Impact of Industrial Wastewater Irrigation on Heavy Metal Deposition in Farm Soils of Bhaluka Area, Bangladesh

Abstract

The study was conducted to determine heavy metal contents in industrial wastewater and contaminated soils of Bhaluka, Mymensingh and to assess their pollution level. A total of 9 industrial wastewater and 12 contaminated farm soil samples were collected directly from the farmers’ fields of Bhaluka area and analysed for this study. Considering EC, salinity and TDS, 56 to 89% wastewater samples were found problematic for long term irrigation. The concentration of CO3, HCO3 and Cl in wastewater ranged from 0.20-1.60, 2.0-11.2 and 1.30-4.79 me L-1, respectively and the content of Ca, Mg, Na and K in wastewater ranged from 16.03-52.10, 4.86-21.87, 101.98-678.90 and 5.59-48.63 mg L-1, respectively. The study results revealed that all wastewater samples were found unsuitable for irrigation in respect of CO3, HCO3 and K. Among the heavy metals studied, Pb, Cd and Fe concentrations in all wastewater samples and Mn content in 5 samples were found above than the acceptable limit for irrigation. The concentration of Zn, Cr, Cu, Pb, Ni, Cd, Mn and Fe in wastewater irrigated soils of Bhaluka industrial area ranged from 50.48 to 448.56, 47.22 to 83.65, 19.13 to 328.23, 42.37 to 77.96, 22.93 to 43.86, 0.70 to 1.40, 161.5 to 341.7 and 38105 to 65399 μg g-1, respectively. Considering geoaccumulation index, the Igeo values for Pb and Cd for all locations of the study area exhibited positive values (0.495< Igeo <1.624), that means Igeo class: 1-2, indicate moderately polluted soil quality. On the other hand, as regards to enrichment factor (EFc), 9 locations for Pb, 5 for Cd, 1 for Zn and 1 for Cu had EFc values > 5.0, indicate contaminated soil quality. The study concluded that industrial wastewater used for irrigation was directly linked with the heavy metals deposition in the farm soils.