A COMPARATIVE STUDY OF MANGANESE OXIDE COATINGS IN A DISTURBED LANDSCAPE IN RURAL KENTUCKY

The Wyatt property is a multi-use land parcel in Breathitt County, Kentucky and is representative of the land disturbance in eastern Kentucky. The property has an extensive history of agriculture, coal mining, natural gas and petroleum as well as logging activities. Preliminary environmental surveys indicate that acid mine drainage is present on the property and that metal pollutants, primarily zinc, are present in stream sediment. One aspect of pollution that has not been investigated in the region is the role Mn-oxide plays in metal sequestration. Mn-oxides should be a major sink for metal pollution in the environment and it is expected that Mn-oxide coatings on the Wyatt property would be enriched in Zn and other pollutant metals. Samples were collected from ten locations on the Wyatt property, five from hill soil exposures and five from stream exposures, for SEM investigation. Diatoms and fungi (hyphae) are very common in stream samples and in some soil samples. Diatoms and fungi tend to increase in relative proportion from higher elevations to lower elevations in the drainage basin. Diatoms are a major structural component of the coatings. The authigenic minerals present are Mn-Fe-oxides and are the dominant structural component of the oxide coatings. Mn-Fe-oxides mineralization also tends to be more abundant at lower elevations. Samples located lower in the drainage basin that displayed a high abundance of Mn-Fe-oxides were expected to have detectable zinc and other anthropogenic metals present but did not. The presence of pyrite samples from lower in the drainage basin indicates a reducing environment, inhibiting oxidation of aqueous metals on Mn-Fe-oxide coatings. This result is very unexpected as Mn-Fe-oxides are well recognized as sequestering numerous metals, especially Zn. This is the first detailed investigation on Mn-oxide coatings in the Appalachians and provides comparative data for future study regionally and in the context of the Wyatt property.