PH11 Global Perspectives on Soil Ecotoxicology
Exhibit Hall
8:00 AM - Thursday
(PH142) Effects of long term in ovo exposure to sodium perchlorate on incubation and growth of sceloporine lizards.
Redick, M1, Janz, D2, Talent, L1, 1 Oklahoma State University, Stillwater, OK, USA2 University of Saskatchewan, Saskatoon, SK, Canada
ABSTRACT- This research was designed to determine the effects of long term in ovo perchlorate exposure on the mass of incubating eggs and post-hatching growth of western and eastern fence lizards, Sceloporus occidentalis and S. undulatus, respectively. Perchlorate is known to prevent iodide uptake by the thyroid gland, which interferes with synthesis of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). Decreases in circulating embryonic thyroid hormones may interfere with growth and development of embryos as well as subsequent growth and development after the lizards hatch. Eggs were collected from laboratory populations of both species of fence lizards on the day of oviposition and incubated on sodium perchlorate-spiked perlite at a constant temperature of 28°C. Eggs were weighed weekly throughout incubation. After hatching, mass and snout-vent length of lizards were determined monthly for four months. Perchlorate crossed the eggshell and accumulated in embryonic tissue at levels exceeding exposure concentrations. All eggs increased in mass during incubation but the mass of eggs exposed to 0.975 mg perchlorate/g incubation substrate was significantly less than control eggs beginning one week after exposure to sodium perchlorate. Doses greater than 0.487 mg perchlorate/g incubation substrate delayed or inhibited the pipping response in both species of fence lizards. For lizards that successfully hatched, mortality was elevated in the higher exposure groups but no differences in growth rates were detected in survivors regardless of exposure level. Ongoing research will determine the effects of embryonic exposure to perchlorate on sprint speeds and reproduction after exposed lizards mature.
Key words: perchlorate, reptile, embryonic, growth