| Abstract
| - The coastal region off Macao is a known depositionalzone for persistent organic pollutants (POPs) in the PearlRiver Delta and Estuary of southern China and an importantgateway for the regional contributions of contaminationto the globe. This paper presents a comprehensive assessmentof the input sources and transport pathways of polycyclicaromatic hydrocarbons (PAHs) found in the coastalsediments of Macao, based on measurements of 48 2−7ring PAHs and 7 sulfur/oxygenated (S/O) PAH derivativesin 45 sediment, 13 street dust, and 68 aerosol samples.Total sediment PAHs concentrations ranged from 294 to12 741 ng/g, categorized as moderate contamination comparedto other regions of Asia and the world. In addition, thePAH compounds appeared to be bound more strongly toaromatics-rich soot particles than to natural organic matter,implying a prevailing atmospheric transport route forPAHs to Macao's coast. Compositional analysis and principalcomponent analysis (PCA) suggested that differentclasses of PAHs in the coastal sediments of Macao mayhave been derived from different input sources via varioustransport pathways. For example, alkylated and S/OPAHs were likely derived from fossil fuel leakage andtransported to sediments by both aerosols particles andstreet runoff. High-molecular-weight parent PAHs werepredominantly originated from automobile exhausts anddistributed by direct and indirect atmospheric deposition. Low-molecular-weight parent PAHs, on the other hand, mayhave stemmed from lower temperature combustion andfossil fuel (such as diesel) spillage from ships and boats andwere transported to sediments by river runoff or directdischarge as well as by air−water exchange.
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