Combined chemical and toxicological evaluation of leachate from municipal solid waste landfill sites of Delhi, India
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In the present study, landfill leachate of three landfill sites of Delhi, India, was toxico-chemically analyzed for human risk assessment. Raw leachate samples were collected from the municipal solid waste (MSW) landfills of Delhi lacking liner systems. Samples were characterized with relatively low concentrations of heavy metals while the organic component exceeded the upper permissible limit by up to 158 times. Qualitative analysis showed the presence of numerous xenobiotics belonging to the group of halogenated aliphatic and aromatic compounds, polycyclic aromatic hydrocarbons (PAHs), phthalate esters, and other emerging contaminants. Quantitative analysis of PAHs showed that the benzo(a)pyrene-toxic equivalence quotient (BaP-TEQ) ranged from 41.22 to 285.557 ng L−1. The human risk assessment methodology employed to evaluate the potential adverse effects of PAHs showed that the cancer risk level was lower than the designated acceptable risk of 10−6. However, significant cytotoxic and genotoxic effects of leachates on HepG2 cell line was observed with MTT EC50 value ranging from 11.58 to 20.44 % and statistically significant DNA damage. Thus, although the leachates contained low concentrations of PAHs with proven carcinogenic potential, but the mixture of contaminants present in leachates are toxic enough to cause synergistic or additive cytotoxicity and genotoxicity and affect human health.
KeywordsLandfill leachate HepG2 cell line Cytotoxicity Genotoxicity Human risk assessment
We would like to express our sincere thanks to the Council of Scientific and Industrial Research, Government of India, New Delhi, for providing SRF (Ghosh, P). We also thank Dr. J.K. Tripathi (SES, JNU, New Delhi) for ICP-AES analysis, Dr. Ajai Kumar (Advanced Instrumentation Research Facility—AIRF, JNU, New Delhi), and Mr. Sanjay Sharma (Sigma Test and Research Centre) for GC-MS analysis. We would also like to extend our sincere thanks to Dr. Mihir Tanay Das and Mr. Subhanjan Sengupta for their excellent technical assistance in preparing the manuscript.
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