1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

SECTION 2:PROBLEM FORMULATION
Fish can be exposed to chemicals in sediment and/or surface water through incidental
ingestion, dermal contact, uptake across the gills, and consumption of contaminated aquatic
plants or invertebrates. However, because no suitable model was available to evaluate
food-chain exposures, food ingestion was not included in the evaluation. Fish also serve as
a major route of food chain transfer because they are prey for other fish and semi-aquatic
wildlife.
Exposure through the food chain is limited to chemicals that bioaccumulate. Chemicals can
be accumulated in plants that are consumed by herbivorous animals, which are then
consumed by omnivorous and insectivorous animals, carnivorous animals, and
decomposers. Pesticides, such as DDT and its metabolites, are of primary concern for
bioaccumulation because these chemicals can also biomagnify up the food chain.
2.6 Biota Sampling in Nearby Areas
Aquatic biota similar to those collected within the Bolsa Chica Lowlands (Sections 2.3.1 and
2.5.1) for the ERA have been sampled in nearby areas through other programs. The Seal
Beach National Wildlife Refuge Study (SWDIV 1995) was conducted to assess the effects of
operations at Naval Weapons Station Seal Beach on the biota of the tidal marsh at Seal Beach
National Wildlife Refuge. The study focused on the potential bioaccumulation of chemicals
in species that are the primary food items of the light-footed clapper rail and California least
terns. Results for invertebrates and fish are summarized in Table 2-24.
Fish also were sampled in Anaheim Bay/Huntington Harbour through the Toxic Substances
Monitoring Program (Rasmussen 1995, 1997). Black perch (Embiotoca jacksoni) and barred
surfperch (Amphistichus argenteus) were sampled in 1992-1993 and yellowfin croaker
(Umbrina roneador) were sampled in 1995. Results for these fish are summarized in
Table 2-25. In 1992, the fish contained elevated levels of total chlordane and total DDT, and
in 1993 they contained elevated levels of chromium and total DDT. In 1995, elevated levels
of total chlordane, total DDT, and total PCB were found in fish.
Transplanted California mussels (Mytilus californianus) were sampled at the Warner Avenue
Bridge on Huntington Harbor in 1994 and 1995 (Rasmussen 1996). (Because no suitable
resident population existed there, mussels from Trinidad Head or Bodega Head were
deployed for 4-6 months prior to sampling). Results are presented in Table 2-26. Mussels
contained elevated levels of cadmium, zinc, chlorpyrifos, total chlordane, total DDT,
dieldrin, and total PCB in both 1994 and 1995. In 1994, concentrations of arsenic, lead,
selenium, and oxadiazon also were elevated, and in 1995, chromium, heptachlor epoxide,
and toxaphene were elevated.
ERA REPORT 2-18 SAC/143368(002.DOC)
7/31/02