Ecological and Toxicological Effects of Exposure to an Acidic, Radioactive Tailings Storage

The persistence of an island of remnant vegetation within a tailings retention system provided an opportunity to conduct a pilot study to develop hypothesis concerning the impacts of acid spray and radiation on arid zone flora and fauna. Ecological changes were investigated by comparing species abundance and condition on both the study island and remote control areas. Hopbush (Dodonaea viscosa), geckos and a common ant species, Iridomyrmex rufoniger sp. B were abundant in control regions but absent from the study region, whereas densities of colonising plant species, Helea beetles and scorpions were unusually high at the impacted site. These disparities are probably attributable to acid spray at the impacted site and hence are potentially useful bioindicators of these impacts. Dragon and skink populations were apparently unaffected by the polluted ecosystem, although Ctenophorus nuchalis proved to be a significant bioaccumulator of radionuclides. Bioaccumulation of the radionuclides, ²³⁸U, ²³⁰Th, ²¹⁰Pb and particularly ²¹⁰Po were significantly greater than that reported elsewhere in the literature. Further radionuclide monitoring of herbivorous dragon species, possibly concentrating upon ²¹⁰Po levels, was the suggested outcome of this pilot study.