Total petroleum hydrocarbons (TPH) is a term used to
describe a large family of several hundred chemical compounds that originally come from crude oil. Crude oil is used
to make petroleum products, which can contaminate the environment. Because there are so many different chemicals in
crude oil and in other petroleum products, it is not practical to measure each one separately. However, it is useful to measure
the total amount of TPH at a site.
TPH is a mixture of chemicals, but they are all made
mainly from hydrogen and carbon, called hydrocarbons. Sci
entists divide TPH into groups of petroleum hydrocarbons
that act alike in soil or water. These groups are called petro
leum hydrocarbon fractions. Each fraction contains many
individual chemicals.
Some chemicals that may be found in TPH are hexane,
jet fuels, mineral oils, benzene, toluene, xylenes, naphthalene,
and fluorene, as well as other petroleum products and gasoline
components. However, it is likely that samples of TPH will
contain only some, or a mixture, of these chemicals.