Water Resources Research Act Program

Details for Project ID 2016AZ554B

Recycled water use for Agriculture: On-farm Demonstration and Evaluation

Institute: Arizona
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $10,000 Total Non-Federal Funds: $22,757

Principal Investigators: Channah Rock

Project Summary: Recent drought pressures in California and the West have forced growers to cut water use by 25% through reduced water diversions under their riparian rights, or fallowing of their land (California Water Resources Control Board; 2015). Toward this end, a growing number of stakeholders are considering recycled wastewater for crop irrigation. Recycled water has the advantage of being a constant and reliable water source, and in the United States alone, an estimated 1.7 billion gallons (6.4 million m3) per day of wastewater is reused. Recycled water use on a volume basis is growing at an estimated 15 percent per year, demonstrating its growing acceptance as a clean, safe product. However, every day millions of Americans consume a vast array of pharmaceuticals, from common over-the-counter medications to prescription and illicit drugs. Much of the medication is absorbed and metabolized by the body, but a percentage passes through unchanged and is released into wastewater treatment systems. Unfortunately, most wastewater treatment plants (WWTPs) are not designed for the removal of these micropollutants and as a result, residual antibiotics are released into the environment with treated wastewater. Many antibiotics can now be easily detected in water resources (Kolpin et al., 2002; Yang and Carlson, 2003), leading to increasing concern regarding their contribution to antibiotic resistance (AR) development (Pauwels and Verstraete, 2006; Auerbach et al., 2007). It has been proposed that the input of resistant bacteria into the environment through WWTPs is an important and key source of AR (Giger et al., 2003; Dhanapal and Morse, 2009). Understandably, one of the primary concerns with the use of recycled water for agricultural irrigation is the potential for bioaccumulation of these emerging contaminants, antibiotics, and AR bacteria. To date, most AR studies have focused on clinical settings, while the potential for AR to enter the human food chain via exposure to, and consumption of, irrigated crops has been largely unexplored. We propose to engage stakeholders in a 2-year project evaluating recycled water quality and its impacts and applicability for produce irrigation. This study will include detailed water quality assessment to identify risk parameters critical for use of recycled water in produce production coupled with stakeholder driven education. Outputs from the proposed project include the development of a Best Management Practices (BMP) Tool-kit containing recommendations for growers interested in utilizing alternative water sources including recycled water as well as a Certificate Program aimed systematically at addressing water recycling implementation through on-farm demonstration coupled with education related to recycled water impacts and use in agriculture. While emerging contaminants may be a potential concern, scientific evidence has not yet substantiated the use of recycled water in agriculture as a significant health threat, but more likely a consistent, high quality water preferable to other available sources of water (eg. surface water, saline ground water). Moreover, recycled water available to agriculture, particularly produce, would be a substantial development for industry facing increased drought conditions. The long-term goal of this project is to assess the risk of consumer exposure to organic contaminants found in recycled irrigation water used in agriculture and to develop industry-based tools and guidelines for its use. This project’s supporting objectives are designed to facilitate produce growers and related stakeholders in making educated decisions about water conservation practices that reduce human health risk while considering the utilization of a renewable resource: recycled water (expected project outcome).