ELEVATED SELENIUM LEVELS IN VEGETABLES, FRUITS, AND WILD PLANTS AFF ECTED BY THE RAŠA COAL MINE WATER CHEMISTRY

Gordana Medunić,Marija Sedak,Željka Fiket,Vanja Geng,Andreja Prevendar Crnić,Nina Bilandžić

doi:10.17794/rgn.2021.1.1

Abstract

Selenium (Se), an essential trace element that is toxic when humans and animals are exposed to it in excess, is ubiquitous in coal. For centuries, superhigh-organic-sulfur (SHOS) Raša coal, enriched in S, Se, U, V, and Mo, was mined and processed across the Mediterranean Raša Bay area, located in the Istrian peninsula (in the northern Adriatic Sea, Croatia). There is concern that Raša coal mine water is contaminating local water, soil, and crops. The aim of this monitoring study was to determine the levels of Se and selected potentially toxic trace (As, Cd, Cu, Cr, Mo, Pb, U, V, and Zn), and minor (Fe and Mn) elements in Raša coal mine water, surface water, and associated vegetables, one fruit, and wild plants. Levels of Se in coal mine water were increased (up to 12 μg/L) compared to the maximum allowed water Se (10 μg/L). Compared to an EU average soil Se (1.15 mg/kg), Raša garden soil showed a 5-fold increase in Se. Compared to Croatian and Greek vegetable Se levels (low to normal), Raša vegetables showed a 20-fold, and a 50-fold increase in Se, respectively. Although approximative only, estimates of daily intake (EDI) of Se for mixed Raša vegetables (n = 21) showed a high level (0.055 mg/day). Namely, recommended dietary allowances (RDA) of Se for females and males are 0.055 mg/day, and 0.070 mg/ day, respectively. The EDI values of the analyzed vegetables contributed to average RDA levels as follows: garlic (183%), turnip (154%), parsley (147%), onion and gourd (76%), lettuce (74%), kale (62%), radicchio (51%), and potato (20%). Although the calculated EDI for the analyzed Raša vegetables was 1/8 the toxic dose (>0.4 mg/day), these results call for further research on the dietary and nutritional status of the residents in terms of Se.

Highlights

Coal is one of the most important sources of energy across a large part of the globe
The levels of Mo, V, U, and Se are increased in surface water, indicating on the problem related to the leaching of SHOS Raša coal (Dai et al, 2015; Medunić et al, 2020a)
This study showed that homegrown vegetables, and wild plants and figs from the Raša town area were highly enriched in Se, U, Mo, and V

Summary

Introduction

Coal is one of the most important sources of energy across a large part of the globe. (Hower et al, 1999; Saikia et al, 2018) Their environmental fate is a matter of great concern for humans. Their adverse effects on humans and animals largely result from drinking contaminated water, and consuming crops grown on contaminated land (Barla et al, 2017; Majumdar et al, 2019; Sasmaz et al, 2019; Upadhyay et al, 2019). One coal-related example is the case of Se pollution of soil, water, and locally grown food in China decades ago (Yang et al, 1983). This pollution resulted in an acute intoxication of humans with Se, in parts of the population of the Chinese Enshi County.

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