PH11 Global Perspectives on Soil Ecotoxicology
Exhibit Hall
8:00 AM - Thursday
(PH140) Preliminary evaluation and review of perchlorate toxicity on terrestrial animals.
Tsao, C.L.1, Sample, B.E., Salice, C.J.2, Arenal, C.A.1, 1 CH2M Hill, Sacramento, CA, USA2 U.S. Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, MD, USA
ABSTRACT- Ammonium perchlorate is used as an oxidizer in rocket propellants, in various explosives, flares and pyrotechnics and in several other industrial uses. Most release of perchlorate to the environment occurs in connection with the manufacture, use and disposal of rocket propellants and explosives. Salts of perchlorates have high solubility in non-aqueous and aqueous environments and are very stable. Hence, there is concern over possible toxicological effects of perchlorate in wildlife. We conducted a literature review and toxicity assessment of the current knowledge of the toxic effects of perchlorate ions (ClO4-) to terrestrial animals. Relevant biomedical, toxicological, and ecological databases were searched to identify primary reports of studies and reviews of perchlorate toxicity. Separate searches were carried out linking the compound to laboratory mammals, birds, reptiles, amphibians, and wild mammals. Secondary sources reviewed included the Perchlorate Study Group's perchlorate literature review, US Air Force perchlorate literature review, US Air Force perchlorate ecological risk studies, and EPA's perchlorate toxicological review. Twenty-four articles were selected for retrieval from the initial 99 hits. Published toxicological studies on perchlorates have primarily focused on laboratory mammals such as rats and mice. Among these, most studies were based on water ingestion rather than food intake. For those studies focused on the systemic effect of perchlorate on growth, reproduction, and body weight, we found that they generally did not attain sufficient effect levels to enable a determination of a NOAEL and/or LOAEL. Reported effects focused primarily on thyroid-to-body weight ratios and thyroid hormone levels; in general NOAELs and LOAELs for laboratory rats and mice ranged from 0.00847 to 10.9 mg/kg/d, and from 0.0423 to 54.3 mg/kg/d, respectively. This preliminary assessment of perchlorate toxicity to terrestrial wildlife species will form the basis of a toxicity reference value (TRV) and may be used to direct future research efforts.
Key words: ecological extrapolation, perchlorate, toxicity reference value, ecological risk assessment