Environmental Science: Processes & Impacts最新文献

Three Quantitative Structure Property Relationship (QSPR) software packages, IFSQSAR, OPERA, and EPI Suite are compared and assessed for prediction accuracy, applicability domain (AD) and uncertainty of the predictions. A database of experimental physical–chemical (PC) properties is compiled, merged, and filtered, and the QSPRs are assessed with datasets of octanol–water (K_OW), octanol–air (K_OA), and air–water (K_AW) partition ratios. Upper and lower limits on PC property predictions are proposed based on theory, data, and applications of the properties in hazard screening and risk assessment. Validations of the uncertainty metrics of the QSPR packages are done for the PC properties using experimental data external to all training datasets. The IFSQSAR 95% prediction interval (PI95) calculated from root mean squared error of prediction (RMSEP) captures 90% of the external data, while OPERA and EPI Suite require a factor increase of at least 4 and 2 respectively for their PI95 to capture a similar 90% of the external experimental data. The assessment of QSPR consensus predictions identified future research and experimental testing to improve the predictive models for data-poor chemicals such as polyfluorinated or per-fluorinated alkyl substances (PFAS), ionizable chemicals, and chemicals with complex and multifunctional structures.

Regional and temporal trends in legal and illicit drug use can be tracked through monitoring of municipal wastewater, ambient air, indoor air, and house dust. To assess the analytical result for the selected environmental matrix, reliable information on the partitioning of the target substance between the different compartments is required. The logarithmic partition coefficients octanol/water (log K_OW), octanol/air (log K_OA) and air/water (log K_AW) are usually applied for this purpose. Most drug molecules are semi-volatile compounds with complex molecular structures, the handling of which is subject to legal regulations. Chemically, they are often acids, bases, or zwitterions. Consequently, the physical and chemical properties are in most cases not determined experimentally but derived from quantitative structure–activity relationships (QSARs). However, the lack of experimental reference data raises questions about the accuracy of computed values. It therefore seemed appropriate and necessary to calculate partition coefficients using alternative methods and compare them with QSAR results. We selected 23 substances that were particularly prominent in European and US drug reports. Different quantum mechanical methods were used to calculate log K_OW, log K_OA, and log K_AW for the undissociated molecule as a function of temperature. Additionally, the logarithmic hexadecane/air partition coefficient log K_HdA ≡ L and the logarithmic vapor pressure of the subcooled liquid log P_L were determined in the temperature range 223 < T/K < 333. Despite the sometimes high variability of the parameters, it is possible to estimate how an investigated substance distributes between air, water and organic material.

Emerging contaminants (ECs) coexist in natural water sources due to contamination from both point and diffuse sources. Photolysis is one of the primary processes contributing to the assimilation capacity of surface water. However, the characterization of pollutant photolysis needs to be updated to account for recently introduced co-contaminants, such as microplastics (MPs) and nanoparticles (NPs). MPs and NPs have unique physicochemical properties that influence the fate and toxicity of ECs. In addition to co-contaminants, extreme environmental conditions, including temperature variations and organic matter concentrations, should be considered to account for climate change. In this study, the photolysis of diclofenac (DCF), diuron (DIU), terbutryn (TER), ciprofloxacin (CIP), and 17α-ethinylestradiol (EE2) (as a mixture) was investigated in the presence of polypropylene microplastics (PP-MPs) and silver sulfide nanoparticles (Ag₂S-NPs) at different temperatures and organic matter concentrations. The presence of PP-MPs and Ag₂S-NPs inhibited the photolysis rates of diuron, EE2, and ciprofloxacin by 3–5-fold while doubling the photodegradation of diclofenac. The effects of organic matter and temperature in the presence of PP-MPs and Ag₂S-NPs varied widely. For example, higher organic matter concentrations enhanced the photodegradation of EE2 and ciprofloxacin (which were otherwise inhibited by these particles), while they suppressed the photodegradation of diclofenac, which was promoted in their presence. The inhibition of photodegradation for EE2, ciprofloxacin, and diuron due to the presence of PP-MPs and Ag₂S-NPs suggests that these pollutants will persist longer in surface water. The findings of this study can support the development of characterization factors for EC photolysis, considering the presence of MPs, NPs, and climate change impacts. These characterization factors could be key parameters in environmental risk assessment and life cycle analysis.

Radiostrontium (⁹⁰Sr), a highly mobile radionuclide of environmental concern, can be strongly retained by soils via interactions with organic and mineral components. This study investigated sorption patterns and mechanisms of ⁹⁰Sr in two contrasting soil types—peaty-podzolic-gleyic (PPG) and alluvial soddy-gleyic (ASG)—through batch experiments with varying experimental conditions and sequential extraction. Despite differences in pH, organic carbon, and clay content, all soil horizons showed high Sr sorption (85–96%) at near-native pH. In organic-rich horizons, Sr was predominantly bound to organic matter via complexation, while in mineral and organo-mineral horizons, ion exchange with clay minerals was the dominant retention mechanism. pH-dependent sorption revealed that Ca²⁺ competition significantly reduces Sr retention at low pH. Sequential extraction confirmed that Sr is mostly exchangeable in mineral horizons but more strongly retained in organic layers. These findings highlight the contrasting sorption mechanisms in different soil compartments and provide key insights for predicting Sr mobility in contaminated environments.

Antibiotics, as emerging contaminants, are increasingly detected in aquatic environments, raising significant concerns about their ecological risks. However, the lack of hydrolysis rate constants (k_H) and aqueous hydroxyl radical degradation rate constants (k_OH) limits the environmental persistent assessment of antibiotics. The present study addresses this gap by developing prediction models using multiple linear regression and three machine learning algorithms (i.e., random forest, support vector machine, and extreme gradient boosting (XGBoost)), based on a dataset of 69 k_H and 80 k_OH values. The XGBoost models, identified as optimal, were employed to fill in missing data in the original dataset. Subsequently, a multi-task model capable of simultaneously predicting k_H and k_OH values was developed with good performance. The application domain was characterized by Williams plots. Furthermore, Shapley Additive exPlanations analysis was employed to identify key molecular descriptors influencing degradation rates, which provides insights into the underlying degradation mechanisms. This approach not only facilitates the simultaneous prediction of k_H and k_OH values for various new pollutants, but also enhances the understanding of how molecular structure affects their synergistic degradation kinetics in aquatic environments, thereby significantly contributing to the assessment of environmental persistence of emerging contaminants.

A first run-of-river power plant built in Nunavik (QC, Canada) lies in a continuous permafrost zone, a substantial carbon (C) rich mercury (Hg) reservoir. Its impoundment could promote permafrost thaw and remobilize Hg and lead to the enhanced production of highly toxic methylmercury (MeHg). To elucidate how RORs can influence C and Hg dynamics and transformations in a subarctic landscape, soils, water and benthic invertebrates were sampled shortly before and after the flooding. Soil Hg concentrations were higher in the organic active layer than in frozen ground. Three months after river impoundment, MeHg concentrations and proportions in the surface organic layer of flooded soils were seven and four times higher, respectively. A similar increase was observed in surface waters of the newly created bay, where MeHg concentration and proportion were, respectively, ∼10 and four times higher. Biological MeHg concentrations increased in low trophic level organisms associated with this flooded environment, namely primary consumers (∼4×) and omnivores (∼3×). However, these rises were limited to the small (<1 km²) newly created bay, highlighting spatial heterogeneity in the production and trophic transfer of MeHg at the river scale in response to recent impoundment.

Since the early 2000s, artisanal and small-scale gold mining (ASGM) has rapidly expanded in Burkina Faso. Mercury (Hg) is widely used to extract gold and its release through burning amalgams has led to soil contamination near mining sites. However, the fate and speciation of Hg in soils remains poorly understood, especially the reactivity or methylation potential of soil particles eroded into rivers. In this study, Hg contamination levels and speciation were assessed in water, soil, and sediments from five ASGM districts along the Mouhoun River. Surface waters near riverside mining sites showed high levels of particulate Hg (11–239 ng L⁻¹), while more arid sites showed Hg contamination localised to ore-washing ponds. Mercury thermodesorption and selective extraction analysis revealed that in soils collected in the vicinity of amalgam burning sites, around 10% of total Hg (THg) was elemental (Hg0), with most remaining Hg bound in the divalent state to amorphous iron oxides (∼60% THg) and organic matter (∼30% THg). In river sediments, Hg bound to amorphous iron was halved, while methyl Hg (MeHg) levels increased fivefold (0.7 ± 0.2 ng g⁻¹) suggesting that iron reduction in sediments promotes MeHg production and accumulation. These results highlight the potential risks of Hg exposure for local communities and the need for regional Hg management in ASGM areas.

Correction for ‘Quantifying ambient concentration and emission profile of D5-siloxane of a residential neighborhood in the Greater Houston area’ by Kyle P. McCary et al., Environ. Sci.: Processes Impacts, 2025, 27, 1266–1276, https://doi.org/10.1039/D4EM00804A.

Air pollution such as fine particulate matter (PM_2.5) may be linked to the increasing prevalence of infertility. However, evidence on the effects of air pollution on embryonic developmental outcomes in populations undergoing assisted reproductive technology (ART) remains limited. Herein, a total of 17 941 couples of patients who underwent in vitro fertilization (IVF) in the reproductive center of the hospital between January 2017 and December 2021 were included. The exposure of couples to PM_2.5 and ozone (O₃) was estimated based on the Tracking Air Pollution in China and their geographic coordinates. Generalized additive models and segmented linear regression analyzed the associations between PM_2.5/O₃ exposure and embryological outcomes, including synergistic interactions. The results revealed that exposure to PM_2.5 and O₃ was significantly negatively associated with normal fertilization rates, high-quality embryo rates, and blastocyst formation rates. PM_2.5 and O₃ exhibited interactive effects in their negative impacts on high-quality embryo rates and blastocyst formation rates. Subgroup analyses revealed that both ambient ozone and PM_2.5 exposures were consistently associated with reduced high-quality embryo and blastocyst formation rates across multiple maternal age and BMI categories, particularly among younger and normal-weight women. Significant interaction effects between ozone and PM_2.5 were observed primarily in women aged < 35 years and those with BMI < 24 kg m⁻², indicating heightened vulnerability in these groups. These findings emphasize the coordinated control of O₃ and PM_2.5 levels to mitigate adverse effects on embryonic development.

In traditional petroleum forensic investigations, source identification primarily relies on chemical fingerprinting of oil, whereas groundwater fingerprinting, which focuses on dissolved constituents, remains rarely used despite its potential as an important forensic tool. This study collected 10 floating oil samples, 10 groundwater samples beneath the floating oil, and 11 pure groundwater samples for chemical fingerprint analysis. The results indicated that the chemical compositions of the groundwater beneath the floating oil were predominantly influenced by the high-solubility chemicals present in the floating oil. Notably, even when floating oil samples had significantly different compositions of low-solubility components but similar compositions in high-solubility components, the groundwater samples beneath the floating oil showed similar chemical compositions. This similarity in groundwater composition reflected the resemblance in the soluble fraction of the floating oils and didn't necessarily indicate identical oil sources. Groundwater beneath the floating oil was dominated by aromatics, whereas pure groundwater was dominated by naphthenes and isoparaffins. Correlation analysis revealed a positive correlation in molecular composition between floating oil and the groundwater beneath it. However, no significant correlation was observed between the groundwater beneath the floating oil and the pure groundwater samples. This study demonstrated that fingerprinting of groundwater beneath the floating oil provided useful information for source identification, while the performance of pure groundwater fingerprinting depended on the distance between the sampling location and the source. Only a “nearby” sampling location retained consistent characteristics with the oil source, rendering it suitable for forensic investigations. However, the definition of “nearby” was highly site-specific.