Inputs and fates of petroleum hydrocarbons in a subtropical marine estuary

Inputs and fates of petroleum from a higly urbanized area to a subtropical marine estuary were investigated by measuring hydrocarbon concentrations in municipal wastewater treatment plants, urban stormwater drains, sediments, and benthic organisms in and around Tampa Bay, FL. The concentrations of petroleum hydrocarbons discharged from secondary and tertiary treatment plants in this area were lower than concentrations previously reported for other treatment plants in temperate regions. Samples collected from urban storm drains under base flow conditions were also low. The generally low levels of petroleum hydrocarbons in the sediments and organisms throughout Tampa Bay suggest that the bay is relatively pristine with respect to petroleum hydrocarbon contamination. Since it is unlikely that the anthropogenic input of hydrocarbons to this estuary is significantly lower than in other urbanized areas, we suggest that elevated annual temperatures in this subtropical system result in increased metabolic rates of microorganisms and more rapid degradation or metabolism of the petroleum hydrocarbons.