Document Type

Article

Language

eng

Format of Original

7 p.

Publication Date

10-2011

Publisher

American Chemical Society

Source Publication

Environmental Science & Technology

Source ISSN

0013-936X

Original Item ID

doi: 10.1021/es202775r

Abstract

In this study, the impact of tertiary-treated municipal wastewater on the quantity of several antibiotic resistance determinants in Duluth-Superior Harbor was investigated by collecting surface water and sediment samples from 13 locations in Duluth-Superior Harbor, the St. Louis River, and Lake Superior. Quantitative PCR (qPCR) was used to target three different genes encoding resistance to tetracycline (tet(A), tet(X), and tet(W)), the gene encoding the integrase of class 1 integrons (intI1), and total bacterial abundance (16S rRNA genes) as well as total and human fecal contamination levels (16S rRNA genes specific to the genus Bacteroides). The quantities of tet(A), tet(X), tet(W), intI1, total Bacteroides, and human-specific Bacteroides were typically 20-fold higher in the tertiary-treated wastewater than in nearby surface water samples. In contrast, the quantities of these genes in the St. Louis River and Lake Superior were typically below detection. Analysis of sequences of tet(W) gene fragments from four different samples collected throughout the study site supported the conclusion that tertiary-treated municipal wastewater is a point source of resistance genes into Duluth-Superior Harbor. This study demonstrates that the discharge of exceptionally treated municipal wastewater can have a statistically significant effect on the quantities of antibiotic resistance genes in otherwise pristine surface waters.

Comments

Accepted version. Environmental Science & Technology, Vol. 45, No. 22 (2011): 9543-9549. DOI. © 2011 American Chemical Society. Used with permission.

Patrick J. McNamara was affiliated with The University of Minnesota at the time of publication.

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