Arsenic in the groundwater of Vojvodina

The northern part of Serbia, Vojvodina, occupies an area of 21,614 km2 and has a population of less than 2,000,000 people. Groundwater, in this area, is the only source of water supply.

Groundwater is tapped from different aquifers of Quaternary to Pliocene.

  • Shallow aquifer also known as the “first” aquifer, taps groundwater from 50 m. This Quaternary aquifer consists of deposits of sand and gravel. Precipitation, river, and channel water replenish the shallow aquifer. The water is characterized with high concentration of iron (usually more than 2 mg/L), KMnO4 and with high hardness (15-30°dH)
  • Basic water-bearing complex (BWC) is aquifer from 50 to 250 m. This is the most useful aquifer for water supply in Vojvodina. The quality of groundwater varies and these variations depend on locality. Groundwater from this aquifer is usually characterized by the presence of organic matter, iron, manganese as well as arsenic.
  • Pliocene sub artesian or artesian aquifers with fine and medium grain sands and gravelly sands are present between 200 and 350 m

In the past 40 years, the problem with over-exploitation of the BWC occurs especially in the Bačka and Banat regions. In addition, lowering of the piezometric head for 20 – 30 m in the zones of water sources is recorded (Dimkić et al, 2010).

Other problem of water supply is groundwater quality, because of the high concentration of arsenic, then boron, iron, manganese, ammonium ion and KMnO4. Therefore, in some parts of Vojvodina high mineralization (more than 1 g/L) of groundwater is recorded.

Fig. 1. Tap water from Zrenjanin

The definition of water as a clean fluid, without color and taste is not the case in Vojvodina. Water is yellow (Fig. 1) and has an odor taste. the color of the water is a consequence of organic matter, while arsenic does not change the color and taste of water. Concentrations of organic matter, present as KMnO4 are 20-150 mg/L, maximum 200 mg/L.

The high concentration of arsenic in groundwater is a consequence of geological conditions and geochemical conditions. Because of the strong influence of water-rock interactions and natural weathering, arsenic is released into groundwater (Kiurski-Milošević et al, 2015). All Quaternary aquifers of the Pannonian Basin contain high concentration of arsenic (Varsanyi and Kovacs, 2006, Jovanović et al, 2011), hence this element has a geogenic origin.

Arsenic is mostly present in the form of mineral, such as arsenopyrite. Arsenic is also the consequence of chemical and hydrogeological conditions and depends on hydraulic gradient, water-bearing capacity of the rock, aquifer, then pH, Eh.

According to the EU Directive (98/83/EC), World Health Organization, and Regulation on the hygienic acceptability of potable water (28/2019), the maximum allowed concentration of Arsenic in groundwater is 10 μg/L. The concentration of Arsenic is usually between 10 and 100 μg/L, often more than 100 μg/L. Consuming the water enriched with arsenic on a long-term may rise a risk of skin, bladder, liver, kidney, and lungs cancer.

This is an important issue for the region of Banat and Bačka, while groundwater of Srem has a better quality (Fig. 2). Novi Sad, the capital of the autonomous province of Vojvodina, and surrounding area, use water from alluvial sediments of Danube River (Renye well). This water has a satisfactory quality.

However, the worse situation is in city Zrenjanin (middle Banat), where the concentration of arsenic in drinking water is reaching value of 72 μg/L, boron 895 μg/L, Ep 928 μS/cm (Petrović et al, 2012). Maximum As level in Zrenjanin reaches 200 μg/L, while in surrounding area (Melenci) the value of arsenic is up to 350 μg/L. The water is unsafe for drinking, while many ideas and solutions for its improvement have not shown the acceptable results.

Fig 2. Arsenic in groundwater of Vojvodina (modified by Dalmacija et al, 2011)



Tanja Petrović Pantić and Katarina Atanasković Samolov
GSS – Geological Survey of Serbia



REFERENCES:

Dalmacija, B.,, Bečelić-Tomin, M., Krčmar, D., Lazić, N. 2011. Water, pp.94-135 in Puzović, S., Radovanović-Jovin, H. (eds) 2011. Environment in Autonomous Province of Vojvodina, Provincial Secretariat for Urbanism, Construction and Environmental Protection, Novi Sad

Dimkić, M., Đurić, D., Jevtić, G. 2010. Solutions for groundwater management in areas affected by high arsenic content: Vojvodina case study. International Conference „Transboundary Aquifers: Challenges and New Directions (ISARM2010)

Jovanović D., Jakovljević, B., Rašić-Milutinović, Z, Paunović, K, Peković, G., Knežević, T. 2011. Arsenic occurence in drinking water supply systems in ten municipalities in Vojvodina Region, Serbia, Environmental Research 111, 315-318

Kiurski-Milošević, J., Vojinović Miloradov M., Ralević, N. 2015. Fuzzy model for determination and assessment of groundwater quality in the city of Zrenjanin, Serbia, Hem.Ind. 69 (1) 17-28

Official Gazette of FRY 42/98, 44/99 and Official Gazzete of RS 28/2019. Regulation on the hygienic acceptability of potable water

Petrović T., Zlokolica-Mandić M., Veljković, N., Papić, P., Poznanović, M., Stojković J., Magazinović S. 2012. Macro- and micro-elements in bottled and tap waters of Serbia, Hem. Ind. 66 (1) 107–122

Varsanyi, I., Kovacs, L.O., 2006. Arsenic, iron and organic matter in sediments and groundwater in the Pannonian Basin, Hungary. Appl. Geochem. 21, 949–963.








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