Aqueous film-forming foams used in Brazil are toxic to neotropical invertebrates

Aqueous film-forming foams (AFFFs) are an efficient firefighting strategy worldwide, and many of these products consist of complex mixtures containing per- and poly-fluoroalkyl substances (PFAS). The use of PFAS-based AFFFs is concerning because some of their constituents are classified as Persistent Organic Pollutants, thus their utilization during firefighting in industrial and harbor areas may increase the environmental impacts. In this study, the AFFFs toxicity to marine invertebrates was assessed using waterborne exposure. Seven PFAS-based commercial AFFFs (AFFF-1 to AFFF-7) employed to combat a major fire in the Port of Santos (Brazil) were obtained tested for acute toxicity to the brine shrimp Artemia salina and chronic toxicity to embryos of the brown mussel Perna perna, the sand dollar Mellita quinquiesperforata, and the sea urchins Lytechinus variegatus and Echinometra lucunter. Chronic toxicity tests on the reproduction of the copepod Nitokra sp. were conducted for two of the samples. All AFFFs were toxic to the marine species tested. Toxic dilutions were reported from 0.0001 % to 0.001 %, equivalent to concentrations between 1 and 10 thousand times lower than the application rates recommended by the manufacturers. AFFF-1, AFFF-5, and AFFF-7 were classified as moderately toxic, whereas AFFF-3, AFFF-4, and AFFF-5 were highly toxic, and AFFF-2 was very highly toxic. The hazard quotient values were elevated, ranging from 100 to 1000 times above the established thresholds. Our findings provide critical insights into the environmental hazards of AFFF use, particularly in Latin America and Caribbean coastal ecosystems, where regulatory frameworks are still being developed.