samples for one sampling period; 5) chloride:sodium ratios indicate possible human influences on the water, and 6) there appears to be a casual relationship between the distribution of BEN and regional geology. Although geochemical differences between BEN and non-BEN areas were evident, not all differences were found to be statistically significant, perhaps due to small sample sizes. Results support our working hypothesis, but it should be noted that these differences can not necessarily be interpreted to be the cause of the geographic distribution of BEN. However, results do show the importance of geochemistry in helping to solve world environmental problems.