The impact of using low-saline oilfield produced water for irrigation on water and soil quality in California

Andrew J Kondash; Jennifer Hoponick Redmon; Elisabetta Lambertini; Laura Feinstein; Erika Weinthal; Luis Cabrales; Avner Vengosh

doi:10.1016/j.scitotenv.2020.139392

The impact of using low-saline oilfield produced water for irrigation on water and soil quality in California

Sci Total Environ. 2020 Sep 1:733:139392. doi: 10.1016/j.scitotenv.2020.139392. Epub 2020 May 12.

Authors

Andrew J Kondash¹, Jennifer Hoponick Redmon², Elisabetta Lambertini², Laura Feinstein³, Erika Weinthal⁴, Luis Cabrales⁵, Avner Vengosh⁶

Affiliations

¹ Nicholas School of the Environment, Duke University, Durham, NC 27708, United States; RTI International, 3040 E. Cornwallis Road, Research Triangle Park, NC 27709, United States.
² RTI International, 3040 E. Cornwallis Road, Research Triangle Park, NC 27709, United States.
³ Pacific Institute, Oakland, CA 94612, United States.
⁴ Nicholas School of the Environment, Duke University, Durham, NC 27708, United States.
⁵ Department of Physics and Engineering, California State University Bakersfield, CA 93311, United States of America.
⁶ Nicholas School of the Environment, Duke University, Durham, NC 27708, United States. Electronic address: vengosh@duke.edu.

PMID: 32446094
DOI: 10.1016/j.scitotenv.2020.139392

Abstract

The consecutive occurrence of drought and reduction in natural water availability over the past several decades requires searching for alternative water sources for the agriculture sector in California. One alternative source to supplement natural waters is oilfield produced water (OPW) generated from oilfields adjacent to agricultural areas. For over 25 years, OPW has been blended with surface water and used for irrigation in the Cawelo Water District of Kern County, as permitted by California Water Board policy. This study aims to evaluate the potential environmental impact, soil quality, and crop health risks of this policy. We examined a large spectrum of salts, metals, radionuclides (²²⁶Ra and ²²⁸Ra), and dissolved organic carbon (DOC) in OPW, blended OPW used for irrigation, groundwater, and soils irrigated by the three different water sources. We found that all 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. We did not, however, find systematic differences in ²²⁶Ra and ²²⁸Ra activities and DOC in soils irrigated by blended or unblended OPW relative to groundwater-irrigated soils. Based on a comparison of measured parameters, we conclude that the 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.

Keywords: Boron; Irrigation; Oilfield produced water; Reuse; Soil; Sustainability; Water quality.