Reacción a "Reaction: Research finds PFAS in toilet paper discharged into US wastewater"

Perfluoroalkylated and polyfluoroalkylated substances (PFAS) are chemical compounds that, due to their properties - they are non-flammable, thermodynamically stable and highly resistant - are used in a range of industrial and commercial applications such as non-stick cookware, food packaging, insecticides, and waterproof and flame retardant fabrics. According to the most recent research, more than 200 use categories and subcategories have been identified for more than 1,400 PFAS compounds. Due to these same properties, PFASs are considered to be extremely persistent in the environment, highly toxic and with the potential to bioaccumulate and biomagnify up the food chain, and have been detected in wildlife and represent a clear potential hazard to human health. In general, these compounds can act as endocrine disruptors and may have many other toxic effects, such as hepatotoxicity, immunotoxicity, reproductive toxicity and tumourigenic effects, among others. 

PFASs can reach the environment, after domestic use, through effluents from Waste Water Treatment Plants (WWTPs) and sludge from these plants. Now, Dr Timothy G. Townsend's research group at the University of Florida has published a paper in the ACS's Environmental Science & Technology Letters warning of an unexpected source of these substances in wastewater systems: toilet paper. The researchers hypothesise that some toilet paper manufacturers may add PFASs during the manufacturing process that converts wood to pulp, adding that recycled toilet paper could be made from fibres derived from PFAS-containing materials. 

Townsend and his group analysed samples of toilet paper from North, South and Central America; Africa; and Western Europe for 34 PFASs. They also analysed samples of sewage treatment plant (WWTP) sludge from the USA and detected several of these compounds, including disubstituted polyfluoroalkylphosphates (diPAPs) and, most notably, diPAP 6:2, which was the most abundant in both types of samples, albeit at very low concentrations, in the order of parts per billion. These results are very important as diPAPs can be converted into other more stable PFASs, such as perfluorooctanoic acid (PFOS), whose production was already banned by the EU in 2008, after being considered as a persistent organic pollutant in the Stockholm Convention, as it is potentially carcinogenic. 

A study published in 2013 by the research group on Food and Environmental Safety of the University of Valencia (SAMA-UV) highlighted the role of WWTPs as possible sources of PFAS contamination in different basins in Spain (Ebro, Guadalquivir, Júcar and Llobregat). The results of the research by Townsend's group confirm these conclusions and add an important factor to be taken into account, such as toilet paper. The researchers calculated that toilet paper contributed approximately 4 % of the diPAP 6:2 in wastewater in the USA and Canada, 35 % in Sweden and up to 89 % in France. As they conclude in their study, toilet paper can be considered a source of PFAS for wastewater treatment systems, becoming a major source in some places.