环境科学与生态学最新文献

Due to global population growth and increased healthcare accessibility, pharmaceuticals and personal care products (PPCPs) are closely linked with human activities and have become new pollutants alongside some legacy priority pollutants, such as polycyclic aromatic hydrocarbons (PAHs). Although PPCPs have been detected in numerous river basins in recent years, a few researches have been carried out on their association with human activities. In this paper, the concentrations of PPCPs and toxicological data were compiled for over 25 representative watersheds in China in the past two decades from various sources, including PubMed, Elsevier and Springer. Comprehensive analysis of the occurrence, spatial distribution, sources and ecological risk assessment was carried out for the 30 most frequently detected PPCPs in water environments. Multivariate statistical methods, including hierarchical cluster analysis (HCA), principal component analysis (PCA) and redundancy analysis (RDA), were employed to classify PPCPs and assess their relationship with human activities. The results indicated that the concentrations of PPCPs in rivers varied significantly across studied regions, ranging from non-detect to 21,885 ng/L. Many detected compounds in PPCPs were antibiotics and their occurrence was closely linked with the economic development, effectiveness of medicines and geographical location. Household emissions were identified as the primary contributor to the occurrence of PPCPs in river basins. A strong correlation has been observed between PPCPs level and socio-economic indicators from multivariate statistical analysis. Ecological risk assessment revealed that caffeine (CAF), ibuprofen (IBU) and anhydroerythromycin (ERY) pose the greatest threat to aquatic life, particularly in the Northern China. The data compiled in this study provide insights into the impacts of PPCPs and the relationship of their ecological risks with various human activities, particularly in the typical Chinese river basins. Our results are valuable for the effective management PPCPs.

Research on the use of organic materials as soil amendments for the remediation of Cd-contaminated agricultural land exists. However, the mechanisms based on which organic materials affect the distribution and availability of Cd in soil aggregates remain unclear. Here, Cd-contaminated paddy soil and different bio-based materials were used for rice pot experiments. Rhizosphere soils were separated into six particle sizes. Cd fractions were analyzed with BCR sequential extraction and specific functional groups associated with Cd were characterized using XPS. We found that bio-based materials promoted the formation of large aggregates to different extents. Cd tended to be enriched in fine- and coarse-grained soil particles, which is mainly related to the soil organic matter. Bio-based materials reduced the relative content of the weak-acid extractable fraction and increased the relative content of the reducible fraction, resulting in soil Cd immobilization. Soil dissolved organic matter (DOM) was the key factor affecting the distribution and availability of Cd in soil aggregates and different organic matter and Cd-binding functional groups in aggregates altered the Cd availability in soil. The results provide insight and guidance for understanding the cadmium immobilization mechanism and screening appropriate materials in the remediation of agricultural land.

The large, shallow Lake Balaton (Hungary) has experienced rapid salinization since the 1970s. This study investigated the causes of salinization and aimed at predicting the effects of climate change. Monthly mass balance models for chloride and sodium were calibrated using water balance and water quality monitoring data (1976-2022) to analyze the effects of climate change (2022-2100) through ensemble modeling under the IPCC RCP 4.5 scenario. Current (2016-2020) emission inventories were developed for both chloride and sodium. The long-term (1921-2022) emission inventory of chloride was used to build a simplified chloride balance model for the catchment. Historical salinization occurred with almost constant external loading, in parallel with the increasing water residence times. According to the mass balance model, 18-28 % of the cumulative chloride and sodium loads has been accumulated in lake sediments, potentially slowing recovery of the lake from salinization. Climate change was predicted to aggravate salinization by further reducing the water balance surplus. Even the extremely high chloride concentrations of the future will remain well below the drinking water limit, but they may adversely affect the aquatic ecosystem. Both agriculture and road deicing contributed about one-third of current chloride emissions. Wastewater accounted for <20 % due to significant wastewater diversion to adjacent catchments. The rapid intensification of Hungarian agriculture from the mid-1960s, followed by a sudden economic collapse in 1990, resulted in a large emission peak of chloride in the 1970-80s, providing a unique opportunity to estimate the long-term retention of chloride in the catchment. We estimated that 30 % of the chloride emitted since 1921 may still be present in groundwater/soils.

Clarifying the driving factors of grassland carbon sequestration is essential for understanding its role in the regional carbon balance. However, there is a lack of studies on the upscaling of carbon flux in the Qilian Mountains (QLMs) and the driving factors of its interannual variation (IAV). Based on long-term eddy covariance observations in the QLMs, this study estimated the net ecosystem CO₂ exchange (NEE), gross primary productivity (GPP), and ecosystem respiration (ER) of the QLMs grassland using four machine learning methods (random forest regression (RF), extremely randomized tree regression (ETR), support vector regression (SVR), and extreme gradient boosting (XGBoost)) to obtain the optimal estimation model. Subsequently, the spatiotemporal variations of GPP, ER, and NEE in the QLMs grasslands were conducted in a comprehensive analysis. The factors influencing the IAV of carbon flux, the contribution of monthly NEE to NEE IAV, and the contribution of different grassland types of NEE to NEE IAV were explored. Our findings revealed that the accuracy and resolution of the grassland carbon flux estimated by the RF method in this study are higher than those of global products. The grassland exhibited a weak carbon sink from 2000 to 2022, with an average NEE of -26.46 ± 6.80 g Cm^-2 yr^-1, and it acted as a carbon sink from May to September. The spatial distribution pattern of carbon sequestration was "low in the northwest and high in the southeast". LAI was the key driving factors of IAV for GPP and ER, while NEE IAV was primarily influenced by precipitation and temperature. Climate and vegetation factors primarily regulated NEE IAV by affecting the GPP and ER of plants, and NEE IAV was primarily driven by GPP. Furthermore, NEE in alpine meadows and alpine steppes dominated the NEE IAV of the entire grassland, and summer NEE contributed the most to the NEE IAV. The results will help us to better understand the carbon cycling mechanism in grassland ecosystems and provide new data support and a theoretical foundation for regional carbon cycling research.

Understanding how animals coexist within an ecosystem is essential for the conservation of biodiversity. In China, large populations of a non-native snail Rumina decollata (a highly invasive species reported by various other countries) coexist with two native snail species (Acusta ravida and Euphaedusa aculus). However, the potential mechanisms that facilitate this non-native and native snail coexistence remain uncertain. Here, we analyzed the fecal microbiomes and dietary compositions of R. decollata, A. ravida, and E. aculus to elucidate the mechanisms that drive the cohabitation of non-native and native species in Nanjing, China. It was found that the composition of the E. aculus fecal microbiome was similar to that of R. decollata, while it was significantly different from that of A. ravida. Furthermore, R. decollata preyed on E. aculus and had similar plant food compositions like A. ravida. These results indicated that the fecal microbiomes of snails may be adaptable to variable environmental conditions, while being minimally influenced by host genetics. R. decollata integrated a portion of the fecal microbes of E. aculus by preying on them. Our findings highlighted that the coexistence of R. decollata with native snails may have been due to abundant environmental resources, which negated the emergence of strong competition. However, the specific dietary changes of R. decollata and their propagation still need to be continuously monitored to better understand the long-term effects of R. decollata on ecosystems. This research provides a new understanding toward the prevention of invasive species and biodiversity conservation.

There is growing experimental and epidemiological evidence linking perfluoroalkyl and polyfluoroalkyl substances (PFAS) exposure to thyroid dysfunction; however, the association between PFAS and their alternatives to subclinical hypothyroidism in children remains to be elucidated. This study investigated the association between 30 PFASs and thyroid function using serum samples from 194 children (aged 3-17 years) who participated in the Zhejiang Human Biomonitoring Program. Various thyroid function indicators, including free triiodothyronine, free thyroxine (FT4), and thyrotropin, were tested, and subclinical hypothyroidism was diagnosed. Linear regression was employed to examine the associations between individual PFASs and thyroid hormone levels, and logistic regression was applied to assess their associations with subclinical hypothyroidism. The quantile g-computation (qgcomp) method was used to examine the combined and individual effects of PFAS mixtures on thyroid function. Both PFASs and their alternatives were associated with altered thyroid hormone levels and subclinical hypothyroidism. A higher level of perfluorohexanoic acid (PFHpA) was associated with decreased FT4 with a reduction of -0.028 pmol/L (95 % confidence interval [95 % CI]: -0.047, -0.008) per unit increase as well as increased odds of subclinical hypothyroidism (odds ratio [OR] = 1.95; 95 % CI: 1.11, 3.53). Moreover, a higher PFAS mixture was associated with elevated odds of subclinical hypothyroidism (OR = 3.72; 95 % CI: 1.08, 12.85), in which PFHpA, in conjunction with 6:2 chlorinated perfluoroalkyl ether sulfonic acid, accounted for the greatest proportion of the variance. These findings augment our understanding of the adverse effects of PFASs and their alternatives on thyroid homeostasis, underscoring the need for further epidemiological research.

PFOS and its precursors are of great concern due to their persistence and widespread presence in the environment. However, few studies have been conducted on their transformation and fate at a regional scale. We aim to address this gap by investigating their fate in the Bohai coastal region of China. Emissions of PFOS and its precursors are estimated based on anticipated POSF production in China from 1976 to 2025. Comparison of emission sources revealed that PFOS primarily originated from direct emissions, while precursors were notably influenced by indirect sources. Dynamic concentration curves of these pollutants in various compartments were simulated and validated against measured values. Spatial analysis indicated higher concentrations of these pollutants in sections 25 (Beijing), 26 (Tianjin), and 48 (Shenyang), with lower concentrations observed in sections 8, 16, and 24. The mass flux results highlighted significantly different pathways: precursors primarily interacted between upper and lower air with notable degradation, while PFOS mainly moved from lower air to soil and freshwater. Mass fluxes into the Bohai Sea suggested that PFOS mainly entered via water flow, while precursors primarily came through air deposition. Uncertainty analysis revealed higher uncertainties in soil and sediments than the oceans, with additional uncertainties in estimated emissions, and seawater salinity. This study provides a theoretical basis for modelling and regulating PFOS.

Soil conservation service (SCS) is crucial for the regulation of fragile ecosystems. As the Loess Plateau is a typically erosion-threatened region, determining the spatial matching pattern and drivers of SCS supply (soil conservation) and demand (soil erosion) is essential for sustainable development and effective resource management. This study innovatively proposed the coupling coordination framework between SCS supply and demand to assess the current state and clarify the subsequent regulation direction. First, the RUSLE model was employed to evaluate the SCS supply and demand from 1990 to 2020 and acquire the ecological supply-demand ratio (ESDR). Then, the SCS supply-demand coordination relationship was spatially quantified by utilizing the coupling coordination degree (CCD) model, and a function fitting was performed between ESDR and CCD. Using the geo-detector model, the Getis-Ord Gi^⁎ method, and the local Moran's I index, the influences of natural, engineering, and socio-economic factors on the SCS supply-demand coordination were explored from global and local perspectives. The results showed that: (1) the annual average supply of SCS increased by 64.93 % in 1990-2020; the average demand decreased by 52.43 %; the average ESDR increased by 28.06 %; supply surplus was the predominant feature, more conspicuously in the central and eastern regions; (2) the highest supply-demand CCD was captured in the central and eastern regions, showing "Moderate balance" and "High balance" respectively, and its area increased by 27 % in 30 years; the lowest CCD regions were mainly in the northwest and their area shrank; (3) enhancing the supply of SCS and reducing demand facilitated the coordination of the supply-demand relationship, and the threshold for the supply-demand coordination state decreased over time; (4) climate, topography and soil properties dominated the spatially non-stationary change of the SCS supply-demand pattern, followed by engineering measures such as afforestation and terraces, and finally socio-economic factors. This study offers support for cross-regional soil erosion management and natural ecosystem restoration on the Loess Plateau.

Accurate soil mapping is crucial for agriculture, land, ecosystem and environmental management. Digital Soil Mapping (DSM) is one of the most conventional and widely used methods for mapping soil. This study introduces a novel strategy for DSM by incorporating the neighborhood effect of environmental covariates (ECs), aiming to enhance mapping accuracy of soil properties. The research focused on modeling organic carbon (OC), cation exchange capacity (CEC), bulk density (BD), and pH in southern Canada using 18 ECs derived from the Soil Landscapes of Canada dataset and satellite imagery. Two strategies were compared: a conventional approach using standard ECs, and a proposed method incorporating neighboring ECs through Inverse Distance Weighting (IDW). Both strategies employed Gaussian Process Regression (GPR) for modeling. Results demonstrated significant improvements in accuracy using the proposed strategy. Mean absolute errors were reduced by 32 %, 36 %, 28 %, and 14 % for OC, CEC, BD, and pH, respectively. The proposed method also decreased the coverage of high-error areas and improved R² values across all soil properties. Moreover, mean uncertainty in soil property modeling decreased by 3.4 % to 3.9 % using the proposed strategy. This study highlights the importance of considering spatial context in DSM through neighborhood effects. The proposed strategy offers a more nuanced and accurate approach to soil property modeling, with potential applications extending beyond soil science to other environmental mapping domains. These improvements in soil mapping accuracy have significant implications for sustainable land management, precision agriculture, and environmental conservation.

Per- and polyfluoroalkyl substances (PFAS) are pervasive environmental pollutants with significant impacts on ecosystems and public health. This study aimed to characterize PFAS concentrations in an environmental justice community impacted by active/legacy copper mining, compounded by wildfires and flash floods. Additionally, the study explored the (re)mobilization of PFAS and co-occurrence with metal(loid)s following these events. Twenty-eight PFAS compounds in 35 residential and 8 control surface soil samples were analyzed via liquid chromatography-tandem mass spectrometry (LCMS/MS). The maximum total PFAS concentration observed in the residential samples was 96.40 μg kg^-1, compared to 1.69 μgkg^-1 in the control samples. Perfluorobutanoic acid (PFBA) had a maximum concentration of 61 μg kg^-1 in residential samples, while Perfluorohexane sulfonic acid (PFHxS) had the highest concentration in the control samples at 0.92 μg kg^-1. Long-chain PFAS were most dominant in this study. Perfluorooctane sulfonic acid (PFOS) (58 % of the samples), Perfluorooctanoic acid (PFOA) (35 %), and Perfluorohexane sulfonic acid (PFHxS) (72 %) exceeded the U.S. EPA Soil-to-Groundwater Risk-Based Screening Levels, highlighting the potential risk of contaminants migrating from soil to groundwater, which could ultimately impact groundwater quality. Co-occurrence analysis showed that increases in PFAS concentrations were positively associated with Zn (β = 1.25, p = 0.0034) and Ba (β = 1.23, p = 0.0284) but negatively associated with Pb (β = -0.83, p = 0.0115) and Co (β = -1.38, p = 0.04671). In general, a spatial distribution map indicated that greater PFAS concentrations were observed near potential sources i.e., active mines. This evidence combined with select metal co-occurrence highlights the potential role of mining activities on PFAS concentration.