Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

to 0, 18,000, 24,000, and 33,000 µg/L of Pb (Ruparelia et al., 1989). Significant decreases in
plasma glucose (hypoglycemic levels) were reported at concentrations of 24,000 and 33,000 Φg
Pb/L after 14 and 21 days of exposure, and at 18,000 µg Pb/L after 21 days of exposure
(Ruparelia et al., 1989). Plasma cholesterol levels dropped significantly in comparison to
controls after 14 days of exposure to 33,000 µg Pb/L and in all test concentrations after 21 days
of exposure (Ruparelia et al., 1989). Similarly, concentrations of blood serum protein, albumin,
and globulin were identified as bioindicators of Pb stress in carp (Cyprinus carpio) exposed to
Pb-nitrates at concentrations of 800 and 8000 µg Pb/L (Gopal et al., 1997).
Tissues
In fish, the gills serve as an active site for ion uptake. Recent studies have examined the
competition between cations for binding sites at the fish gill (e.g., Ca 2+ , Mg 2+ , Na + , H + , Pb 2+ )
(MacDonald et al., 2002; Rogers and Wood, 2003, 2004). Studies suggest that Pb 2+ is an
antagonist of Ca 2+ uptake (Rogers and Wood, 2003, 2004). MacDonald et al. (2002) proposed a
gill-Pb binding model that assumes Pb 2+ has a ∃100 times greater affinity for binding sites at the
fish gill than other cations. More toxicity studies are required to quantify critical Pb burdens that
could be used as indicators of Pb toxicity (Niyogi and Wood, 2003).
Growth Responses
A negative linear relationship was observed in the marine gastropod abalone (Haliotis)
between shell length and muscle Pb concentrations (Arai et al., 2002). Abalones were collected
from two sites along the Japanese coast. Haliotis discus hannai were collected from along the
coast at Onagawa; Haliotis discus were collected from along the coast at Amatsu Kominato. The
authors did not report significant differences between the two sampling sites. From samples
collected at Onagawa, Pb concentrations of 0.03 and 0.01 µg/g were associated with abalone
shell lengths of 7.7 cm (3 years old) and 12.3 cm (6 years old), respectively. From samples
collected at Amatsu Kominato, Pb concentrations of 0.09 and 0.01 µg/g were associated with
abalone shell lengths of 3.9 cm (0 years old) and 15.3 cm (8 years old), respectively (Arai et al.,
2002). The authors theorized that young abalones, experiencing rapid growth, do not
discriminate between the uptake of essential and nonessential metals. However, as abalones
grow larger and their rate of growth decreases, they increasingly favor the uptake of essential
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