Intertidal zone, a transitional boundary between terrestrial and marine environments, has significant ecological functions. Pollutants from human activities have impacted ecosystems in intertidal zone.

Polycyclic aromatic hydrocarbons (PAHs) have been identified as priority pollutants. However, how and to what extent anthropogenic factors influence PAHs distribution in the intertidal environment remains largely unknown. 

Researchers led by Prof. CHEN Lingxin from the Yantai Institute of Coastal Zone Research (YIC) of the Chinese Academy of Sciences and their collaborators examined the direct and indirect effects of various factors, including anthropogenic factors, total organic carbon (TOC) and climate factors, on profiles of PAHs in intertidal sediment. 

They found that spatial distribution of TOC-normalized PAHs in intertidal zones clearly exhibited discrepancy in development status in coastal regions of China.

Anthropogenic factors, in particular population size and economic development, urbanization, and energy consumption structure, could directly influence PAHs patterns in intertidal sediment.

In contrast to the influence of population size and economic development on normalized high molecule weight (HMW) PAHs, urbanization exerted more effect on TOC-normalized low molecule weight (LMW) PAHs. Meanwhile, human activities could indirectly influence PAHs concentrations by affecting TOC content. 

The findings provide continental-scale evidence that human activities exert key and differential impacts on distribution and deposition of PAHs in intertidal sediments, and pollution status and profile of PAHs can be used to index regional status of industrialization and urbanization. 

The study was published in Nature sustainability on June 29.