PFAS in pelagic Sargassum: A growing concern for the mexican caribbean coastline

Biraj Saha ¹, Mohamed Ateia ², Sujan Fernando ³

⁰Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, ND 58102, United States.

Journal of Hazardous Materials +

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July 5, 2025

View abstract on PubMed

Summary

Per- and polyfluoroalkyl substances (PFAS) were detected in Sargassum seaweed impacting coastlines. These persistent chemicals accumulate in seaweed, posing challenges for its use and disposal.

Area Of Science

Environmental Chemistry
Marine Biology
Pollution Studies

Background

Intensified global pelagic Sargassum blooms since 2011 impact over 30 countries.
Sargassum blooms present significant environmental and economic challenges worldwide.
The presence and impact of per- and polyfluoroalkyl substances (PFAS) in Sargassum remain largely uninvestigated.

Purpose Of The Study

To conduct the first investigation of PFAS contamination in Sargassum seaweed.
To analyze the types and concentrations of PFAS in Sargassum from the Mexican Caribbean.
To understand the distribution and bioaccumulation potential of PFAS within Sargassum.

Main Methods

Analysis of 40 different PFAS compounds in Sargassum samples collected from the Mexican Caribbean.
Quantification of total PFAS concentration and identification of dominant PFAS classes (perfluorocarboxylic acids vs. perfluorosulfonic acids).
Assessment of PFAS mass distribution across different morphological parts (blades, stems, bladders) and calculation of bioaccumulation factors (BAF).

Main Results

Ten PFAS were detected, with a total concentration of 3.88 ± 0.19 ng/g (dry weight).
Perfluorocarboxylic acids (80.7%) dominated over perfluorosulfonic acids (19.3%), and long-chain PFAS (57.1%) were more prevalent than short-chain.
PFAS mass varied by part, with lipid-rich bladders significantly contributing to long-chain PFAS; Log BAF increased with PFAS carbon chain length.

Conclusions

Sargassum acts as a vector for PFAS, accumulating these persistent pollutants.
The findings complicate Sargassum's use and disposal, necessitating pollution mitigation strategies.
Estimated annual PFAS loading highlights the scale of the issue in the Mexican Caribbean and Atlantic Sargassum Belt.

Keywords:

Bioaccumulation Ocean pollution PFAS distribution Sargassum Belt Seaweed