Assessing potential human health impacts associated with the use of oilfield produced water for crop irrigation

The overarching objectives of the proposed study are to: (1) Provide quantitative evidence of potential human health risks from foodborne and incidental exposure to chemical contaminants potentially present in oil produced water (OPW) used for edible crop irrigation, and (2) Use findings to interactively improve the management and watershed governance of this key resource. The study focuses on Central California due to its urgent need for viable water management strategies. Results and risk modeling tools are applicable nationwide.The long-term objective of this study is to establish criteria for safe beneficial use of OPW for irrigation of selected crops, provided the quality of the water applied to fields does not pose food safety risks as compared to conventional irrigation water. Additional long-term objectives are to foster agricultural sustainability by maintaining soil quality and crop health. Specific action strategies advanced by the proposed project in support of long-term goals include: (a) Creating a database of OPW quality for the major metals of food safety and crop health concern; (b) Building and applying a comprehensive quantitative human risk assessment to evaluate health impacts of multi-pathway exposure to irrigation OPW (foodborne, farmworkers, and community members); (c) Exploring factors related to extraction operations and produce farm management that may affect health risks associated with OPW irrigation, and could be leveraged to mitigate risks; (d) Assessing policy and watershed governance scenarios to facilitate the sustainable management of non-traditional irrigation water sources, including OPW. These research goals will be integrated with extension outreach and communications with farmers, consumers, and other stakeholders, and will be used to develop curriculum to train the next generation of agriculture professionals.The specific project objectives are:Research: - Objective 1: OPW Risk Screening Analysis Leveraging Existing DatasetsThe main goal of the research activities is to assess potential human health and food safety risks resulting from use of OPW for irrigation, with focus on oilfields and OPW irrigation practices in Central California.- Objective 2: Baseline Field Survey of Blended OPW Used for Irrigation, Soil, and CropsIn addition to data on unblended OPW at the oil well obtained as part of Obj. 1, we plan to conduct a focused field sample collection and laboratory analysis of irrigation water, soil, and edible crops on Central California farms that use OPW, to establish a baseline survey of metals, salts, and NORM tracers in fields that irrigated with OPW for at least two consecutive years.- Objective 3: Multimedia Human Health Risk Assessment ModelingThis Objective involves developing and applying a modular probabilistic risk model to estimate the fate and main human health impacts of metals potentially occurring in OPW, from the moment of irrigation water application, through transport in the soil column, uptake by plant cultivars' roots, partitioning in plant tissues, until human consumption of the edible portion of the plant (fruit or seed) as food.- Objective 4: Policy Scenario AnalysisThe objective is to provide a comprehensive and integrated understanding of the potential for POW for crop irrigation, we also plan to carry out a policy analysis to understand not only the scientific constraints, but the institutional ones.Extension: - Objective 5: Stakeholder EngagementThe main goal of the proposed extension activities is to foster a regional stakeholder platform to advance knowledge, governance, and decision-making on agricultural water quality management, with focus on non-traditional water sources and chemical contaminants.- Objective 6: Outreach and Dissemination of Study ResultsExtension goals will be advanced through the following activities:? _Two in-person stakeholder discussion forums (years 1 and 3)? _A web-based consumer survey to collect information related on food safety concerns and risk/benefit perception (years 1-2)? _Communication and discussion of study outcomes to farmers and other regional stakeholders via one workshop, web articles, and fact sheetsEducation: - Objective 7: Develop university curriculum on irrigation water quality and the Water-Food-Energy Nexus based on the project case studyThis Objective will contribute novel curriculum at the upper-undergraduate and graduate levels, and could be offered both at Duke and CSUB with the main goals of: (a) developing highly trained agriculture professionals who understand the interactions between irrigation water quality, soil quality, and food, in the context of environmental, water scarcity, and regulatory constraints; and (b) foster systems-based multidisciplinary thinking with curriculum combining issues and students from agriculture, engineering, environmental sciences, economics, policy, public health, and community development, in the context of Energy-Water-Food nexus.