A study of iodine concentration in drinking waters of Bryansk and Oryol regions

The aim of the research was to study iodine in natural waters of different age aquifers in the Bryansk and Oryol regions (Russia), primarily in the waters used by local residents of these regions for drinking purposes. The low iodine concentration in food and drinking water can lead to the development of thyroid gland pathologies, which is typical for the non-Chernozem zone of Russia, including the Bryansk and Oryol regions.

The analysis was based on the original data on the sample collected the field work in the Bryansk region (2007-2013) and in the Oryol region (2016-2017). In addition to iodine concentration, the main geochemical parameters (pH, Eh, salinity) were determined in the selected waters.

The results confirmed the previously established significant variation of iodine concentration, both in the Bryansk region (0.7 - 41.19 mcg/l, n=267) and in the Oryol region (1.12 - 36.8 mcg/l, n=23). The most contrasting values of iodine are found for groundwater’s originating from upper Devonian and Cretaceous aquifers. The dependence of iodine concentration in the waters of the Bryansk region on salinity (r=0.39, n=267), as well as on the content of Ca (r=0.38, n=119, wells) and Mg (r=0.33, n=110, water supply), was shown earlier [1]. The relationship of the iodine concentration in waters of the Oryol region to their salinity appeared to be also significant (r=0.32, n=23).

Surface waters of the Oryol region were characterized by low iodine concentration (median-7.40 mcg/l, n=8). Even the maximum value (9.32 mcg/l) does not exceed the lower limit of the hygienic standard, equal to 10 mcg/l. The obtained value is rather close to median one found for the Bryansk region (6.76 mcg/l, n=110). The lowest median iodine concentration in the Oryol region was registered in borehole waters (2.96 mcg/l, n=9), which is likely to be due to their aquifer features. In the Bryansk region, iodine concentration in borehole waters is lower than in surface and well waters (5.82 mcg/l, n=30). This seems to be due to the fact that the ground water of Quaternary alluvial and fluvioglacial deposits are used for decentralized water supply in both areas. High iodine level of the concentration Oryol region was observed in tap water (median-27.16 mcg/l, n=6). Similar values of iodine concentration were found in deep-lying groundwater in the North-Eastern area of the Bryansk region. The higher amount of iodine in the underground waters of deep-lying areas can be explained by their chemical composition high salinity this was proved the Bryansk region [1, etc.].

The study was carried out with partial financial support by RFBR grant No. 13-05-00823.

References

1. Kolmykova L. I., Korobova E. M., Korsakova N. V., Berezkin V. Yu., Danilova V. N., Khushvakhtova S. D., Sedykh E. M. Assessment of iodine and selenium content in drinking waters of the Bryansk region depending on water-bearing rocks and migration conditions. "Actual problems of ecology and nature management" Collection of scientific works. 2014. Pp. 140-144.