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

Herkovits and Pérez-Coll (1991) examined Pb toxicity to amphibian larvae (Bufo
arenarum). Larvae (n = 50) were exposed for up to 120 h at two Pb concentrations, 8 mg Pb 2+ /L
and 16 mg Pb 2+ /L. Relative to controls, the 8 mg Pb 2+ /L treatment group exhibited 40%
mortality and the 16 mg Pb 2+ /L group 60% mortality after 120 h (p < 0.05). The authors reported
behavioral effects, erratic swimming, and loss of equilibrium during the tests, symptoms that are
consistent with the action of Pb on the central and peripheral nervous systems (Rice et al., 1999).
Behavior (i.e., righting, body turnover, seeking cover), growth, and survival of hatchling
slider turtles (Trachemys scripta) exposed to Pb-acetate were investigated in one study (Burger
et al., 1998). In the first part of the study, 6-month-old hatchlings received single Pb-acetate
injections at 50 or 100 µg/g body weight (bw). In the second part of the study, 3-week-old
turtles were injected once with doses of 250, 1000 or 2500 µg/g bw. There were no differences
in survival, growth, or behavior for hatchlings in the first study, however, several effects were
reported from the second part of the study at doses in the range of 250 to 2,500 µg/g bw. As the
dose increased, so did the plastron length (i.e., ventral section of the shell), carapace length, and
weight. The highest dose group had the lowest survival rate with an LD50 of 500 µg/g bw.
Behavioral effects included slower times of righting behavior and seeking cover. The authors
suggested a NOEL of 100 µg/g bw for slider turtles for survival and behavior.
AX7.2.4.4 Recent Studies on Effects of Lead on Decomposers
In this section, decomposers are defined as being bacteria and other microorganisms.
Many invertebrates are also potentially considered decomposers, but the effects of Pb to
invertebrates have been described in previous sections. There were no toxicity studies located on
the effects of Pb to aquatic decomposers in the time period of interest.
AX7.2.4.5 Summary
Lead in all its forms is known to cause adverse effects in aquatic organisms (Eisler, 2000).
Effects to algal growth have been observed at b concentrations ranging from 100 to
200,000 µg/L. Clinical signs of Pb toxicity in plants include the deformation and disintegration
of algae cells and a shortened exponential growth phase. Other effects of Pb include a blocking
of the pathways that lead to pigment synthesis, thus affecting photosynthesis, cell cycle and
division, and ultimately resulting in death. The toxicity of Pb to macrophyte growth has been
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