Environmental Science: Processes & Impacts最新文献

Continuous carbon (C) and nitrogen (N) inputs significantly affect cadmium (Cd) redistribution in soil aggregates, yet their impacts remain poorly understood. This study investigates Cd redistribution under labile C and two N sources (glucose + nitrate [CN], glucose + ammonium [CA], and glucose alone [CT]). CN and CA treatments increased Fe and Mn oxide-bound Cd (F3-Cd) by 99.7% and 38.7% in bulk soil, respectively, while CT reduced F3-Cd by 33.1%. Increased dissociative Fe oxides (DCB-Fe) and decreased Fe²⁺, coupled with NO₂^- consumption, confirmed enhanced NO₂^- reduction and Fe²⁺ oxidation in F3-Cd formation. Carbonate-bound Cd (F2-Cd) and organic matter-bound Cd (F4-Cd) also increased significantly (42.0-121.5%) across all treatments. Feature importance analysis highlighted dissolved organic carbon (DOC) as a key driver for F2-Cd, while DOC, amorphous Fe (oxalate-Fe), and soil organic carbon (SOC) influenced F4-Cd. Micro-aggregates (MAs) had higher F4-Cd levels compared to large macro-aggregates (LMAs) and small macro-aggregates (SMAs). Partial least squares path modeling showed that DOC influenced F2-Cd in LMAs, nitrate and ammonium cycling affected F3-Cd in SMAs, and genes related to Fe cycling and nitrification drove F4-Cd in MAs, potentially impacting mineral-associated SOC. Understanding C and N inputs' effects on Cd redistribution can improve remediation strategies for Cd pollution in agricultural soils.

Arsenic exposure is a major global health challenge. In addition to well-documented toxic effects in exposed people and animals, there is evidence that exposure to arsenic may lead to transgenerational effects. Transgenerational effects of low levels of exposure are challenging to study in species with long generation times. The model organism Caenorhabditis elegans offers the ability to quickly carry out transgenerational experiments with very large sample sizes of isogenic animals, reducing variation, and numerous biological replicates, to increase statistical rigor. An important challenge historically associated with this species for such work is uncertainty about internal dosimetry and toxicokinetics. Here, we report a 4-generation experiment in which C. elegans were exposed during larval development to sodium arsenite concentrations in the parental generation at concentrations resulting in no or mild growth inhibition up to significant growth inhibition. These exposures resulted in internal concentrations between 0.4 and 6.7 nM and rapid excretion (t_1/2 = 3 hours), despite the lack of arsenic methylation in this species. These exposures had strong and significant effects on the exposed generation later in life, but no transgenerational effects were detected. We discuss possible reasons for this "negative" result. We also report strong similarity of the nematode transcriptomic, metabolomic, and fat accumulation responses in the exposed generation to responses reported in other organisms, including persistent alterations in cysteine and fatty acid metabolism, phase II and III metabolic processes, and increased adiposity. Finally, we discuss ways to take advantage of this species difference in arsenic metabolism for the use of C. elegans in toxicology testing.

Fires in the wildland-urban interface (WUI) introduce pyrogenic organic contaminants to surface waters, but their impacts on microbial dynamics have not been evaluated. We studied the interactions between microbial communities and pyrogenic carbon during post-fire storms in a WUI fire-impacted creek in Orange County, CA. The first storms following the fire (low intensity) brought about the highest discharges of polycyclic aromatic hydrocarbons (PAHs), e.g. benzo[a]pyrene, benz[a]anthracene. Dissolved organic carbon (DOC) loads reached up to 11.2 g-C s^-1 during the more severe storms. PAHs correlated with each other but not with DOC or fluctuations in turbidity, suggesting these two variables might not be good predictors of PAH flushes, especially in low-intensity storms. Microbial genera with known PAH-degrading members were differentially abundant during post-fire storms (Pseudomonadota, Bacteroidota, Cyanobacteriota, Actinobacteriota, Bacillota). In addition, predicted metabolic pathways related to the PAH biodegradation intermediates, catechol and protocatechuate, increased significantly at sites downstream of the fire. Overall, our findings suggest pyrogenic carbon from the fire resulted in a detectable shift in microbial community function and composition to favor PAHs degradation just a few months after the fire. This response suggests that PAH-degrading microorganisms are readily found after WUI fires.

Predicting aquatic photodegradation remains challenging due to the simultaneous occurrence of multiple degradation pathways. While direct photolysis rates can be predicted from molar absorptivity and quantum yield, predicting indirect photodegradation requires quantifying both the bimolecular reaction rate constants with various photochemically produced reactive intermediates (PPRI) - including hydroxyl radicals (˙OH), singlet oxygen (¹O₂), and triplet excited states of chromophoric dissolved organic matter (³CDOM*) - and the steady-state concentrations of the PPRI. Yet, using laboratory measurements of these properties to predict photodegradation in environmental waters and quantify the relative contributions of individual pathways have not been evaluated across diverse chemical structures. In this study, photodegradation rates of 30 pesticides were measured in two CDOM solutions and compared to predicted values. The dominant degradation pathway was predicted to be direct photolysis for five pesticides, ˙OH reactions for five pesticides, and ³CDOM* reactions for 20 pesticides. Nevertheless, predicted rates often overestimated measured rates seemingly because of (1) higher reactivity of the selected triplet excited state model sensitizer (3-methoxyacetophenone, ³3-MAP*) relative to ³CDOM*, (2) the effects of antioxidants, and (3) overestimating reactive [³CDOM*]_ss due to using a probe compound that is more reactive with ³CDOM* than many organic pesticides. Adjusting for these factors, when possible, and accounting for quenching of ˙OH by the probe compound resulted in predicted rates 0.24-13.1 times the measured rates. Reactions with ˙OH became the dominant pathway for most of the pesticides previously predicted to primarily react with ³CDOM*. Based on these results, environmental half-lives under near surface conditions were predicted to range from 0.04 to 202 days across pesticides depending on the dominant pathway and environmental conditions. Notably, pesticides sharing the same dominant degradation pathway had similar t_1/2 ranges, indicating that environmental conditions will have a large influence on potential photodegradation rates. Consequently, identifying the relevant photodegradation mechanisms for a given chemical can be used to more accurately model environment-specific persistence, and this mechanistic approach should be integrated into regulatory frameworks.

Calcium carbonate (CaCO₃) polymorphs are some of the most abundant minerals in natural environments on the Earth's surface. They are normally linked to fields including biomineralization, global CO₂ exchange or pollutant remediation due to the strong surface interaction with heavy metals in the environment. The aim of this work is to study the crystallization of CaCO₃ through precipitation experiments from aqueous solutions in the presence of different amounts of As(V), thus evaluating the capacity of the precipitating phases to remove As from solutions. Surprisingly, the results confirmed that, although the uptake mechanism operates relatively well, decreasing the initial concentration of arsenic in all the experiments conducted, the wonder is that the presence of this element controls the crystallization of calcium carbonate polymorphs by inhibiting the crystallization of calcite and stabilizing the vaterite, which is the least stable phase among those two. The combination of several techniques allowed us to confirm the increased uptake of As by precipitates from increased As-bearing supersaturated solutions. The gradual disappearance of calcite and the persistence of vaterite from precipitates in which As is present suggest that a potential incorporation of As into a crystalline CaCO₃ polymorph would be more likely in the vaterite. Even though the sequestering mechanism remains unclear, vaterite lattice distortions suggest that As could be absorbed inside the vaterite structure. Additionally, adsorption on the unstable polymorph would be the reason for the stabilization, by preventing its dissolution and therefore its transformation into calcite.

Climbing shoe abrasion generates fine rubber particles, leading to elevated concentrations of rubber-derived compounds (RDCs) in airborne particulate matter and settled dust of indoor climbing halls, in some cases comparable to levels measured near high-traffic roads. Indoor climbing halls therefore represent a hotspot of RDC exposure for visitors and employees. While the health implications remain uncertain, several RDCs present in climbing halls have demonstrated toxicity in vitro and in animal studies. Previous work, limited to a small number of facilities, left open whether climbing hall characteristics can mitigate RDC contamination. Here, we analyzed more than 200 samples of settled dust and foothold powder (abrasion material) collected from 41 climbing halls across 10 countries. RDCs were detected in every sample, confirming their ubiquity. Unsupervised analyses (hierarchical clustering, principal component analysis) revealed distinct patterns in concentrations and profiles, but supervised approaches (redundancy analysis, partial least squares, univariate correlations) showed only weak associations with hall characteristics. These results demonstrate that hall design and operation exert only a minor influence on RDC levels, underscoring that effective mitigation will require material-level solutions, specifically safe and sustainable-by-design (SSbD) innovations in the material used in climbing shoe soles to replace substances of concern with safer alternatives.

Cobalt (Co) is a transition metal essential for human and animal health. Cobalt is classified as a beneficial element for plants, but its precise physiological roles in plant metabolism remain enigmatic. Despite the significant projected 200-500% increase in the industrial application of Co, there is limited literature available on the role of Co in the soil-plant-human continuum compared with other heavy metal(loid)s. Notwithstanding its beneficial roles, Co can negatively affect physiochemical processes in plants both at higher (toxic) and lower (deficient) levels of application. High concentrations of Co cause irreversible changes to plant cells, primarily through the enhanced production of reactive radicals. Similarly, Co deficiency inhibits certain essential plant physiological/biochemical processes. While the optimum levels of Co regulate numerous metabolic and developmental traits of plants. Henceforth, monitoring and understanding the dynamics of Co across deficient, beneficial, and toxic levels is imperative. This review presents a data analysis of the latest literature on Co, including (i) levels and sources in soil, (ii) mobility and phyto-availability, (iii) phytouptake and translocation, (iv) toxic, deficient, and beneficial effects, (v) plant tolerance mechanisms, and (vi) role under environmental stresses. A literature data analysis of 1681 plant observations revealed that plant responses vary significantly for different applied conditions and levels, plant species, and physiological attributes. Overall, the current review provides an updated and critical representation and mechanistic interpretation of the biogeochemical behavior of Co in soil-plant-human systems.

The release of microplastics (MPs) from nylon tea bags poses a critical concern for human exposure; however, their detection and quantification remain challenging especially in beverage matrices, and hence, this study pioneers the use of high-resolution optical coherence tomography (OCT) integrated with an image processing algorithm to rapidly detect and quantify the size and count of the MPs directly in the water extractions simulating tea brewing. The water extractions prepared by simulating tea brewing conditions, hot (100 °C, 1-5 min), cold (2 °C, 1 h), and ambient (30 °C, 1 h), were observed employing OCT imaging and validated through Nile Red (NR) staining and digital microscopy. The nylon tea bags steeped in hot water for 5 minutes released 16 000 to 24 000 LMPs (>30 µm) and SMPs (12-30 µm) per millilitre. The estimated daily intake (EDI) of MPs indicates a higher exposure for children (ranging from 0.201 to 0.349 mm³ kg^-1 day^-1) compared to adults (0.046 to 0.080 mm³ kg^-1 day^-1). In contrast, cold brewing for 1 hour released fewer LMPs but an equal quantity of small MPs (SMPs) compared to hot brewing. This OCT-based approach offers a rapid, versatile platform for the detection and quantification of MPs from diverse packaging materials and provides a powerful tool for comprehensive risk assessment when combined with chemical and toxicological analyses.

Correction for ‘The sinking behavior of micro–nano particulate matter for bisphenol analogues in the surface water of an ecological demonstration zone, China’ by Yuanfei Cai et al., Environ. Sci.: Processes Impacts, 2021, 23, 98–108, https://doi.org/10.1039/D0EM00366B.

The growing demand for rare earth elements (REEs) in high-tech applications has elevated their concentrations in aquatic environments. However, comprehensive investigations into their ecological and human health risks remain limited. Forty-two river water samples from the Jiulong River basin, a representative coastal watershed, were analyzed to elucidate the occurrence, distribution, and risks of REEs. The inverse distance weighting (IDW) analysis revealed distinct spatial heterogeneity, typical fractionation between heavy and light REEs (HREEs and LREEs), and pronounced Ce and Eu anomalies. Redundancy analysis (RDA) indicated that REE concentrations were influenced by both natural geochemical processes and human activities. The key novelty of this work lies in the combined ecological risk assessment of ΣREE, highlighting the significance of mixture toxicity over individual-element evaluation. Additionally, the age-differentiated health risk assessment demonstrated that children are more susceptible to LREEs and Y exposure, although all hazard quotient (HQ) values remained below 1. Several tributaries (West river and upper North river) exhibited ΣREE risk quotient (RQ) values exceeding 1, indicating localized ecological concerns. These findings provide new insights into REE geochemical behavior and cumulative risk mechanisms in coastal rivers, establishing an integrated framework linking spatial geochemical characteristics with multi-scale risk assessments of REE contamination in coastal aquatic systems.