This study aimed to determine whether the bioaccessibility of lead (and arsenic and cadmium) in Trail soils could be lowered by adding amendments to the soil. In this first phase of work, samples of Trail soils were amended with phosphate, based on research indicating that phosphorus reacts with lead in soil to form compounds that are less soluble in the human gastrointestinal tract. Iron was also included with phosphate in one of the amendments tested, because research elsewhere had shown that iron could reduce the bioaccessibility of arsenic in soil.
These trials involved applying the amendments to the soils with grass left in place, as a first step to see whether amendments could be effective when applied without removing lawn cover. This phase found that although the combination of phosphate and iron reduced the bioaccessibility of lead in soil, the bioaccessibility of arsenic appeared to increase, and all amendment combinations appeared to kill the grass on the soils.