On a recent Sunday, Tracy Quinn assessed the damage to the coastline caused by the Palisades Fire as she drove along the Pacific Coast Highway. The once pristine water was now tainted by ash, and burnt remnants of household appliances littered the shoreline. The sludge at the water's edge posed an environmental threat, especially as high tide carried debris and potentially toxic ash into the ocean. Quinn, president and CEO of the environmental group Heal the Bay, expressed her dismay at the scene, noting that their team had identified hazardous materials as far as 25 miles (40 kilometers) south of the affected area.
The Palisades and Eaton fires devastated thousands of structures, including homes, businesses, and cars, converting everyday items into hazardous ash composed of various toxins such as pesticides, asbestos, and heavy metals. With these dangers potentially washing into the Pacific Ocean, officials are increasingly concerned about the impact on marine life and beachgoers alike.
Quinn emphasized the uniqueness of the situation, noting that never before had so many homes been burned so close to the water. Fire debris and toxic ash pose immediate risks to surfers and swimmers, particularly after rainfall that can carry harmful contaminants into the ocean. These worries intensified following recent atmospheric rivers and mudslides that threatened to exacerbate the contamination.
Concern regarding ocean water contamination arose early for Mara Dias, water quality manager for the Surfrider Foundation, when the fires ignited in January. Smoke and ash carried by the wind settled on ocean waters, with scientists on a research vessel detecting ash as far as 100 miles (161 kilometers) offshore. Marine ecologist Julie Dinasquet from the University of California, San Diego's Scripps Institution of Oceanography described the ash's smell as reminiscent of burning electronics, highlighting the hazardous nature of what was entering the ocean.
Additionally, storm runoff represents an immediate hazard. Rainfall can transport pollutants from the landscape into the ocean via a network of drains and rivers, potentially introducing nutrients, heavy metals, and hazardous organic compounds into the water. Mudslides and debris flows resulting from the Palisades Fire's burn scars could further increase hazardous waste dumping into marine environments. With less organic material post-fire to secure the soil, the risk of such flows increases significantly.
In response, Los Angeles County officials have deployed concrete barriers, sandbags, and silt socks to prevent debris from contaminating beaches. The LA County Board of Supervisors is also seeking additional state and federal support for expanded cleanup efforts, storm runoff preparations, and ocean water testing. State water officials are conducting extensive sampling for harmful metals like arsenic and lead, along with pollutants such as microplastics and polychlorinated biphenyls (PCBs), known to have severe health implications.
Although recent water sample tests did not indicate immediate health threats, public health officials still advised caution for beachgoers. Dinasquet and her research team are focused on mapping the spread of toxic ash and debris in the ocean, analyzing how deep contaminants sink, and tracking the long-term consequences of urban fire debris on marine ecosystems.
While forest fires can contribute beneficial nutrients like iron and nitrogen to the ocean ecosystem, the toxic ash resulting from urban coastal fires poses severe risks. Dinasquet pointed out evidence of lead and asbestos within the ash, emphasizing the potential harm not only to human health but also to marine organisms. There is a pressing concern regarding how these toxins may enter the food chain, and researchers intend to test fish tissue samples for heavy metals and other contaminants. Understanding the full impact of urban fires on the marine ecosystem and human food supplies will take time, but the situation is already dire due to the compounded effects of multiple environmental disasters.
