Plasma fluoride level expected in a healthy, fasting, long-term resident of a community with a water fluoride level of 1 ppm is approximately?

The  ionic  fluoride  is of  public health significance. It varies  according  to the concentration of fluoride in the drinking water.  Its  plasma  concentration  is approximately  twice  as  high  as  that associated with the blood cells. Since plasma fluoride  levels  are  not  homeostatically regulated, there is no normal physiologic concentration.  Plasma  fluoride  level expected in a  healthy, fasting, long-term resident of a community with a water fluoride level of 1 ppm is approximately 1 µM (0.019 ppm). There is evidence that plasma fluoride levels increase slightly with age.