Assessment of Toxicity Characteristics in Leachate from the Textile Industry–Based Sludge Using Leachate Pollution Index

The toxicity, Leachate Pollution Index (LPI), and risk assessment of the leachate of hazardous sludge are very rarely and scantly studied. This study evaluates the leachate characteristics of the textile industry–central effluent treatment plant sludge. X-ray fluorescence (XRF) analysis determines the sludge’s chemical composition. The Toxicity Characteristic Leaching Procedure (TCLP) is a sample extraction method performed to simulate the leaching through landfills. The leachate samples are tested using inductively coupled plasma-optical emission spectrometry (ICP-OES) techniques for the metal ions. The 30 TCLP tests are performed as per the scheme generated by the Central Composite Design of Experiment (CCDoE). The study provides a novel and flexible framework for developing the Textile-Leachate Pollution Index (T-LPI) using a hybrid fuzzy analytical hierarchical process (FAHP). The metal ions’ weights in the leachate (Al, Cu, Cr, Fe, Mn, Ni, Pb, Zn, K, Mg, Ca) are obtained using FAHP infused with inter-valued triangular fuzzy numbers. The membership grade functions are derived for each metal ion, and the Leachate Pollution Index is estimated for 30 experiments. The experimental runs are ranked based on their LPI values. Pearson’s correlation coefficient indicates a poor association between the metal ions and their presence from different sources. The Human Health Risk Assessment (HHRA) of metal ions (Al, Cu, Cr, Fe, Pb, Zn, Mn, Ni) present in leachate shows the potential non-carcinogenic impact by Ni, Pb, Zn, Cu, Cr, and Mn. In contrast, Fe and Al have shown no adverse non-carcinogenic effect. The carcinogenic risk by Pb and Cr metal ions in leachate lies in the high- and very high-risk levels. The ranking of hazardous sludge sites can help in the immediate disposal of higher LPI value sludge to treatment storage disposal facilities (TSDF) as compared to the sludge with lower LPI. The study provides insight into the human health risk associated with the consumption (oral intake and skin absorption) of leachate-polluted surface water.