Study of the dyeing industry pollution after mandatory installation of ETP in Madhabdi municipality, Bangladesh

Madhabdi municipality of the Narsingdi district of Bangladesh, the “Manchester of the East,” is famous for its cloth market and fabric dyeing industries. The untreated effluent discharge has been mixed with the water and soil, degrading the environmental standards of this area for years. Installing an effluent treatment plant (ETP) in all textile industries in Bangladesh is mandatory. This study evaluates the soil condition, surface water quality, and heavy metal contamination in cultivated vegetables after the compulsory installation of ETP. Soil and water samples from eight locations and cultivated vegetable samples from three locations are collected and analyzed for this study. The pH, EC (electric conductivity), TDS (total dissolved solids), DO (dissolved oxygen), and heavy metal concentrations are observed. The water quality index, contamination index, metal evaluation index, pollution load index, and metal pollution index are calculated from the collected samples. The study found that the physico-chemical properties of water pH (9.19), EC (2232.38 µScm-1), and DO (0.79 mgL-1) violate the national standards. The mean TDS is below the maximum permissible level. The heavy metal concentrations of Cr and Pb in water are 1.03 and 0.13 mgL-1, crossing the permissible limit, respectively, but Mn, having 0.89 mgL-1, is within the limit. The water quality is unsuitable for domestic and agricultural use, contamination is “medium,” and metal evaluation is “medium.” The soil is alkaline, having a pH of 8.58. The soil’s Cr, Pb and Mn concentrations are 68.21 µgg-1, 52.73 µgg-1and 805.16 µgg-1, respectively. The soil contamination level is low to moderate. Cultivated leafy vegetables have a concentration of Cr, Pb and Mn; 2.61 µgg-1, 0.30 µgg-1and 288.67 µgg-1, respectively, where Cr has crossed, Pb is within, and Mn is lower than the permissible limit. Produced vegetables have high (12.10–33.09) MPI (metal pollution index) and are at a high-risk level for consumption as food.