ABSTRACT
Low to high concentrations of petroleum hydrocarbons and industrial chemicals (polyphenyl ether, polychlorinated biphenyls, DDE; phthalates, adipates) have been detected in nearly all benthic and sandy intertidal sediment samples collected from the Southern California borderland. Low levels of petroleum contamination in combination with recent biogenic contributions were interpreted primarily on the basis of fully-saturated cycloalkanes in the absence of cyclic alkenes, the presence of a gas chromatographically-unresolved baseline envelope, and the presence of an homologous series of alkyl aromatic hydrocarbons.
The inner basins of the Southern California Bight exhibit higher concentrations of weathered petroleum than either the farther offshore basins, or the sandy intertidal zone. Near Tanner-Cortez banks and in the San Nicolas Basin, sediments appear to contain unweathered petroleum and high levels of anthropogenic chemicals. The possible sources of hydrocarbons found in the Southern California borderland sediments, in addition to shipping losses and harbor traffic, include municipal and industrial waste waters, as well as previously-undetected submarine oil seeps, submarine chemical dumps, and geochemically-mature, organic-rich Tertiary shales.
N2
: Ar, nitrification and denitrification in southern California borderland basin sediments1
