The MassDEP drinking water standard is based on studies of the six PFAS substances in laboratory animals and
studies of exposed people. Overall, these studies indicate that exposure to sufficiently elevated levels of the
six PFAS compounds may cause developmental effects in fetuses during pregnancy and in breastfed infants.
Effects on the thyroid, the liver, kidneys, hormone levels and the immune system have also been reported.
Some studies suggest a cancer risk may exist following long-term exposures to elevated levels of some of
It is important to note that consuming water with PFAS6 above the drinking water standard does not mean
that adverse effects will occur. The degree of risk depends on the level of the chemicals and the duration of
exposure. The drinking water standard assumes that individuals drink only contaminated water, which
typically overestimates exposure, and that they are also exposed to PFAS6 from sources beyond drinking
water, such as food. To enhance safety, several uncertainty factors are additionally applied to account for
differences between test animals and humans, and to account for differences between people. Scientists are
still working to study and better understand the health risks posed by exposures to PFAS. If your water has
been found to have PFAS6 and you have specific health concerns, you may wish to consult with your doctor.