Abstract
The Akre–Bardarash region was selected as the focus of this study due to its strategic geographical setting and its long-standing agricultural importance in northern Iraq. Located southeast of Duhok City, the area lies between latitudes 36°39′56.36″ N and 36°29′23.42″ N and longitudes 43°52′53.24″ E and 43°40′24.27″ E. This region comprises a broad and fertile plain that forms one of Iraq’s most productive agricultural zones, particularly well known for the cultivation of rice, potatoes, and tomatoes. The landscape is dominated by flat to gently undulating terrain, occasionally interrupted by sporadically distributed hills that add minor topographic variation. These physiographic conditions, combined with favorable soil properties and groundwater availability, have made Akre–Bardarash a key center for agricultural activity and rural development.
To evaluate groundwater conditions, forty groundwater samples were systematically collected from wells distributed across the Akre–Bardarash Basin within the Duhok Governorate. The wells vary in depth, spatial location, and hydrogeological setting, providing a comprehensive representation of groundwater characteristics throughout the basin. Sampling was conducted in two periods: October 2024 to represent the dry season, and May 2025 to represent the wet season. The overarching objective of the study was to conduct a full hydrochemical assessment of the basin and to investigate the impact of anthropogenic activities on groundwater quality. Particular attention was given to variations in heavy metal concentrations, as groundwater from these wells serves as an essential drinking-water supply for the surrounding communities.
For the dry season, concentrations of nine heavy metals—Cadmium (Cd), Zinc (Zn), Selenium (Se), Nickel (Ni), Chromium (Cr), Lead (Pb), Copper (Cu), Manganese (Mn), and Arsenic (As)—were analyzed. The study additionally aimed to determine whether the concentrations of these metals, along with major cations and anions, complied with the Iraqi Drinking Water Standards (IQS). To evaluate contamination levels and potential risks, several indices were computed: the Heavy Metal Pollution Index (HPI) for the dry season, the Health Risk Index (HRI) for assessing possible human health impacts, and both the Metal Index (MI) and Water Quality Index (WQI) for evaluating suitability during dry and wet seasons.
The results indicated that the mean HPI value across the basin was below the threshold of 100, suggesting that groundwater at all sampled sites was not considered polluted according to HPI criteria. However, the health risk assessment revealed concern, with ten sampling locations (S10, S15, S16, S20, S27, S32, S34, S35, S37, and S39) exhibiting HRI values greater than 1, the limit established by the US EPA. Elevated concentrations of Cd, Pb, Zn, Cr, Ni, Cu, and Mn at these locations may pose significant health risks to local residents. Spatial patterns further suggest that groundwater quality degradation is linked to human activities, particularly industrial discharge, agricultural inputs, and expanding urban development in the northeastern and southwestern sections of the basin.
Seasonal hydrochemical changes were also evident. Major cations—including calcium, magnesium, sodium, and potassium—showed slightly reduced concentrations during the wet season due to rainfall dilution and altered water–rock interactions. Similarly, major anions such as bicarbonate, sulphate, nitrate, and chloride exhibited moderate seasonal fluctuations influenced by carbonate lithology, hydrological cycles, and anthropogenic activities. Overall, the interaction of natural processes and human pressures plays a significant role in shaping groundwater quality in the Akre–Bardarash Basin
