Accumulation and effects of HMX in the green anole (Anolis carolinensis)

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2007-08

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Abstract

The use and subsequent environmental contamination of energetic compounds is an ever increasing international concern. Perhaps one of the greatest lapses in knowledge, and therefore threats to the natural environment, of these compounds is their toxicity to reptiles, particularly with respect to reproduction. To that end, a three-part study was conducted in an effort to define the role of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX, High Melting Explosive), one of the top four explosive compounds of the twentieth century, in the reproductive toxicology of the green anole (Anolis carolinensis), a common reptilian model species. First, the acute oral toxicity (LD50) was measured in adult anoles using the up-and-down method described by the Organization for Economic Co-Operation and Development and United States Environmental Protection Agency. Then, part two of the study used artificially contaminated nesting media to assess accumulation of HMX into eggs at different combinations of incubation time and concentration. Also, initial growth parameters were measured for all hatchlings. The third part of the study was designed to assess HMX transfer from the diet of adults to eggs. In addition to assessing accumulation, hatching rates of eggs, growth rate of hatchlings, and signs of toxicity and abnormal reproductive function in adults were monitored.
HMX was not acutely toxic to adult anoles and the LD50 was estimated at greater than 2,000 mg HMX/kg body weight. A dose-dependent accumulation of HMX into the egg was observed, though no significant developmental differences were observed among treatment groups. Exposed adults also exhibited dose-dependent accumulation of HMX, as well as treatment-related food aversion. From these studies it can be concluded that HMX readily accumulates in reptiles both directly (via ingestion of contaminated prey and/or contact with contaminated soil) and indirectly (via maternal transfer). Further study to determine the effect of HMX over two breeding seasons may be warranted.

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Keywords

Reproduction, Green anole, High melting explosive (HMX)

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