Year Established: 2016 Start Date: 2016-03-01 End Date: 2018-02-28
Total Federal Funds: $42,041 Total Non-Federal Funds: $82,740
Principal Investigators: Xuelian Bai, Kumud Acharya
Abstract: Emerging contaminants have been a critical issue in Lake Mead and Lower Colorado River due to their continuous release and ubiquitous distribution. As a main inflow to Lake Mead, Las Vegas Wash receives wastewater discharge from the municipal wastewater treatment plants in Las Vegas Valley. The untreated pharmaceutical and personal care products and steroidal hormones (emerging contaminants) in the wastewater discharge enter Lake Mead. A major concern associated with this is the adverse effects on aquatic species at trace levels. Lake Mead is a habitat for diverse wildlife including endangered species, and the health of the wildlife is potentially threatened by the emerging contaminants. The aquatic wildlife is likely exposed to the emerging contaminants in water as well as via the food chain. Food web transfer can result in magnification of the contaminants at higher trophic levels. Phytoplankton (e.g., algae) can uptake the contaminants and serve as a food source to zooplankton (e.g., mussel), and the pseudofeces produced by mussels can be consumed by other organisms in the benthic zone. Consequently, the contaminants are concentrated in the upper food web. Quagga mussel is an invasive species that has spread in Lake Mead and the Lower Colorado River waterways. However, the uptake of trace organic chemicals in quagga mussel is poorly understood so far, and the role that quagga mussel plays in the removal and persistence of trace organic chemicals in the aquatic environment is still unclear. The goal of this proposed research is to understand the uptake rates and pathways of trace organic chemicals by quagga mussels in the Lake Mead ecosystem. The objectives of this study are to evaluate the ambient concentrations and the uptake rates of the selected trace organics (i.e., antibiotics, antidepressants, anticonvulsants, and estrogens) in quagga mussels, and to clarify the exposure routes in the Lake Mead ecosystem, either via water directly or via the food chain. Field sampling and observations and bench-scale experiments, combined with trace-level chemical analysis will conducted. This research will help develop ecological risk assessments for emerging contaminants in the aquatic environment and evaluate the health of the aquatic ecosystem in Lake Mead by providing insight into the exposure routes of trace organic chemicals in a lake ecosystem and their potential adverse effects on non-target species.