Environmental Science: Processes & Impacts最新文献

Atmospheric particulate matter (PM) pollution in remote, tropical island environments remains underexplored, a significant knowledge gap compared to extensive studies in polar and high-altitude regions (e.g., Arctic, Antarctic, and Tibetan Plateau). The Andaman and Nicobar (A & N) Islands provide a unique setting to study background pollution due to minimal industrial activity and coal combustion. This study addresses this gap by analyzing elemental concentrations and Pb isotopic compositions in PM₁₀ and PM_2.5 aerosols along with potential end members, collected in Port Blair during winter and monsoon 2023. Ship fuel (diesel, lubricants, and coolants), an underexplored source of atmospheric Pb was characterized for metal concentrations and Pb isotopes. The results indicate that while crustal components (up to 76% in monsoon and 53% in winter) and marine sources (up to 28% in monsoon and 15% in winter) contribute significantly to Pb in aerosols, anthropogenic sources such as vehicular and ship emissions (up to ≥10%), non-exhaust emissions, and transboundary aerosols (up to ∼10%) also play key roles. Notably, Pb isotopic signatures reveal a distinct source that cannot be explained by conventional contributors. By comparing Pb isotopic compositions with global ammunition data, we identify military activities, particularly bullet-derived Pb, as a significant and previously unrecognized source in the region (up to 23% in monsoon and 30% in winter). This study advances our understanding of atmospheric Pb sources in remote tropical archipelagos, reporting the first comprehensive Pb isotopic composition of PM from these islands.

Triphenyl phosphate (TPHP) is a commonly used flame retardant and plasticizer with well-documented toxicity at environmentally relevant concentrations. We tested the hypothesis of covalent protein binding as a mechanism of TPHP toxicity by using chemical proteomics to identify adducted targets from human and rat hepatic proteomes. Results via in-gel fluorescent imaging showed that the TPHP-probe covalently bound many proteins with substantial interspecies variation. Using shotgun proteomics, we confirmed liver carboxylesterases as major targets in rat liver but identified liver fatty acid binding protein (L-FABP) as a novel and predominant target in human liver cells. The binding of TPHP to L-FABP was also confirmed by using recombinant L-FABP protein. We confirmed that TPHP binding to L-FABP is structurally selective, demonstrating that aryl side chains and the phosphate ester center are both essential for binding. Thus, we conclude that L-FABP is a predominant and selective target of TPHP in human hepatic proteome and that covalent protein adduction is an understudied toxicity mechanism for TPHP, presenting concerns regarding its widespread usage.

The bacterium Comamonas terrigena strain HJ-2 has been reported as a nitrate-dependent iron-oxidizing bacterium, surprisingly with Fe(III) reduction ability. The control of iron redox cycling by the strain HJ-2 in the Fe(II)–Fe(III) co-existing system is mysterious and worthy of exploration. The present study demonstrates that HJ-2 utilizes nitrate as an electron acceptor to rapidly oxidize Fe(II), with negligible Fe(III) reduction, under neutral pH and anaerobic conditions in a co-existing Fe²⁺ and ferrihydrite system. Nitrate significantly influences the iron transformation mediated by HJ-2. The final conversion ratio of Fe(II) increased from 27.94% to 96.67%, and the bio-oxidation rate of Fe(II) escalated from 0.000143 to 0.013 h⁻¹ as nitrate concentrations rose from 0.1 to 10 mM. X-ray diffraction results indicated that in the absence of HJ-2, goethite was the sole product, regardless of the nitrate concentration. While in the presence of HJ-2, the minerals formed transitioned from crystalline goethite and lepidocrocite to amorphous or weakly crystalline minerals with increasing nitrate concentration. Scanning electron microscopy and energy-dispersive X-ray spectroscopy showed that the morphology of the final mineral formed under high nitrate conditions resembled ferrihydrite, with higher carbon content on the mineral surface at elevated nitrate concentrations, suggesting enhanced production of bio-iron oxides and increased adsorption capacity for aqueous Fe(II). X-ray photoelectron spectroscopy results confirmed higher Fe(II) content on the amorphous minerals surface than goethite. This work provides new insights into microbial-mediated Fe–N cycling in natural environments, highlighting the significance of nitrate in driving iron redox processes and the iron mineral transformation by strain HJ-2.

Potentially toxic elements (PTEs) in soil pose significant ecological and human health risks due to their persistence and bioaccumulative nature. This study investigates PTE contamination in soils collected from ten representative contaminated sites across Japan, including industrial zones, construction sites, and shooting ranges. While previous research has focused on specific PTEs such as arsenic (As) and lead (Pb), comprehensive multi-element risk assessments across diverse contamination scenarios remain limited. To address this, a suite of pollution indices, including the geo-accumulation index (I_geo), Pollution Index (PI), Nemerow Pollution Index (PI_N), Potential Ecological Risk Index (RI), Pollution Load Index (PLI), multi-element contamination index (MEC), and the Mean Effects Range-Median Quotient (MERMQ), was employed to assess contamination levels and ecological risks. Additionally, human health risks were assessed using deterministic models and probabilistic Monte Carlo simulations. Results identified As and Pb as primary contaminants, with leaching tests revealing concentrations significantly exceeding environmental standards in most soils. Elevated I_geo and PI values for cadmium (Cd), chromium (Cr), and nickel (Ni), despite concentrations remaining within regulatory thresholds, suggest localized safety concerns. High MEC values revealed extremely high pollution in industrial and shooting range soils, threatening the local ecosystem. Non-carcinogenic risk assessments indicated Pb and As as major contributors, with hazard index (HI) values > 1 in several samples. Carcinogenic risks associated with Cr and As exceeded acceptable thresholds in most samples, emphasizing the need for protective health measures. The findings provide critical data to support local governments and policymakers in implementing targeted remediation strategies for managing PTE-contaminated areas.

Our study investigated the interactions between colloids present in various aquatic environments and the surface of microplastics (MPs), with a specific focus on their behavior in tap water, lake water and marine water systems. This phenomenon is commonly referred to as “eco-corona”. Polypropylene microplastics, although extensively utilized in various applications, have been less studied than polystyrene and polyethylene microplastics. The prepared polypropylene microplastics were characterized by ATR-FTIR and Raman spectroscopy, and the formation of eco-corona was monitored at specific time intervals (24, 48, 72, 96 and 120 h). Fluorescence spectroscopy was used to measure the corresponding fluorescence intensity. Further investigations through FTIR spectroscopy revealed a reduction or complete disappearance of the characteristic polymer peaks upon suspension in natural water systems. Eco-coronated MPs exhibit more cadmium adsorption than raw MPs. The combined exposure of eco-coronated MPs and cadmium to the brine shrimp Artemia leads to the bioaccumulation of microplastics. At its peak concentration (0.5 mg mL⁻¹), both weathered and true-to-life microplastics significantly increased reactive oxygen species production (p < 0.001) in a concentration-dependent manner. Similarly, superoxide dismutase activity increased in a dose-dependent manner, with weathered microplastics showing significant elevation (p < 0.001). Conversely, total protein content was reduced at higher concentrations of both weathered and true-to-life microplastics. The interaction between microplastics and biomolecules/colloids diminishes their presence in the environment, acts as a vector for pollutants, and mimics food for aquatic organisms. Additionally, it facilitates bioaccumulation in lower-to-higher aquatic organisms and contributes to the collapse of the food web.

To effectively manage water resources and safeguard food security, it is essential to comprehend the impact of climate change and human activities on non-point source (NPS) pollution within agricultural watersheds. This study utilized SWAT+ to model the water balance and nutrient balance of the Xiaowei River Basin (XRB) in Shaanxi Province, China. Different scenarios were used to quantify the effects of human activities and climate on NPS pollution loads. Model validation achieved R² values of 0.87 (streamflow) and 0.71 (total nitrogen load), indicating good performance. The baseline period (1998–2023) was divided into four evolution scenarios. Results showed climate dominated total nitrogen (TN) load contributions (average 93.6%), while human activities contributed 6.4%. However, human activities increased from 4.5% (1998–2003) to 9.7% (2018–2023), increasing TN load. TN loads decreased relative to the initial scenario, due to reduced precipitation. Future pollution loads were simulated using CMIP6 data (five GCMs) and projected population and LULC. Under SSP2-4.5, TN loads increased (2024–2040) and then decreased. Under SSP5-8.5, TN loads exhibited a consistent upward trend, driven by agricultural land expansion and reduced precipitation. Human activities' contribution is continually increasing. Projections indicate TN load under Best Management Practices (BMPs) is lower than that in other scenarios across all timeframes. Notably, in the long term (2071–2100), TN load under BMPs is lower than the baseline. Relevant decision-makers may consider implementing Best Management Practices (BMPs) such as precision fertilization and the establishment of vegetative buffer strips, which can help mitigate the effects of human activities.

Surfactant-rich aqueous media are common in natural environments. The sea surface microlayer and sea spray droplets are good examples and are also frequently markedly enriched in organic pollutants. This study focuses on the degradation kinetics of organic pollutants initiated by the hydroxyl radical in such surfactant-rich environments. The apparent second-order rate constants of the reaction of the hydroxyl radical with two model pollutants, carbamazepine and phenanthrene, were determined in the presence of sodium dodecyl sulfate or rhamnolipids at concentrations below and above their critical micelle concentration (CMC). The results show that the apparent rate constant remains unaffected below the CMC, unless additional reactive processes are induced. From the results obtained above the CMC, second-order rate constants were derived for the reaction of the hydroxyl radical with the pollutant trapped in the surfactant micelles. A rather similar decrease of about a factor of 3 in comparison to pre-micellar conditions was observed for all three experimental conditions tested. This work appears to provide a suitable foundation for evaluating the impact of such surfactant-rich environments on the half-lives and fates of organic pollutants and a preliminary indication of how reaction kinetics may be modified in various organized surfactant structures.

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants whose presence in the environmental matrices can provide insights into historical emissions and inputs from surrounding areas. In this study, we analyzed ten PAHs in eight sediment cores collected from the northern part of Taihu Lake, a region adjacent to one of the most developed areas in China, to assess the impacts of anthropogenic activities on PAH distributions over recent decades. PAH distributions were characterized using concentration fraction profiles of four light PAHs (CFL) and six heavy PAHs (CFH). The results reveal a consistent upward trend of increasing CFH and decreasing CFL within the sediment cores. This pattern is primarily attributed to the substantial rise in coal and oil consumption in the local region over recent decades, given that heavy PAHs are mainly emitted from coal combustion and vehicle exhaust rather than from wood combustion. Additionally, heavy PAHs preferentially bind to ultrafine particles which are less efficiently captured by conventional particle interception technologies, causing them to be more prone to environmental release. Expanding the analysis globally, four distinct types of CFH and CFL profiles were identified in 19 other aquatic areas, reflecting variations in regional energy consumption structures and industrialization levels. By integrating data on energy use, emission sources, PAH partitioning and sedimentary deposition patterns, this study provides a comprehensive framework for interpreting the historical and regional characteristics of PAH input to the aquatic environment.

Pesticides are intensively used but understudied in tropical regions in America. We therefore investigated their occurrence and dissipation in soils of 18 potato (Solanum tuberosum L.) producing farms in Mayabeque, Cuba, between 2018 and 2022. Between two and 17 active ingredients (AIs) were used per site, and the cultivation period and sums of AIs ranged from 0.001 to 26 kg_AI ha⁻¹. Soil concentrations of 38 individual target compounds ranged from 0.1 to 658 μg kg_{dry weight}⁻¹. Observed half-lives (DT_50,obs) of the five most prevalent AIs were up to eight times lower than the DT₅₀ from temperate climate in the Pesticides Properties Database. The fate and behaviour of pesticides rather depended on their physico-chemical than on soil properties. Several sites posed a high risk to earthworms (cumulative risk quotient >1) during periods of peak pesticide application to harvest, with azoxystrobin and cyproconazole contributing the most.