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

number of U.S. rivers and lakes was then added to the test system, and the LT50 was reported.
NOM was found to reduce the toxic effects of Pb to rainbow trout.
Fish size is an important variable in determining the adverse effects of Pb. Alam and
Maughan (1995) exposed two different sizes of common carp (Cyprinus carpio) to Pb
concentrations to observed effects on carp mortality. Water chemistry parameters were reported
(pH = 7.1; temperature = 20 ΕC). Smaller fish (3.5 cm) were found to be more sensitive to Pb
than were larger fish (6.5 cm). The reported LC50s were 0.44 mg/L and 1.03 mg/L, respectively.
Marine Fish
There were no studies available that examined the toxicity of Pb to marine fish species for
the time period examined (1986 to present). However, Eisler (2000) reviewed available research
on Pb toxicity to marine species and reported studies done prior to 1986. Acute toxicity values
ranged from 50 µg/L to 300,000 µg/L in plaice (Pleuronectes platessa) exposed to organic and
inorganic forms of Pb (Eisler, 2000). Organolead compounds (e.g., tetramethyl Pb, tetraethyl Pb,
triethyl Pb, diethyl Pb) were generally more toxic to plaice than inorganic Pb (Maddock and
Taylor, 1980).
Other Aquatic Biota
A paucity of data exist on the effects of Pb to growth, reproduction, and survival of
aquatic stages of frogs and turtles. Rice et al. (1999) exposed frog larvae (Rana catesbeiana) to
780 µg Pb/L and two oxygen concentrations (3.5 or 7.85 mg/L) for 7 days (Table AX7-2.4.3).
Exposure conditions included water hardness of 233 to 244 mg CaCO3/L, pH from 7.85 to 7.9,
and temperature at 23 ΕC. Frog larvae were found to display little to no activity in the low
oxygen and high Pb treatment. Hypoxia-like behavior was exhibited in larvae exposed to both
low and high oxygen concentrations and high Pb. Therefore, larvae of R. catesbeiana showed
sensitivity to Pb and responded with hypoxia-like behavior. Additionally, the larvae in the Pb
treatment were found to have lost body mass relative to controls and the other treatments. Rice
et al. (1999) suggested that the decrease in mass likely indicated the beginning of a period of
reduced growth rate. Larvae exposed for longer periods (>4 weeks) were smaller and
metamorphosed later compared to unexposed individuals.
AX7-191