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Advanced treated municipal wastewater is an important alternative water source for agricultural irrigation. However, the possible persistence of chemical and microbiological contaminants in these waters raise potential safety concerns with regard to reusing treated wastewater for food crop irrigation. Two low-cost and environmentally-friendly filter media, biochar (BC) and zero-valent iron (ZVI), have attracted great interest in terms of treating reused water. Here, we evaluated the efficacy of BC-, nanosilver-amended biochar- (Ag-BC) and ZVI-sand filters, in reducing contaminants of emerging concern (CECs),Escherichia coli (E. coli)and total bacterial diversity from wastewater effluent. Six experiments were conducted with control quartz sand and sand columns containing BC, Ag-BC, ZVI, BC with ZVI, or Ag-BC with ZVI. After filtration, Ag-BC, ZVI, BC with ZVI and Ag-BC with ZVI demonstrated more than 90% (> 1 log) removal ofE. colifrom wastewater samples, while BC, Ag-BC, BC with ZVI and Ag-BC with ZVI also demonstrated efficient removal of tested CECs. Lower bacterial diversity was also observed after filtration; however, differences were marginally significant. In addition, significantly (p < 0.05) higher bacterial diversity was observed in wastewater samples collected during warmer versus colder months. Leaching of silver ions occurred from Ag-BC columns; however, this was prevented through the addition of ZVI. In conclusion, our data suggest that the BC with ZVI and Ag-BC with ZVI sand filters, which demonstrated more than 99% removal of both CECs andE. coliwithout silver ion release, may be effective, low-cost options for decentralized treatment of reused wastewater.

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Abstract Young adults are increasingly using non-cigarette products, such as hookahs, since they are perceived as healthier alternatives to cigarette smoking. However, hookah users are exposed to not only carcinogenic compounds but also microorganisms that may play an active role in the development of both infectious and chronic diseases among users. Nevertheless, existing hookah research in this area has focused only on microorganisms that may be transferred to users through the smoking apparatus and not on bacterial communities associated with hookah tobacco. To address this knowledge gap, we conducted time-series experiments on commercially available hookah brands (Al Fakher (flavors: two apple, mint, and watermelon) and Fumari (flavors: white gummy bear, ambrosia, and mint chocolate chill)) stored under three different temperature and relative humidity conditions over 14 days. To characterize bacterial communities, the total DNA was extracted on days 0, 5, 9, and 14, PCR-amplified for the V3V4 region of the bacterial 16S rRNA gene, sequenced on the Illumina HiSeq platform, and analyzed using R. Diversity (alpha and beta) analyses revealed that the microbiotas of Fumari and Al Fakher products differed significantly and that flavor had a significant effect on the hookah microbiota. Overall, Pseudomonas , Bacillus , Sphingomonas , and Methylobacterium were the predominant bacterial taxa across all products . Additionally, we observed compositional differences between hookah brands across the 14-day incubation . These data suggest that the bacterial communities of hookah tobacco are diverse and differ across brands and flavors, which may have critical implications regarding exposures to specific bacteria among hookah users. Key points • Commercial hookah products harbor diverse bacterial communities . • Brands and flavors impact the diversity of these communities . • Research on their viability and transmission to users’ respiratory tracts is needed . Graphical abstract 

ABSTRACT Phylogenetic distribution and extended spectrum β-lactamase (ESBL) activity of Escherichia coli recovered from surface and reclaimed water in the mid-Atlantic U.S. were evaluated. Among 488 isolates, phylogroups B1 and A were the most and least prevalent, respectively. Water type, but not season, affected phylogroup distribution. The likelihood of detecting group A isolates was higher in reclaimed than pond ( P <  0.01), freshwater river ( P <  0.01) or brackish river (P <  0.05) water. Homogeneity in group distribution was lowest in pond water, where group B1 comprised 50% of isolates. Only 16 (3.3%) isolates exhibited phenotypic resistance to one or more cephalosporins tested and only four had ESBL activity, representing groups B1, B2 isolates, and D. Phylogroup was a factor in antimicrobial resistance ( P <  0.05), with group A (8.7%) and D (1.6%) exhibiting the highest and lowest rates. Resistance to cefoxitin was the most prevalent. Multi- versus single drug resistance was affected by phylogroup ( P <  0.05) and more likely in groups D and B1 than A which carried resistance to cefoxitin only. The most detected β-lactam resistance genes were bla CMY-2 and bla TEM . Water type was a factor for bla CTX-M gene detection ( P <  0.05). Phenotypic resistance to cefotaxime, ceftriaxone, cefuroxime and ceftazidime, and genetic determinants for ESBL-mediated resistance were found predominantly in B2 and D isolates from rivers and reclaimed water. Overall, ESBL activity and cephalosporin resistance in reclaimed and surface water isolates were low. Integrating data on ESBL activity and β-lactam resistance among E. coli populations can inform decisions on safety of irrigation water sources and One Health. IMPORTANCE Extended spectrum β-lactamase (ESBL) producing bacteria, that are resistant to a broad range of antimicrobial agents, are spreading in the environment but data remain scarce. ESBL-producing Escherichia coli infections in the community are on the rise. This work was conducted to assess presence of ESBL-producing E. coli in water that could be used for irrigation of fresh produce. The study provides the most extensive evaluation of ESBL-producing E. coli in surface and reclaimed water in the mid-Atlantic United States. The prevalence of ESBL producers was low and phenotypic resistance to cephalosporins (types of β-lactam antibiotics) was affected by season but not water type. Data on antimicrobial resistance among E. coli populations in water can inform decisions on safety of irrigation water sources and One Health.