Abiogenic particulate and plankton size affecting polycyclic aromatic hydrocarbons in coastal plankton

This study assessed biogenic (e.g., plankton cells and detritus) or abiogenic (e.g., mineral debris from physical or chemical processes) in PAH cycling along Kaohsiung's coast, highlighting that neglecting abiogenic sources may overestimate PAH levels in plankton. To assess pollutant distribution more accurately, we separate biogenic and abiogenic particulates through size fractionation, sedimentation, centrifugation, and siphoning. Sixteen priority PAHs were quantified in two particle size fractions (55-120 μm and 120-1000 μm). Particulate type significantly influenced PAH accumulation, with biogenic particulates showing higher PAH levels (p < 0.05), suggesting potential bioaccumulation. In contrast, particle size had no statistically significant effect, although smaller particulates consistently retained slightly higher PAH concentrations. A spatial gradient showed slightly increased high-molecular-weight PAHs (HPAHs) in southern stations, likely due to industrial emissions. Abiogenic particulates had about 33 % of biogenic TPAH levels in the smaller and about 13 % in the larger fraction. Bulk plankton samples may overestimate PAH levels, without separating abiogenic debris, distorting bioaccumulation assessments. Source analysis pointed to mixed combustion origins, indicating widespread pyrogenic pollution. These findings provide new field-based evidence that current monitoring may overestimate PAH contamination in plankton and highlight the importance of biogenic and abiogenic particulates partitioning into coastal pollution assessments.