Water Resources Research Act Program

Details for Project ID 2018AZ584B

Microplastic Contamination in the Lower Santa Cruz River

Institute: Arizona
Year Established: 2018 Start Date: 2018-03-01 End Date: 2019-02-28
Total Federal Funds: $8,641 Total Non-Federal Funds: $17,338

Principal Investigators: Michael Bogan, David Quanrud, Drew Eppehimer

Abstract: In arid environments, treated wastewater is increasingly recognized as a resource for irrigation, aquifer recharge, and riparian habitat restoration. Water reuse is an important strategy for managing water supply; however, it presents unique challenges in regard to water quality. Microplastics, a type of anthropogenic litter, are an emerging pollutant affecting marine and freshwater systems throughout the globe. Although wastewater treatment removes the majority of microplastics in sewage, wastewater effluent discharge is a significant source of environmental microplastic pollution, and its potential impact on ecological and/or human health is unclear. The lower Santa Cruz River near Tucson, AZ is an effluent-dependent system supported by discharge from Agua Nueva and Tres Rios Water Reclamation Facilities. In a preliminary effort, we have documented the presence of microbeads (a type of microplastic) up to 18 river miles downstream from the Tres Rios effluent outfall. Although we know that microplastics are present in the Santa Cruz, we do not know how abundant they are or what impact they may have on aquatic species. Here, we propose to examine how the density of microplastics varies across space and time in the water column and riverbed sediments of the Santa Cruz River, as well as quantify microplastic consumption rates by resident fish. Work will be conducted along a 2-mi reach downstream from the Agua Nueva and a 22-mi reach downstream from the Tres Rios effluent outfalls. These reaches are separated by ~1.5 miles of dry streambed where rapid infiltration rates limit surface water connectivity to brief periods during flood events. As urban development continues, discharge of effluent into rivers and streams will become more common. This novel study will provide baseline data necessary for water managers, policy makers, and the public to incorporate consideration of these contaminants of emerging concern within effluent management. The project will facilitate education and training of four graduate and three undergraduate students and provide data to support a future larger proposal for federal funding.