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Lookup NU author(s): Professor David Graham
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).
Landfills receive about 250 million tons of unsorted solid wastes per year globally, including antibiotics, heavy metals and other co-selecting agents that impact antimicrobial resistance (AMR). However, little is known about AMR in landfills, especially as a function of landfill aging and condition, which is a massive issue given that over 65% of wastes disposed in the emerging world are at uncontrolled sites. Here we quantified antibiotics, heavy metals, and AMR genes (ARGs) in refuse and leachates from landfills of different age (< 3, 5-8, and 15-25 years, respectively). Antibiotics levels were consistently lower in refuse and leachates in older landfill samples, whereas ARG levels significantly increased with landfill age (one-way ANOVA, F = 76.5, P < 0.001). To explain increasing ARGs with age, microbial communities, mobile genetic elements (MGEs) and environmental factors were compared between refuse and leachate samples. Communities in refuse were closely structured with ARG levels (Procrustes test; M2 = 0.369, r = 0.855, P = 0.001), whereas microbial community structure and environmental factors were less important in leachates, with ARG levels being more associated with heavy metals and MGEs. Although antibiotics levels tend to decrease in landfills as they age, ARGs increase, suggesting antibiotics themselves may be less important to AMR released to the environment. ARG releases are more driven by co-selecting agents, such as heavy metals, implying old landfills are more important sources of AMR than believed, especially in the emerging world where landfill leachates are often poorly managed.
Author(s): Wu D, Huang X, Sun J, Graham DW, Xie B
Publication type: Article
Publication status: Published
Journal: Environmental Science & Technology
Print publication date: 07/11/2017
Online publication date: 09/10/2017
Acceptance date: 12/10/2017
Date deposited: 14/10/2017
ISSN (print): 0013-936X
ISSN (electronic): 1520-5851
Publisher: American Chemical Society
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