# Water Supply Systems for Settlements with Arsenic-Contaminated Groundwater--Making the Right Choice
###### Abstract  
The environmentally and economically sustainable provision of safe drinking water remains one of the most significant public health challenges facing society. It is particularly difficult in small municipalities that lack the human and financial resources to maintain complex and/or expensive water treatment systems, especially in regions where the water is naturally contaminated with toxic substances such as arsenic. This paper analyses two municipalities (Kanjiza and Senta) in northern Serbia with groundwater arsenic concentrations significantly higher than the 10 \(\mathrm{\SIUnitSymbolMicro g}/\mathrm{L}\) maximum allowable concentration. Two different water supply approaches are compared: (1) local supply, where each settlement has their own treatment plant using existing sources; (2) creation of a centralised network, which connects several settlements together with better quality water sources. The analysis considers techno-economical aspects and the quantity and quality of available water, as well as the yields investment and exploitation cost projections for both approaches. The results demonstrate that for small municipalities, a holistic approach to decision making is necessary to find the best solutions for drinking water supply, which in the case of the two municipalities studied is connection to a centralised system supplied from better quality water sources and the creation of connections beyond municipal administrative boundaries. water supply; groundwater; arsenic; microregional systems +
Footnote †: journal: Medical  
With this in mind, the control of arsenic contents in drinking water is of particular importance, as chronic exposure of this pollutant leads to an unacceptably high risk of disease. Sustainable Development Goal 6 specifically mentions, in subgoal 6.4, the need to increase the sustainability of water withdrawals and the supply of freshwater [6]. In order to do so in regions subject to natural groundwater contamination, it is important to take into account the availability of alternative water sources, the concentration of those contaminants, and the local financial capacity to install and maintain the appropriate treatment technology. Groundwaters often contain complex mixtures of contaminants, and frequently even the presence of safe levels of a different chemical can affect the performance water treatment technologies. The correct choice of arsenic removal technology will, therefore, depend on the other water constituents. For example, in the groundwater used for the municipal water supply in the region presented in this paper, natural organic matter (NOM) is also present, whereby total organic carbon (TOC) values as high as 13 mg/L have been detected. This NOM can have a great effect on the behaviour of arsenic during water treatment. The Republic of Serbia is one of the many countries with significant issues because of natural arsenic in the groundwater, especially in the Autonomous Province of Vojvodina, situated in the northern part of the country [7]. Many settlements near the borders with Hungary and Romania are affected by this issue, with groundwaters in this region containing unacceptably high concentrations of arsenic (up to 250 ug/L). Unfortunately, most of the water supply systems in Vojvodina do not have the technology to remove arsenic from groundwater. Instead, local statutes prohibit the human consumption of tap water received from public water utilities, effectively transferring responsibility for the consequences of this issue to the consumers. Figure 1 shows the locations of the affected drinking water wells, which serve approximately 600,000 people (about one-third of the entire population of Vojvodina) with tap water containing more than the 10 ug/L of the maximum allowable concentration of arsenic [8]. Given the status of the tap water in these locations as technical water, the majority of the inhabitants use bottled waters as their main source of drinking water.