Groundwater effects of land applied alum residuals

Soil columns of predominantly Peawick and Slagle soils had various amounts of alum residuals, lime and plant nutrients incorporated into the topsoil. A weekly dose of rainwater was applied to each column over a six month period. Leachate and soil constituents were analyzed to evaluate migration of specific constituents from the alum residuals through the soil profile and into the groundwater.

Soil analysis indicated little, if any, migration of metals from the alum residuals occurred. Metal constituents found within the leachate appear to have originated from the soil rather than the alum residuals.

Of the measured anions, nitrate - nitrogen was the only component which had increasing concentrations within the leachate. Much, if not all, of the nitrate can be attributed to the plant nutrients incorporated into the topsoil and disturbance of the topsoil.

Nitrate and zinc were the only components that consistently degraded the leachate quality beyond Virginia Water Control Boards' Groundwater Standards, but were within observed ranges of non-sludge amended soil columns. Groundwater contamination is not likely as a result of land application of alum residuals up to a loading of four percent.