Huanjing Kexue/Environmental Science最新文献

Zhari Namco is situated in the alpine grassland belt of northwestern Xizang with a fragile ecological environment. As the third-largest lake in Xizang, there has been a long-term lack of research data concerning its basin water environment. In an effort to elucidate the surface water environment characteristics of the basin and the factors influencing them, an extensive investigation was conducted from August 2021 to June 2022, encompassing periods of high flow, low flow, and base flow. Further, the study also involved comprehensive assessments of the water chemistry characteristics and spatial-temporal variation in lake sampling sites of the basin that were not significant by using mathematical statistics, hydrochemical analysis, correlation analysis, and principal component analysis. The findings revealed the following： ① The water in the Zhari Namco Basin exhibited an alkaline nature, with dominant ionic compositions in the lake comprising Na⁺, SO₄^2-, and Cl^-, whereas the rivers were primarily characterized by Ca²⁺, HCO₃^-, and SO₄^2-. ② The main pollutants exceeding established standards included sulfates, arsenic, chlorides, and total phosphorus. The study identified significant spatiotemporal variations in water quality. Temporally, the exceedance of sulfates, arsenic, and total phosphorus was most pronounced during high-flow periods, followed by that during low-flow and base flow periods, with chloride levels showing less temporal variation. Spatially, river water quality surpassed that of the lakes, with arsenic, total phosphorus, TDS, sulfate, chloride, K⁺, and Na⁺ concentrations in lakes 1 to 2 orders of magnitude higher than those in rivers. Water qualities exceeding the established standard were primarily found in the lake, with less spatial variations within the lake itself. ③ Hydrochemical processes within the basin were found to be primarily influenced by natural phenomena, including evaporation-concentration and rock weathering. Various elements entered the lakes via surface runoff, where they continuously accumulated under the influence of evaporation-concentration processes, ultimately leading to exceedances. ④ Temporal variations in water quality were primarily attributed to increased elemental loss and intensified evaporation during high-flow periods. The spatial discrepancies in water quality were predominantly a consequence of the differing hydrodynamic conditions between flowing water bodies and enclosed water bodies.

Groundwater is one of the major water sources for production, living, and agricultural irrigation in the Yinchuan Plain. Owing to the influence of the regional environmental background and long-term effects of human activities, groundwater quality is generally inferior. To deeply analyze the formation mechanism and source of hydrochemical components in groundwater in the Yinchuan Plain, the traditional hydrochemical graphic method and mathematical statistics and principal component analysis-multivariate linear statistical model were used. Based on inorganic component contents of 100 phreatic water samples and 46 confined groundwater samples, the hydrochemical characteristics and quality status, spatial distribution of over-limit toxicological components, and contribution rate of hydrochemical components were analyzed. The results showed that the chemical components of groundwater were controlled by rock weathering and evaporation concentration. Dissolution-enrichment （F1）, original geological environment （F2）, and human activities（F3） were the principal factors that influenced groundwater hydrochemistry with the contribution rates of 73.67%, 14.45%, and 11.88%, respectively. The major over-limit toxicity indices in groundwater were NO₃^--N and F^-. High NO₃^--N phreatic water was mainly influenced by agriculture activities, followed by the discharge of domestic sewage. Enrichment of groundwater F^- was mainly caused by leaching of F-bearing minerals and cation exchange adsorption.

To screen for Pb, Zn, and Cd composite heavy metal hyperaccumulator plants, a survey, sampling, and analysis of dominant plants in typical lead-zinc mines and smelter areas in Baoji City were conducted. Potential Pb, Zn, and Cd composite heavy metal hyperaccumulator plants were initially screened, and a pot experiment of soil cultivation was carried out to observe the response characteristics of chlorophyll （chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll）, antioxidant enzymes （SOD, CAT, and POD）, and other physiological indicators （MDA and proline） under the stress of Pb, Zn, and Cd composite heavy metals. A field experiment was also conducted to further verify and determine their enrichment ability for Pb, Zn, and Cd composite heavy metals, aiming to provide scientific basis and technical support for the remediation of Pb, Zn, and Cd composite heavy metal-polluted soil. The field survey revealed that Symphytum officinale L. met the international hyperaccumulator plant index requirements for the enrichment of Pb, Zn, and Cd, with enrichment quantity, bioconcentration factor （BCF）, and transfer factor （TF） all meeting the requirements. It was a potential hyperaccumulator plant for Pb, Zn, and Cd composite heavy metals. The soil cultivation pot experiment showed that as the gradient of Pb, Zn, and Cd composite heavy metal stress increased, the content of chlorophyll a, chlorophyll b, and total chlorophyll in S. officinale L. leaves gradually decreased, causing disruption to the plant's photosynthetic system when the gradient was greater than or equal to IV. The chlorophyll content in Ricinus communis L. leaves exhibited a "low-stimulation-high-inhibition" phenomenon, while excessive stress stimulated the activation of its own protective systems, leading to reduced toxicity. In addition, there were significant differences （P < 0.05） in the content of chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll between S. officinale L. and R. communis L. both compared to the control treatment and between stress gradients. The SOD activity in the leaves of S. officinale L. and R. communis L. showed a trend of increasing first, then decreasing, and then increasing. The CAT activity in the leaves of S. officinale L. exhibited a "low-stimulation-high-inhibition" effect, whereas the CAT activity in the leaves of R. communis L. showed a trend of continuous decrease. The POD activity in the leaves of S. officinale L. generally increased, whereas in the leaves of R. communis L., it increased first, then decreased, and then increased. The MDA content in the leaves of S. officinale L. generally decreased, whereas in the leaves of R. communis L., it exhibited an upward trend. In addition, whether compared to the control between stress gradients, there were significant differences （P < 0.05） in the SOD, CAT, POD, MDA, and proline co

To understand the land use development trends in Shaanxi Province under different scenarios and effectively assess the spatiotemporal evolution of terrestrial ecological carbon stocks in Shaanxi Province under land use changes, the study used Markov-FLUS and InVEST models to analyze the impact of land use changes in Shaanxi Province from 2000 to 2020. The impact of carbon storage changes and the spatiotemporal changes in land use structure, carbon storage, and carbon density under three different scenarios were simulated and assessed in Shaanxi Province in 2025 and 2030. The results showed： ① The ROC values of various categories in the coupled Markov-FLUS model were all above 0.7, showing high accuracy and excellent classification performance. The model had a good ability to explain the land use driving factors in the study area, with high accuracy and excellent classification performance. ② From 2000 to 2020, the cultivated land in Shaanxi Province increased significantly. Forest land increased significantly, and the increase in forest land area with high carbon sequestration efficiency caused the carbon storage in Shaanxi Province to increase from 1 546.95 Tg to 1 616.25 Tg. The changes in various regions in Shaanxi Province from 2000 to 2020 were different, among which the carbon storage in Yan'an was significantly increased by 18.89 Tg, whereas the carbon storage in Yulin significantly decreased by 3.29 Tg in 20 years. ③ Altitude, precipitation, and temperature became the main factors affecting the spatiotemporal changes in carbon storage in Shaanxi Province from 2020 to 2030. In three of the years between 2025 and 2030, under different scenarios, the carbon stocks under the ecological priority scenario were 1 632.27 Tg and 1 647.43 Tg, respectively. The carbon storage and its growth rate were significantly higher than in the natural development scenario and the cultivated land protection scenario. ④ The proportion of carbon storage increase areas under the ecological priority scenario was high. In the cultivated land protection scenario, the proportion of reduction areas was lower than that of the natural development scenario, and the distribution of carbon storage was the most balanced. At the same time, the southern and northern areas of the Loess Plateau in northern Shaanxi need to focus on the protection of the ecological environment in future development. The research results can, to a certain extent, provide reference for promoting the construction of ecological Shaanxi and formulating carbon neutral strategic planning.

The microplastics in aquatic ecosystems pose a serious threat to ecological security and environmental health, which have received widespread attention. To reveal the response of a water-Vallisneria natans-sediment system to microplastics exposure, the V. natans was exposed to polyethylene microplastics （PE-MPs） with different mass fractions （1%-5%, sediment wet mass fraction）, and the effects of PE-MPs on the physiochemical indicators of water quality, morphological characteristics of submerged plants, physiological characters, antioxidant system, and microbial community structure in sediments were studied respectively. The results showed that the physiochemical properties of the water body were not significantly changed in the PE-MPs treatment group, whereas the plant height, oxidative stress index, and antioxidant system were significantly inhibited. For the plant height, the 1% PE-MPs treatment group height was only 47.44% of that in the control group. Chlorophyll a content was 81.04% of that in the control group, and the activities of catalase （CAT）, malondialdehyde （MDA）, and peroxidase （POD） increased by 233.70%, 117.82%, and 61.62%, respectively. Different mass fractions of PE-MPs had a certain impact on microbial community structure in sediments. The above results are helpful to improve the evaluation system of PE-MPs ecological risk in the water-submerged plant-sediment system.

Ten typical industries in Luohe City were selected for the sampling of organized emissions of volatile organic compounds （VOCs）, and 114 VOCs components of each sample were detected to analyze their source characteristics and effects. The results showed that VOCs emissions of packaging and printing were mainly composed of OVOC （60.9%）. In terms of the industrial coating, aromatic hydrocarbons （42.4%） and OVOC （38.9%） were the main VOCs species. The emissions of the footwear, furniture manufacturing, and paper industries were mainly composed of OVOC （32.3% - 42.6%） and aromatic hydrocarbons （20.7% - 33.7%）, with noticeable halogenated hydrocarbons. Chemical and pharmaceutical industries mainly emitted halogenated hydrocarbons, with the proportions of 59.3% and 46.6%, respectively. The emissions of the brick industry were primarily composed of alkane （62.7%）, and OVOC （48.5%）, and halogenated hydrocarbons （19.7%） were the main contributors to VOCs emissions of the thermal industry. OVOC （48.1%） and alkane （29.4%） were the dominant species for the food manufacturing industry. In the packaging and printing industry, acetone （14.8%）, isopropanol （14.0%）, ethylacetate （11.1%）, and toluene （10.2%） were the characteristic VOCs species. The emissions of industrial coating were dominated by isopropanol （25.6%）, toluene （15.0%）, m/p-xylene （12.4%）, and acetone （7.1%）. In the furniture manufacturing industry, m/p-xylene （15.8%）, followed by hexanal （15.1%）, 1,2-dichloroethane （9.6%）, and acetone （8.4%） were the characteristic VOCs species. The emissions of the footwear industry were dominated by acetone （18.9%）, toluene （18.1%）, methylene chloride （8.0%）, and acetaldehyde （6.8%）. The characteristic species of the chemical industry were methylene chloride （23.9%）, 1,2-dichloroethane （14.7%）, acetone （12.7%）, and trichloromethane （11.1%）, and those for the pharmaceutical industry were bromoethane （36.7%）, acetone （19.2%）, benzene （5.0%）, and vinyl acetate （3.0%）. The emissions of the brick industry were mainly ethane, propane, ethylene, and benzene. Acetone, toluene, acetylene, and acetaldehyde were the primary VOCs species in the paper industry. The emissions of the food manufacturing industry were dominated by acetaldehyde, n-pentane, acrolein, and n-heptane. The emissions of the thermal industry were characterized by acetone, acetaldehyde , benzene, and toluene. Although different industries emitted various characteristic VOCs species, in general, acetone, isopropanol, benzene, toluene, m/p-xylene, ethane, acetaldehyde, and methylene chloride were the main characteristic species in most industries in Luohe. OVOC and aromatic hydrocarbons had higher contributions to ozone generation potential （OFP）, and aromatic hydrocarbons contributed over 80.0% to secondary organic aerosol formation potential （SOAP）. The source reactivity of ozone [SR（O₃）] of the food and furniture manufacturing industries were higher, w

Studying the status and source analysis of heavy metal pollution in farmland in typical mining and processing areas is an important prerequisite for promoting farmland soil ecological restoration and farmland protection in concentrated mining areas. In this study, the heavy metal content of farmland soil around a mining area in southwest China was detected, and the pollution status, distribution law, health risks, and sources of heavy metals were studied by using the land accumulation index method, comprehensive pollution index method, kriging interpolation method, health risk assessment method, and PMF receptor model on the sampling data. The results showed that the mean values of eight heavy metals in farmland soil except Ni exceeded the local soil background values, and the results of the ground accumulation index evaluation showed that Cd and Hg were extremely polluted； Pb and As showed medium pollution-heavy pollution； and Cr, Zn, Ni, and Cu were lightly polluted. In the health risk assessment, oral ingestion was the main exposure route posing a health risk to the human body； the main element that constituted non-carcinogenic health risks was As, and the carcinogenic risks were from As and Cd. PMF model analysis showed that the contribution rate of weathering natural sources of iron-bearing ore was 28.02%, and the main factors were Ca and Fe. The contribution rate of agricultural sources was 3.02%, and the main factors were Pb and As. The contribution rate of industrial and atmospheric deposition composite sources was 33.09%, and the main factor was Hg. The contribution rate of the parent material source was 17.27%, and the main factor was Ca. The contribution rate of mining activities such as mining and smelting was 18.60%, and the main factors were Zn and Cd.

The contents of eight heavy metals （Cr, Ni, Cu, Zn, Cd, Pb, As, and Hg） were determined based on the surface soil samples of sewage irrigation and industrial complex in Kaifeng City. The absolute factor analysis-multiple linear regression （APCS-MLR） model and positive matrix factorization （PMF） model were used to analyze the sources and contribution rates of heavy metals in soil combined with correlation analysis and systematic cluster analysis. The results showed that： ① The average values of ω（Cr）, ω（Ni）, ω（Cu）, ω（Zn）, ω（Cd）, ω（Pb）, ω（As）, and ω（Hg） in the study area were 52.19, 25.00, 42.03, 323.53, 1.79, 53.45, 9.43, and 0.20 mg·kg^-1, respectively, and Cr, Ni, and As are lower than the background values of tidal soil. Cu, Zn, Cd, Pb, and Hg are higher than the background values of the tidal soil. ② There were four sources of the eight heavy metals： natural sources, agricultural sewage irrigation sources, industrial atmospheric sedimentation sources, and transportation sources. Cr and Ni were mainly from natural sources； Cu, Zn, Cd, and Pb were mainly from agricultural sewage irrigation and transportation sources； As was mainly from natural sources and agricultural sewage irrigation； and Hg was mainly from industrial atmospheric sedimentation. ③ The APCS-MLR and PMF source analysis results indicated that industrial and agricultural activities were the main sources of heavy metals in the soil of the study area. The average contribution rates of APCS-MLR in the nine sampling areas of the research area were 76.01% （natural sources and agricultural sewage irrigation sources）, 22.71% （industrial atmospheric sedimentation sources and transportation sources）, and 1.28% （unknown sources）. The average contribution rates of PMF were 59.66% （natural sources and agricultural sewage irrigation sources） and 40.34% （industrial atmospheric sedimentation sources and transportation sources）. The source analysis results of the LZ, XZ, NLT, PT, YLZ, and BC models were basically consistent, and WL was better in the APCS-MLR model, whereas SG and QT were better in the PMF model. The research results can provide a scientific basis for the prevention and control of soil heavy metal pollution and environmental remediation.

To explore the prevalence and source of antibiotic resistant genes （ARGs） and pathogenic antibiotic resistant bacteria （PARB） associated with bioaerosols in wastewater treatment plants （WWTPs）, metagenomic sequencing and assembly were applied to elucidate the antibiotic resistome of bioaerosols and wastewater in WWTPs. The results showed that more subtypes of ARGs and a higher abundance of PARB were found in bioaerosols from WWTPs and downwind than those from upwind. Multidrug and macB were respectively the most dominant type and subtype of ARGs in bioaerosols from WWTPs. In total, 37 types of PARB carried at least two or more ARG types and were characterized by multiple drug resistance. At the fine grid, aerated tank, and sludge dewatering room, wastewater was the main source of bioaerosol ARGs and PARB. A total of 32 PARB were easily aerosolized in at least one wastewater treatment unit, such as Pseudomonas aeruginosa and Escherichia coli. This study will provide theoretical support for the risk assessment and health protection of antibiotic resistant pollution associated with bioaerosols from WWTPs.

Based on the carbon emission accounting method for domestic sewage, combined with the current situation of rural domestic sewage treatment, the carbon emissions of traditional schemes and source separation schemes under the three scenarios of single household, multi-household, and pipeline treatments were calculated. The results showed that the net carbon emissions （calculated as CO₂） of the single household, multi-household, and pipeline treatment traditional schemes were 1.21, 3.37, and 2.69 kg·m^-3, respectively. The net carbon emissions （calculated as CO₂） of the single household, multi-household, and pipeline treatments in source separation schemes were -0.50, -0.04, and -0.54 kg·m^-3, respectively, achieving zero or even negative carbon emissions. The direct and indirect carbon emissions of the source separation scheme were lower than those of the traditional scheme under all three scenarios. The carbon compensation measures in the source separation scheme mainly came from the land use of urine after storage and treatment. By separating blackwater from graywater at the source, the Source Separation Program achieved resource utilization of highly concentrated pollutants in blackwater, reducing emissions while generating significant carbon offsets. Therefore, efforts should be made to promote the separation and treatment of rural domestic sewage sources, improve the utilization rate of rural domestic sewage resources, and achieve green and low-carbon development of rural domestic sewage treatment.