Micropollutant content of Sargassum drifted ashore: arsenic and chlordecone threat assessment and management recommendations for the Caribbean

Abstract

Massive Sargassum beachings occur since 2011 on Caribbean shores. Sargassum inundation events currently involve two species, namely S. fluitans and S. natans that are circulating and blooming along the North Atlantic subtropical gyre and in the entire Caribbean region up to the Gulf of Mexico. Alike other brown seaweeds, Sargassum have been shown to bioaccumulate a large number of heavy metals, alongside with some organic compounds including the contamination by historical chlordecone pollution in French West Indies (FWI), an insecticide used against the banana’s weevil Cosmopolites sordidus. The present study reports, during two successive years, the concentration levels of heavy metals including arsenic in Martinique and Guadeloupe (FWI). We found that Sargassum can also accumulate high concentration of chlordecone. Sargassum contamination by chlordecone is observed in areas that are close to contaminated river mouth. Our results further demonstrate that algae bleaching raises a number of questions about inorganic and organic pollutants bioaccumulation, transport and dissemination.

Free-swimming fauna associated with influxes of pelagic sargassum: Implications for management and harvesting

“…Sargassum influx events are now considered the new 'normal' for the region (Desrochers et al, 2020) and show a trend of increasing severity (The Sargassum Watch System (SaWS), 2022). As the region continues to adapt to this new reality, there has been a surge in research and publications on impacts (Milledge and Harvey, 2016;Ramlogan et al, 2017;van Tussenbroek et al, 2017;United Nations Environment Programme, 2018;Resiere et al, 2019), forecasting (Wang and Hu, 2017;Johnson et al, 2020;Marsh et al, 2021;Marsh et al, 2022), potential uses (Desrochers et al, 2020;Thompson et al, 2020;Amador-Castro et al, 2021;Oxenford et al, 2021;United Nations Environment Programme -Caribbean Environment Programme et al, 2021) and chemical composition (Devault et al, 2019;Davis et al, 2020;Nielsen et al, 2021;Devault et al, 2022;Tonon et al, 2022). Research into the sargassum phenomenon reveals considerable spatial and temporal complexities associated with management due to its transboundary nature and unpredictability (Cox et al, 2021).…”