Environmental Science: Processes & Impacts最新文献

Phytoremediation is an effective technology for removing heavy metal cadmium (Cd) from soil without harming the soil; however, it is limited by its long remediation time and low efficiency. In this study, a plant growth regulator (PGR), triacontanol, was sprayed on the leaves of the hyperaccumulator Tagetes patula L. at different growth stages to enhance the accumulation of soil Cd, thereby ultimately enhancing the efficiency of phytoremediation. Results showed that leaves were the main site of Cd accumulation in T. patula, and foliar application of triacontanol increased the leaf biomass and Cd content, with maximum values of 14.69% and 15.44%, respectively. Furthermore, the Cd removal rate in the soil increased to 11.53%. The effect of a single application of triacontanol on Cd accumulation was better than that of two applications, and the bloom period was found to be the best application stage. The proportion of Cd in the cell walls increased, enhancing Cd fixation ability. The photosynthetic efficiency and antioxidant capacity of T. patula improved significantly. In the roots, metabolomic and transcriptomic analyses indicated that triacontanol promoted the metabolism of low-molecular-weight organic acids, leading to an increase in the available and exchangeable Cd in soil, with maximum values of 14.72% and 2.29%, respectively. The upregulation of Cd transport-related genes and pathways in the roots strengthened their ability to absorb Cd and resist Cd stress. These findings systematically elucidated the molecular mechanism of triacontanol-enhanced Cd accumulation in T. patula and provide technical support for its wide application.

The agricultural sector plays a pivotal role in Hainan Province, China; therefore, the utilization of pesticides is indispensable. The current ban on traditional pesticides and ongoing replacement of current-use pesticides (CUPs) have not been accompanied by extensive research on the presence of CUPs in reservoirs, which are vital centralized sources of drinking water. In this study, 26 CUPs was investigated in a drinking water source reservoir, the surrounding watershed, and the surrounding agricultural and domestic discharge water in Hainan Province. The predominant detected CUPs in the study area were clothianidin (CLO), thiamethoxam (THM), acetamiprid (ACE), imidacloprid (IMI), and dichlorvos (DCH). Neonicotinoids (NNIs) were the primary type of pesticide contamination in the study area, with a concentration ranging from not detected (n.d.) to 755 ng L^-1 (median of 71.0 ng L^-1). The upstream watersheds of the reservoir were primarily contaminated due to agricultural activities, and the highest concentration of individual CUPs, ranging from 102 to 821 ng L^-1 (median of 468 ng L^-1), was found in agricultural source water. Source identification analysis revealed that the presence of CUPs in the reservoir primarily stemmed from three types of activities: the cultivation of fruit trees around the reservoir, the daily activities of residents, and the agricultural practices in the upstream watershed basin. Risk assessment indicated that DCH, IMI, and THM posed moderate or high risks to aquatic organisms, with an emphasis on the effects of NNIs. The chronic cumulative risk assessment of NNIs was conducted by the relative potency factor approach, and it indicated that infants and young children were the most vulnerable groups and exhibited heightened susceptibility. The potential exposure to NNIs through drinking water was below the recommended relative chronic reference dose, thereby posing no discernible health risks. The results of this study will support the regulation of CUPs in drinking water sources.

Textiles play an important role in the accumulation of harmful chemicals and can serve as a secondary source of chemical pollutants in indoor environments, releasing these chemicals back into indoor air, as well as a vector from which indoor pollution can be released by laundering to wastewater systems. Among harmful indoor pollutants, aromatic amines (AAs) are particularly concerning due to their mutagenic and carcinogenic properties, but have received limited attention in non-occupational indoor environments. We have characterized the distribution of 19 AAs between cotton, wool, and polyester textiles and air. Chamber exposure experiments were conducted under controlled laboratory conditions to quantify textile-air distributions of AAs and identify key parameters impacting the distribution. The mass-normalized textile/air distribution coefficients (K_TA) of AAs for polyester, cotton, and wool range from 5.28 to 9.52 log units (L kg^-1). The findings suggest that cotton generally exhibits higher distribution coefficients than polyester and wool for most analytes. Overall, the results show a strong positive relationship between octanol-air distribution coefficients (K_OA) and K_TA values. The consistent uptake capacity of all tested textiles for AAs highlights the potential for textiles to play a key role in AA indoor distributions.

Antimony (Sb) has gained increased attention over the past few decades due to its possible detrimental effects on biota and its potential to leach and disperse from contaminated soils. The fate of Sb in the environment is largely controlled by its chemical speciation, as well as the speciation of solid phases (e.g. Mn/Fe-oxyhydroxides) that interact with Sb in soils. Microbes have the capacity to facilitate a multitude of oxidation and reduction reactions in soils. Therefore, they exert control over the reactivity of Sb in the environment, either directly and/or indirectly, by changing Sb speciation and/or affecting the redox state of soil solid phases. Here, we outline processes that determine the behaviour of Sb in soils. We conclude that based on laboratory studies there is a good theoretical understanding of pure soil components interacting with Sb species. However, comparatively little is known concerning the contribution of these interactions in complex natural systems that are dynamic in terms of biogeochemical conditions and that can hardly be simulated using laboratory incubations. We note that important biochemical foundations of microbially driven Sb conversions (i.e. molecular constraints on organisms, genes and enzymes involved) have emerged recently. Again, these are based on laboratory incubations and investigations in environments high in Sb. In this regard, an important remaining question is which microorganisms actively impact Sb speciation under real-world conditions, in particular where Sb concentrations are low. Multiple dissolved Sb species have been described in the literature. We note that more analytical development is needed to identify and quantify possible key Sb species in natural systems, as well as anthropogenically impacted environments with only moderate Sb concentrations. With these research needs addressed, we believe that the Sb fate in the environment can be more accurately assessed, and remediation options can be developed.

The impact of nanoplastics (NPs) and microplastics (MPs) on ecosystems and human health has recently emerged as a significant challenge within the United Nations Agenda 2030, drawing global attention. This paper provides a critical analysis of the influence of plastic particles on plants and soils, with the majority of data collected from recent studies, primarily over the past five years. The absorption and translocation mechanisms of NPs/MPs in plants are first described, followed by an explanation of their effects-especially particles like PE, PS, PVC, PLA, and PES, as well as those contaminated with heavy metals-on plant growth, physiology, germination, oxidative stress, and nutrient uptake. The study also links the characteristics of plastics (size, shape, concentration, type, degradability) to changes in the physical, chemical, and microbial properties of soils. Various mitigation strategies, including physical, chemical, and biological processes, are explored to understand how they address these changes. However, further research, including both laboratory and field investigations, is urgently needed to address knowledge gaps, particularly regarding the long-term effects of MPs, their underlying mechanisms, ecotoxicological impacts, and the complex interactions between MPs and soil properties. This research is crucial for advancing sustainability from various perspectives and should contribute significantly toward achieving sustainable development goals (SDGs).

Exploring the adsorption of organic compounds onto microplastics (MPs) is of great significance for understanding their environmental fate and evaluating their ecological risks. To date, various techniques, e.g., experiments, simulations, and prediction models, have been utilized for exploring the adsorption of different organic compounds onto MPs. In this review, we systematically introduce the sources of MPs, the interactions between MPs and organic compounds, the factors influencing the adsorption of organic compounds onto MPs, and research advances in investigating the adsorption of organic compounds by microplastics with different techniques. We also point out that the structures of MPs and environmental factors can have distinct effects on the adsorption mechanisms, and the adsorption mechanisms for numerous organic compounds onto MPs are still unclear. Besides, there is a paucity of multi-dimensional models for predicting the adsorption of organic compounds by MPs under different environmental conditions with a single click. We hope that our review can provide insights into the environmental behavior and fate of organic compounds and microplastics, as well as also guiding future research on the adsorption of organic compounds onto microplastics.

Particulate air pollution is an environmental problem recognized as a global public health issue. Although the toxicological effects of environmental particle matter (PM) have been reported, the mechanism underlying the effect of PM on protein conformational changes, which are associated with the development of various diseases, has yet to be elucidated. In this study, we investigated the effect of urban PM on the secondary structure of proteins using bovine serum albumin (BSA). An urban aerosol (CRM28) was used as the original PM (PMO) and washed with acetone to investigate the effect of PM with two different chemical compositions. After washing with acetone, the remaining PM fraction contained decreased amounts of ions and carbon, while the metallic concentration was increased; thus, this PM fraction was labeled as PMM. After incubation of BSA with PM, the samples were subjected to Fourier-transform infrared (FT-IR) spectroscopy to investigate the changes in the absorption peak of the amide I band. BSA incubated with PMO and PMM showed an increase in the β-sheet ratio to the total secondary structure. Furthermore, the β-sheet content was more significantly increased when mixed with PMM (by 22.6%), indicating a more significant effect of the metallic fraction on the formation of β-sheets. In comparison, the lowest total amount of α-helix and β-sheets (with a decrease of 8.5%) was observed after incubation with PMO, associated with the protein partial unfolding in the presence of ions and carbonaceous PM constituents. The potential of a long-term effect of PM composition on protein structure would be of future interest in in vivo time-course studies.

Volatile organic compounds (VOCs) are released from many sources indoors, with ingress of outdoor air being an additional source of these species indoors. We report indoor VOC concentrations for 124 homes in Bradford in the UK, collected between March 2023 and April 2024. Whole air samples were collected over 72 hours in the main living area of the home. Total VOC (TVOC) concentrations in the homes were highly variable, ranging from 100 μg m^-3 to >8000 μg m^-3 (median concentration ∼1000 μg m^-3). Acetaldehyde and 1,3-butadiene concentrations in >75% of homes were found to be in exceedance of the 1 in 1 000 000 lifetime cancer risk threshold. Higher concentrations of benzene, toluene, ethylbenzene and xylene (BTEX) as well as trimethylbenzenes were found in urban houses (summed xylene median 2.35 μg m^-3) compared to rural homes (summed xylene median 1.22 μg m^-3, p-value = 0.02), driven by ingress of elevated outdoor BTEX and trimethylbenzenes (outdoor urban BTEX median 1.69 μg m^-3, outdoor rural BTEX median 0.78 μg m^-3). Inferred air change rate (ACR) exhibited a degree of seasonality, with average ACR varying between median values of 1.2 h^-1 in the summer and 0.70 h^-1 in winter. Time-averaged emission rate data provided additional insight compared to measured concentrations, such as seasonal variability, with highest total VOC time-averaged emission rates occurring in summer months (median 51 953 μg h^-1), potentially a product of both increased occupancy times during school holidays as well as off-gassing of VOCs from surfaces. This comprehensive analysis underscores the critical role of seasonal, spatial, and contextual factors in shaping indoor VOC exposure, as well as potential health risks associated with consistently elevated concentrations of specific VOCs.

Abamectin, one of the most widely used pesticides globally, is known for its effectiveness in protecting crops and animal health. However, the residual risk of abamectin in agricultural products and the environment may be exacerbated by other pollutants, posing greater potential hazards. One such emerging environmental pollutant is N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), a common tire antioxidant found in various environments, including agricultural products and human urine. Our study is the first to reveal the co-existence of 6PPD and abamectin in water and soil, and it demonstrated that 6PPD significantly enhances the residual persistence of abamectin in environmental media and vegetables. Specifically, 6PPD extended the half-life of abamectin by 79% in pak choi and by 70% in cabbage. Additionally, 6PPD increased the photolysis half-life of abamectin by 191% in water and by 50% on soil surfaces. Furthermore, 6PPD also prolonged the photolysis half-life of four other macrolides in water. This study reveals the mechanism through which 6PPD extends the half-life of abamectin: by scavenging free radicals and inhibiting hydroxylation and oxidation, thus slowing its degradation. And this paper highlights that 6PPD significantly exacerbates the environmental risks and food safety issue associated with abamectin. Moreover, it provides valuable insights for studying the safe use of pesticides in complex environments with multiple contaminants.

Plutonium (Pu)-containing acidic liquid radioactive waste was injected into a deep sandy aquifer disposal (314-386 m) at the Seversk site, Tomsk Region, Russia, over several decades. Herein, laboratory simulation of the near-field conditions of the injection well was conducted, including the waste zone (acetic acid, hydrothermal conditions at 150 °C, pH 2.4), the zone of displacement solutions (nitric acid, pH 1.9, low-level waste, decreasing temperature) and the remote zone with unaltered disposal sands and neutral pH. A study of Pu behavior in the waste zone during 1 and 3 injection cycles (for 50 h) and an additional 3 months of hydrothermal conditioning revealed Pu(IV) sorption on the surface of secondary precipitates, emphasizing the main role of pH in Pu retention and mobility. X-ray absorption fine structure (XAFS) spectroscopy and high-resolution transmission electron microscopy (HRTEM) were used to determine Pu speciation and preferential phases responsible for Pu retention. Long-term leaching of sorbed Pu proved effective but slow reversible Pu sorption, while multiple injection cycles and additional hydrothermal conditioning reduced the mobility of dissolved Pu species by stabilizing solids containing Pu. Pu(V), partly flowing from the nitric acid zone, is largely retained in the remote zone with neutral pH and fresh sands, serving as a natural migration barrier.