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Screening legacy and emerging organic pollutants in the contaminated soil of Dhaka, Bangladesh

Authors :
Nigar, Refayat
Zhao, Shizhen
Liu, Xin
Huang, Huanfang
Tian, Lele
Xiao, Yuwei
Habib, Ahsan
Zhang, Gan
Source :
Emerging Contaminants; September 2024, Vol. 10 Issue: 3
Publication Year :
2024

Abstract

The current understanding of the legacy and emerging organic pollutants in the soil of Bangladesh remains limited. Inadequate disposal practices, particularly in e-waste, landfills, and industrial operations, may lead to the pervasive presence of persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) in the country. This study aimed to systematically investigate the concentrations, sources, and risk assessment of halogenated flame retardants (HFRs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), organochlorine pesticides (OCPs), chlorinated paraffins (CPs), and PAHs in the contaminated soil of Dhaka's dumpsites, e-waste, and industrial areas collected in 2017. The total concentration of investigated pollutants averaged at 4790 ± 4040 ng g−1dw, with the following order: ∑44CPs (4110 ± 4140 ng g−1dw) > ∑16PAHs (422 ± 491 ng g−1dw) > ∑16HFRs (190 ± 538 ng g−1dw) > ∑209PCBs (43.5 ± 73.5 ng g−1dw) > ∑50PCNs (17.7 ± 21.0 ng g−1dw) > ∑27OCPs (9.41 ± 9.61 ng g−1dw). The e-waste site exhibited the highest total concentration of the target pollutants, reaching 12,700 ng g−1dw. CPs were the predominant contributors, accounting for averages of 81.8%, 70.5%, and 68.5% to waste landfills, e-waste, and industrial sites, respectively. A comprehensive analysis of 209 PCB congeners revealed their primary origin from Aroclor PCBs, with minor contributions from unintentionally produced PCBs. The highest incremental lifetime carcinogenic risk (ILCR) occurred in e-waste sites, contributed by dioxin-like PCBs, with a maximum value of 5.9 × 10−5for adults, exceeding the limit 1.0 × 10−6set by the U.S. EPA. The non-carcinogenic hazard quotients (HQs) were much lower, suggesting no significant risk from the investigated pollutants. Our findings highlight the importance of proper waste management and regulated e-waste recycling to mitigate potential hazardous risks to the Bangladeshi population.

Details

Language :
English
ISSN :
24056650
Volume :
10
Issue :
3
Database :
Supplemental Index
Journal :
Emerging Contaminants
Publication Type :
Periodical
Accession number :
ejs66291362
Full Text :
https://doi.org/10.1016/j.emcon.2024.100356