Trace elements in soils of the south Texas uranium district: concentrations, origin, and environmental significance

Mo, As, and Se are concentrated with uranium in ore deposits in South Texas. Two sets of oil samples were collected and analyzed for Mo, As, Se, and Cu. Two hundred and fifty-six samples were collected in a statistically random design from soils developed on the Whitsett Formation, Catahoula Formation, or Oakville Sandstone, the major uranium hosts of the area, and 182 samples were collected nonrandomly from areas of mining or mineralization. Random sampling results show that the Whitsett Formation has higher Mo and lower Cu concentrations than the other two formations. With the exception of Mo in the Whitsett Formation and Cu in all three formations, the trace element concentrations are similar to published average concentrations in soils worldwide. Sampling in areas of mining and mineralization indicates that high concentrations of Mo, As, or Se occur dominantly in areas of shallow mineralization and in drainages adjacent to older abandoned mines. Moderately high concentrations also occur in a few reclaimed areas. Windblown dust from mining areas has not measurably affected trace element concentrations in adjacent areas. Comparison of Mo and Cu concenrations in soils and grasses suggest that forage in the area studied could induce molybdenosis in cattle