Progress 05/01/17 to 04/30/20
Outputs
Target Audience:The traget audience of this project are (1) general public; (2) scientific and profetional community; (3) California government authority such as Central Valley Water Quality Board, Cawelo Water District,and the sub-committe on food saftey; (4) stakeholders interested in the use of oilfield water for supplement water resources for irrigation in California including oil companies, water managers, and framers; and (5) local communities in Centrval Valley, California. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Duke University: The project involved two PhD students from Duke University: Andrew Kondash took an active role in the fieldwork, samples collection and water and soil analyses, and was the leading author of the paper that was published in Science of the Total Environment. This study became one of the chapters of his PhD thesis. The production collaboration between Duke University and RTI also enabled Kondash to become a researcher at RTI, following his graduation from Duke University. Ekta Patel took an active role in the policy analysis, conducted interviews with members of the Central Valley Water Board and other government and local stakeholders in California, and wrote the policy analysis of the study. During Fall and Springs semesters of 2017, 2018, and 2019 PI Dr. Vengoshtaught a water quality class at Duke developed for undergraduate and masters degree students at Duke University. The course "Water Quality and Health" is designed to provide an introduction to basic water chemistry and quality and teach students how to evaluate the links between water quality and human health. As part of the course the results from the USDA project were presented and discussed to showcase how water quality decisions and development can impact local communities. California State University Bakersfield: During the Fall semester of 2018, from August to December, PI Dr. Cabrales taught an Environmental Engineering class at CSUB. This course is required for students graduating with the Biosystems and Agricultural Engineering emphasis within the Engineering Sciences program. The course is also available to the rest of engineering students. A total of 19 engineering students attended the class. In this class, the main topics includes water usage and conservation, water chemistry, air quality, solid waste disposal, fate and transport of contaminants in lakes, design and analysis of mechanical, physicochemical and biochemical water and wastewater treatment processes. The class has a laboratory component and the majority of the laboratory practices focus on water quality and water treatment processes. Within this class, the topic of produced water was introduced to the students, in particular, they learned about the details of the ongoing project with Duke University. The students were exposed to the water quality requirements for irrigation in produced water, and to the water treatment processes commonly used in oil industry. The students learned about changing environmental regulations, and how the Central Valley Water Board is involved in investigating the safe use of produced water in the region. Innovative water process treatments were presented in class, and the students had the opportunity to use one of them (electrooxidation) to remove organic compounds from water. This particular technology has been investigated by Dr. Cabrales to treat produced water, which could advance the reutilization of produced water for agricultural applications. In addition, other students working in Dr. Cabrales research laboratory were exposed to the details of this project. Students were involved in learning about state efforts to regulate the use of produced water for irrigation. How have the results been disseminated to communities of interest?The results of this study weredisseminated in different ways to different stakeholders: General public: A web site entitled "Oilfield Produced Water for Crop Irrigation in California" dedicated to the project with the data and results: (https://sites.nicholas.duke.edu/oilfieldwater/) General scientific and Professional Community * Presentation at the annual Geological Society conference: Kondash, A.J., Lambertini, E., Redmon, J., Cabrales, L., Weinthal, E., Vengosh, A. (2019) Can low-saline oilfield water be used for irrigation in California? GSA Annual Meeting in Phoenix, Arizona, USA, 2019) *Publication of two papers in peer-reviewed journals: -Kondash,A.J.,Redmon, J.H., Lambertini, E.,Feinstein, L.,Weinthal, E.,Cabrales, L., Vengosh, A. (2020)The impact of using low-saline oilfield produced water for irrigation on water and soil quality in California.Science of the Total Environment,Volume 733, 139392 (https://www.sciencedirect.com/science/article/pii/S0048969720329090). - Hoponick Redmon; J., Kondash, A.J., Womack, D., Lillys, T., Feinstein, L.; Weinthal, E.; Cabrales; L., Vengosh, A. Is food irrigated with oilfield produced water in the California Central Valley safe to eat? A probabilistic human health risk assessment evaluating trace metals exposure.Risk Analysis. In Review. 2020. Local communities in California Central Valley (government, farmers, energy companies) * Presentation ( March 21th, 2018)at a local group, "Bakersfield Area Skeptics Society Monthly Meetup" on produced water and the project carried with USDA. (https://www.meetup.com/skeptics-155/events/lkjdnyxfbcc/) Organization of a workshop entitled "Alternative Irrigation Water Workshop How can oilfield produced water be safely and sustainably used for crop irrigation?"inat the campusCalifornia State University Bakersfieldon February 7th, 2020.Themain objective of the event was to disseminate results from the USDA project to increase the participation of different stakeholders in the topic of produced water reuse. The workshop was part of an effort to increase the availability of irrigation water of appropriate quality through non-traditional sources by matching the right water for the right use. Through our study, we hope to demonstrate the importance of data-based decision-making in sustainably and safely using OPW as an alternative irrigation water source. The conference's ultimate purpose was to meet with stakeholders and experts to discuss how we can sustainably and safely support increased reuse of non-conventional irrigation water sources. Speakers at the workshop induced representatives from the agriculture and oil industry, government, and academia. Total participants of 90 included researchers from national laboratories, engineers from Central Valley Water Quality Control Board, engineers from oil industry (CRC, Chevron, Berry Petroleum), irrigation experts from agricultural industry (Wonderful, Grimmway), farmers, oil producers, among many others. Several stakeholders agreed that future collaboration, cooperation, and projects could result from this conference. The attendees were particularly interested in the results of this project and were looking forward for the publications of this investigation, which we agreed to share with them when available. *PIs Vengosh and Redmon communicated several times and presented the results of this study to the Central Valley Water Board official meetings on April 2019 and March 2020. In these meetings the PIs discussed with the members of the Central Valley Water Board the implications of the results and the importance of water and soil quality monitoring, the risks particularly for salts and boron accumulation in irrigated soil and the importance of the current policy practice of blending the OPW with fresh water as a condition for allowing the use for irrigation. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Objective 1 -OPW Risk Screening Analysis Leveraging Existing Datasets:We have collected archivedata on the quality of oilfield produced water (OPW) and groundwater fromsouthern San Joaquin Valley in California. Objective 2: Baseline Field Survey of Blended OPW Used for Irrigation, Soil, and Crops:?We examinedsalts, metals, radionuclides (226Ra and228Ra), and DOCin OPW, blended OPW used for irrigation, groundwater, and soils irrigated by the 3 different water sources. We collected 17 irrigation water samples in multiple seasons to represent a range of irrigation water quality differences in areas used to grow pistachios and almonds, eight from groundwater sources, and seven from Cawelo Canal water used for irrigation in Cawelo district. Additionally, 20 surface soil grab samples were collected from the top 5 cm of soil at a distance of at least 20 meters into each agricultural areas.The results indicate thatall studied water quality parameters in the blended OPW were below current California irrigation quality guidelines.Yet, soils irrigated by blended OPW showed higher salts and boron relative to soils irrigated by groundwater, implying long-term salts and boron accumulation. The study did not, however, find systematic differences in Raactivities and DOC in soils irrigated by blended or unblended OPW relative to groundwater-irrigated soils. Based on a comparison of measured parameters, we conclude thatthe blended low-saline OPW used in the Cawelo Water District of California is of comparable quality to the local groundwater in the region. Nonetheless, the salt and boron soil accumulation can pose long-term risks to soil sodification, groundwater salinization, and plant health; as such, the use of low-saline OPW for irrigation use in California will require continual blending with fresh water and planting of boron-tolerant crops to avoid boron toxicity. Objective 3: Multimedia Human Health Risk Assessment Modeling:A probabilistic modeling framework was applied to evaluate potential risks from eating foods grown in OPW-irrigated soil. The probabilistic modeling framework consists of four main components: (1) the land-based source module, which models the fate and transport of constituents in OPW used for irrigation through the soil column; (2) the farm food chain module, which models the distribution and uptake of the constituents by plant roots, potential accumulation in edible fruits or seeds; (3) the human exposure module, which estimates human exposure due to consumption of the crops considered and soil consumed incidentally with the crops; and (4) the human health module, which estimates human health impacts (in the form of noncancer hazard or cancer risk) that result.The source module is based on the peer-reviewed U.S. Environmental Protection Agency (EPA) land application unit model developed as part of the Multipathway, Multimedia, Multireceptor Risk Assessment Modeling System. The food chain, exposure, and human risk algorithms were based on the USEPA's Human Health Risk Assessment Protocol (HHRAP) for Hazardous Waste Combustors.Based on probabilistic human health risk assessment results evaluating trace inorganics in low-saline OPW that is currently used for irrigation in Kern County in Central Valley, the study found that the use of OPW for crop irrigation is unlikely to cause accumulation of metals in soil and products and thus have low human health risks. The study found that the accumulation of arsenic in soil and crops presents the greatest risk to human health. Objective 4: Policy Scenario Analysis:Interviews were carried out in CA with experts at the Central Valley Water Board (CVWB) to assist with a policy analysis of the regulatory framework regarding the use of OPW in California. The analysis sought to capture the complexity of the various regulations and voluntary actions at the state, regional, and district levels, chiefly in the state's oil-producing and drought-prone Central Valley. Data was collected regarding the interests of different stakeholders in the management of OPW for agriculture besides the regional water boards, which include oil and gas companies; water districts and farmers; environmental, food, and public health safety advocacy groups; and the general local public, who live and work in the involved communities and consume affected produce. A policy analysis brief focused on the mounting impact of drought conditions for the continuing use of OPW for the agricultural sector along with the role of the Food Safety Expert Panel. Following the policy analysis, we made the following recommendations: (1)TheCVWBshould explore third-party grants and other sources of funding to support ongoing and independent research. While the financial aid from OPW producers and users can strengthen the buy-in from those stakeholders, it is prudent to keep scientific research free from conflicts of interest; (2)To ensure clear communication and transparency, theCVWBshould a) maintain a singular document where updates from the public meetings of the Food Safety Expert Panel are logged, b) outline the process by which the Food Safety Expert Panel was formed, and c) clarify how decisions about Waste Discharge Requirements (WDRs) are made; (3)Additional WDRs for the use of OPW for food crop irrigations should not be granted in the Central Valley until final recommendations from the Food Safety Expert Panel are made; and (4)Although it would have been beneficial to include representatives from other stakeholder groups such as farmers and pro-environment activists within the Food Safety Expert Panel at the onset, future follow-ups should be deliberate about including wide representation. Objective 5: Stakeholder Engagement:PIs Vengosh and Redmon communicated several times and presented the results of this study to the Central Valley Water Board official meetings on April 2019 and March 2020. In these meetings the PIs discussed with the members of the Central Valley Water Board the implications of the results and the importance of water and soil quality monitoring, the risks particularly for salts and boron accumulation in irrigated soil and the importance of the current policy practice of blending the OPW with fresh water as a condition for allowing the use for irrigation. Objective 6: Outreach and Dissemination of Study Results:Outreach and dissemination were conducted through presentations at a national conference(Geological Society of America Annual Meeting in Phoenix, Arizona, USA, 2019), publication of two papers in peer-reviewed journals (one published in the JournalScience of the Total Environmentand one in review in the journalRisk Analysis), presentation to the local community (Bakersfield Area Skeptics Society Monthly Meetup), and a workshop entitled "Alternative Irrigation Water Workshop How can oilfield produced water be safely and sustainably used for crop irrigation?"inat CSUB on February 7th, 2020. Objective 7-Develop university curriculum on irrigation water quality and the Water-Food-Energy Nexus based on the project case study:The results of the project enabled PI Vengosh to develop a new curriculum for a new course at Duke University on the Water-Food-Energy Nexus, in addition to curriculum development on this topic at California State University Bakersfield.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Kondash,A.J., Redmon, J.H., Lambertini, E., Feinstein, L., Weinthal, E., Cabrales, L., Vengosh, A. (2020) The impact of using low-saline oilfield produced water for irrigation on water and soil quality in California. Science of the Total Environment, 139392. (https://doi.org/10.1016/j.scitotenv.2020.139392).
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Hoponick Redmon, J., Womack, D., Kondash, A.J.*, Lillys, T., Feinstein, L., Cabrales, L., Weinthal, E., and Vengosh, A. (in press). Is food irrigated with oifield produced water in the California Central Valley safe it eat? A probabilistic guman health risk assessment evaluating trace metals exposure. Risk Analysis. (in press)
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Progress 05/01/18 to 04/30/19
Outputs
Target Audience:*California Water Quality Control Board * Food Safety Committee facilitated by the California Water Board *California Certified Organic Farmers * Local farmers in southern Central Valley, California Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Graduate students have been participating in project meetings, and contributing to the preparation of materials, sample planning, sample collection, laboratory analysis, and data analysis. Specifically, they have collected data on water quality and quantity delivered to irrigation water districts, created maps outlining produced water use and chemistry across Kern County, and aggregated contaminant limits for comparison with collected samples. They have gained field and laboratory experience by collecting and analyzing samples, and interacting with farmers. A graduate student is also involved in policy analysis and is working on policy secario analysis. One doctoral graduate student at Duke has included this project in their dissertation research, and has successfully graduated in March 2019. He will continue to be involved as coauthor. How have the results been disseminated to communities of interest? The Duke Team identified, contacted, and communicated with stakeholders, and prepared and disseminated recruiting materials for participants and stakeholders. RTI, PI, and the Duke Team prepared and conducted a publicly-available presentation to the Food Safety Committee facilitated by the California Water Board on June 27, 2017 (https://www.waterboards.ca.gov/rwqcb5/water_issues/oil_fields/food_safety/meetings/2017_0628_fs_duke_pres.pdf). RTI, PI, and the Duke Team prepared and conducted an internal presentation to the Food Safety Committee facilitated by the California Water Board on September 20, 2017. The Duke Team issues a call for participants in a blog post on the California Certified Organic Farmers website in September 2017 (https://www.ccof.org/blog/call-participants-usda-funded-study-seeks-enroll-california-farmers-study-alternative). The Duke Team initiated a website for the project to allow interested stakeholders to obtain information online:https://sites.nicholas.duke.edu/oilfieldwater/ PI has communicated with researchers, environmental groups, state agencies and agricultural stakeholders to disseminate information and answer questions about the project. RTI has communicated with experts to better understand context and parameters to be adopted in the risk model. Duke, RTI, and PI conducted a presentation of preliminary results to the California Water Quality Control Board and members of the Food Safety Expert Panel on April 9, 2019 at the CWQCB office in Rancho Cordova, CA. The meeting was very positive and the study was well received. What do you plan to do during the next reporting period to accomplish the goals?Objective 3 - Multimedia Human Health Risk Assessment Modeling In the next phase, RTI will incorporate the feedback received, identify and incorporate any additional available datasets, run additional QA, and carry out final model runs to obtain a probabilistic multi-pathway, multimedia assessment using the 3MRA model that quantifies health risk estimates from potential human exposure to potential chemicals present in select crops as a result of OPW used for crop irrigation. Stakeholder engagement and extension activities will continue tosupport and augment the regional stakeholder platform facilitated by the Water Board, to allow for the advancement of shared governance and decision making on agricultural water quality management and appropriate use of alternative water sources. Needs and constraints faced by growers and irrigation water districts have been included in the discussion. Objective 4 - Policy Scenario Analysis Dr. Erika Weinthal and a graduate student from Duke will continue to work onliterature review and the possible implications of the data generated in this studyon current irrigation water policies and practices.
Impacts
What was accomplished under these goals?
Summary of work to-date:Our integrated project has included research, education, and extension components since project initiation in May 2017. We have completed the assembly of existing datasets (Task 1), collection and analysis of new samples (Task 2), and model development activities are in progress (Task 3). Model QA, model running, and result compilation are well under way (preliminary results complete). Policy analysis work (Task 4) has started. We have continued stakeholder engagement efforts (Tasks 5), including meetings and presentations with the Food Safety Expert Panel organized by the Central Valley Regional Water Quality Control Board, and communications with select organizations such as California Certified Organic Farms, commodity boards, and local growers and farmers. We have completed the collection and analysis of water and soil samples from select locations in the Central Valley that use oilfield produced water for crop irrigation, and completed the analysis of oil field water from the Central Valley. Two manuscripts are in the process of being drafted (Task 6). Graduate students have been involved in each aspect of the work and the work is part of the graduate student curriculum for Duke and CSU-B (Task 7). The multi-institution team meets regularly via conference calls to plan and carry out project activities, and four in-person meetings with team members have occurred since project initiation. Function 1: Research (Objectives 1-4) Objective 1 - OPW Risk Screening Analysis Leveraging Existing Datasets Duke and RTI haveconducted a review of the publicly available OPW water quality datasets. We have collected publicly available data and linked it to geographic areas within the Central Valley. In addition, the Duke team has been generated water quality data from oilfield water from different fields in Central Valley. Objective 2 - Baseline Field Survey of Blended OPW Used for Irrigation, Soil, and Crops Objective 2 efforts completed to date are described according to 1) planning and access,2) survey and sampling efforts, and 3) laboratory analysis. We have collected 51 water samples and 33 soil samples. Planning and Access (completed) The Duke Team planned potential sampling efforts, which included identifying regions that use OPW for irrigation, main OPW producers, main water districts that distribute OPW. We identified crops potentially supplied with OPW in Kern-Tulare. In the Cawelo irrigation district, it appears that OPW is used to supply canal water. Additional planning and access efforts carried out include: CSUB and PI assisted Duke University in obtaining access to conduct sampling and grower surveys. Survey and Sampling Efforts (completed) CSU-B and Duke traveled to several farms to conduct sample collection and shipped samples to Duke University for analysis.. A number of inorganic contaminants were identified and measured in obtained samples.We found levels of sodium, chloride, and boron at levels higher than Basin Plan recommendations being used on one private farm Soil samples were also analyzed and distinct chemicaldifferences between OPW irrigated fields and non-OPW irrigated fields were noted, particularly for salinity, boron and sodium contents. Analysis of radionuclides did not show systematic difference betweenOPW irrigated fields and non-OPW irrigated fields. Laboratory analyses (completed) The Duke team has analyzed 35 oilfield water, 8 oil-field irrigation water, and 8 groundwater samples as well as 33 soil samples from sites irrigated by local groundwater, diluted and undiluted oilfield water. Samples were analyzed for a wide spectrum of inorganic constituents including major elements, trace elements, and radionuclides. Objective 3 - Multimedia Human Health Risk Assessment Modeling The RTI team has reviewed model variables based on literature and expert consultation, has customized and QAed the model code for scenarios considered in this project, and run the model to obtain preliminary results. Specifically, to advance the modeling component of the project, the RTI Team performed the following: Reviewed the current 3MRA risk model that has been approved by the U.S. EPA Scientific Advisory Board, and identified modifications needed to convert the wet deposition module to simulate irrigation, with a focus on drip irrigation. RTI Reviewed the published literature as needed to update parameters of the 3MRA model. PI and RTI contacted experts from the University of California and other research organizations to better understand parameters related to soil characteristics, availability to plants, and uptake. RTI has combined existing water concentration datasets into a database. Multiple sources of concentration information have been considered to augment the knowledge basis for the model, hence making outputs more reliable. RTI has customized the code of the 3MRA model to account for scenario-specific processes and updated variables. RTI has performed model QA, and run the model over multiple scenarios to obtain preliminary results. Objective 4 - Policy Scenario Analysis Erika Weinthal and PhD student began compiling literature for review. Additionally, stakeholder engagement efforts have provided background information on current irrigation water policies and practices. Function 2: Extension (Objectives 5-6) Objective 5: Stakeholder Engagement The Duke Team identified, contacted, and communicated with stakeholders, and prepared and disseminated recruiting materials for participants and stakeholders. RTI, PI, and the Duke Team prepared and conducted a publicly-available presentation to the Food Safety Committee facilitated by the California Water Board on June 27, 2017 (https://www.waterboards.ca.gov/rwqcb5/water_issues/oil_fields/food_safety/meetings/2017_0628_fs_duke_pres.pdf). RTI, PI, and the Duke Team prepared and conducted an internal presentation to the Food Safety Committee facilitated by the California Water Board on September 20, 2017. The Duke Team issues a call for participants in a blog post on the California Certified Organic Farmers website in September 2017 (https://www.ccof.org/blog/call-participants-usda-funded-study-seeks-enroll-california-farmers-study-alternative). The Duke Team initiated a website for the project to allow interested stakeholders to obtain information online:https://sites.nicholas.duke.edu/oilfieldwater/ PI has communicated with researchers, environmental groups, state agencies and agricultural stakeholders to disseminate information and answer questions about the project. RTI has communicated with experts to better understand context and parameters to be adopted in the risk model. Duke, RTI, and PI conducted a presentation of preliminary results to the California Water Quality Control Board and members of the Food Safety Expert Panel on April 9, 2019 at the CWQCB office in Rancho Cordova, CA.The meeting was very positive and the study was well received. Objective 6: Outreach and Dissemination of Study Results Objective 6 efforts have begun, and have thus far centered around 1) communication with the Food Safety Expert Panel andCalifornia Water Quality Control Board, and 2) drafting manuscripts.The project team has started drafting two manuscripts for peer-reviewed publication. Function 3: Education Objective 7: Develop university curriculum on irrigation water quality and the Water-Food-Energy Nexus based on the project case study This project is continuing to support novel curriculum at the graduate level, with the main goals of: (1) developing highly trained agricultural professionals who understand the interactions between irrigation water quality, soil quality, and food, and (2) Develop curriculum for the energy-water nexus course at Duke Univeisty.
Publications
|
Progress 05/01/17 to 04/30/18
Outputs
Target Audience:* Scientific community * Farmers * State officials (California Centravel valley Water Board) Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Graduate and undergraduatestudents working on issues related to water pocity, oil brines chemistry, soil chemistry, risks for plants. How have the results been disseminated to communities of interest?It too early to disseminated the results What do you plan to do during the next reporting period to accomplish the goals?Continue to work according to teh reserrach plan - Sampling additional sites, analyzing oil brines, local groundwater, soil and some food products Modeling risks for human health Modeling risks for soil degradation and boron toxcicity
Impacts
What was accomplished under these goals?
Summary of work to-date: Our integrated project has included research, education, and extension components since project initiation in May 2017. We have participated in various stakeholder engagement efforts, including meetings and presentations with the Food Safety Expert Panel organized by the Central Valley Regional Water Quality Control Board, and communications with select organizations such as California Certified Organic Farms, commodity boards, and local growers and farmers. We collected and analyzed samples from select locations in the Central Valley that use oilfield produced water for crop irrigation, and completed analysis of oil brines from Central Valley through a collaboration with the USGS. Additionally, publicly available datasets have been identified for screening analysis. Graduate students have been involved in each aspect of the work and the work is part of the graduate student curriculum for Duke and CSU-B. We are currently in the process of requesting additional access for expanded sample collection during the first quarter of 2018. The multi-institution team meets regularly via conference calls to plan and carry out project activities, and two in-person meetings have occurred since project initiation. Function 1: Research (Objectives 1-4) The main goal of the overall research activities for the project is to assess possible human health and food quality impacts from the use of OPW for irrigation, with a starting focus on oilfields in Central California. Objective 1 - OPW Risk Screening Analysis Leveraging Existing Datasets Duke and RTI have conducted a review of the publicly available OPW water quality datasets. PI has coordinated with the Duke team to orient them to publicly available datasets on relevant public datasets. We have collected publicly available data and linked it to geographic areas within the Central Valley. In addition, the Duke team has been generated water quality data from oilfield brines from different fields in Central Valley. The results of the investigation are presented in the Supplement document. Objective 2 - Baseline Field Survey of Blended OPW Used for Irrigation, Soil, and Crops Objective 2 efforts completed to date are described according to 1) planning and access, and 2) survey and sample efforts. Planning and Access The Duke Team planned potential sampling efforts, which included identifying regions that use OPW for irrigation, main OPW producers, main water districts that distribute OPW, selected independent producers (e.g. growers that have oil wells on their property and use OPW for irrigation, instead of purchasing it from a water district), and categories of growers (organic, conventional). We identified crops potentially supplied with OPW in Kern-Tulare. We have crop information for other districts, and plan to submit FOIA requests to the different districts during the first half of 2018 to obtain lists or maps of which farms are receiving OPW. In the Cawelo district, it appears that OPW is used to supply canal water, thus any farm that uses canal water thereby uses OPW. Additional planning and access efforts are listed as follows: The Duke Team discussed the study sampling approach based on information provided in initial stakeholder engagement efforts. A field survey template was prepared. CSUB and PI assisted Duke University in obtaining access to conduct sampling and grower surveys. CSU-B and Duke contacted farmers to arrange visits. PI has contacted regional stakeholders to set up potential visits. Survey and Sampling Efforts CSU-B and Duke traveled to 2 farms to conduct sample collection and shipped samples to Duke University for analysis in December 2017. A number of inorganic contaminants were identified and measured in obtained samples. These include 3 of primary importance: arsenic, chloride, and boron in addition to sodium, aluminum, beryllium, cadmium, copper, fluoride, iron, lead, manganese, molybdenum, nickel, selenium, and vanadium. We found levels of sodium, chloride, and boron at levels higher than Basin Plan recommendations being used on one private farm (see report in Supplement). Soil samples were also analyzed and distinct chemical differences between OPW irrigated fields and non-OPW irrigated fields were noted (see report in Supplement). The Duke Team has regular conference calls to discuss survey and sampling planning, including access, analytes, survey questions, and data management. Additionally, Duke and RTI have had two in-person meetings since project initiation. Objective 3 - Multimedia Human Health Risk Assessment Modeling To advance the modeling component of the project, the RTI Team performed the following: Reviewed the current 3MRA risk model that has been approved by the U.S. EPA Scientific Advisory Board, and identified modifications needed to convert the wet deposition module to simulate irrigation, with a focus on drip irrigation. RTI Reviewed the published literature as needed to update parameters of the 3MRA model. PI contacted a soil chemistry expert from the University of California - Riverside (Stacia Dudley, Jay Gan's lab) to better understand the impact of soil characteristics on availability to plants. After additional sampling and analyses are conducted, RTI will incorporate the analytical data and field survey information to conduct a probabilistic multi-pathway, multimedia assessment using the 3MRA model that quantifies health risk estimates from potential human exposure to potential chemicals present in select crops as a result of OPW used for crop irrigation. Objective 4 - Policy Scenario Analysis Objective 4 efforts have not yet begun, pending completion of Objectives 1-3. PI and Dr. Erika Weinthal of Duke have met to begin compiling literature for review. Additionally, stakeholder engagement efforts have provided background information on current irrigation water policies and practices. Function 2: Extension (Objectives 5-6) Objective 5: Stakeholder Engagement The Duke Team identified, contacted, and communicated with stakeholders, and prepared and disseminated recruiting materials for participants and stakeholders. RTI, PI, and the Duke Team prepared and conducted a publicly-available presentation to the Food Safety Committee facilitated by the California Water Board on June 27, 2017 (https://www.waterboards.ca.gov/rwqcb5/water_issues/oil_fields/food_safety/meetings/2017_0628_fs_duke_pres.pdf). RTI, PI, and the Duke Team prepared and conducted an internal presentation to the Food Safety Committee facilitated by the California Water Board on September 20, 2017. The Duke Team issues a call for participants in a blog post on the California Certified Organic Farmers website in September 2017 (https://www.ccof.org/blog/call-participants-usda-funded-study-seeks-enroll-california-farmers-study-alternative). The Duke Team initiated a website for the project to allow interested stakeholders to obtain information online: https://sites.nicholas.duke.edu/oilfieldwater/ PI has communicated with researchers, environmental groups, state agencies and agricultural stakeholders to disseminate information and answer questions about the project. Stakeholder engagement and extension activities will continue to bolster a regional stakeholder platform that allows for the advancement of shared governance and decision making on agricultural water quality management. Needs and constraints faced by growers and irrigation water districts are being identified through current efforts.
Publications
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