Removal of selected PPCPs, EDCs, and antibiotic resistance genes in landfill leachate by a full-scale constructed wetlands system

• Published in: Water research (Oxford) 2017-09, Vol.121, p.46-60
• Main Authors: Yi, Xinzhu, Tran, Ngoc Han, Yin, Tingru, He, Yiliang, Gin, Karina Yew-Hoong
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents; Antibiotic resistance genes (ARGs); Bacteria - genetics; Constructed wetlands (CWs); Drug Resistance, Microbial - genetics; Emerging contaminants (ECs); Landfill leachate; Pharmaceuticals and personal care products (PPCPs); Refuse Disposal; Singapore; Water Pollutants, Chemical; Water Purification; Wetlands
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2017.05.008

Landfill leachate could be a significant source of emerging contaminants (ECs) and antibiotic resistance genes (ARGs) into the environment. This study provides the first information on the occurrence of selected ECs and ARGs in raw leachate from 16-year old closed landfill site in Singapore. Among the investigated ECs, acetaminophen (ACT), bisphenol A (BPA), clofibric acid (CA), caffeine (CF), crotamiton (CTMT), diclofenac (DCF), N,N-diethyl-m-toluamide (DEET), gemfibrozil (GFZ), lincomycin (LIN), salicylic acid (SA), and sulfamethazine (SMZ) were the most frequently detected compounds in raw landfill leachate. The concentrations of detected ECs in raw landfill leachate varied significantly, from below quantification limit to 473,977 ng/L, depending on the compound. In this study, Class I integron (intl1) gene and ten ARGs were detected in raw landfill leachate. Sulfonamide resistance (sul1, sul2, and dfrA), aminoglycoside resistance (aac6), tetracycline resistance (tetO), quinolone resistance (qnrA), and intl1 were ubiquitously present in raw landfill leachate. Other resistance genes, such as beta-lactam resistance (blaNMD1, blaKPC, and blaCTX) and macrolide-lincosamide resistance (ermB) were also detected, detection frequency of 90%) in the investigated hybrid CW system. This hybrid CW system was also found to be effective in the reduction of several ARGs (intl1, sul1, sul2, and qnrA). Aeration lagoons and reed beds appeared to be the most important treatment units of the hybrid CW for removing the majority of ECs from the leachate. •Fifteen out of 29 target PPCPs and EDCs were detected in raw landfill leachate.•Eleven target antibiotic resistant genes (ARGs) were found in landfill leachate.•Aeration lagoon played a major role in removing PPCPs in constructed wetlands.