Science of the Total Environment最新文献

Groundwater-dependent ecosystems in areas with industrial land use are at risk of exposure to a PFAS chemicals. We investigated one such system with several known PFAS source areas, where high and low permeability sediments (glacial) coupled with groundwater-lake and groundwater/surface-water interactions created complex 'source to seep' dynamics. Using heat-tracing and chemical methods, numerous preferential groundwater discharge zones were identified and sampled across the upper Quashnet River stream-wetland system in Mashpee, MA, USA, downgradient of Joint Base Cape Cod (JBCC). Surface-water and groundwater samples were analyzed for 40 PFAS compounds between March and October 2022. Samples were collected from groundwater seeps identified as preferential discharge points (PDPs), wells upgradient of the stream-wetland system, contributing flow-through kettle lakes, and along Quashnet River surface-waters. PFAS from sampled waters contained perfluorinated carboxylates (PFPea, PFHxA, PFNA), perfluorinated sulfonates (PFBS, PFPeS, PFHxS, PFOS), fluorotelomer sulfonates (6:2, 8:2 FtS), and perfluoroalkyl sulfonamides (PFOSA). Samples from PDPs and wells had measured PFAS concentrations ranging from non-detect to 4677 ng/L ng/L (mean = 418 ng/L, std. = 709 ng/L), and a range of deuterium excess values (3.2 to 15.9 per mil) indicative of varying degrees of groundwater-lake interaction prior to groundwater flowpath emergence at PDPs. Correlations (p < 0.01) between deuterium excess, %PFAS precursors, and terminal PFAS compounds highlighted potential precursor transformations associated with lake-groundwater exchange along flowpaths sourcing PDPs. However, some seepages had higher total PFAS concentrations (>1000 ng/L) than upgradient kettle lakes despite showing lake (evaporative) isotopic signatures, indicating the potential for groundwater flowpath convergence at wetland discharge zones and the influence of lakebed PFAS precursor reactions. Results from these synoptic surveys address gaps in the existing PFAS literature by demonstrating the importance of subsurface fate and transport on PFAS compound concentrations and mass loading in preferential groundwater discharge zones.

The adsorption reaction on clay minerals is crucial for understanding the environmental behavior of various cations, including cesium (Cs). However, its details remain unclear because of multiple adsorption sites of the clay minerals, a significant difference between concentrations in the atomic-scale experiments and the actual environment, and difficulties of evaluating bonding states of the adsorbed cations. It is expected that systematic experiments at the atomic-scale with a wide concentration range and application of density functional theory (DFT) calculations overcome the problems and bring crucial insights to link laboratory experiment results with environmental sample analysis. This study obtained adsorption isotherms and conducted X-ray diffraction and extended X-ray absorption fine structure (EXAFS) measurements at various concentrations of Cs⁺ or barium (Ba²⁺). Additionally, high-energy resolution fluorescence detection (HERFD) X-ray absorption near edge structure (XANES) measurements was performed for Cs⁺ to estimate its bonding state. To interpret the results, DFT calculations were also conducted. The results clarified the transition process of the adsorption site and local structures of adsorbed cations depending on the adsorption concentrations. Especially, the combination of EXAFS and DFT calculations succeeded in revealing the intermediate state between frayed edge site at a low concentration and collapsed interlayer site at a high concentration. Furthermore, HERFD-XANES and DFT calculations suggested the ionic bonding nature of Cs⁺, regardless of the adsorption sites.

The rupture of Vale S.A. mining tailings dam in Brumadinho, Brazil, in January 2019 had significant environmental impacts on the Paraopeba River basin. Additionally, severe floods in early 2022 contributed to the transport of particles in the river. This study aimed to evaluate the cytotoxic and genotoxic potential of Paraopeba River water. Thus, the Allium cepa test system was applied, along with physicochemical analyses, flow cytometry, and metal concentration, comparing the results between the rainy and dry seasons three years after the dam rupture. The tests were conducted on water samples collected during three periods: January 2022, July 2022, and January 2023, at five points along the river and its tributaries. Allium cepa seeds were exposed to the collected water samples, as well as negative (water) and positive (trifluralin) controls. Cytotoxicity was evaluated using the mitotic index and flow cytometry, and genotoxicity by the chromosomal alterations index. The analysis of metals and physicochemical parameters revealed that most values complied with current regulations. However, there were exceptions, with ammonia levels exceeding the permitted limits at all points in the three collections. High levels of aluminum, iron and nitrite were found at most points, before and after the dam collapse, mainly during the rainy season. This indicates the impact of rainfall on water quality, which increases the transport of contaminating particles, probably resulting from human activities and the high concentration of nitrogen compounds released into the Paraopeba River. The results of the bioassay suggest a relatively low cytotoxic and genotoxic potential of the samples evaluated. However, this study highlights the continuous contamination of the river by unidentified anthropogenic factors, requiring continuous monitoring and analysis to track the evolution of water quality and its environmental effects.

Seagrasses represent a significant class of marine foundation species, yet the distribution of seagrasses in the Yellow Sea and Bohai Sea remains uncertain, thereby impeding the efficacy of conservation and restoration practices. In this study, the spatial and temporal distribution pattern of seagrasses was simulated by the MaxEnt model based on the construction of marine environment and human activity datasets. The main controlling factors affecting seagrass potential distribution were analyzed, and the response of seagrass distribution to global change was clarified. Additionally, the current status of protected and disturbed seagrass meadows was determined. The results indicate the accuracy of the MaxEnt model was enhanced (AUC = 0.987) through the integration of a human activity index, pinpointing a highly suitable seagrass area of 867.64 km². The primary factors dictating seagrass distribution were identified as human activities index (18.4 %), water quality indicators (including nitrate 20.9 %, silicate 11.3 %, and dissolved iron 6.4 %), and topographic elements (such as bathymetry 15.1 % and slope 12.0 %). The highly suitable areas for seagrasses showed a gradual expansion in the future, with a projected increase of 12 % in 2100 under the SSP585 scenario. A binary overlay analysis showed that only 2.61 % of seagrass potential habitats (highly and moderately suitable areas) were adequately protected, highlighting a significant conservation gap in the Yellow Sea and Bohai Sea regions. On the contrary, seagrass potential habitats exposed to mariculture activities were as much as 49.76 %. These findings underscore the urgent need for monitoring and protecting seagrasses in the study area, with the establishment of MPAs emerging as a viable conservation strategy. This research provides a scientific basis for understanding the degradation and conservation status of seagrass meadows and has important practical implications for targeted conservation and restoration efforts of these critical marine foundation species.

Abies alba Mill. is a prominent European tree species predominantly inhabiting cool and humid montane environments. However, paleoecological evidence reveals that during the Eemian and mid-Holocene, A. alba thrived in much warmer and drier climates. This capacity is nowadays reflected in cryptic meso- and sub-Mediterranean lowland populations. To link A. alba populations across diverse climates spanning from the Mediterranean lowlands to the Alpine timberline, we genotyped 421 specimens from Italy and Switzerland at 190 single-nucleotide polymorphisms (SNPs). Population genetic structure analyses indicate that isolated meso- and sub-Mediterranean lowland populations in Tuscany and Ticino align genetically with higher elevation populations in each region, suggesting that their capacity to thrive in warmer, drier conditions cannot be attributed to plantations with planting stock originating from different climates or to the occurrence of a single warm-adapted lineage showing a disjunct distribution, unless migration between Tuscany and Ticino stands occurred. Genotype-environment associations reveal that temperature seasonality, precipitation during critical seasons, and relative humidity are important for explaining the species' genetic variation. With genotype-environment and genotype-phenotype associations, we identified candidate adaptive genes potentially linked to climatic conditions and drought response. While certain adaptive alleles may have spread from Tuscany and Southern Italy or could be explained by a shared ancestry of Ticino and Tuscan populations, local adaptation may have occurred at specific loci. These findings underscore the importance of considering the hitherto overlooked lowland Mediterranean populations of A. alba to better understand the species' climatic niche and its potential for forest conservation and management under global warming.

Mason bees (Osmia spp.) are solitary, tunnel-nesting bees. Several species, including the horn-faced bee (Osmia cornifrons) and the blue orchard bee (Osmia lignaria), are commercially managed, primarily for the pollination of fruit trees and tree nuts. They are efficient pollinators and have high pollen fidelity, and so can greatly benefit orchard yields compared to honey bees (Apis mellifera) alone. Apis mellifera are often used as surrogates for other pollinators during pesticide risk assessment. Non-Apis bee species, however, can be more sensitive to certain pesticides, so it is also important to research the impact of novel pesticides on other bee species. This study investigated the effect of two formulated pesticide products containing recently approved active ingredients, sulfoxaflor and flupyradifurone, on the survival of A. mellifera and three species of mason bees (O. lignaria, O. cornifrons, and Osmia californica). Bees were orally exposed to sulfoxaflor or flupyradifurone and their survival was measured over four days following exposure. Bee sensitivity to the insecticides varied by species and sex of bee. Apis mellifera was the least sensitive, followed by O. cornifrons, with O. lignaria and O. californica as the most sensitive. Male Osmia spp. bees were less sensitive than females. These insecticides may pose a higher risk to the health of Osmia spp. compared to A. mellifera.

The toxicity of electronic cigarette (EC) aerosol is influenced not only by the type of e-liquid but also by various operational parameters of the device used to vaporize it. In this study, we utilized a flask and heating mantle system, instead of a conventional EC device, to systematically evaluate the effects of EC device operational parameters, including vaporization temperature, airflow rate, and the materials of coils and wicks, on the generated mass of EC aerosol and the production of toxic carbonyl compounds. The results demonstrated that these parameters significantly impact aerosol mass and toxicant composition. Specifically, increasing vaporization temperature and airflow rate drastically affect aerosol mass, showing exponential and logarithmic increases. Using the ISO 20768 method, aerosol mass (from 20 μL e-liquid) escalated over threefold from 3100 μg at 200°C to 10,300 μg at 400°C, illustrating temperature's pivotal role. Formaldehyde levels rose from 0.21 μg to 60.2 μg with temperature increases from 200°C to 400°C. At a realistic vaporization temperature of 300°C, the formaldehyde mass was 2.21 μg (3.28 ppm), exceeding the lowest-observed-adverse-effect level for acute respiratory toxicity in humans. While cotton wicks modestly affected aerosol mass, they significantly raised formaldehyde and acetaldehyde levels by 36.2%. In contrast, silica, kanthal, and nichrome materials increased aerosol mass and chemicals like propylene glycol, vegetable glycerin, nicotine, formaldehyde, and acetaldehyde by 22.7% to 63.2%. Our findings underscore the urgent need for regulations encompassing e-liquids and EC devices to mitigate health risks associated with EC use, providing a scientific basis for safety-focused regulatory measures.

Despite the vital importance of wetlands globally, these habitats have increasingly received anthropogenic materials, such as plastics, which can impact the wildlife these habitats support. Despite commonly found in the nests of Eurasian spoonbill (Platalea leucorodia), the presence of such materials has never been quantified. Here, we monitored the occurrence of anthropogenic nesting materials (ANM) in spoonbill nests in the Camargue wetland in Southern France during two breeding seasons (2021-2022). We also investigated their potential function by associating their presence with breeder experience (based on their age) and hatching success. Out of 439 nests, 39 % contained at least one anthropogenic material item, usually plastic of sheet-like shape and white-transparent colours. Throughout the breeding season, the proportion of ANM in the nest lining increased, coinciding with a decrease in natural materials (i.e. vegetation). A higher proportion of natural green materials was detected during the egg phase compared to other phases of nest development. Our results did not support a correlation between the proportion of ANM and breeder experience, nor with hatching success. Further studies (e.g., physiological through necropsy or fine temperature nest assessment) may disentangle the benefits and adverse effects of such materials on waterbird breeding success.

Climate change affects groundwater availability and residence times, necessitating a thorough understanding of aquifer characteristics to define sustainable yields, particularly in regions where water is heavily exploited. This study focuses on the Volvic volcanic aquifer (Chaîne des Puys, France), where groundwater recharge has decreased due to climate change, raising concerns about water use sustainability. To address these challenges, this work proposes a multi-tracer approach, based on hydrogeological monitoring, including the estimation of groundwater ages, major elements chemistry and water stable isotopes to better characterise this resource decrease and more peculiarly its origin and its impact on the environment that has never been addressed. Relative fractions of ancient and modern water contributions (up to 20 %) to the aquifer have been thus estimated as well as the apparent ages of groundwaters (34 years). We highlight the complementarity of tracers used, allowing a better definition of recharge sources and transit times of groundwaters within the aquifer. These results led to the proposal of a hydrogeological conceptual model, highlighting a bi-modal recharge, distinguishing between a long-term recharge upon 30 years, supplemented by a recent component (≃ 1 year) related to annual precipitation. This study provides valuable information on groundwater circulation and the response of volcanic aquifers systems to climate change, while highlighting the importance of assessing residence times. By addressing the challenges posed by systems with contrasting permeability and recharge gradients, it improves understanding of volcanic hydrology and provides a basis for the development of (numerical) hydrological models to assess the impacts of global change.

Knowledge of the dynamics of biodiversity intactness and its spatial differentiation over different geographic regions of the world is crucial for the improved design of effective biodiversity conservation strategies. However, comprehensive investigations of the multiple indicators of biodiversity intactness across several spatial scales are lacking. The current study used an annual time series (2000-2020) of the biodiversity intactness index (BII) to investigate the mean magnitude, temporal trajectory, and relative changes in biodiversity intactness at the national, regional, and global levels. Global mean magnitude of BII was estimated to be 76 ± 16 % between 2000 and 2020, accompanied by the highly diverse BII variations across geographic regions. There has been a gradual decrease in biodiversity intactness over the past 20 years, with the global mean BII trend of -0.3 ± 1.9 %/decade. Africa and Europe have the largest decrease and increase in BII of -1.4 ± 2.2 %/decade and 1.0 ± 1.7 %/decade, respectively. The countries with the top ten BII parameters are mainly located in Africa and Asia, whereas the opposite is true in Europe. The top 10 countries with positive BII trends were mainly in Europe (70 %), followed by Africa (80 %) and Asia (20 %). There was a negative difference between the global mean BII for 2011-2020 and 2000-2010, as evidenced by the relative change in BII of 4.1 %. This study provides an elaborate interpretation of the current status and possible future paths of abundance-based biodiversity intactness at multiple spatial scales, which is beneficial in elucidating biodiversity intactness dynamics and potentially supports biodiversity conservation.