Pollution Assessment of Selected Heavy Metals in Irrigation Water in Rajshahi City of Bangladesh

Abstract

As Bangladesh is an agricultural country, irrigation water is an important factor in proper crop production. Thus irrigation water plays a vital role in food safety and security. This study, therefore, focuses on the estimation of the concentration of four heavy metals in irrigation water along with their pollution assessments. Twenty water samples were collected from different areas of Rajshahi City in Bangladesh. The concentration of heavy metals found in this study followed the order of Mn (0.0913-0.3701 mg/L) > Pb (0.0211-0.2104 mg/L) > Cd (0.0004-0.0222 mg/L) > Cr (0.00105-0.00937 mg/L). In a few cases, the concentrations of heavy metals exceed the permissible limit for irrigation water recommended by the Food and Agricultural Organization. Pollution assessments were carried out using the enrichment factor, geoaccumulation index, contamination factor, and modified degree of contamination. This study revealed that the enrichment factor for lead and chromium showed no enrichment, whereas cadmium showed minor to moderate enrichment, and manganese was used as a reference element. The geoaccumulation index and contamination factor demonstrate that lead and chromium were uncontaminated, but manganese and cadmium denote moderate contamination. The modified degree of contamination indicated nil to the lower degree of contamination for all samples. Therefore, awareness should be raised among the people about the adverse health effects of these metal contaminations. Proper steps by the government and different organizations should be taken to identify the reasons for their sources, and appropriate techniques should be implemented to reduce their concentrations.