Spatial Pattern of Arsenic Concentration and Associated Health Risk Assessment: A Case Study on Gangni Union of Chuadanga District of Bangladesh

Abstract

Underground water is one of the world's most important sources of fresh drinking water. However, various contaminants mix with groundwater, such as arsenic. This study aimed to ascertain the present condition of arsenic concentration, its spatial pattern, and its relationship with depth and to assess the associated health risks in the Gangni Union in Alamdanga Thana of Chuadanga district. Systematic sampling was used to gather water samples (í µí±› = 100) along with depth information from these tube wells. Water samples were analyzed with the Hach EZ, Dual-Range Arsenic Test Kit (Range: 0.00-0.5 mg/L). This study used both geostatistical (spatial autocorrelation, Hotspot analysis, and IDW) and statistical (descriptive and correlation statistics) methods. The arsenic content of the samples tested ranged from 0.0004 (mg/l) to 0.10 (mg/L). Arsenic levels in almost 42% of the samples were above the WHO standard, 21% were above the Bangladesh standard, and 37% were below both standards. With the same standard, the spatial distribution shows that 63% of the total area is arsenic contaminated. Hotspot’s analysis reveals that the central and southern northern parts of the study area are more arsenic-contaminated than the other parts. Children have a higher average daily dose (ADD) range (8.33E-06-0.00181) than adults (2.78E-06-0.0006). Similarly, the hazard quotient (HQ) value is also higher for children (0.0277-6.033) than for adults (0.0092-2.011). Finally, the Pearson correlation coefficient, r (98) =-.7580, p = 0.000, proved that there is a negative linear relationship between concentration values and depth, meaning that increasing depth will reduce arsenic contamination from tube well water.