Using Fresh Water Algae to Remove Lead from Water

 Amanda Minke1 and Jean E. McLain2, Joel L. Cuello3, Robert Root4

1Department of Hydrology and Atmospheric Sciences

2Water Resources Research Center

3Agricultural and Bio-Systems Engineering

4Robert Root

The University of Arizona, Tucson AZ

Human exposure to lead (Pb) is a global-priority environmental health concern. Lead(Pb) is a known neurotoxin, and has been linked to diminished IQ and serious health problems, affecting the welfare of millions of people worldwide through natural and anthropogenic contamination of drinking water sources. This project will investigate metal-microbe phytoremediation (removal) of Pb from drinking water using common freshwater algae. The preliminary data show that wet algae packed on filter paper can remove nearly 100 µg Pb per gram of algal biomass. Removal of lead increased with algae availability, as 1.0 mg Pb in a 1-liter water sample was reduced to Pb = 0.45, 0.30, 0.26. Furthermore, a kinetic response was observed for increased reaction durations, indicating that control of Pb sequestration in algae is driven by both diffusion and biochemical interactions. Lead removal by algae showed an inverse relation with free-sulfur, possibly indicating that the mechanism of Pb bioremediation by fresh water algae involves sulfur functional groups. This project investigates contact time, algal species, and removal mechanisms under expected water chemistry conditions of drinking water to further characterize Pb removal, information that will be critical to the development of cost effective and sustainable bioremediation strategies.