DISTRIBUTIONS AND FATE OF CHLORINATED PESTICIDES, BIOMARKERS AND POLYCYCLIC AROMATIC-HYDROCARBONS IN SEDIMENTS ALONG A CONTAMINATION GRADIENT FROM A POINT-SOURCE IN SAN-FRANCISCO BAY, CALIFORNIA
We. Pereira et al., DISTRIBUTIONS AND FATE OF CHLORINATED PESTICIDES, BIOMARKERS AND POLYCYCLIC AROMATIC-HYDROCARBONS IN SEDIMENTS ALONG A CONTAMINATION GRADIENT FROM A POINT-SOURCE IN SAN-FRANCISCO BAY, CALIFORNIA, Marine environmental research, 41(3), 1996, pp. 299-314
The distribution and fate of chlorinated pesticides, biomarkers, and p
olycyclic aromatic hydrocarbons (PAHs) in surficial sediments along a
contamination gradient in the Lauritzen Canal and Richmond Harbor in S
an Francisco Bay was investigated. Compounds were identified and quant
ified using gas chromatography-ion trap mass spectrometry. Biomarkers
and PAHs were derived primarily from weathered petroleum. DDT was redu
ctively dechlorinated under anoxic conditions to DDD and several minor
degradation products, DDMU, DDMS, and DDNU. Under aerobic conditions,
DDT was dehydrochlorinated to DDE and DBP. Aerobic degradation of DDT
was diminished or inhibited in zones of high concentration, and incre
ased significantly in zones of lower concentration. Other chlorinated
pesticides identified in sediment included dieldrin and chlordane isom
ers. Multivariate analysis of the distributions of the DDTs suggested
that there ave probably two sources of DDD. In addition, DDE and DDMU
ave probably formed by similar mechanisms, i.e. dehydrochlorination. A
steep concentration gradient existed from the Canal to the Outer Rich
mond Harbor, but higher levels of DDD than those found in the remainde
r of the Bay indicated that these contaminants are transported on part
iculates and colloidal organic matter from this source into San Franci
sco Bay. Chlorinated pesticides and PAHs may pose a potential problem
to biota in San Francisco Bay.