Intertidal zone, a transitional boundary between terrestrial and marine environments, has significant ecological functions, while gathers intense human activities. With the rapid growth of population, the pollutants from human activity are increasing and have a strong impact on ecosystems. Polycyclic aromatic hydrocarbons (PAHs) have been identified as priority pollutants by the USEPA long time ago and the semivolatile and persistent properties of PAHs enhance their dissemination and iniquitousness in the environment.

Previous studies have reported PAHs distribution and composition from different regions. However, how and to what extent anthropogenic factors influence PAHs distribution in the intertidal environment remains largely unknown.

To address this issue, research team of Prof. Lingxin Chen from Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (CAS), together with researchers from famous universities and research institutes, examined the direct and indirect effects of various factors (anthropogenic factors, total organic carbon (TOC) and climate factors) on profiles of PAHs in intertidal sediment.

The study reveals that spatial distribution of TOC-normalized PAHs in intertidal zones clearly exhibits discrepancy in development status in coastal regions of China. Anthropogenic factors, in particular population size and economic development, urbanization, and energy consumption structure, are demonstrated to 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 plays a major role on TOC-normalized low molecule weight (LMW) PAHs. Meanwhile, human activities can indirectly influence PAHs concentrations by affecting TOC content.

The result provides 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 has been published in the journal Nature sustainability with the title of "Human impacts on polycyclic aromatic hydrocarbons patterns in Chinese intertidal zones". https://www.nature.com/articles/s41893-020-0565-y