Ecotoxicology of Gold Nanomaterials: Effects on Periphyton, L. Stagnalis, and H. Azteca in an Aquatic Food Chain Study

Abstract

The growing use of nanomaterials poses serious concerns to aquatic environments. Research into the toxicity and potential trophic transfer of nanomaterials in aquatic ecosystems is needed to assess the risk of these novel pollutants. Our study investigates the movement of gold nanomaterials (AuNM) through an aquatic food chain. Field-collected (Huron River, Ann Arbor, Michigan) and lab cultured (Oscillatoria) periphyton (60 replicates per periphyton type) were exposed to AuNM in a closed recirculating flume system with three treatments: control (0 μg/L), low (100 μg/L), and high (500 μg/L), respectively. Hyalella azteca and Lymnaea stagnalis were then exposed to periphyton from the flumes. AuNM quickly aggregated and precipitated from the water column and gold was measured in periphyton. After feeding trials, gold was detected in L. stagnalis (high average 2.3 μg/L and low average 1.8 μg/L dry weight) but not in H. azteca. Although gold was detected in L. stagnalis, we observed no significant mortality or biomagnification in either L. stagnalis or H. azteca. These data suggest that trophic transfer of AuNM can occur, but the exposure is organism specific and does not have toxicological effects to exposed organisms. These results suggest that environmentally relevant concentrations of AuNM will not adversely affect aquatic ecosystems.