However, little data supported that premise and less described how much arsenic moved in different soils. Factors that influence arsenic movement include the degree of soil acidity, aeration and the presence of other elements such as phosphorus. Vegetation also immobilizes some arsenic, taking it up in its roots. There are now about 30 varieties of plants growing and reproducing on Smelter Hill. With or without liming, arsenic can move through soil, says Inskeep.
Chemical bonds determine how much and how quickly arsenic moves.
When the chemical bonds are broken, as can happen when lime is added to soils that have arsenic, arsenic is freed to move through the soil system. After Inskeep added lime to arsenic-contaminated soils in his laboratory study, the arsenic in water that percolated through the soil column increased 10 to 100 times. Variations in the quantity of arsenic mobilized were related to specific characteristics of the mine waste. Inskeep's data support and add detail to our understanding of arsenic movement through soils. He recently received additional support from the EPA to study this in more detail.