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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.

This grant is a collaboration between the C-HaWQ lab, Dr. John Scarpa (TAMUCC) and  Dr. Bryan W. Brooks (Baylor University).

 

COMPARISON OF BIOCONCENTRATION AND KINETICS OF GENX IN TILAPIA, OREOCHROMIS MOSSAMBICUS IN FRESH AND BRACKISH WATER

Chemosphere 2022, 287, 132289

Contaminants of emerging concern (CEC) are a broad suite of chemicals commonly found in the environment, aquatic organisms and even drinking water. They include pharmaceuticals, personal care products, industrial chemicals and compounds added to consumer products. The CEC ammonium 2,3,3,3-tetrafluoro-2-heptafluoropropoxy propanoic acid, which is more commonly known as generic name GenX, is a replacement of common processing aid longer chain perfluorinated compounds (PFAS) due to a manufacturing shift in 2002 following the EPA stewardship program of 2015/16 in USA (USEPA, 2006). However, recently reported in North Carolina drinking water, GenX raising concerns about its accumulation in aquatic organisms, both wild and cultured, which could be a pathway for human exposure. To examine GenX accumulation and potential for human exposure, tilapia (Oreochromis mossambicus) fingerlings were dosed with GenX for up to 96 h in fresh (0 ppt) or brackish (16 ppt) water to determine uptake and bioconcentration. Depuration values were also determined after a 96 h exposure followed by 96 h without exposure. Bioconcentration was in decreasing order of plasma > liver > carcass > muscle, with higher distribution to liver followed by carcass and muscle. Muscle was found to have the highest half-life (1278 h) followed by carcass (532 h), plasma (106 h), and liver (152 h). The rate of uptake and depuration was positively affected by the salinity. As bioconcentration in all tissues increased with increasing salinity, this may raise concern for marine organisms and human exposure.

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CONTIGUOUS U.S. SURFACE WATER AVAILABILITY AND SHORT-TERM TRENDS OF WASTEWATER EFFLUENT FLOWS IN SAN ANTONIO, TX

Environ Pollut 2020, 265, (Pt B), 115036

Surface water is a vital and sometimes stressed resource in the U.S. The quantity of this resource is threatened by population shifts and growth concurrently with climate change intensification. Additionally, growing population centers can impact water quality by discharging treated wastewater effluent, which is typically of lower quality than its receiving surface waters. Depending on baseflow and environmental factors, this could decrease water quality. From a previous model prepared in our lab, this study can improve the understanding of water resource quality and quantity, surface water availability for the contiguous U.S. was estimated for each USGS Hydrologic Unit Code (HUC) during 2015. The Mississippi River generally served as a dividing line for surface water availability, with five of the six regions with very low water availability (<24,000 LD(-1)Km(-2)) residing in the west. These same areas also experience more drought as well as more severe droughts than regions in the east. In regions with lower surface water flows, their water quality is more susceptible to the influence of wastewater effluent discharges, especially near large and growing population centers like San Antonio, Texas. A prediction model was established for this city, which found that from 2009 to 2017 wastewater effluent increased by 1.8%. As cities grow, especially in the Southwest and Western U.S. together with intensified climate change, surface water quantity and quality become more crucial to sustainability. This study shows where surface water availability is already an issue and provides a model to estimate, as well as project, wastewater effluent flows into surface water bodies. (C) 2020 Elsevier Ltd. All rights reserved.

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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.

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