Metals and PAHs in watershed soil and reef sediment at Olowalu and leeward Maui, February 2022

Fine-sediment elemental chemistry and short-lived cosmogenic radionuclides (Beryllium-7, Cesium-137, and Lead-210) were quantified to describe land-based sediment sources and runoff to Olowalu Reef in February 2022. Charcoal counts, total organic carbon contents, and 76 urban- and wildfire-associated contaminants called polycyclic aromatic hydrocarbons (PAHs) were quantified to explore urban and wildfire effects in watersheds above Olowalu Reef and in reef sediment. Sampling occurred approximately two months after winter flooding and one month after tsunamigenic waves impinged on the Maui shore from the eruption of Hunga-Tonga volcano in the South Pacific. The USGS Coastal and Marine Hazards and Resources Program gratefully acknowledges funding for contaminant analyses from The Nature Conservancy and Maui Nui Marine Resource Council, and support from the Hawaii Association for Marine Education and Research, Inc.