THE URBAN WATER CYCLE & AQUACULTURE
USDA NIFA Funded Research
This project began in Spring 2016 and has been funded by the U.S. Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA) Agriculture and Food Research Initiative (AFRI) Water for Agriculture Challenge Area.
Recent growth in aquaculture is fueled by the demand for affordable fish protein, but its sustainability will be determined by water availability and the safety, or perceived safety of its product. As aquaculture grows it will consume more water along with other sectors as they adapt to increasing population and climate change stressors. In some regions aquaculture will be in direct competition for limited water resources, some of which may also be lower quality water, raising concerns about product safety. In the future, decisions will have to be made regarding the viability of aquaculture in some regions and the ability to safely use lower quality water resources. Before these judgments can be made, it is imperative that research examines the future of water supplies for both quantity and quality as it relates to aquaculture. This must include both projections for water resources and the influence of reduced water quality on product safety. This research will use existing data, historic trends and socio-economic and climate scenarios to create projections for aquaculture susceptibility to reductions in water quantity and quality. Next, contaminants of emerging concern (CECs) that are found in surface waters receiving wastewater treatment effluent were studied to assess mechanisms that influence their bioaccumulation in an effort to update and improve existing uptake models. The projections and improved bioaccumulation models for farmed fish will provide aquaculturists with the knowledge to make proactive management decisions while improving our general understanding of human exposure to pollutants from non-traditional water use.
AN ANALYSIS OF U.S. WASTEWATER TREATMENT PLANT EFFLUENT DILUTION RATIO: IMPLICATIONS FOR WATER QUALITY AND AQUACULTURE
Science of The Total Environment 2020, 721, 137819
Wastewater discharge and surface ﬂow data from 2007 to 2017 was used to calculate wastewater dilution factors (WWDF) for U.S. Geological Society hydrologic unit codes (HUC) in the contiguous U.S. HUC 10-year average WWDF values generally increased from the east coast (HUC 1–3: WWDF range 125–466) as you move west to the Mississippi River (HUC 7, 8, 10: 1435–1813) before further declining moving west (HUC 13–18: 7–908), particularly in the California (HUC 18: 9) and southwestern states (HUC 13–16: 7–351). Within HUCs, watersheds with higher population centers had lower WWDF values. This population effect on WWDF was greater in drier regions (e.g. Southwestern U.S.) or during drought. This is particularly pronounced in the regions of the Southwest and West where populations are growing in an already water-limited region. Moderate WWDF improvement was observed and projected through 2022 in these regions. A few areas of the country where surface water is used for aquaculture overlap with areas of low WWDF, but it is not widespread for the period examined. With continued population growth and the intensiﬁcation of climate change, the proportion of treated wastewater efﬂuent in surface waters may grow and potentially inﬂuence users of that water, but over the 10 year period examined WWDF values were relatively stable or improving for most regions of the contiguous U.S.