Pollutant exposure
Habitat condition
Sediment samples were collected with a 0.1 m2 Van Veen grab and washed through a 1.0-mm mesh screen. The retained material was sorted in the laboratory and all organisms were counted and identified to species or the lowest taxonomic unit possible. Species abundance data were used to calculate the benthic response index (BRI), which summarized the relative impact from pollution at each station. Total biomass (wet weight) of the sorted sample was also measured.
Epibenthic fish were collected using a semiballoon otter trawl (7.6 m head rope, 3.8 cm body mesh) which was towed for about 600 m along the bottom. The catch was identified to species, counted, and weighed. Each individual was measured for standard length and examined for external pathology.
The outer surface of each fish was examined for evidence of fin erosion, tumors, parasites, color and skeletal anomalies, and lesions.
Chlorinated hydrocarbons were measured in liver tissue from three species of flatfish: Pacific sanddab, longfin sanddab, and Dover sole. Livers from 10-15 fish/species were composited and analyzed for DDT, DDE, DDD, other chlorinated pesticides (e.g., Chlordane and Endosulfan), and 27 PCB congeners.
Surface sediment (upper 2 cm) from the Van Veen grabs was analyzed for contaminants. The analytes included: polynuclear aromatic hydrocarbons (acenaphthene, acenaphthylene, anthracene, benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, benzo[a]pyrene, chrysene, dibenz[ah]anthracene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, naphthalene, phenanthrene, and pyrene), chlorinated pesticides (DDT, DDE, DDD, Aldrin, -Chlordane, Dieldrin, Endosulfan, Endrin, heptachlors, Lindane, Mirex, and trans-nonachlor), and metals (antimony, arsenic, cadmium, chromium, copper, iron, lead, mercury, nickel, selenium, silver, and zinc).
Surface sediment (upper 2 cm) from the Van Veen grabs was evaluated for toxicity using two tests. A 10-day amphipod (Ampelisca abdita) survival test was conducted on whole sediment. Interstitial water was extracted from the sediment and evaluated using a 72-hour sea urchin (Strongylocentrotus purpuratus) embryo development test.
Dissolved oxygen in the water column was measured at 1 m intervals using an electronic sensor mounted on a CTD.
The presence or absence of debris in the fish trawl catch was noted (the amount was not recorded). The type of debris was recorded and included the following categories: glass bottles, cans, fishing gear, terrestrial vegetation, and marine vegetation.
Surface sediment (upper 2 cm) from the Van Veen grabs was measured for grain size (laser light scattering) and total organic carbon (combustion). The percent of sand, silt, and clay were calculated from the grain size data.
Salinity in the water column was calculated from conductivity and temperature data recorded at 1 m intervals using a CTD.
Water column temperature was recorded a 1 m intervals using an electronic sensor on a CTD.
Bottom depth was measured at the time of sampling using a fathometer.
Water clarity (% light transmission) was measured using a transmissometer (25 cm path length) mounted on a CTD.