Determination of passive sampler-water partition coefficients of emerging polycyclic aromatic hydrocarbons and a field application in a Korean industrialized bay

초록

Polycyclic aromatic hydrocarbons (PAHs) are well-known carcinogenic and mutagenic compounds. To measure freely dissolved concentrations (C-free), representing the bioavailable fraction in aquatic environments, low-density polyethylene (LDPE) has been widely used as a passive sampler. However, only a limited number of experimentally determined passive sampler-water partition coefficients (K-PW) are available, and they primarily focus on priority PAHs. In this study, absorption kinetic experiments were conducted to determine K-PW values for 19 emerging PAHs (e-PAHs). All target compounds reached equilibrium within 6 h to 4 days. The determined logK(PW) values ranged from 2.1 for 2-nitronaphthalene (2-NNAP) to 6.6 for 1-chloropyrene (1-CPYR) and showed a strong correlation with logK(OW) (R-2 = 0.89). Using the obtained K-PW values, C-free of e-PAHs in surface seawater from Busan Port, Korea, was measured. Shipping-related activities were identified as major contributors to PAH contamination, and nitrated PAHs, particularly 1-nitronaphthalene (1-NNAP) and 2-NNAP, were dominant. The summed freely dissolved e-PAHs ranged from 94 to 1200 ng/L, averaging 350 +/- 330 ng/L, and were significantly higher than priority PAHs. Diagnostic ratios incorporating e-PAHs provided improved insights into source apportionment and atmospheric transport. Water column toxicity unit (WCTU) assessments indicated low ecological risk (<0.1) at all sites, with e-PAHs contributed up to 36% of Sigma WCTU. When all e-PAHs were considered under sensitivity scenarios, their contribution to Sigma WCTU increased to an average of 94%, highlighting the importance of including e-PAHs in mixed toxicity assessments.

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