Sargassum toxicity is being studied; UNAM analyses health risks

Scientists from Mexico’s National Autonomous University (UNAM) are investigating the potential health risks posed by hydrogen sulfide gas released during the decomposition of seaweed along coastal areas in Quintana Roo. The study focuses on residents living near beaches where large accumulations of seaweed have gathered, raising concerns over long-term exposure to the toxic gas. The research began with assessing the health impacts on workers who manually remove seaweed from shores in Puerto Morelos, Playa del Carmen, and Mahahual. These individuals were exposed to high levels of hydrogen sulfide, which has been linked to respiratory and other health issues. Now, scientists are expanding their investigation to include nearby communities, aiming to determine how far the gas spreads and its effects on non-workers living close to these accumulation zones. Rosa Rodríguez, a researcher at the Institute of Marine Sciences and Limnology (ICMyL) at UNAM's Puerto Morelos unit, explained that nine fixed sensors have already been installed in residential areas near the coast to monitor gas concentrations. These devices are designed to operate autonomously and avoid vandalism. The placement of sensors in homes aims to capture data on how gas levels decrease with distance from the shoreline. Rodríguez noted that previous studies in Martinica suggest hydrogen sulfide can travel up to two kilometers from the coast. In Quintana Roo, however, some homes are located just 40 meters away from seaweed accumulation sites, prompting concern over increased exposure this year due to higher volumes of seaweed. Researchers are monitoring whether gas concentrations have similarly risen. Residents in affected areas have reported physical discomfort, including breathing difficulties and gastrointestinal symptoms, leading some to seek medical advice. Additionally, property rental platforms have seen a decline in bookings due to the presence of decomposing seaweed, affecting local economies. Access to beaches and the ocean has also become challenging in regions where seaweed accumulates heavily. This phase of the study is part of a larger initiative funded by Canada’s government through the University of Victoria and conducted in collaboration with the University of São Paulo in Brazil. It builds upon earlier research carried out in Martinica and other French Caribbean islands, where similar health concerns were observed among populations living near seaweed deposits. In Martinica, researchers compared two groups: one residing in areas with regular seaweed accumulation and another in less affected zones. Medical records showed an increase in certain symptoms, particularly respiratory, neurological, and gastrointestinal, in the group exposed to higher levels of hydrogen sulfide. This finding underscores the need for further investigation into the long-term health implications for residents in Quintana Roo. Rodríguez emphasized that while initial studies focused on workers handling seaweed, the current phase seeks to understand the broader public health impact. She highlighted that many residents live near accumulation sites and may experience prolonged exposure, even if they do not directly engage in seaweed removal activities. The goal is to establish safe thresholds for gas concentration and identify vulnerable populations. The installation of new sensors continues, with plans to expand the network to cover more locations. Scientists hope to gather comprehensive data that will inform public health policies and guide efforts to mitigate risks associated with seaweed decomposition. As the study progresses, ongoing monitoring will remain critical to understanding the evolving situation.