Skip to main content
ARS Home » Pacific West Area » Maricopa, Arizona » U.S. Arid Land Agricultural Research Center » Water Management and Conservation Research » Research » Publications at this Location » Publication #386304
Research Project: The Use of Treated Municipal Waste Water as a Source of New Water for Irrigation

Location: Water Management and Conservation Research

Title: The dissemination of antibiotics and their corresponding resistance genes in treated effluent-soil-crops continuum, and the effect of barriers

Author
item SEYOUM, MITIKU MIHIRET - Ben Gurion University Of Negev
item OBAYOMI, OLABIYI - Ben Gurion University Of Negev
item BERNSTEIN, NIRIT - Volcani Center (ARO)
item Williams, Clinton
item GILLOR, OSNAT - Ben Gurion University Of Negev

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/4/2021
Publication Date: 12/15/2021
Citation: Seyoum, M., Obayomi, O., Bernstein, N., Williams, C.F., Gillor, O. 2021. The dissemination of antibiotics and their corresponding resistance genes in treated effluent-soil-crops continuum, and the effect of barriers. Science of the Total Environment. 807(2). Article 151525. https://doi.org/10.1016/j.scitotenv.2021.151525.
DOI: https://doi.org/10.1016/j.scitotenv.2021.151525

Interpretive Summary: The use of plastic mulches can provide an extra barrier to contamination of food crops by treated municipal waste water. The research evaluated if the fate of antibiotics and antimicrobial resistance genes found in municipal wastewater were affected by the use of plastic mulches. It found that the persistence of antibiotics was increased by plastic mulch under both subsurface and surface irrigation. It was also found that over two years there was no link between antibiotic concentration and antimicrobial resistance genes.

Technical Abstract: The use of treated effluent for crop irrigation is expanding but hampered by growing concerns that effluent may spread pharmaceuticals, and specifically antibiotics and resistance elements to the irrigated soil and crop. To evaluate this concern, freshwater and effluent were applied by drip irrigation to low growing crops (cucumber or melon) cultivated in soil, treated by subsurface drip irrigation and/or plastic mulch cover, during two consecutive growing seasons. We hypothesized that effluent carries antibiotics and resistance elements to the drip irrigated soil or crops regardless of the treatment. To test our hypotheses, we monitored water, soil, and crop samples for antibiotic abundance (erythromycin, sulfamethoxazole, tetracycline, chlortetracycline, oxytetracycline, amoxicillin, and ofloxacin) and corresponding resistance genes (ermB, ermF, sul1, tetW, tetO, blaTEM and qnrB), together with class 1 integron (intl1), and the bacterial 16S rRNA, over the two cultivation seasons. The results showed that an array of antibiotic and corresponding resistance genes were detected in the effluent but not the freshwater. Yet, there were no significant differences in the distribution or abundance of antibiotic and resistance genes, regardless of the irrigation water quality, or crop type (p>0.05), yet plastic covered soil retained some antibiotics (p<0.05). However, we could not detect significant correlations between the detected antibiotics and the corresponding resistance genes. Our findings disproved our hypotheses suggesting that the antibiotics and resistance genes in treated effluent may not carry to the irrigated soil and crops, although plastic mulch covered soil may retain some antibiotics.