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Microplastics are widespread in the environment, including in the bodies of freshwater fish, with their concentrations influenced by factors such as proximity to point sources, such as wastewater treatment plants (WWTPs), and trophic level. However, few studies have simultaneously assessed the combined effects of these factors on microplastic abundance in urban stream fish. To do so, we measured microplastics and assessed trophic level via N stable isotope (δ15N) content in 6 species of small-bodied fishes (species = Lepomis macrochirus Rafinesque, 1819, Neogobius melanostomus [Pallas, 1814], Fundulus notatus [Rafinesque, 1820], Pimephales notatus [Rafinesque, 1820], Notemigonus crysoleucas [Mitchill, 1814], and Dorosoma cepedianum [Lesueur, 1818]) collected upstream, at, and downstream of a large WWTP in Chicago, Illinois, USA. Additionally, we analyzed stomach contents for 2 of these species (L. macrochirus and N. melanostomus). Four of the six species exhibited δ15N enrichment at and downstream of the WWTP, indicating prolonged residence times at the study sites (i.e., several weeks). Stomach contents of the 2 species measured supported this pattern, showing high chironomid consumption at the WWTP and variable stomach contents elsewhere. For microplastics, 1 species had higher concentrations near the WWTP, but microplastic concentrations did not differ among locations in the other 5 species. We found no evidence of a relationship between δ15N enrichment and microplastic concentration. Overall, the stable isotope and stomach content results suggest a strong relationship of WWTP effluent with fish diet but not with microplastic concentrations in fish. The results suggest that microplastic concentrations in fish is are shaped by interacting, species-specific factors including behavior (i.e., movement and foraging) and physiology (i.e., egestion rates and feeding mechanisms), in addition to proximity to point sources. Our study highlights the complexity of microplastic infiltration into food webs and underscores the need for further research to disentangle the drivers of microplastic accumulation in aquatic organisms. 

Copper-mediated methodologies for the arylation of bis-azolium salts and bis-azoles are efficient pathways to access symmetrical and unsymmetrical N-heterocyclic carbene precursors. The arylation of bis-azolium salts with various aryl halides was achieved in moderate yields to furnish numerous C2-arylated bis-azolium salts. Access of C2-arylated bis-azolium salts from bis-azoles was also achieved in a single pot domino reaction via the use of iodonium salts as embedded electrophiles. The latter methodology utilizes the aryl iodide byproduct from the N-arylation step for the C–H activation step to mitigate waste and the need to recycle. We also demonstrated the use of these azolium salts in metalation and found success in obtaining metal complexes containing abnormal N-heterocyclic carbenes. 

Retrofitting building stock through heating electrification and energy efficiency improvements is essential for achieving carbon neutrality. Understanding the effects of electrification and efficiency retrofits on building-resident satisfaction and adaptive behaviors is important, as these directly impact retrofitting success, adoption rates, energy consumption, and performance. There is a gap in understanding the combined effects of heating electrification and building efficiency retrofits. Using data collected over 2.5 years, we performed integrated qualitative and quantitative analyses to evaluate the combined effects of heat pump electrification and a roof insulation retrofitting in a 10-unit New York City apartment building. Building-resident satisfaction with each strategy was assessed, and impacts on occupant thermal comfort, energy behavior, indoor thermal environment, and energy consumption were analyzed. Despite perceived challenges and resident skepticism, air source heat pumps (ASHPs) provided adequate indoor thermal comfort. ASHPs were preferred over steam boiler heating for controllability, noise reduction, and improved thermal comfort. Unintended benefits included improved aesthetics, reduced real estate needs, and decreased burn potential. With heat pumps, some residents adopted energy-conservative behaviors while others adopted “comfort-taking” behaviors, prioritizing comfort over conservation. The roof insulation retrofit further improved resident thermal comfort and decreased total building heating energy requirements by 25.3–34.2% and heating peak power requirements by 10.7%. The retrofit also improved ASHP efficiency in previously uninsulated spaces, effectively mitigating heat pump undersizing effects. Combined energy retrofitting strategies could play a key role in ensuring thermal comfort and building energy efficiency toward carbon neutrality.