Paper Abstracts

The fate of arsenic in Noah's Flood

A.R. Hutchison, C.F. Bortel

Discipline: Chemistry

Abstract: One potential consequence of Noah's Flood would be the mobilization of toxic elements such as arsenic (As), a group 15 metalloid with a significant solubility and redox chemistry in water and a high toxicity to human beings. This paper discusses the likely chemistry of arsenic during the Flood. The Flood would have released arsenic through hydrothermal activity, volcanic eruptions, and weathering of crustal rock. Arsenic in hydrothermal fluid would likely be rapidly precipitated by sulfides. Likewise, much of the arsenic in volcanoes would actually be deposited sub-surface as sulfides. In the presence of oxygen-rich waters, these sulfide minerals can undergo oxidative dissolution, releasing the arsenic back into the water to join that liberated by the weathering of the surface. Iron oxyhydroxides would form in such an environment, however, and these will sorb and remove arsenic from the water once again. In waters rich in organic-carbon, reducing conditions can return periodically. This would lead to reductive dissolution to liberate the arsenic from the iron oxyhydroxides. However, these conditions can also reduce sulfates to sulfides and thus reprecipitate the arsenic sulfide minerals. Furthermore, the extremely rapid formation of sedimentary rock during the Flood would likely bury both the original sulfide minerals and the arsenic-sorbed iron oxyhydroxides before they could be significantly dissolved. The modern distribution of arsenic gives evidence of this; the element is often concentrated in large sedimentary basins adjacent to orogenic belts. It appears that arsenic sulfides (formed during the Flood) were in some cases subject to uplift during orogenesis associated with the Flood and underwent oxidation, resulting in the arsenic being sorbed to iron minerals and clays. These eroded into the foreland basins and were buried before the arsenic could leach into local waters to a major degree. In modern times, however, reductive dissolutions of these deposits has resulted in arsenic poisoning. While arsenic does not threaten the Flood model (rather the Flood explains the modern distribution of arsenic), modern arsenic contamination is an ongoing result of the judgement of the Flood.