Environmental Science & Technology Letters Environ.最新文献

Cyclotriphosphazenes (CTPs) are widely used as flame retardant electrolyte additives in lithium-ion batteries. However, their environmental occurrence, levels, and risks have until now remained unexplored. To address this gap, this study screened, identified, and prioritized six CTPs in dust samples from various urban environments, including e-waste recycling plants, residential households, underground parking lots, and outdoor roads. Notably, all six CTPs were detected in the samples, with hexaphenoxycyclotriphosphazene (HPCTP) being identified as the most predominant congener. The total concentrations of six CTPs in dust from e-waste recycling plants ranged from 24.0 to 1790 ng/g (median of 150 ng/g), which were significantly higher than those from residential houses (median of 50.5 ng/g) and other urban environments. Different composition profiles of CTPs were observed between indoor and outdoor environments, indicating that multiple sources or variations in environmental behaviors influenced contamination levels. Exposure assessments revealed that e-waste recycling workers ingested more CTPs than did the general population. Among the newly identified CTPs, HPCTP emerged as a significant pollutant owing to its abundance, ubiquity, persistence, mobility, and toxicity. Overall, this study is the first to report the occurrence of CTPs in the environment. Our findings point to the emerging concern regarding CTPs as extensively used yet insufficiently evaluated chemicals.

Recent studies have demonstrated the widespread occurrence of rubber-derived chemicals (RDCs) in the environment, raising global attention toward this group of emerging contaminants. However, few studies have systematically investigated human internal exposure to the RDCs. Herein, we screened for 21 emerging RDCs in plasma samples from pregnant women (n = 150), sanitation workers (n = 80), and rubber manufacturing workers (n = 162) to explore internal exposure to RDCs in these populations. The results revealed varying detection frequencies (DFs) and concentrations of selected RDCs among different populations. Specifically, N-isopropyl-N′-phenyl-p-phenylenediamine (IPPD), and N,N′-diphenyl-p-phenylenediamine (DPPD) exhibited high DF (>50%) across the three populations, but the levels differed significantly. While rubber manufacturing workers were found to have significantly higher levels of IPPD (median 0.41 ng/mL) than the other two populations (0.31 ng/mL for pregnant women and 0.22 ng/mL for sanitation workers), pregnant women contained the highest levels of DPPD (0.84 ng/mL versus 0.27 ng/mL for sanitation workers and 0.26 ng/mL for rubber manufacturing workers). In addition, five RDCs showed a DF higher than 50% of that in rubber manufacturing workers with age- and sex-specific distributions. These findings constitute a preliminary understanding of human exposure to RDCs, raising concerns about potential health effects.

In intertidal zones (crucial areas for biodiversity and blue carbon storage), P cycling is essential because the amount of this element in the environment can limit primary productivity. However, owing to the significant spatiotemporal variations in water cycling driven by fluctuations in surface water, submarine groundwater discharge (SGD), and seawater, our understanding of P cycling remains inadequate. Therefore, we applied a passive sampling method using a Zr-loaded resin (Pas-Zir method) to analyze the phosphate oxygen isotope ratio (δ¹⁸O_PO4) at a tidal flat dominated by SGD on Ikuchijima Island in western Japan. A Zr-loaded resin that selectively adsorbed phosphate ions was installed, and the δ¹⁸O_PO4 values were monitored at the tidal flat bottom, at 5 cm above the bottom, in SGD, and in seawater for a month. The range of δ¹⁸O_PO4 values at the tidal flat bottom and above the bottom (17.0‰–18.8‰) exceeded the analytical precision of the δ¹⁸O_PO4 analysis (±0.4‰) and deviate from the expected isotopic equilibrium by pyrophosphatase. The results indicate that the time-integrated δ¹⁸O_PO4 data can provide information on the P cycling during tidal cycles. Our study demonstrates that the Pas-Zir method is advantageous for understanding the P cycling in intertidal zones.

Extended-spectrum beta-lactamases (ESBLs) are a growing group of antimicrobial resistance (AMR) enzymes that can result in severe clinical outcomes. The CTX-M gene (≈ 876 base pairs) encodes for ESBLs in bacteria, confers resistance to third-generation cephalosporins, and is of high clinical concern. We developed a targeted, long-read sequencing method utilizing unique molecular identifiers to generate accurate, full length CTX-M gene sequences from wastewater. We characterized CTX-M in Seattle area wastewater influent from April 2020 to March 2021. We identified a core community of alleles that persisted across time and treatment plant. The CTX-M-15 containing protein variant (CTX-M-15/216/28) was detected in all but three samples and made up, at most, 30% of CTX-M alleles. We observed significant diversity across the CTX-M gene at the nucleic acid level, although most nucleotide mutations were synonymous─resulting in two to three amino acid variants across 19 loci. By average relative abundance, 23% of protein variants were novel, defined as those not represented in CARD. This method provides full length gene sequences that cannot be obtained through other culture-independent methods. This flexible approach can be expanded to additional targets and implemented in settings where AMR surveillance is a priority, such as hospital wastewater.

Rapid growth in the emissions of nitrogen trifluoride (NF₃), a potent greenhouse gas, poses a threat to the environment and the climate system. This study estimated NF₃ emissions and their spatial distribution in China from 2017 to 2021 based on atmospheric observations from nine background stations in China, by employing a Lagrangian-dispersion-model-based Bayesian inversion technique. We found that NF₃ emissions in China increased from 0.95 (0.82–1.07) Gg yr^–1 in 2017 to 1.41 (1.28–1.55) Gg yr^–1 in 2021, representing a substantial growth of 48% over this period. The absolute increase in NF₃ emissions in China over 2017–2020, 0.65 (0.57–0.74) Gg yr^–1is comparable to the increase in global emissions (0.63 (0.50–0.75) Gg yr^–1) over the same period. We identified substantial NF₃ emissions in the Pearl and Yangtze River Delta regions and Hubei Province, where well-established semiconductor industries could have contributed to NF₃ emissions. Moreover, large NF₃ emissions were identified in northern China, including Hebei, Henan, and Shandong Provinces. If control measures are not implemented, increasing NF₃ emissions may delay China’s progress toward achieving its carbon neutrality target by 2060.

Methanol is commonly used as a carrier solvent in environmental chemistry experiments; however, the possible influence of methanol on the kinetics of chemical transformations is often overlooked. The effects of methanol and other frequently used carrier solvents on the chlorination rates of aromatic precursors of disinfection byproducts during water chlorination were investigated. At concentrations as low as 0.50 vol %, methanol increased chlorination rates of ethylparaben, phenol, 4-hydroxybenzoic acid, ethyl 3-hydroxybenzoate, and ethyl 2-hydroxybenzoate. Methanol did not increase the chlorination rates of salicylic acid, dimethenamid, or 1,2-dimethoxybenzene. Ethylparaben and phenol chlorination were especially sensitive to methanol, with pseudo-first-order rate constants (k_obs) increasing by a factor of >2 in water containing 2.0 vol % methanol compared to those in methanol-free controls. Rate enhancements persisted across differing reaction conditions (pH 6–10 and in buffers containing borate or phosphate). The rate enhancements of unsubstituted and para-substituted phenols were larger than those of meta- and ortho-substituted phenols. The carrier solvents acetone, acetonitrile, and tert-butanol had no appreciable impact on the chlorination rates of ethylparaben. Overall, our findings suggest that methanol as a carrier solvent can cause systematic errors in lab-scale chlorination experiments. To avoid experimental artifacts, researchers should prepare stock solutions in water (when feasible) or minimize carrier solvent concentrations present in reaction solutions.

Since the Eocene, oviparous deep-sea sharks and rays have used deep-sea hydrocarbon seeps and hydrothermal vents as nurseries, where they lay eggs en masse. Benthic fluxes in these extreme habitats may enrich seawater with toxic metals such as mercury (Hg). We asked whether this phenomenon may lead to Hg accumulation in elasmobranchs. We thus analyzed total Hg (THg) in muscle, liver, and kidney tissues of oviparous Galeus melastomus catsharks and their embryos, which aggregate in vast numbers near deep-sea brine pools in the southeastern Mediterranean Sea. These Hg-rich brines (≤238 ng L^–1) are a likely liable geogenic Hg source in this nursery. Shark tissues carried substantial THg [2.7 μg (g of wet weight)⁻¹, median], and extreme values were found in kidneys [≤26.7 μg (g of wet weight)⁻¹], likely due to environmental uptake. Increased THg in embryos [0.64 ± 0.31 μg (g of wet weight)⁻¹] implies substantial maternal offloading (∼20%). Our results hint at the potential adaptation of elasmobranchs to Hg-enriched environments via accumulation and elimination of Hg in kidneys.

Brown carbon (BrC) is a crucial light-absorption component in the atmosphere, playing a profound role in the radiation budget. Variations in the light-absorption properties and molecular composition of BrC due to atmospheric photochemical aging process have not been well constrained, leading to high uncertainty in evaluating its global radiative effect. The molecular composition of atmospheric BrC were investigated to stress the BrC photobleaching in this work. In total, 896 organic compounds were identified, which accounted for 2.5%–26.1% of organic aerosol in mass concentration. We found that solar radiation led to the declined mass absorption coefficient at 375 nm (MAC₃₇₅), indicating BrC photobleaching, coinciding with an elevated mass fraction of carboxylic acids (CAs). This phenomenon was more pronounced under higher-energy solar radiation. Specifically, the mass fraction of nitrocarboxylic acids (NCAs) in CAs increased during BrC photobleaching, which was potentially caused by the oxidation of nitrophenols, resulting in an ∼83.3% decrease in MAC₃₇₅. Our findings provide direct observational evidence of BrC photobleaching from a molecular-level perspective and elucidate a potential BrC photobleaching pathway in the urban atmosphere.

A limited understanding of urban methane (CH₄) emissions in China challenges the evaluation of the coal-to-gas switch toward carbon neutrality by 2060. CH₄ flux was measured in urban Beijing using the eddy covariance method during a summer campaign. With a mean of 152.6 ± 107.9 nmol/m²/s, the CH₄ flux was estimated to depend little on the intensity of human activities, with minimal influence from biogenic sources. Emission hotspots with large temporal variability were identified in the study fetch area, which increased the mean CH₄ flux by 12.5%. Based on the lack of large, known biogenic sources in nonhotspot (background) areas, we attributed the CH₄ flux in these areas (135.6 ± 70.56 nmol/m²/s) mainly to natural gas. Thus, we estimate as an upper limit that natural gas contributes 88.9% to the total CH₄ flux in urban Beijing. However, poor alignment between the dominant sources in the inventories and the characteristics of the measured CH₄ flux were observed, suggesting substantial underestimation of emissions from natural gas sources in the inventories. A leakage ratio of 1.4% (0.7–2.1%) of consumed natural gas was determined in Beijing. Pinpointing emissions with more granular methods could improve our understanding of the urban CH₄ source profile in Beijing.