Cobweb as a bioindicator of polycyclic aromatic hydrocarbons in household cooking energy sources: Health risk...

The study examined cobwebs (CBWs) as a potential bioindicator for indoor polycyclic aromatic hydrocarbons (PAHs) resulting from four household cooking energy sources: Firewood-Dependent Kitchen (FDK), Kerosene Stove-Dependent Kitchen (KSDK), Gas-Dependent Kitchen (GDK), and Electric Cooker-Dependent Kitchen (ECDK) after 60 days of exposure. Total PAH levels were significantly higher compared to the control group, with FDK, KSDK, GDK, and ECDK showing averages of 15.4, 12.8, 7.6, and 5.7 times higher, respectively. High molecular weight PAHs dominated, making up approximately 67%-72% of the total PAHs. The toxic equivalent quantity ranged from 0.109 to 1.188, decreasing in the order FDK > KSDK > GDK > ECDK. The hazard index via inhalation and dermal exposure routes ranged from 4.01 × 10^-13 to 7.45 × 10^-3 in both children and adults, indicating no potential non-carcinogenic health risks. However, the total carcinogenic risk (CR) exceeded 10^-4, pointing to a serious CR. Partial least squares discriminant analysis revealed distinct PAH signatures between traditional fuel sources (firewood and kerosene) and cleaner or control environments (gas, electric, and no cooking activity). The coefficient plot identified 2-methylnaphthalene and indeno(1,2,3-cd)pyrene as key contributors to the variance among the different facilities. This study confirmed the usefulness of CBWs as a cost-effective bioindicator for particulate PAHs. It emphasized the urgent need for a transition to cleaner energy sources, moving away from traditional fuels. These findings provide a baseline for future PAH environmental monitoring and public health policies in Nigeria.