The combined effect of depleted uranium, sodium arsenite and gamma radiation on survival, growth and reproduction of Caenorhabditis Elegans

Abstract

The purpose of this work was to study the effect of depleted uranium, sodium arsenite and gamma radiation on three biological endpoints of Caenorhabditis Elegans. The three endpoints studied were survival, growth, and reproduction. The nematodes were exposed to the stressors individually and in combination. Six different concentrations of uranium and arsenic were used. For uranium, the molar concentrations used were 100 μM (U1), 50 Μm(U2), 25 Μm(U3), 12.5 μM (U4), 6.25 μM (U5), and 3.1 Μm (U6). The concentrations used for arsenic were 1 mM (As1), 0.5 mM (As2), 0.25 mM (As3), 0.125 mM (As4), 0.63 mM (As5), and 0.315 mM (As6). The gamma radiation doses studied were 9.61 Gy and 19.22 Gy (~ 100 mGy/h and ~ 200 mGy/h dose rate during the 96 hours exposure). In most of the cases all the nematodes survived. Only at the highest concentration of sodium arsenite there were cases of 100% mortality in the populations exposed; however this was not necessarily the rule. There were many cases in which the nematodes survived, although their growth was compromised. All the stressors had detrimental effects on growth, except exposure to gamma radiation alone. There was a reduction in growth in that case but it was not statistically significant. The detrimental effects are particularly strong when exposed to sodium arsenite or combinations of sodium arsenite and uranium. Reproduction was affected by all the stressors. The effects are always led by arsenic, in the statistical sense, but when mixed plates were exposed to gamma radiation, at the lowest dose of 9.61 Gy, no statistical significant for detrimental effects could be established, as opposed to the higher dose of 19.22 Gy, for which statistically significant results were found on the effects on growth and reproduction when the populations were exposed to gamma radiation at that dose and the mixture of depleted uranium and arsenic