Evaluation of iron contamination in groundwater with its associated health risk and potentially suitable depth analysis in Kushtia Sadar Upazila of Bangladesh

Iron contamination in groundwater is one of the potential drinking water-related problems that can pose adverse health effects on humans. This study examined iron (Fe) contamination in groundwater and searched for potentially suitable depth in the water table using geostatistical techniques in Kushtia Sadar Upazila. Water samples (n = 100) were collected through systematic sampling and analyzed with a digital Hanna HI-721 Iron Checker Handheld Colorimeter (Range: 0.00-5.00 mg/L) with Hanna HI-721 reagents. Depth information also was collected from the corresponding tube wells. Hotspot analysis, correlation statistics, hazard quotient evaluation, and suitability analysis were used in this study. The results reveal that 77% of the groundwater samples exceeded the WHO standard and 80% exceeded the Bangladesh standard, and only 43% met both standards. About two-thirds of the area studied found moderate (1.01-2 mg/L) to high (2.01-5 mg/L) contamination levels. The hotspot analysis depicts that the majority of the hotspots are in the northern part, and almost all the cold spots are in the southern part. The hazard quotient value shows that the non-carcinogenic health risks due to ingestion of iron in adults were 0.16-0.92 and in children were 0.39-2.13 and thus indicating the high health consequences for the children. The result of the Pearson correlation coefficient, r (98) = -0.570, p = 0.000, stated that there is a strong negative linear relationship between tube well depth and iron concentration level. The suitability analysis found that, the ideal depth for dealing with iron contamination was found to be between 66 and 128 m based on the linear relationship.