CEM India - Abstract

Abstract Information :

Uncontrolled combustion of solid wastes is reported to be a major source of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) which are regulated through the Stockholm convention and are classified as unintentionally produced persistent organic pollutants (U-POPs or dioxin-like POPs). Dioxins (representative term for PCDD/Fs) are highly lipophilic compounds with a half-life period of 7-12 years inside biological systems and has been classified as class-A carcinogens by International Agency for Research on Cancer. Several diseases such as skin lesions, neurological disorders, learning disability etc. have been reported elsewhere following the exposures with dioxins and furans in humans. Though periodic monitoring of identified sources such as incinerators and industrial stacks are enforced in the country, very little efforts are taken to monitor the hazardous substance releases from fire accidents. The present study assessed the emissions of dioxins, furans and heavy metals during a massive fire accident at a Combined Biomedical Waste Treatment Facility (CBWTF) in the state of Kerala. The accidental fire started at the waste storage building at CBWTF on 16/01/2022 afternoon and fire remained uncontrollable for almost 6 days. Approximately 600-800 tonnes of biomedical waste were present in the storage facility of about 16,000 sq.ft area at CBWTF and several hundred tonnes of waste got burned off. Comprehensive environmental sampling was conducted at the site to understand the background levels of dioxins, furans and heavy metals. Total of 6 ambient air samples, 2 residual ash samples, 7 vegetation soil samples, 5 vegetation parts samples and 4 sediment samples were collected from the site. High-volume PUF samplers were used for the ambient air sampling and coning and quartering method was followed for surface soil sampling. The sample preparation, analysis and quantification of dioxins and heavy metals were carried out at the NABL accredited (ISO/IEC 17025:2017) laboratory at CSIR-NIIST. The ambient air sample from inside the CBWTF showed highest value of 958.9 pgTEQ/m3 and the lowest value was observed at site 6, ie. 0.1 pgTEQ/m3. All the levels observed outside the facility were comparatively very lower indicating very high dilution of air emissions occurring at the site due to local meteorological conditions and thick vegetation. The sediment levels of PCDD/Fs ranged from 16.0 to 41.6 pgTEQ/g dw. Ash residue levels ranged from 54.7 to 56.7 pgTEQ/g dw and vegetation part sample levels ranged from 0.34 to 17.1 pgTEQ/cm2. A rapid declining trend in the concentration of dioxins with respect to distance from fire focal point in the studied samples was observed. The congener fingerprint analysis showed that the ambient air, ash residue and the vegetation parts samples from the site have similar fingerprint indicating same source of formation. The research noted that the burned residues collected from the CBWTF premises contained significantly higher levels of dioxins and furans. This suggests that it would be advisable to dispose of these residues in a secure landfill to reduce human exposure.