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Antibiotic residues in the environment threaten soil and aquatic organisms and human and livestock health through the building of antimicrobial resistance. Manure spreading associated with animal agriculture is one source of environmental antibiotic residues. To better understand the risk of contamination, we studied the adsorption of erythromycin, a model macrolide antibiotic used across human and animal medicine. We conducted a series of equilibrium batch experiments to determine the kinetics and extent of adsorption and a continuous-flow column adsorption experiment to observe non-equilibrium adsorption patterns. We determined that the adsorption equilibration time to soil was approximately 72 h in our batch experiments. Erythromycin adsorbed to soil relatively strongly (K - 8.01x10-2 L/mg; qmax - 1.53x10-3 mg/mg), adsorbed to the soil in the presence of manure with less affinity (K - 1.99x10-4 L/mg) at a soil: manure ratio of 10:1 by mass, and did not adsorb to manure across the solid ratios tested. We observed multi-phased adsorption of erythromycin to the soil during the non-equilibrium column experiment, which was largely absent from the treatments with both soil and manure present. These results suggest that erythromycin is more mobile in the environment when introduced with manure, which is likely the largest source of agriculturally sourced environmental antibiotics. [ABSTRACT FROM AUTHOR]

An alternative material to activated carbon for water remediation is reported: a porous material based on crosslinked cyclodextrins that is better than activated carbons at adsorbing a range of pharmaceuticals, pesticides and other anthropogenic pollutants. Near-instant removal of organic micropollutants from water Water purification and remediation is often carried out using various forms of activated carbon; it is inexpensive, but only partially removes many organic pollutants. However, regenerating activated carbon for reuse is energy intensive, requiring high temperatures, and performance decreases upon recycling. Now William Dichtel, Damian Helbling and colleagues have developed an alternative to activated carbon for water remediation: a high-surface-area, mesoporous polymer of [beta]-cyclodextrin. Not only does the material outperform activated carbons at adsorbing a range of pharmaceuticals, pesticides and other pollutants, but it is easily regenerated by washing at room temperature. The global occurrence in water resources of organic micropollutants, such as pesticides and pharmaceuticals, has raised concerns about potential negative effects on aquatic ecosystems and human health.sup.1,2,3,4,5. Activated carbons are the most widespread adsorbent materials used to remove organic pollutants from water but they have several deficiencies, including slow pollutant uptake (of the order of hours).sup.6,7 and poor removal of many relatively hydrophilic micropollutants.sup.8. Furthermore, regenerating spent activated carbon is energy intensive (requiring heating to 500-900 degrees Celsius) and does not fully restore performance.sup.9,10. Insoluble polymers of [beta]-cyclodextrin, an inexpensive, sustainably produced macrocycle of glucose, are likewise of interest for removing micropollutants from water by means of adsorption.sup.11. [beta]-cyclodextrin is known to encapsulate pollutants to form well-defined host-guest complexes, but until now cross-linked [beta]-cyclodextrin polymers have had low surface areas and poor removal performance compared to conventional activated carbons.sup.11,12,13. Here we crosslink [beta]-cyclodextrin with rigid aromatic groups, providing a high-surface-area, mesoporous polymer of [beta]-cyclodextrin. It rapidly sequesters a variety of organic micropollutants with adsorption rate constants 15 to 200 times greater than those of activated carbons and non-porous [beta]-cyclodextrin adsorbent materials.sup.7,8,11,12,13. In addition, the polymer can be regenerated several times using a mild washing procedure with no loss in performance. Finally, the polymer outperformed a leading activated carbon for the rapid removal of a complex mixture of organic micropollutants at environmentally relevant concentrations. These findings demonstrate the promise of porous cyclodextrin-based polymers for rapid, flow-through water treatment., Author(s): Alaaeddin Alsbaiee [sup.1] , Brian J. Smith [sup.1] , Leilei Xiao [sup.1] , Yuhan Ling [sup.2] , Damian E. Helbling [sup.2] , William R. Dichtel [sup.1] Author Affiliations: (1) [...]

The global occurrence in water resources of organic micropollutants, such as pesticides and pharmaceuticals, has raised concerns about potential negative effects on aquatic ecosystems and human health (1-5). Activated carbons are the most widespread adsorbent materials used to remove organic pollutants from water but they have several deficiencies, including slow pollutant uptake (of the order of hours) (6, 7) and poor removal of many relatively hydrophilic micropollutants (8). Furthermore, regenerating spent activated carbon is energy intensive (requiring heating to 500-900 degrees Celsius) and does not fully restore performance (9, 10). Insoluble polymers of β-cyclodextrin, an inexpensive, sustainably produced macrocycle of glucose, are likewise of interest for removing micropollutants from water by means of adsorption (11). β-cyclodextrin is known to encapsulate pollutants to form well-defined host-guest complexes, but until now cross-linked β-cyclodextrin polymers have had low surface areas and poor removal performance compared to conventional activated carbons (11-13). Here we crosslink β-cyclodextrin with rigid aromatic groups, providing a high-surface-area, mesoporous polymer of β-cyclodextrin. It rapidly sequesters a variety of organic micropollutants with adsorption rate constants 15 to 200 times greater than those of activated carbons and non-porous P-cyclodextrin adsorbent materials (7, 8, 11-13). In addition, the polymer can be regenerated several times using a mild washing procedure with no loss in performance. Finally, the polymer outperformed a leading activated carbon for the rapid removal of a complex mixture of organic micropollutants at environmentally relevant concentrations. These findings demonstrate the promise of porous cyclodextrin-based polymers for rapid, flow-through water treatment., Porous β-CD-containing polymers (P-CDPs) were derived from nucleophilic aromatic substitution of hydroxyl groups of (β-CD by tetrafluoroterephthalonitrile (1). Although 1 has been copolymerized with bifunctional catechols previously (14), its reaction [...]

Changes in chlorine residual concentrations in water distribution systems could be used as an indicator of microbial contamination. Consideration is given on how to model the behavior of chlorine within the distribution system following a microbial contamination event. Existing multispecies models require knowledge of specific reaction kinetics that are unlikely to be known. A method to parameterize a rate expression describing microbially induced chlorine decay over a wide range of conditions based on a limited number of batch experiments is described. This method is integrated into EPANET-MSX using the programmer's toolkit. The model was used to simulate a series of microbial contamination events in a small community distribution system. Results of these simulations showed that changes in chlorine induced by microbial contaminants can be observed throughout a network at nodes downstream from and distant to the contaminated node. Some factors that promote or inhibit the transport of these chlorine demand signals are species-specific reaction kinetics, the chlorine concentration at the time and location of contamination, and the system's unique demand patterns and architecture. DOI: 10.1061/(ASCE)EE.1943-7870.0000080 CE Database subject headings: Water distribution systems; Chlorine; Probe instruments; Models; Drinking water; Water quality.

Suspect screening is a valuable tool for characterizing per- and polyfluoroalkyl substances (PFASs) in environmental media. Although a variety of data mining tools have been developed and applied for suspect screening of PFAS, few suspect screening workflows have undergone a comprehensive performance evaluation or optimization. The goals of this research were to: (1) evaluate and optimize three independent suspect screening workflows for the detection of PFASs in water samples; and (2) apply the optimized suspect screening workflows to an environmental sample to determine the extent to which suspect screening results converge. We evaluated and optimized suspect screening workflows using Compound Discoverer v3.2, enviMass v4.2, and FluoroMatch v2.4 using test samples containing 33 target PFASs. The average sensitivity (Sen) and selectivity (Sel) for each workflow across the test samples was: Compound Discoverer Sen = 71%, Sel = 85%; enviMass Sen = 89%, Sel = 80%; FluoroMatch Sen = 51%, Sel = 82%. We then applied the optimized workflows to a contaminated groundwater sample containing an unknown number of PFASs. Each workflow managed to annotate unique PFASs that were not annotated by the other workflows including 2 by Compound Discoverer and 19 each by enviMass and FluoroMatch. Thirty-two enviMass hits and 28 of the Compound Discoverer and FluoroMatch hits were annotated by at least one of the other workflows. Sixteen PFASs were annotated by all three of the optimized workflows. This work provides a basis for conducting suspect screening for PFASs that will lead to more consistent reporting of suspect screening data. [ABSTRACT FROM AUTHOR]