Cobwebs (spider webs) as a proxy for monitoring polycyclic aromatic hydrocarbons in indoor environments

Environmental context Polycyclic aromatic hydrocarbons are one of the most pervasive organic pollutants in the world that exhibit a variety of harmful effects including carcinogenicity, mutagenicity and teratogenicity, as well as impairment of endocrine functions. The study highlights the use of spider webs as a low-cost, effective, readily available bioindicator for monitoring polycyclic aromatic hydrocarbon depositions from different sources in indoor environments, and the need to exploit their usefulness for monitoring other persistent organic pollutants. Relationships between the distribution, homologue compositions and sources of polycyclic aromatic hydrocarbons are established, which inform our understanding of their potential risk to humans in the indoor environment. Rationale Cobwebs (spider webs) were used as a proxy for monitoring the concentrations, sources and risks of polycyclic aromatic hydrocarbons (PAHs) in indoor environments. The results demonstrated that spider webs are an effective and useful bioindicator for monitoring PAH depositions from different sources in indoor environments. Methodology PAHs were monitored in different indoor settings, including electronic workshops (EWs), public buildings (PBs) and residential buildings (RBs), using cobwebs as a proxy. PAH concentrations in cobwebs obtained from different indoor environments were analysed by gas chromatography–mass spectrometry. Results The PAH concentrations in the cobwebs ranged from 100 to 3610, 10 to 8830 and 400 to 6750 µg kg−1 for EWs, PBs and RBs respectively. Discussion The homologue compositions suggested prevalence of 3- and 4-ring PAHs in the cobwebs. The risk evaluation of PAHs in the cobwebs suggested no adverse non-carcinogenic risk, but an adverse carcinogenic risk for adults and children. The preliminary source apportionment results indicated that PAHs in the cobwebs originated mainly from combustion processes.