Depth profiles of dissolved and particulate lead indicate reversible scavenging in deep waters of the West Subtropical Pacific

• Depth profiles from 14 stations in the West Subtropical Pacific are presented, comprising 382 dissolved lead samples covering the full water column and 115 particulate lead samples collected from the upper 0–1600 m. • Surface lead concentrations decrease away with decreasing contribution of Asian aerosols, indicating atmospheric input. • Subsurface dissolved lead maxima reflect the intrusion of North Pacific Intermediate Water carrying elevated lead concentrations from the subarctic Pacific. • Deep-water dissolved lead concentrations resemble surface patterns across the Pacific, highlighting the key role of reversible scavenging in moving lead from surface waters to the deep ocean. Despite the global phase-out of leaded gasoline, contemporary industrial sources, particularly from East Asia, continue to deliver lead (Pb) to the marine environment via atmospheric deposition. Here, we present depth profiles of dissolved Pb (dPb) and particulate Pb (pPb) in the western subtropical Pacific Ocean. Our results reveal pronounced northwest-to-southeast gradients in surface dPb, consistent with ongoing aeolian inputs. The distinct subsurface maxima, associated with the North Pacific Intermediate Water, align with observations from previous studies. Below 500 m, we observe both quasi-conservative transport of dPb with water masses and evidence of additional Pb inputs near the continent, likely supplied by advective transport and sinking particles with reversible scavenging. Combining our new data with published datasets reveals that deep-water (> 1200 m) dPb concentrations resemble the geographical distribution of surface dPb across the whole Pacific, indicating that particle-mediated vertical transport is a key pathway for delivering anthropogenic Pb to the deep ocean independently of deep-water formation. This study highlights the sustained influence of Asian emissions on the North Pacific and underscores the central role of reversible scavenging in the oceanic Pb cycle, providing new constraints on both external Pb inputs and internal cycling in a region of global significance.