Trace organic contaminants in field-scale cultivated alfalfa, soil, and pore water after 10 years of irrigation with reclaimed wastewater

Priyamvada Sharma; Andrew Poustie; Paul Verburg; Krishna Pagilla; Yu Yang; David Hanigan

doi:10.1016/j.scitotenv.2020.140698

Trace organic contaminants in field-scale cultivated alfalfa, soil, and pore water after 10 years of irrigation with reclaimed wastewater

Sci Total Environ. 2020 Nov 20:744:140698. doi: 10.1016/j.scitotenv.2020.140698. Epub 2020 Jul 6.

Authors

Priyamvada Sharma¹, Andrew Poustie¹, Paul Verburg², Krishna Pagilla¹, Yu Yang¹, David Hanigan³

Affiliations

¹ Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557-0258, United States of America.
² Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV 89557-0258, United States of America.
³ Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557-0258, United States of America. Electronic address: DHanigan@unr.edu.

PMID: 32693273
DOI: 10.1016/j.scitotenv.2020.140698

Abstract

Several studies have assessed the presence of trace organic contaminants (TrOCs) in reclaimed wastewater and their uptake into crops but there are limited data from field-scale studies. In this research, we studied the fate of 12 TrOCs in wastewater samples, 11 in plants and in soil pore water, and 10 in soil at an agricultural research farm, which was irrigated with reclaimed wastewater for more than 10 years. First, we examined the presence of the compounds in the primary, secondary, and treated effluent of a regional water reclamation facility which provides the irrigation water. The agricultural field produced alfalfa, and we measured the contaminants in the alfalfa, soil, and pore water. Reclaimed wastewater contained 11 of 12 TrOCs, with concentrations ranging from 26 ± 9 ng/L (DEET) to 1539 ± 1899 ng/L (trimethoprim). Atrazine was not detected. Pore water collected during non-irrigating periods contained all analyzed TrOCs, from 3 ± 0.1 ng/L (diphenhydramine) to 343 ± 360 ng/L (primidone). TrOCs measured in pore water samples indicated that they may leach to shallow groundwater even when fields are not being irrigated. Soils from 0 to 60 cm contained nine TrOCs from below the reporting limit (fluoxetine) to 329 ng/g (carbamazepine). Atrazine was not detected. TrOC concentrations decreased with increasing soil depth, except carbamazepine, which was more recalcitrant. Nine TrOCs were present in the shoots and leaves of alfalfa grown in the reclaimed wastewater irrigated plots, at concentrations ranging from <1 ng/g (diphenhydramine and fluoxetine) to 49 ng/g dry weight (carbamazepine). Atrazine and caffeine were not detected. We estimated that a maximum of 14% of DEET from the reclaimed wastewater was accumulated in alfalfa. Overall, despite some accumulation of TrOCs in the soil, alfalfa uptake was limited, which results in low exposure to foraging animals.

Keywords: Agriculture; Pharmaceutical and personal care products; Reclaimed wastewater irrigation; Rhizosphere; TrOCs.