Levels of radium-226 in the rainbow trout, macroinvertebrates-substrates and water adjacent to the mining concession Loma Larga, Azuay-Ecuador

Abstract

Mineral processing has been identified among the twelve main industrial processes that must be under control due to the expose to natural radioactive sources. The modification and, generally, the increase in the concentration of Naturally Occurring Radioactive Materials (NORM) in the earth's crust cause an imbalance in the ecosystem. Imbalance that affects the fauna, which are able to bio accumulate these radioisotopes and introduce them into the trophic chain. The main purpose of this work was to establish a radio-ecological baseline. For this purpose, the concentration levels of 226Ra in rainbow trout, in macro invertebrate matrices-substrates and water from the Irquis and Portete rivers were evaluated. A study area adjacent to the Loma Larga mining concession was selected. The measurements were made using the Lucas cells coupled to a Pylon AB6A counter and the "Can Technique", using LR-115 passive detectors. The results indicated that rainbow trout bio accumulated in bones and organsa mean of 94.7% of the total 226Ra detected, which values varied from 4.69 to 2.46 Bq/kg, while macro invertebrate-substrate matrices showed a concentration that ranged between 0.7 and 1.3 Bq/kg in the Irquis River, while in the Portete River was between 1.1 and 19.3 Bq/kg. The water samples, in the sampling points of the Irquis River, showed concentrations that ranged between 37.3 and 119.1 mBq/l and in the Portete River between 43.5 to 146.4 mBq/l.