20 June 2024

Fluoride contamination affects British otters


Otters deceased near a factory in the UK show traces of toxic perfluorinated alkylated substances that have spread into the environment and soil, a Cardiff University study says

by Matteo Cavallito


Contamination by PerFluorinated Alkylated Substances or PFAS affects British otters. This was reported by a Cardiff University research published in the journal Environmental Science and Technology. The phenomenon once again raises concerns about the impact of these chemicals on water, soil and human health.

“PFAS chemicals are highly soluble in water, and often enter the environment via wastewater from industry, as well as run off from sewage, landfill, and PFAS-based firefighting foam,” explains Emily O’Rourke, a researcher at the same university in a statement. “As otters are top predators in British freshwaters, they can accumulate PFAS chemicals through their diet, making them effective indicators of environmental contamination.”

Otters in the crosshairs

The study is part of a research project on otters across the UK. The investigation, in particular, set out to analyse concentrations of 33 types of PFAS in otters found dead between 2015 and 2019, focusing on an area near a factory that had previously used these same substances in its processes.

“Despite cessation of usage in 2012, PFOA (perfluorooctanoic acid, ed.) concentrations remained high near the factory (>298 μg/kg ww <20 km from factory) and declined with increasing distance (<57 μg/kg ww >150 km away),” the research states.

According to the authors, as a result, otters end up acting as authentic “sentinels for evaluating mitigation success and highlights the value of continued monitoring.”

The substances will persist in the soil

PFAS are also called forever chemicals, an expression that indicates their persistence in soils. These substances, the journal Scientific American wrote, “are both highly stable and useful in products designed to repel grease and water. But it also means they do not readily biodegrade.”

Hosting them, among others, are products such as fluorinated pesticides – those containing one or more fluorine atoms in their molecular structure – which are particularly effective in combating plant pests precisely because of their chemical stability.

This characteristic, in fact, favours their prolonged action, while limiting their disposal potential. According to some estimates, the half-life of some fluorinated substances – i.e. the time it takes for their presence in the environment to be halved after spraying – can be up to two and a half years. The EPA, the US Environmental Protection Agency, defines ‘persistent’ as pollutants with a half-life of at least 60 days.

Substitutes do not look like a viable solution

The Cardiff University study also looks at “substitute” substances that have partly supplanted traditional PFAS in recent years. Older chemicals, which are now regulated, are still present in otters in higher concentrations, the authors note. But some new compounds were still detected in most of the specimens.

According to O’Rourke, therefore, many replacement substances “are, or have the potential to become, global contaminants. This is especially concerning due to their possible toxicity. Studies on rats, mice, and fish have started to demonstrate that they have the potential to cause toxic effects.”