Long, DT; Voice, TC; Niagolova, ND; Mcelmurry, SP; Petropoulos, EA; Ganev, VS; Havezov, I; Chou, K
The environmental hypothesis for the cause of Balkan
Endemic Nephropathy (BEN) suggests that the spatial distribution of BEN is related to the
biogeochemistry of the environment (e.g., soils, water and food). Little is known about the
hydrogeochemistry of groundwater from such regions. Therefore, samples of well, tap, and spring
waters were collected from BEN and non-BEN areas in the Vratza region of Bulgaria. In the field,
samples were 1) collected using clean techniques; 2) analyzed for alkalinity, pH, temperature,
conductivity, redox, and nitrogen species; and 3) split into subsamples, filtered and preserved
for further analyses. In the laboratory, major anions and nutrients were determined by ion
chromatography and major, minor, and trace elements determined by either atomic absorption or
HEX-ICP-MS. Graphical (e.g., x-y plots, Piper plots) and geochemical (thermodynamic models using
PHREEQC) and general statistical techniques (e.g. Student t) were used to study the data.
Selected results include: 1) the water for the region is a calcium-bicarbonate water, 2) most
chemicals in both types of locations were not above recommended drinking water standards; 3)
arsenic concentrations were typically higher in BEN samples than non-BEN samples; 4) uranium
concentrations were above WHO suggested limits in many well and spring water samples, whether
from a BEN or non-BEN village; 5) nitrate levels were very high in well water from both BEN and
non-Ben villages, were higher in springs from BEN villages than non-BEN villages, and may
indicate possible pathways for contaminants to enter the groundwater system; and 6) CI:Na ratios
along with NO3 levels indicate possible human influences on the water supply The results show
biogeochemical differences between BEN and non-BEN villages. However, these differences are not
fully understood and therefore cannot be related to the cause or distribution of BEN at this
time. This ambiguity is in part related to a lack of data on groundwater biogeochemistry and the
hydrogeology of the area. More work needs to be done on water quality in the Balkans to address
not only historical heath issues (e.g., BEN), but also new and immerging environmental and
environmental health issues.