Environmental Science & Technology Letters Environ.最新文献

Atmospheric formation of persistent perfluoroalkyl carboxylic acids (PFCAs) is a route to global contamination, including drinking water sources. We present high time resolution measurements of C₂–C₆ PFCAs in ambient air made over 6 weeks each in winter and summer 2022 in Toronto, Canada. Observations were made using chemical ionization mass spectrometry with acetate ionization, with care taken to avoid system contamination. Measurements of trifluoroacetic acid (C₂ PFCA) are reported at 1 min time resolution, while those for C₃–C₆ PFCAs are at 10 min time resolution. Variations with time and relationships to meteorology and other pollutants show evidence of secondary formation of all observed PFCAs except perfluoropropionic acid (C₃ PFCA). High time resolution data allow these unique observations, allowing for improved process and source understanding moving forward. Mixing ratios of TFA were larger than predicted from models that describe TFA formation from known precursors, indicating additional atmospheric sources of this molecule have yet to be identified.

Synthetic antioxidants (SAOs) are additive chemicals with diverse commercial applications, yet knowledge of the occurrence of these emerging contaminants in households on a large geographical scale is lacking. We thus explored the levels and regional patterns of 56 SAOs in 1407 household dust samples from 29 provincial administrative regions across China. Total SAO concentrations in province-based pooled samples ranged from 1810 to 18 280 ng/g (median of 4010 ng/g). Twenty-five SAOs were detected in >60% yield, including 15 novel SAOs. SAO concentrations and compositions varied significantly across China, with coastal regions such as Hong Kong and Shanghai showing higher levels and a greater prevalence of novel SAOs. Despite these differences, either 1,3-diphenylguanidine (DPG) or 2,6-di-tert-butyl-4-methylphenol (BHT) was the dominant SAO nationwide, indicating widespread usage. Results indicated that anthropogenic factors (e.g., GDP and population density) significantly influenced SAO levels and distributions in household dust across China (p < 0.001). Risk assessments showed low hazard quotients for SAOs, suggesting minimal risks overall. However, novel SAOs posed higher risks than traditional ones, particularly for toddlers. Our study highlights the need for further monitoring and improved understanding of the health consequences of SAOs to better inform future policies and raise public awareness.

Storm events can mobilize organic contaminants from hard surfaces in urban areas and can impact receiving water quality. Traditional water quality assessments predominantly rely on chemical analysis, which inadequately capture the collective effects of diverse chemical mixtures released during storm events. We applied effect-based methods (EBM) to detect arylhydrocarbon receptor (AhR) activity, estrogenic activity, neurotoxicity and oxidative stress response in water samples from an urban tributary during a storm event and compared it with base flow conditions. AhR activity and neurotoxicity peaked during the storm event, with neurotoxicity exceeding the interim effect-based trigger value and showing a high specificity of effect. This suggests unacceptable water quality during the storm event. Conversely, estrogenic activity was relatively low, and there was little difference between base flow conditions and the storm event. The absence of wastewater, industrial and agricultural inputs in the catchment suggests that the observed bioactivity was related to road runoff, specifically from two adjacent major motorways. The effects on AhR and neurotoxicity were linearly correlated with detected concentrations of 15 tire additive chemicals from an accompanying study. This study demonstrates that EBM provides complementary information to chemical analysis for water quality monitoring and that there is an increased chemical pressure on receiving water bodies during rain events in urban areas.

Tires are a ubiquitous part of on-road transport systems serving as the critical connecting component at the interface of the motive power and road surface. While tires are essential to automobile function, the wear of tires as a source of particulate air pollution is still poorly understood. The variety of reported emissions found in the secondary literature motivated us to summarize all known mass-based tire wear emission factors for light-duty vehicles in primary research. When excluding road wear and resuspension, mean emissions of 1.1 mg/km/vehicle (median 0.2 mg/km/vehicle) were found for tire wear PM₁₀ and mean emissions of 2.7 mg/km/vehicle (median 1.1 mg/km/vehicle) when including studies with resuspended tire wear. Notably, these factors are substantially lower than broadly cited and accepted factors in the secondary literature with mean emissions of 6.5 mg/km/vehicle (median 6.1 mg/km/vehicle). As revealed by our analysis, secondary literature reports emission factors systematically higher than those of the primary sources on which they are based. This divergence is due to misunderstandings and misquotations that have been prevalent since the year 1995. Currently accepted mass-based emission factors for directly emitted airborne tire wear particles need revision, including those from the United States Environmental Protection Agency and the European Environment Agency.

Tires are a ubiquitous part of on-road transport systems serving as the critical connecting component at the interface of the motive power and road surface. While tires are essential to automobile function, the wear of tires as a source of particulate air pollution is still poorly understood. The variety of reported emissions found in the secondary literature motivated us to summarize all known mass-based tire wear emission factors for light-duty vehicles in primary research. When excluding road wear and resuspension, mean emissions of 1.1 mg/km/vehicle (median 0.2 mg/km/vehicle) were found for tire wear PM₁₀ and mean emissions of 2.7 mg/km/vehicle (median 1.1 mg/km/vehicle) when including studies with resuspended tire wear. Notably, these factors are substantially lower than broadly cited and accepted factors in the secondary literature with mean emissions of 6.5 mg/km/vehicle (median 6.1 mg/km/vehicle). As revealed by our analysis, secondary literature reports emission factors systematically higher than those of the primary sources on which they are based. This divergence is due to misunderstandings and misquotations that have been prevalent since the year 1995. Currently accepted mass-based emission factors for directly emitted airborne tire wear particles need revision, including those from the United States Environmental Protection Agency and the European Environment Agency.

Freshwater pollution is, together with climate change, one of today’s most severe and pervasive threats to the global environment. Comprehensive and spatially explicit scenarios covering a wide range of constituents for freshwater quality are currently scarce. In this Global Perspective paper, we propose a novel model-based approach for five water quality constituents relevant for human and ecosystem health (nitrogen, biochemical oxygen demand, anthropogenic chemicals, fecal coliform, and arsenic). To project the driving forces and consequences for emissions and impacts, a set of common data based on the same assumptions was prepared and used in different large-scale water quality models including all relevant demographic, socioeconomic, and cultural changes, as well as threshold concentrations to determine the risk for human and ecosystem health. The analysis portrays the strong links among water quality, socio-economic development, and lifestyle. Internal consistency of assumptions and input data is a prerequisite for constructing comparable scenarios using different models to support targeted policy development.

Contaminants of emerging concern (CECs) in aquatic environments have attracted a considerable amount of attention from the public and regulatory groups. Due to their wide variety of chemical properties, simultaneous analysis of multiclass CECs presents a great challenge. This study develops an innovative liquid chromatography-mass spectrometry (LC-MS) method that integrates both large volume injection (LVI) and online solid phase extraction to quantify 102 CECs. The method utilizes three columns: a reversed phase (RP) column, a custom-built mixed weak cation/anion exchange trap column, and a mixed-mode ion exchange (MMIE) column. With valve switching, highly polar/ionic CECs that are not retained by the RP column are captured by the trap column while other CECs are separated by the RP column. Subsequently, the trapped highly polar/ionic CECs are transferred to the MMIE column for further separation. Matrix effects from sewage effluent and urine samples were assessed, and the method accuracy and precision were also determined using spike recovery. LVI notably enhanced the method sensitivity, with the method quantification limits for 93 of the 102 CECs in various water matrices being <10 ng L^–1. Overall, this novel column-switching LC-MS method enables the rapid and simultaneous determination of multiclass CECs in diverse aqueous samples.

Several methods exist for determining ozone formation sensitivity using observational data, each potentially yielding different sensitivity classifications. This study examined the seasonal characteristics of MAX-DOAS data collected from both urban and rural sites in the Beijing–Tianjin–Hebei region. A multiple linear regression model was employed to isolate secondary HCHO data. The thresholds derived from four distinct methods were assessed, and the performance of these methods was evaluated across various elevations at both sites. Based on the findings, recommendations and the applicable ranges for each method are provided.

Incineration is commonly used to dispose of waste contaminated with per- and polyfluoroalkyl substances (PFAS), despite few experimental data supporting the efficacy of this technique. To investigate the prevalence of PFAS in residuals from Swedish municipal waste incineration (MWI) plants, samples of fly ash, bottom ash, and flue gas condensate were collected from 27 of Sweden’s 38 plants and analyzed for 13 perfluoroalkyl acids (PFAAs). ∑₁₃PFAA concentrations ranged from 0.28 to 180 ng/L, 0.22–1.6 μg/kg, and 0.18–38 μg/kg, in condensate, bottom ash, and fly ash, respectively (detection frequencies of 79, 21, and 30%, respectively). Total fluorine (TF) measurements in a subset of samples revealed concentrations of <0.20–11 mg F/L in condensate (n = 8) and 120–5400 μg F/g in ashes (n = 8), the former of which was primarily attributed to inorganic fluorine. Extractable organofluorine (EOF) exceeded ∑₁₃PFAA concentrations by up to 3 orders of magnitude (0.70–16 μg F/g in fly ash [n = 3] and <0.80–9.0 μg F/L for condensate [n = 2]), suggesting that the majority of fluorine occurring in MWI residuals remains unidentified. Collectively, these data demonstrate that despite temperatures exceeding 1000 °C, PFAAs and other fluorinated substances may form and/or persist during incineration and risk being released to the environment via MWI residues.

Following global regulations on traditional per- and polyfluoroalkyl substances (PFAS), alternative PFAS raise emerging concerns. Our study focused on a group of bis-perfluoroalkyl sulfonimides (bis-FASIs) and explored whether electronic waste (e-waste) dismantling and recycling constitute a potential source of bis-FASIs to the environment. The study revealed ubiquitous occurrence of bisperfluoromethane sulfonimide (bis-FMeSI) in dust from e-waste sites, surrounding regions (20–50 km distant from e-waste sites), and urban areas with the levels in a descending order along with the distance from the e-waste sites. The median level of bis-FMeSI was 12 ng/g in e-waste dust, constituting approximately 10% of the total PFAS levels (117 ng/g). The levels dropped to a median of 0.45 ng/g in indoor and outdoor dust from surrounding regions as well as 0.67 and 1.1 ng/g in dust from traffic roads and underground parking lots, respectively, from a megacity located 100 km away from the e-waste sites. Our findings indicate that bis-FASIs appear as an emerging type of PFAS with widespread distribution in the urban environment. Therefore, they should be included into PFAS monitoring networks regionally or globally for a better understanding of their sources, distribution, and fate, as well as human exposure scenarios and associated health risks.