Biological damage to Sprague-Dawley rats by excessive anions contaminated groundwater from rare earth metals tailings pond seepage

Abstract

Abstract Current research on groundwater contamination due to mining tailing ponds seepage has concentrated on the toxicological effects of metals on organisms and ecosystems. However, recent studies found that the most hazardous pollutants that affect water quality in some rare earth metals smelting tailings pond are the large amount of ions but not metals. Whether these excess ions can cause genetic damage in organisms needs further study. Thus, the hazardous contaminant components in groundwater from five different sites in and near a rare earth elements (lanthanides) tailings pond were analyzed. Then, the biological damages to Sprague-Dawley (SD) rats caused by tailings seepage-contaminated groundwater at the individual, organ, tissue, and cellular levels were systematically studied. Following that, the correlations between the pollution components in the contaminated groundwater and tissue damages in SD rats were further analyzed. The results showed that the main hazardous pollution ions in the rare earth metals tailings seepage-contaminated water were F−, Cl−, and SO42−. Contamination was increasingly severe closer to the tailings dam. Water from the study sampling sites caused liver and kidney damage to the SD rats. Further, the results from microscopic morphology and flow cytometric apoptosis analyses showed that the damages caused to the kidney epithelia cells by F− and Cl− showed an increasing trend as the sites neared the tailings dam, and there were positive correlations. The effect of SO42− was not significant. Therefore, this study provides a foundation to scientifically and effectively evaluate the genetic damages caused to organisms by groundwater near tailings ponds, and also provides a theoretical basis to reveal the mechanism underlying this effect.