Environmental Science & Technology Letters Environ.最新文献

Nitrogen in wastewater can be recovered to prevent negative environmental, human health, and economic impacts and to enable distributed chemical manufacturing. We developed novel flexible electrochemical stripping (FECS) for tunable recovery of ammonia/ammonium (total ammonia nitrogen, TAN) from urine as (NH₄)₂SO₄ and aqueous NH₃. Batch and continuous experiments demonstrated that product speciation could be readily controlled by modifying electrochemical cell operation frequency, duration, and applied current without affecting TAN removal. During continuous experiments, FECS recovered NH₃ solutions with concentrations similar to ready-to-use cleaners (1% and 2% NH₃ (w/w) or 8.22 and 16.4 g/L TAN) and cleaner concentrates (5% NH₃ (w/w) or 41.1 g/L TAN), as well as (NH₄)₂SO₄ solutions between 5 and 18.4 g/L TAN, approaching commercial fertilizer concentrations (28.4 g/L TAN). Beyond modifying applied current, future process engineering and operating condition optimization should reduce energy consumption, increase recovery efficiency, and enhance economic viability of FECS. Our findings will enable the development and deployment of electrochemical nitrogen recovery in contexts with varying needs for ammonia-based products, paving the way for circular economies that integrate distributed chemical manufacturing with sanitation systems.

Plasmid pBI143 has recently been identified as being highly abundant in the human gut microbiome, suggesting potential as a fecal water quality indicator and normalization marker in wastewater-based surveillance. We evaluated the relative concentration efficiency and spatial–temporal distribution in raw wastewater to inform its development as a marker. The results showed significantly higher (p < 0.01) enrichment in raw wastewater solids (mean of 9.2 × 10⁷ GC/mL) than in liquid fractions [mean of 2.3 × 10⁶ genome copies (GC)/mL]. The relative concentration efficiencies were 28% for nanotrap particles, 23% for Amicon ultrafiltration, 3.6% for pH drop and filtration, 4% for skim milk flocculation, and 0.04% for poly(ethylene glycol) precipitation compared to direct wastewater extraction. DNase pretreatment reduced pBI143 levels by 90.3%, indicating that it is mainly extracellular in raw wastewater. Over 21 days, pBI143 levels remained stable and were consistently a mean of 1.3 log₁₀ higher than other fecal indicators (Carjivirus, PMMoV, and HF183). In raw wastewater from eight states (n = 16), pBI143 concentrations averaged 2.2 × 10⁶ GC/mL (95% confidence interval of 1.7–2.7 × 10⁶) and pBI143 was detected in all samples. The findings support pBI143’s potential as a fecal indicator and normalization marker, though further validation is needed to confirm its specificity to humans.

Accidental blowouts in oil and gas wells can result in large and prolonged methane emissions, which are often unreported when happening in remote places. The rapid advancement of space-based methods for detecting and quantifying methane plumes provides an essential tool for uncovering these superemission events. We use a number of methane-sensitive satellite missions, including the Sentinel-5P/TROPOMI global mapper and several high-resolution instruments, to document a methane leak from a well blowout happening in Kazakhstan’s Karaturun East oil field in 2023. A dense time series of plume detections from those satellites shows that the leak was active during 205 days and that most of the emissions were in the range 20–50 t/h. Using 48 high-quality emission rate estimates, we calculate that a total of 131 ± 34 kt of methane was released to the atmosphere during this leak, which exceeds the total emissions from all previously documented accidents. Our study characterizes the evolution and magnitude of the 2023 Karaturun East methane leak and showcases how different types of satellite instruments can be combined to document and quantify methane leaks active during long time periods.

Rapid and naked-eye detection of water-borne contaminants using molecularly precise nanomaterials has emerged as a promising strategy to reduce the impact of chemical pollution. This study presents a luminescence-based arsenic (As) sensor, eliminating the need for sample preparation. Incorporating red-emitting spheroidal cluster-assembled superstructures (CASs), comprised of Cu₁₇ nanoclusters (Cu₁₇NCs), coprotected by l-cysteine (l-Cys) and 1,2-bis(diphenylphosphino) ethane (DPPE) ligands, the sensor exhibits notable sensitivity toward arsenite (As³⁺) and (As⁵⁺) ions. A detection limit of 1 ppb in tap water was achieved through luminescence-based quenching. Remarkably, it demonstrates selective detection of As amidst common interfering metal ions such as Cd²⁺, Hg²⁺, Fe³⁺, Pb²⁺, Cu²⁺, and Cr³⁺. A sensor disc made of CASs coated on nonwoven polypropylene (PP) mats has been devised for practical field applications. Electron microscopy reveals disrupted morphology of the spheroids due to As interaction. Moreover, the CASs exhibit significant antibacterial efficacy against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus and antibiofilm properties against Bacillus subtilis. This research highlights the effectiveness of atomically precise clusters for a practical application with direct societal relevance.

The UV/sulfite process shows great potential for reductively degrading or eliminating pollutants. While its mechanism in neutral and alkaline environments has been well-elucidated, the reaction pathway under acidic conditions remains unclear. Herein, we report the novel findings of the formation of reductive SO₂^•– radicals and their derivatives in the UV/sulfite process at pH levels below 4. Mechanistic investigation revealed that H• radicals and SO₃^•– radicals formed by the photolysis of sulfite under acidic conditions, with the H• radicals being scavenged by sulfite to produce SO₂^•– radicals. Subsequently, these SO₂^•– radicals are transformed into dithionite, thiosulfate, hydrogen sulfide, and elemental sulfur through a series of intricate reactions. This study is expected to expand the potential application of the UV/sulfite process under acid conditions.

Per- and polyfluoroalkyl substances (PFAS) comprise >10 000 synthetic compounds that are globally distributed and highly persistent but remain challenging to monitor. Here we assess the utility of baleen─an accreting, keratinaceous tissue that baleen whales use for filter-feeding─to track PFAS dynamics in marine food webs. In six species investigated, PFAS were detected in all baleen tested (n = 18 plates, 220 samples, ∑₁₀PFAS range of 0.02–60.5 ng/g of dry weight), at levels higher than those of other tissue types besides liver. Three of the species in our data set had not been tested for PFAS contamination previously, and two of those species (blue whale and North Atlantic right whale) are internationally endangered species. Apparent links were observed between PFAS and life-history events by testing successive subsamples along the growth axis of the baleen plates. These results establish baleen as a viable sample matrix for assessing PFAS contamination in marine ecosystems by enabling multiyear time-series analyses through single-tissue sampling with seasonal resolution.

The undisclosed and ubiquitous use of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in consumer products has led to a growing issue of environmental pollution, particularly within the solid waste community, where the fate of volatile (neutral) PFAS in landfilled refuse is not well understood. Here, three municipal solid waste landfills in Florida were assessed for neutral PFAS in landfill gas and ionic PFAS in landfill leachate to compare the relative mobility between the two pathways. Landfill gas was directly sampled using a high volume, XAD-2 resin based sampling approach developed for adsorption and analysis of 27 neutral PFAS. Across sites, 13 neutral PFAS were identified from fluorotelomer alcohol (FTOH), fluorotelomer olefin (FTO), secondary FTOH, fluorotelomer acetate (FTOAc), and fluorotelomer methyl acrylate (FTMAc) classes; however, FTOHs dominated concentrations (87–97% total neutral PFAS), with most detections surpassing utilized calibration levels. Even under conservative assumptions, the mass of fluorine leaving in landfill gas (32–76%) was comparable to or greater than the mass leaving in landfill leachate (24–68%). These findings suggest that landfill gas, a less scrutinized byproduct, serves as a major pathway for the mobility of PFAS from landfills.

Increasing radical yields to reduce energy consumption for micropollutant degradation would make advanced oxidation processes more sustainable in the context of the United Nations’ Sustainable Development Goals and carbon neutrality. We herein demonstrate that switching the UV radiation source from conventional low-pressure UV (UV₂₅₄) to far-UVC (UV₂₂₂) increases the UV fluence-based concentration of hydroxyl radicals (HO^•) in the UV/peracetic acid (UV/PAA) process by 4.1-fold and 27.9-fold in deionized water and real surface water, respectively. Acetyloxyl radicals (CH₃C(O)O^•) are generated in the UV₂₂₂/PAA process at a steady-state concentration of 2.4 × 10^–12 M in deionized water, while they are undetectable in the UV₂₅₄/PAA process under the comparable conditions. The enhancement to radical production is mainly attributed to the 15.7-fold higher molar absorption coefficients of PAA⁰ at 222 nm than 254 nm (50 vs 3.5 M^–1 cm^–1), which suppresses the compromised 1.1-fold lower innate quantum yield at 222 nm than 254 nm (0.78 vs 0.86 mol einstein^–1). The enhanced radical generation and direct photolysis promote the fluence-based degradation rate constants of bisphenol A, phenol, and nitrobenzene by 4.1-fold, 3.3-fold, and 2.9-fold in the UV₂₂₂/PAA process than the UV₂₅₄/PAA process.