From my understanding, in biogeochemistry point of view TPH would be a sum of two fractions both F1 containing aliphatic hydrocarbon (linear, branching and cyclic) and F2 containing PAHs. In bioremediation aplcation field, TPH refers to the extractable organic material using n-hexane as a solvant that surely contains F1 and some lesser extent of apolar compound (PAHs have slightly polar).
In theory, PAH (F2) are a small fraction of TPH. TPH includes several other compounds, such as n-alkanes, unresolved peaks, unresolved complex mixture, all of them F1.