Toxic Sargassum Threatens Quintana Roo Coast

Sargassum, a type of seaweed, is washing up on the shores of Quintana Roo with increasing levels of pollutants, microplastics, arsenic, and other heavy metals. These pose a health risk to humans due to the release of toxic gases as the seaweed decomposes.

Esteban Amaro Mauricio, director of the Quintana Roo Sargassum Monitoring Network, explains that the seaweed becomes a source of marine pollution as soon as it hits the coast. The seaweed carries with it heavy metals, arsenic, and microplastics. "While it's in the sea, it releases a lot of organic matter, which later decomposes. Once it lands on the beach, the dried Sargassum breaks down, generating toxic gases such as ammonia, hydrogen sulfide, carbon dioxide, and carbon monoxide," Mauricio explains.

Due to its heavy metal content, the sargassum is considered hazardous waste upon reaching the beach and should be treated as such. This is a stark contrast to how it would be handled if it were considered fishing cargo.

Mauricio notes, "If it were collected in the high seas, it would be much easier for everyone. Sargassum in the sea can be managed and does not emit gases or toxic substances. The problem arises when it reaches the beach and begins to break down."

Fortunately, when the sargassum is used for entrepreneurial projects, techniques exist to remove these heavy metals and primarily arsenic, using alkaline substances or aluminum gels. Mauricio points out that only 10 percent of the total sargassum that reaches the Yucatan Channel ends up on the state's shores. Therefore, it would be beneficial to collect it before it reaches the coast, providing an abundant, fresh, and easily processable raw material.

He estimates that 15 to 20 million metric tons of sargassum pass through the Atlantic Ocean and the Caribbean each year. Interestingly, Quintana Roo has seen fewer sargassum deposits in 2024, as the seaweed that was heading towards the state's coasts was diverted to the Lesser Antilles.