Reproductive Ecology and Body Burden of Resident ... - The Love Lab

came from an oil platform (PL4, 3 of 8 fish) and a natural area (NA4, 9 of 10 fish), kelp rockfish came from
an oil platform (PL2, 1 of 10 fish) and two natural areas (NA3, 8 of 10 fish; and NA5, 2 of 10 fish), and Pacific
sanddab came from four oil platforms (PL2, 2 of 8 fish; PL3, 1 of 10 fish; PL4, 3 of 10 fish; and PL5, 1 of
10 fish) and a natural area (NA3, 3 of 10 fish). Although mercury is a potent neurotoxin capable of causing
outright mortality in fish and wildlife, sublethal effects may include suppression of sex hormones, altered
reproductive behavior, and impaired reproduction, along with maternal transfer of potentially toxic doses
of mercury to embryos during oogenesis (Wiener et al. 2003; Scheuhammer et al. 2007).
Selenium concentrations in only two Pacific sanddab, both from a natural area (NA2, 2 of 10 fish),
equaled or exceeded the toxicity threshold of 0.75-1.0 µg Se/g wet weight. According to Maher et al. (1997),
selenium recovered from fish muscle tissues are associated with proteins and consist mostly of selenocysteine.
Lemly (2002) reported that adverse effects from excessive selenium concentrations in fishes can include
severe tissue pathology, teratogenic deformities, and reproductive impairment, along with high mortality.
High concentrations of total DDT and total PCB have been implicated as the probable cause of reproductive
impairment in white croaker (Genyonemus lineatus) sampled from San Pedro Bay in the Southern
California Bight (Schiff et al. 2000). Damage to DNA and other subcellular evidence of contaminant exposure
in marine fishes have also been associated with high concentrations of chlorinated hydrocarbons
(Schiff et al. 2000). However, to our knowledge, no one has linked adverse ecotoxicological responses in
fishes, marine birds, or marine mammals from the Southern California Bight to elevated elemental concentrations
such as those measured during our study.
Relation of Elemental Concentrations in Fish to Human Health
The USEPA (2000) provided guidance on development of risk-based meal consumption limits for
inorganic arsenic, cadmium, methylmercury, selenium, and tributyltin in fishes for use in generating fish
consumption advisories (Table 4). However, these consumption limits for humans are based on skinless fillets
(axial muscle tissue), and not whole fishes. We estimated fillet concentrations from our data on whole
fishes by using average ratios of fillet and whole-body concentrations for arsenic, mercury, and selenium in
three marine fish species from the Salton Sea in southern California (Saiki 1990). We also estimated fillet
concentrations for cobalt, copper, iron, lead, nickel, vanadium, and zinc even though USEPA has not provided
guidance for these elements.
We were unable to find conversion factors for cadmium and tin, so we compared USEPA risk-based
meal consumption limits using whole-fish data. These comparisons indicated that cadmium concentrations
in 14 of 18 kelp bass, 31 of 80 kelp rockfish, and 96 of 98 Pacific sanddab exceeded 0.088 µg Cd/g wet weight,
which indicates that fish consumption should be restricted to 16 or fewer meals per month. Judging from
data for whole fishes (Figure 5), cadmium concentrations in fillets are not expected to differ substantially
between oil platforms and natural areas. None of the measured concentrations exceeded 5.6 µg Cd/g wet
weight, which corresponds to no consumption of fishes. Stapleton (1968) reported that muscle tissue in kelp
bass from the Scattergood Steam Plant in Santa Monica Bay contained average concentrations of 3.0-4.0
µg Cd/g dry weight (about 0.75-1.0 µg Cd/g wet weight, assuming 75% moisture), whereas kelp bass from
Catalina Island contained 2.0-3.0 µg Cd/g dry weight (about 0.50-0.75 µg Cd/g wet weight). Although tin
concentrations in 18 of 18 kelp bass, 53 of 80 kelp rockfish, and 4 of 98 Pacific sanddab exceeded 0.088 µg
Sn/g wet weight, indicating that fish consumption should be limited to 16 or fewer meals per month, the
risk-based consumption limit was based on highly toxic tributyltin, whereas we measured total tin concentrations
that possibly included relatively non-toxic inorganic tin. We did not attempt to estimate the proportion
of tributyltin in our fish samples because it can vary widely in marine fishes (organotins may represent
as little as 3-6% or as much as 18-52% of total tin; Eisler 1989).
Arsenic concentrations estimated for fillets were seemingly elevated in fishes sampled from oil platforms
and natural areas during our study, with the lowest concentration (0.674 µg As/g wet weight in kelp
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