Distribution, fate and sources of polycyclic aromatic hydrocarbons (PAHs) in atmosphere and surface water of multiple coral reef regions from the South China Sea: A case study in spring-summer

Our previous study revealed PAHs? wide occurrence in corals from multiple coral reef regions (CRRs) in the South China Sea. However, little is known about their occurrence, distribution, fate, and sources in the ambient environment of these CRRs. This study aimed to resolve these research gaps. The results showed ?15PAHs (total concentrations of 15 US EPA priority controlled PAHs exclude naphthalene) in the atmosphere (gas-phase: 0.31?49.6 ng m- 3; particle-phase: 2.6?649 pg m-3) were mainly influenced by air mass origins. Southwesterly wind caused higher ?15PAHs than the southeasterly wind. The ?15PAHs in seawater from the nearshore (462 ? 244 ng L-1) was higher than that from offshore Zhongsha Islands (80.5 ? 72.1 ng L-1) because of the effect of terrigenous pollution and ocean current. Source apportionment indicated that the mixed sources of spilled oil and combustion from neighboring countries were the main contributors to PAHs in these CRRs. The total deposition fluxes showed that PAHs tended to migrate from the atmosphere to seawater. Global warming may inhibit this process, but PAHs still have a migration pattern of atmosphere-ocean-corals, which will further increase the environmental pressure on coral reef ecology.

Automated summary

The study revealed the wide occurrence and sources of PAHs in coral reef environments in the South China Sea. PAH concentrations in the atmosphere were influenced by air mass origins, while concentrations in seawater were affected by terrigenous pollution and ocean currents. Source apportionment identified spilled oil and combustion in neighboring countries as the main contributors to PAHs in coral reef regions.