A new study has found that not only are some water filters incapable of removing potentially harmful ‘forever chemicals’ from drinking water, they may actually increase the quantity of these toxins if not maintained properly. The study comes from researchers with Duke and North Carolina State Universities; the team found that not all home water filters can remove toxic perfluoroalkyl substances (PFAS).
The toxins called PFAS most commonly originate from things like repellants and the foams used by firefighters. Unlike some toxins, these substances are called ‘forever chemicals’ because they remain in the environment, particularly in drinking water. Exposure to these chemicals may result in negative health effects with potential issues including things like thyroid disease and cancer.
Some water filters can remove these chemicals, but their effectiveness varies, according to the new study, which looked at nearly 100 point-of-entry, whole-home, and point-of-use water filters. Generally speaking, the two-stage and under-sink reverse osmosis filters were able to remove almost all of the PFAS toxins from water.
However, the more commonly used activated-carbon filters found in things like faucet filters and pitchers had far more variability in whether they could remove these substances. The whole-house water filtering systems, meanwhile, were found to actually increase the levels of PFAS water in some cases; an increase was noted in four out of six tested systems.
Whereas the two-stage and reverse osmosis filters were able to remove PFAS at levels of 94-percent or more, the activated-carbon filters averaged 73-percent removal; some were able to strip out all PFAS toxins whereas others didn’t have any noticeable effect. The researchers note that the most effective options are, sadly, also much more expensive, meaning people with lower incomes are more vulnerable to the toxins than wealthier households that can afford these systems.