Use of sorbents for purification of lead, copper and antimony in runoff water from small arms shooting ranges.

Different sorbents were tested in situ for their ability to reduce the concentration of Cu, Sb and Pb in drainage water from a shooting range. The sorbents tested were: Brimac(®) charcoal, olivine mixed with elemental iron powder, magnetite and Kemira(®) iron hydroxide. The mean sorption of Cu, Sb and Pb was 84%, 66%, 85% with Brimac(®) charcoal and 58%, 78% and 69% with Kemira(®) iron hydroxide. Good sorption of Cu and Pb was achieved using olivine with 5% elemental Fe powder, which resulted in a sorption of 81% and 87%, respectively. The Fe-olivine filters were less efficient in reducing the concentration of Sb, but increasing the Fe content improved Sb sorption. In periods with high concentrations of Pb, Cu and Sb in the creek, such as during precipitation, the sorbent efficacy improved. This might be due to changes in the physico-chemical form of the metals, or to a higher fraction of elements being physically retained in the form of particles or colloids.