Does Sargassum on Beaches Pose Health Risks to Children Through Arsenic Exposure During Recreational Play?

Sargassum seaweed (Sargassum fluitans and Sargassum natans) bioaccumulates arsenic, an element that is toxic at low concentrations. With increasing sargassum strandings attributed to warmer oceans and climate-driven shifts in winds/currents, and increased nutrient availability, concerns now arise regarding potential health impacts on vulnerable populations, especially children. The objective of this study was to employ the risk assessment framework (hazard identification, exposure analysis, dose-response evaluation, and risk characterization) to assess non-cancer and cancer health risks from arsenic for children across different age groups who play at beaches impacted by sargassum. Risk simulations using a Monte Carlo approach were based upon ranges of arsenic levels measured in sargassum at beaches in southeast Florida (9.9 to 64.3 mg/kg in sargassum). Exposure analysis considered oral, dermal, and inhalation routes, accounting for potential contacts with beach water, sand, and sargassum that contain arsenic. Given the limited data on the release of arsenic from sargassum, samples of fresh and dried sargassum were analysed in this study using the Simulated Precipitation Leachate Protocol (SPLP). Results showed that non-cancer risks across all exposure routes were negligible with hazard quotients less than one. For cancer, low increased risks (10− 4) were driven by dermal exposures. Exposure through particulate inhalation was considered negligible and exposure through non-dietary ingestion contributed towards low increased cancer risks (10− 4) for children who engaged in pica activity (a condition associated with the intentional consumption of non-food items). Results from SPLP tests showed that between 7 and 59% of the arsenic is released from fresh and dried sargassum, supporting that the arsenic may be in an accessible form for exposure. Overall results underscore the cumulative nature of risks across exposure routes and age groups, necessitating a comprehensive understanding of beachgoers’ behaviors, fate of arsenic during sargassum decay, and confirmation of dermal uptake rates of arsenic through environmental media. The findings advocate for enhanced beach hygiene practices, public health awareness, and potential sargassum removal to reduce arsenic exposures.