1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

SECTION 2:PROBLEM FORMULATION
Benthic Macroinvertebrates – Benthic macroinvertebrates (various species) are primary
consumers that fulfill many of the selection criteria. They would be in direct contact with
potentially contaminated sediments and surface water, and as such, they would be exposed
to COPECs. They have a relatively small range, have high reproductive rates, and serve an
integral role in the aquatic and semi-aquatic ecosystem. They serve as a primary prey item
for fishes and some semi-aquatic representative bird species (e.g., stilt). Horned snails
(Certhidea californica), mussels (Ischadium demmissum), and grass shrimp (Palaemon
macrodactylus) were collected in 1998 as part of the ERA Sampling and Analyses.
Fish – Fish are secondary or tertiary consumers and would be exposed to COPECs in surface
water and prey items. They serve as forage for a variety of higher tropic-level fish, birds
(e.g., night-herons, egrets, cormorants, and mergansers), and mammals. Mosquitofish
(Gambusia affinis), topsmelt (Atherinops affinis), killifish (Fundulus parvipinnis), and tilapia
(Tilapia zillii) were collected for tissue analyses during the 1998 ERA Sampling and Analyses.
Semi-Aquatic Birds – Semi-aquatic birds (e.g., black-crowned night-heron [Nycticorax
nycticorax] and least tern [Sterna antillarum browni]) primarily feed on species associated with
aquatic habitats. Their habit of feeding in shallow waters for fish, amphibians, crustaceans,
and insects gives them a high potential for incidental ingestion of sediment and surface
water. Black-necked stilt (Himantopus mexicanus) eggs were collected in 1998 as part of the
ERA Sampling and Analyses.
Terrestrial Plants – Terrestrial plants are in direct contact with potentially contaminated
soils and surface waters. They are non-mobile and would have high exposure to COPECs.
Plants may also bioaccumulate COPECs in the leaves and other above-ground structures.
They serve as a food source for terrestrial birds and mammals. Saltgrass (Distichlis sp.),
pickleweed (Salicornia sp.), bassia (Bassia sp.), and alkali heath (Frankenia sp.) were collected
as part of the ERA Sampling and Analyses. (However, these invertebrates were scarce at the
time of sampling, and only a few were collected.)
Terrestrial Invertebrates – Terrestrial invertebrates, such as insects and spiders, would be in
direct contact with potentially contaminated soils or may consume contaminated prey, and,
as such, they would be exposed to COPECs. They have a relatively small range, have high
reproductive rates, and serve an integral role in the upland ecosystem. They serve as
primary prey items for some upland birds and small mammals. Spiders, beetles, and
grasshoppers were collected as part of the ERA Sampling and Analyses. (However, these
invertebrates were scarce at the time of sampling, and only a few could be collected).
Upland Birds – Upland birds, such as the American kestrel (Falco sparverius) and Belding’s
savannah sparrow (Passerculus sandwichensis beldingi), are found year-round and may be
exposed to COPECs through ingestion of contaminated food items.
Mammals – Western harvest mouse (Reithrodontomys megalotis) and coyote (Canis latrans) are
fairly common and may be exposed to COPECs through ingestion of food items. Western
harvest mouse, deer mouse (Peromyscus maniculatus), and California vole (Microtus
californicus) were trapped as part of the 1998 ERA Sampling and Analyses, primarily to
evaluate exposure of their consumers.
ERA REPORT 2-16 SAC/143368(002.DOC)
7/31/02