The two areas cover about 0.2 acre, are about 6 feet deep, and are covered by a highly permeablegravel-base material. Landfill No. 1, active from 1966 to 1971, was used to dispose of phosphoric acid sludge containing more than 700 pounds of arsenic. Landfill No. 2, active between 1972 and 1974, received primarily plastic drums of sludge containing some 800 pounds of arsenic. In June 1979, Monsanto began collecting data from two monitoring wells, one downgradient from each area. The drinking water standard for arsenic is 50 ppb.
Most residents use private wells.
Gracewood, about 2.5 miles from the site, uses the Tuscaloosa Aquifer to supply its 1,500 residents. Water in the shallow aquifer probably can move to the deeper aquifer because the two appear to be separated by layers of sand. In November l983, Monsanto completed the removal of contaminated soil from both areas. The State then collected soil samples from the excavated areas and found that arsenic, cobalt, cadmium, barium, and lead are not present in toxic concentrations. In January l984, after receiving State approval, Monsanto backfilled the excavation.