Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in municipal waste dumping site, incinerator and brick kiln residues: evaluation for potential risk assessment

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) consist of a group of organohalogenated compounds which are ubiquitous, anthropogenic, toxic and persistent organic pollutants. Human exposure to PCDD/Fs is associated with severe health risks. In the current study, levels of PCDD/Fs were determined in soil from municipal waste (MW) dumping site and ash residues from hospital waste incinerators (HWIs) and brick kilns (BKs) in Peshawar, Khyber Pakhtunkhwa (KP) Province, Pakistan. A total of 17 congeners (7 PCDDs and 10 PCDFs) were quantified using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) 6890 Series (Agilent, USA). The PCDD/Fs contamination levels in the studied samples followed an order of HWIs > BKs > MW dumping site. Among HWIs, highest toxicity values of 2343 ng international toxicity equivalency factors (I-TEQ)/kg and 2138 ng World Health Organization-toxicity equivalents quantity (WHO-TEQ)/kg were observed for Khyber Teaching Hospital (KTH), while toxicity values for Hayatabad Medical Complex (HMC) were found to be 1493 ng I-TEQ/kg and 1416 ng WHO-TEQ/kg, respectively. The TEQ values were found in order of HWIs > BKs > MW site. Potential for both non-cancer and cancer risk (CR) in three pathways was found in order as ingestion > dermal > inhalation. Based on the finding it can be inferred that the onsite workers and general public exposed to such levels are under potential risk for both carcinogenic and non-carcinogenic risk.