Source: UNIVERSITY OF CALIFORNIA, RIVERSIDE submitted to NRP
RECYCLED WATER IRRIGATION: CROP PAIRING AND IRRIGATION ALTERNATION TO MINIMIZE CEC ACCUMULATION IN FOOD PRODUCE
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1030211
Grant No.
2023-67019-39702
Cumulative Award Amt.
$750,000.00
Proposal No.
2022-09290
Multistate No.
(N/A)
Project Start Date
Jun 1, 2023
Project End Date
May 31, 2027
Grant Year
2023
Program Code
[A1411]- Foundational Program: Agricultural Water Science
Recipient Organization
UNIVERSITY OF CALIFORNIA, RIVERSIDE
(N/A)
RIVERSIDE,CA 92521
Performing Department
(N/A)
Non Technical Summary
Changing precipitation patterns and population growth are putting unprecedented stress on freshwater supply, posing formidable challenges to the sustainability of irrigation agriculture. Treated wastewater (recycled water) is one of several nontraditional water sources that may be used to augment agricultural irrigation. However, recycled water irrigation introduces numerous chemicals of environmental concern (CECs) into agroecosystems. The potential accumulation of CECs in food represents a significant hurdle to the broader adoption of this practice. Research to date has stopped at surveying occurrence of CECs in plants, while risk-mitigation strategies are urgently needed to truly advance nontraditional water use in agriculture. In response to the program area "Water Quantity and Quality" (A1411), this research is focused on novel strategies to minimize CEC accumulation in edible plant tissues. Through a comprehensive field-plot study, we will demonstrate that CEC accumulation in fruiting row crops (e.g., tomato, pepper, cucumber, melon, bean) is limited. We will further evaluate CEC accumulation in fruit trees (e.g., apple, peach, citrus, avocado) that are common in arid and semi-arid regions to test the hypothesis that CEC accumulation in tree fruits is low. Study findings will allow the pairing of specific crop types with recycled water use to minimize CEC accumulation. We will also explore the use of irrigation alternation, i.e., recycled water irrigation early in the season, followed by conventional freshwater irrigation, to achieve further reductions in CEC accumulation. The project contributes to sustainable U.S. agriculture by offering several safe reuse practices of nonconventional water to strengthen water security in agriculture.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1330210200040%
1330110200030%
1331499115020%
1331119115010%
Knowledge Area
133 - Pollution Prevention and Mitigation;

Subject Of Investigation
1119 - Deciduous tree fruits, general/other; 1499 - Vegetables, general/other; 0110 - Soil; 0210 - Water resources;

Field Of Science
2000 - Chemistry; 1150 - Toxicology;
Goals / Objectives
The overall aim of this project is to develop implementable strategies to minimize CEC accumulation in food produce when using recycled water for irrigation. Field studies, coupled with greenhouse/laboratory experiments and modeling, will be carried out. Specifically, we will:1) Under field conditions with recycled water irrigation, evaluate CEC accumulation in the edible part of non-fruiting and fruiting row crops. The derived BCFs in edible tissues and human exposure from dietary consumptions will be used to test the hypothesis that fruits generally have reduced CEC accumulation.2) Under field conditions, compare accumulation of CECs in tree fruits produced with recycled and conventional water. Given the large biomass, long growing season, and distinct physiology of perennial fruit trees, CEC accumulation from recycled water irrigation in tree fruits may be very limited. Validation of this assumption improves our understanding of contaminant uptake, translocation, and accumulation in fruit trees, providing an opportunity for greatly expanding the scope of using nontraditional water for agricultural irrigation.3) Under greenhouse and field conditions, quantify further reductions in CEC accumulation in fruits by alternating recycled water and potable water for irrigation. When recycled water is used only for the first half of a growing season, CEC accumulation in edible organs is minimized due to extensive metabolism and growth dilution.
Project Methods
This research is focused on novel strategies to minimizeaccumulation of contaminants of emerging concern (CECs) in edible plant tissues. Through a comprehensive field-plot study, we will demonstrate that CEC accumulation in fruiting row crops (e.g., tomato, pepper, cucumber, melon, bean) is limited. We will further evaluate CEC accumulation in fruit trees (e.g., apple, peach, citrus, avocado) that are common in arid and semi-arid regions to test the hypothesis that CEC accumulation in tree fruits is low. Study findings will allow the pairing of specific crop types with recycled water use to minimize CEC accumulation. We will also explore the use of irrigation alternation, i.e., recycled water irrigation early in the season, followed by conventional freshwater irrigation, to achieve further reductions in CEC accumulation.

Progress 06/01/24 to 05/31/25

Outputs
Target Audience:Scientific community, regulatory agencies, water/sanitation districts and agencies, growers, and students Changes/Problems:Nothing significant. We have refined our target list of contaminants to work on, and the focus will be on PFAS and tire wear chemicals, because of the recent recognition of these contaminants as priority contaminants. What opportunities for training and professional development has the project provided?We have two Ph.D. students working on this project. The first Ph.D. student successfully defended her dissertation and graduated before the summer of 2024. She is currently working as a scientist at the California Department of Toxic Substances Control. The second Ph.D. student entered the Environmental Toxicology (ENTX) graduate program in fall 2023 and is actively working on this project. The second-year Ph.D. student has received adequate receiving training on the use of analytical instruments as well as protocols for sample processing. We have also provided training to one undergraduate student at UC Riverside. The undergraduate student is a first-generation college student. How have the results been disseminated to communities of interest?Results from the field study have been written up as a manuscript and is currently undergoing revision for Environmental Science & Technology, a tier-1 journal in the field of environmental science. In addition, several poster and oral presentations have been made by students and PI at regional, national meetings and international meetings. What do you plan to do during the next reporting period to accomplish the goals?During the third year of this project, we plan to carry out greenhouse experiments to test out the use of irrigation scheme modifications to achieve maximum reductions of emerging contaminant accumulation in edible tissues of vegetables. The data will be analyzed statistically and with structural models to identify variables contributing the most to the contaminant accumulation reductions. In these experiments, an emphasis will be placed on PFAS, and this shift in the target chemicals is justified given the new attention to this class of contaminants. We will also plan and prepare for the field study to evaluate accumulation of emerging contaminants by different types of crops, and to test the hypothesis that accumulation in tree fruits is much less compared to other food crops. The field study will address objective 2), and will take a longer time because of the long growing season of fruit trees.

Impacts
What was accomplished under these goals? During the last reporting period, we have made good progress on specific objectives 1) and 3), and have started working on objective 2). A Ph.D. student had worked exclusively on this project, and a new Ph.D. student has been introduced into this project. Under objective 3), we have completed a series of greenhouse experiments and the results have been published as a journal article in the highly competitive journal Water Research. A field plot study was successfully completed where tertiary treated wastewater was used to irrigate multiple vegetable crops. Water, soil and plant tissues were collected and analyzed for a suite of emerging contaminants including PPCPs, tire wear particle chemicals, and PFAS compounds. The field study was a chapter of the student's dissertation, which was developed into a manuscript. The manuscript was submitted to Environmental Science & Technology, the top journal in the field, and is currently undergoing revision. A new Ph.D. student was recruited in the fall 2023. The student has finished taking courses and has started carrying out greenhouse experiments under objective 3).

Publications

  • Type: Peer Reviewed Journal Articles Status: Published Year Published: 2024 Citation: Alternating water sources to minimize contaminant accumulation in food plants from treated wastewater irrigation


Progress 06/01/23 to 05/31/24

Outputs
Target Audience:Scientific community, regulatory agencies, water/sanitation districts and agencies, growers, and students Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?We have two Ph.D. students working on this project. The first Ph.D. student is a senior student who successfully defended in May 2024. The second Ph.D. student entered the Environmental Toxicology (ENTX) graduate program in fall 2023 and is actively working on this project. The first year Ph.D. studenthas been receivingtraining on the use of analytical instruments as well as protocols for sample processing. We have also provided training to one undergraduate student at UC Riverside. The undergraduate student is a first-generation college student How have the results been disseminated to communities of interest?Results from the field study are currently being prepared as a manuscript for submission to a journal. In addition, several poster and oral presentations have been made by students and PI at regional and national meetings. What do you plan to do during the next reporting period to accomplish the goals?During the seocnd year of this project, we plan to carry out greenhouse experiments to test out the use of irrigation scheme modifications to achieve maximum reductions of emerging contaminant accumulation in edible tissues of vegetables. The data will be analyzed statistically and with structural models to identify variables contributing the most to the contaminant accumulation reductions. We will also plan and prepare for the field study to evaluate accumulation of emerging contaminants by different types of crops, and to test the hypothesis that accumulation in tree fruits is much less compared to other food crops.

Impacts
What was accomplished under these goals? During the first year of this project, we started working on specific objectives 1) and 3). A senior Ph.D. student redirected her research to work on the specific objective 1). A field plot study was successfully completed where tertiary treated wastewater was used to irrigate multiple vegetable cropss. Water, soil and plant tissues were collected and analyzed for a suite of emerging contaminants including PPCPs and PFAS compounds. The field study was a chapter of the student's dissertation, which is being developed as a manuscript for submission for publication. A new Ph.D. student was recruited in the fall 2023. The student has finished taking courses and has received training to work on this project. Greenhouse experiments are planned for the summer of 2024 to address specific objective 3).

Publications