Welcome To Whitehall Township Whitehall Township is located in the center of the Lehigh Valley. The Township is one hour north of Philadelphia and an hour and half from New York City.
SALINITY OVERVIEW Salinity is the concentration of dissolved salts in water, usually expressed in parts per thousand (ppt). Objects float higher in salt water than fresh water because salt water is denser (heavier per unit of volume).
A PPD test involves injecting small amounts of protein from the mycobacteria that cause tuberculosis into the skin. PPD stands for 'purified protein derivative', indicating that the substance injected is non-infectious. This is known as the Mantoux-method TST (tuberculin skin test) . PPD is only recommended in people who have not had a prior positive test. It should be repeated annually in anyone who is at high-risk of acquiring TB.