Phosphorus (P) and Arsenic (As) are chemical analogues of the same main group, with similar chemical properties and behaviors. Arsenic has attracted widespread attention due to its diverse forms of occurrence, strong bioaccumulation and high toxicity. It mainly exists in the form of arsenate (As⁵⁺) in soil. Phosphorus is an essential nutrient for plants and an important factor causing soil non-point source pollution and water eutrophication. Phosphorus in soil mainly exists in the form of organic phosphorus, accounting for 40%-95% of the total, with phytic acid being an important component, accounting for 20%-50% of total phosphorus and 50%-80% of organic phosphorus. Phytic acid molecule contains 6 phosphate groups and 12 dissociative protons, which can strongly affect the occurrence forms and bioavailability of arsenic and phosphorus in soil through chelation, displacement, acidification and other effects. Clarifying the impact, process, and mechanism of phytic acid on the transformation and release of arsenic and phosphorus forms in soil is of great significance for effectively controlling arsenic/phosphorus pollution in soil and water bodies. Therefore, this paper reviews the contents, sources and forms of As, P and phytate in soils and sediments, with more emphasis on the effects and mechanisms of phytate on As and P transformation and bioavailability changes. In addition, further researches are proposed. The information helps to provide reference for reducing arsenic and phosphorus pollution in soil and sediment.

Accurate prediction the future patterns of cultivated land and well-facilitated farmland in China is crucial for ensuring food security and improving the quality of cultivated land. In this study, to ensure the stable grain contributions of each province, we assume that the area proportions of cultivated land and well-facilitated farmland for each province in China will remain unchanged in the future. Based on the data of the current areas of cultivated land and well-facilitated farmland in each province, as well as predictions of the national cultivated land area in 2030 and 2050, the national well-facilitated farmland area in 2025, 2030, and 2050, and well-facilitated farmland area in 2025 and 2030 at the provincial level, we used quadratic polynomial fitting by least square method to predict the areas of cultivated land and well-facilitated farmland at both levels from 2025 to 2050. Then, we calculated the indices of the retention rate of cultivated land area and the area proportion of well-facilitated farmland to cultivated land at the provincial level in the future. The results indicate that the retention rate of cultivated land area in China will remain stable at 100% in 2050, with the total cultivated land area keeping at 1.20×10⁸ hm². In 2050, the area of well-facilitated farmland in China will be 1.03×10⁸ hm², which will reach nearly a doubled growth, and the area proportions of well-facilitated farmland to cultivated land will rise from 43.59% in 2020 to 85.89% in 2050. In the seven sub-regions of China, all of the retention rate of cultivated land area will be stable at 100% in 2050. Affected by the trends from stable to slightly declining in the cultivated land proportions, the area proportions of well-facilitated farmland to cultivated land will be more than 90% in the regions of Huang-Huai-Hai, the Middle and Lower Reaches of Yangtze River, the Southeast, and the Qinghai-Tibet in 2050, and the proportions will range from 70% to 90% in the Northeast, the Northwest, and the Southwest regions in the same year. At the provincial level, retention rate of cultivated land area will be higher in northern China such as the Inner Mongolia, Heilongjiang, Liaoning, Jilin, and Shandong, while area proportions of well-facilitated farmland to cultivated land will exhibit higher in southern provinces such as Jiangxi, Zhejiang, Fujian, and Guangdong. Our prediction can provide a scientific basis for future planning in national spatial planning, and can also support the studies on layout of cultivated land and farmland use at the provincial level.

Clarifying water quality tendency and its responses to extreme weather in Xukou Bay of Lake Taihu is critical to water management. Here, 他 the water quality tendency of Xukou Bay from 2016 to 2022 was reported, and its responses to water temperature (WT) and water level (WL) were tested as well. The results show that the water quality of Xukou Bay was relatively stable. Moreover, the total nitrogen (TN), ammonia nitrogen (NH₃-N), total phosphorus (TP), and COD_Mn concentrations decreased gradually. However, the annual average WT increased rapidly, with an average rate of 0.086 ℃·a^-1, presumably threatening the ecological stability in this basin. Redundancy analysis (RDA) confirmed that although WT and WL contributed to less than 5% of total variation of the water quality, the effects caused by WT were significant (P＜0.01). In contrast, WL was failed to explain the changes of water quality. Nevertheless, TN, NH₃-N, COD_Mn, and pH were sensitive to high WT (＞30 ℃), and high WL (＞3.8 m) significantly and affected the concentrations of NH₃-N, TN, TP, and chlorophyll-a. In summary, the ecological environment of Xukou Bay was stable, but high WT and high WL are the main factors interfered the stability. This study provides significant references for water quality management under extreme weather conditions.

Nitrogen pollution is one of the most serious water environmental problems in watershed water pollution control. It is of great theoretical and practical significance to study the characteristics and sources of nitrogen pollution in typical agricultural watersheds in southeast China under the multiple impacts of human activities and climate change. To explore the nitrogen pollution pattern and pollution source of surface water in Jiulong River Watershed, this study carried out multi-point and multi-section in situ observation of surface water in the whole watershed during wet (July) and dry (January) periods of Jiulong River Watershed. Positive Matrix Factorization was used to analyze the sources and contribution rates of nitrogen pollution of surface water under different water seasons. Coupling correlation statistical analysis method was used to clear the key factors of nitrogen pollution of surface water under different water seasons. The results show that the characteristics of nitrogen pollution of surface water in Jiulong River Watershed had obvious water season differentiation. The concentration of TN ranged from 0.72-13.14 mg·L^-1, which was 1.39-10.95 mg·L^-1 in wet season and 0.72-13.14 mg·L^-1 in dry season. NO₃^--N, NH₄⁺-N, NO₂^--N and DON concentrations were higher in wet season than those in dry season, but PN concentration was higher in dry season than that in wet season. NO₃^--N, NH₄⁺-N and DON were the main forms of nitrogen pollution in wet season, and NO₃^--N, DON and PN were the main forms of nitrogen pollution in dry season. PMF model analysis of nitrogen pollution sources in surface water show that agricultural non-point source pollution, domestic sewage, biological residue, microorganisms and mineral particles in the river were the main sources of nitrogen pollution in the watershed during wet season, while agricultural fertilizer pollution, urban industrial sewage discharge and suspended micro-particle of biological residue in the river during the dry season were the main sources of nitrogen pollution in the watershed water. The results of the study can strengthen the understanding that nitrogen pollution of surface water in Jiulong River Watershed is affected by agricultural production activities and runoff changes. The study has also put forward the idea that the source control of nitrogen pollution from agricultural and industrial production and the water season differentiation of nitrogen pollution can be effectively brought into the comprehensive management of nitrogen pollution in Jiulong River Watershed.

Urban aerosol pollution island (UAPI) has significant impacts on human health, urban thermal environment, urban climate, atmospheric radiation transmission, etc. In this paper, the PM_2.5 data of multiple stations in Xi'an from 2016 to 2019 were used to quantitatively calculate the intensity of UAPI, and then the daily and annual variations of PM_2.5 and the intensity of UAPI were analyzed. Additionally, the empirical mode decomposition (EMD) method was employed to analyze the multi-scale characteristics of the long-term time series of UAPI intensity. The results show that there was obvious urban aerosol pollution island effect in Xi'an, and the proportion of UAPI intensity greater than 10 μg/m³ reached 87.63%. In terms of intraday variations, UAPI intensity exhibited a characteristic of being higher at night and lower during the day time; in the annual variations, a "U"-shaped distribution was observed with higher values in winter and spring, and lower values in summer and autumn. On an interannual scale, the UAPI effect showed a gradual weakening trend from 2016 to 2019. The EMD decomposition can effectively reveal the multi-scale characteristics of UAPI intensity, such as IMF2, IMF4, and IMF6, which respectively reflect the characteristics of UAPI intensity with weekly, monthly, and annual cycles. By comparing PM_2.5 time series with UAPI time series, this study can be helpful for the effective elimination of the influence of cross regional transmission pollution and large-scale secondary pollution on the intensity of UAPI.

Forests are important ecological resources in the terrestrial biosphere, and clarifying the long-term forest loss status and its influencing factors is of great significance to the protection of forest resources and the coordinated development of social economy. Based on the Global Forest Change dataset, this paper used ArcGIS spatial analysis technology to analyze the spatial and temporal evolution characteristics of forest loss in the 58 counties in Fujian Province from 2001 to 2019, and used the Geographically and Temporally Weighted Regression Model to explore the main influencing factors of forest loss in the counties, and the spatial and temporal differentiation characteristics. The results show that: (1) During 2001-2019, the rate of forest loss in the counties of Fujian Province showed a basic trend of fluctuating increase, and the cumulative area of forest loss amounted to 1 128 900 hm², and the forest loss situation could be divided into three stages: the stage of significant increase, the stage of decline followed by an increase, and the stage of significant decrease. (2) On the whole, forest loss in counties in Fujian Province had strong positive correlation and spatial clustering characteristics. The spatial correlation of forest loss rate among neighboring regions was significant, and the spatial clustering effect showed a basic trend of low in the northwest and high in the southeast. (3) The urbanization rate, per capita GDP, road mileage, population density and timber production all had certain influences on forest loss in the counties in Fujian Province, but there was obvious spatial and temporal heterogeneity. This study effectively reveals the spatio-temporal dynamic characteristics and influencing factors of forest loss in the counties of Fujian Province, which can provide a theoretical basis for the sustainable management of forest resources.

Currently, the water supply source is complex, and the trend of water quality changes in the receiving reservoir is unclear. To evaluate the ecological health of the water body, it is important to quantify and determine the impact of the phytoplankton community in the water supply on the growth of phytoplankton in the receiving water. In this study, the physic-chemical factors of the water in the supply and receiving reservoirs were measured during different seasons of water transfer period. The changes in cell density and community structure of phytoplankton in the mixed water treatment of different ratios of the supply and receiving water were compared and analyzed by using the algae growth potential test. The results show that the concentrations of nitrogen and phosphorus nutrients in the receiving reservoir did not change significantly during the water transfer period (P＞0.05). The algae growth potential tests conducted in different seasons showed that the peak time of phytoplankton cell density in the treatment groups of summer and winter was 4 days earlier than that in the control group, and the peak density increased with the increase of the mixing ratio. However, the density of phytoplankton in the treatment group in the end of the summer cultivation period (20 days) was lower than that in the control group. Additionally, the actual peak density of phytoplankton in the treatment groups in summer, autumn and winter was 10%, 17%-24%, and 31% lower than the theoretically estimated value, respectively. The changes in community structure in the treatment group show that the absolute dominant species in the receiving reservoir during summer was replaced by the dominant species in the input water, and the relative abundance of the dominant species in autumn and winter increased with the increase of the water mixing ratio, indicating that they were significantly affected by the growth of the dominant species in the supply water. Overall, the difference in nutrient concentrations between the supply and receiving water bodies is the main factor affecting the growth of phytoplankton. Continuous water transfer significantly affects the community structure of phytoplankton in the receiving water body but also reduces the risk of algal blooms to some extent.

There is a need to clarify the relationship between macrobenthic diversity and land use under urban-rural gradient changes. This is crucial for river ecological restoration and protection, as well as regional land use planning. Taking the typical plain area in northern Jiangsu as a case, the relationship between macrobenthic community characteristics and land use structure under different urban-rural gradients was studied by using correlation analysis, principal component analysis and regression analysis. The results reveal that from north to south, as the level of urbanization increased, the area of paddy fields and ponds showed a decreasing trend, while the area of construction land and roads continued to increase. Besides, there was a decreasing trend in the diversity, species richness, abundance, and biomass of macrobenthos. In general, the morphology and structure features of ponds, paddy fields, roads and construction land had a significant impact on macrobenthic diversity. Additionally, the changes including increased regularity in river morphology, greater complexity in construction land morphology, and declined neighborhood landscape diversity in ponds led to the decrease in the diversity of macrobenthic animals. It is recommended to strictly control the scale of construction land, and build an orderly land use pattern. Furthermore, to adopt paddy field cultivation as much as possible in agricultural areas where conditions permit, and foster diverse wetland landscape in suburban, peri-urban and urban areas. The results can provide scientific basis for optimizing land use pattern and establishing integrated regional management systems in river network areas.

This paper studied the degradation performance of fluoxetine by Shewanella oneidensis MR-1 under anaerobic conditions and analyzed the genetic molecular metabolic mechanism from transcriptome. The removal rate of fluoxetine was 93.12% within 12 h, and the degradation rate was 0.94 mg·L^-1·h^-1. The transcriptome sequencing of Shewanella oneidensis MR-1 was performed using the Illumina high-throughput sequencing platform to understand the degradation mechanism of fluoxetine. Profiling and functional analysis of differentially expressed genes for tolerance and fluoxetine degradation using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that envelope stress response membrane protein, ABC transporter, phage shock protein PspA and oxidative stress defense protein played important roles in the tolerance of Shewanella onedensis MR-1 to the environment stress. And the cytochrome C, nitroreductase NfsB and lactate utilization protein played key roles in the degradation and transformation of fluoxetine. This research enhances our understanding of the mechanism of fluoxetine degradation at the transcriptome and suggested a potential application of Shewanella oneidensis MR-1 in environmental remediation.

The aim of the paper is to understand the effects of sodium dodecyl benzene sulfonate (SDBS) on the embryo developmental toxicity and neurotoxicity of Pelteobagrus fulvidraco and to scientifically assess the environmental and ecological risks of SDBS contamination in water. The embryos of Pelteobagrus fulvidraco were exposed to SDBS at 0, 0.2, 0.4, 0.6, and 0.8 mg·L^-1 mass concentration for 4 h after fertilization to observe the cumulative mortality and malformation rate of embryos at hatching, and to explore the potential mechanism of neurotoxicity by detecting the transcript levels of acetylcholinesterase activity and related genes, 5-hydroxytryptamine levels and related genes in brain tissue of 5-day-old larvae. The results show that compared with the control group, the hatching malformation rate of exposed treated Pelteobagrus fulvidraco embryos increased by 4.5-14.5 percentages (P＜0.05) and the mortality rate increased by 7.8-23.4 percentages (P＜0.05). The acetylcholinesterase activity in exposed normal and deformed littermates was significantly reduced by 12.0%-50.5% (P＜0.05) and 15.0%-53.9% (P＜0.05), respectively. And the mRNA expression level of acetylcholinesterase gene decreased in exposed littermates. The 5-hydroxytryptamine content in exposed normal and deformed littermates was significantly reduced by 2.6%-9.9% and 3.0%-11.1% (P＜0.05), respectively. The transcript levels of 5-hydroxytryptamine gene were significantly reduced in normal and deformed fish. The above results indicate that SDBS exposure significantly increased the mortality and malformation rate of Pelteobagrus fulvidraco embryos at hatching. SDBS affected neurotransmission and inhibited neurotransmitter-related gene expression by inhibiting acetylcholinesterase activity and 5-hydroxytryptamine level, thus producing embryo developmental toxic and neurotoxic effects on Pelteobagrus fulvidraco.

Pollutants from land and coastal aquaculture lead to the serious eutrophication of China's coastal and estuary waters. In this study, Salicornia europaea, which can grow in tidal zone, and with highly salty and alkaline-tolerant characteristics, was used to investigate its purification effect on eutrophic seawater through cultivating on floating bed. A circulating water system with flounder culture pond and floating bed purification pond was constructed to simulate the continuously polluted eutrophic seawater environment. By transplanting the seedlings of Salicornia europaea on the floating bed, the changes of 4 nutrient indexes, including ammonia nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), nitrite nitrogen (NO₂^--N) and phosphate (PO₄^3--P) concentrations in different water bodies, as well as the survival and growth of plants, were measured to study the purification effect of Salicornia europaea. The results show that the notable absorption of NH₄⁺-N and NO₂^--N by Salicornia europaea was observed (P＜0.05), and the maximum removal rate was 32.97% for NH₄⁺-N and 35.66% for NO₂^--N under the hydraulic retention time of 12 h, respectively. However, for PO₄^3--P and NO₃^--N, there was some but not significant removal effect. The survival rate of Salicornia europaea on the floating bed was more than 93%, and the plants had obvious growth. Within 25 days, the overall length of plant increased by about 12%, the fresh weight increased by 102%, and the dry weight increased by 83%. The findings of this study suggest that Salicornia europaea can be used as a tool plant for the ecological floating bed to purify the eutrophic seawater near the shore and at the estuary, and provide technical support for the protection of the marine ecological environment.

Due to the different in soil physicochemical properties, the suitable types of organic materials may vary on red soil with different fertility levels. To precisely guide the classification and selection of appropriate organic materials for red soils of different fertility levels, soil samples were collected from peanut and rapeseed intercropping red soils under long-term rotation. Soil samples were taken at depths of 0-20 and ＞20-40 cm, representing high fertility soil and low fertility soil, respectively. Five treatments were established, including no organic carbon (C0), rapeseed straw carbon (OSC), rice straw carbon (RSC), maize straw carbon (MSC), and pig manure carbon (PMC). The carbon input for each organic material treatment was the same. The samples were subjected to continuous incubation in the dark for 90 days, and the different treatments were analyzed for aggregate composition and soil organic carbon (SOC) and total nitrogen (TN) content. The relationship between the C/N ratio of organic material input and the C/N ratio of aggregate components was analyzed. The results indicate that: (1) Compared with the C0 control, all organic material treatments significantly increased the proportion of ＞2 mm aggregates. In high fertility soils, the proportions of ＞2 mm aggregate components increased by 217.89%, 283.97%, 286.63%, and 210.63% with OSC, RSC, MSC, and PMC treatments, respectively. In low fertility soils, the increases for the above treatments were 72.25%, 84.45%, 72.11%, and 46.47%, respectively. (2) After organic material inputs, the organic carbon content of ＞2, ＞0.25-2, ≥0.053-0.25, and ＜0.053 mm aggregate components all significantly increased. However, there were significant differences in the increase of organic carbon content among aggregate components under different organic material treatments in soils with different fertility levels. For example, in ＞2 mm aggregate components, RSC and MSC treatments showed higher values in high fertility soils, while OSC treatment exhibited higher values in low fertility soils. (3) Adding different organic materials significantly increased the TN content of ＞0.25-2 and ＜0.053 mm aggregate components in both high and low fertility soils, with PMC treatment generally showing the highest trend among treatments. (4) Organic material inputs increased the C/N ratio of aggregate components in both high and low fertility soils, but there were obvious differences between them. For example, in ＞0.25-2 mm aggregate components, OSC, RSC, and MSC treatments showed higher values in high fertility soils, while RSC and MSC treatments exhibited higher values in low fertility soils. Moreover, the trend generally showed that the C/N ratio of soil aggregate components under PMC treatment was significantly lower than that under other organic material treatments. (5) In high fertility soils, increasing the C/N ratio of organic materials significantly increased the C/N ratio of ＞2 and ＞0.25-2 mm aggregate components. In low fertility soils, only the C/N ratio of ＞0.25-2 mm aggregate showed a significant positive correlation with the C/N ratio of organic material inputs. Analysis of the slope of the fitted equations reveals that when the C/N ratio of organic material inputs increased by 1 unit, the increase in the C/N ratio of ＞0.25-2 mm aggregate components was significantly smaller in high fertility soils than in low fertility soils. Compared with pig manure, straw-type organic materials showed better promotion effects on aggregate carbon and nitrogen accumulation. It is suggested to accurately adjust the C/N ratio of organic material inputs according to soil fertility levels to effectively improve the C/N ratio of soil aggregate components.

Experiments of bagging in greenhouse were performed to investigate the effect of organic fertiliser, biochar, sepiolite and the mixture of biochar and sepiolite (1∶1) on soil pH and the contents of available Cd and available Pb in heavy metal contaminated soil, and the changes in the cadmium and lead contents of Tetrastigma hemsleyanum roots were analyzed. The results show that the different passivators all increased soil pH in varying degrees, reduced the contents of available Cd and available Pb in soil and reduced the contents of Cd and Pb in Tetrastigma hemsleyanum roots. Compared with the control, the addition of 1% to 5% passivators could increase soil pH value by 0.05 to 1.03, respectively, reduce the contents of available Cd and available Pb in soil by 2.95%-42.46% and 6.21%-55.77%, respectively, and reduce the contents of Cd and Pb in Tetrastigma hemsleyanum roots by 15.61%-48.33% and 8.18%-61.67%, respectively. The addition of 5% of the mixture of biochar and sepiolite had the greatest effect on pH value on the contents of available Cd and available Pb in soil, and on those of Cd and Pb in the Tetrastigma hemsleyanum roots, which indicates that the addition of 5% mixed passivator (the weight ratio of biochar and msepiolite is 1∶1) was the most effective in the passivation remediation of heavy metals in the soil-Tetrastigma hemsleyanum system.

The remediation of Cd contamination in farmland soil is of great significance to the safety of food production. Sedum plumbizincicola is a Cd hyperaccumulator discovered and reported in China. This study explored the characteristics of cadmium accumulation in S. plumbizincicola at different growth periods and its effects on available Cd content in rhizospheric soil. Moderately and lightly Cd contaminated farmland with the same parent material were selected for in-situ phytoremediation experiments, the aboveground biomass and Cd absorption of S. plumbizincicola were analyzed at early branching, branching peak, flowering peak and late flowering growth period, as well as the profiles distribution characteristics of soil pH and available Cd content in rhizospheric soil. The results show that: the biomass, Cd content and the amount of Cd accumulation in aboveground of S. plumbizincicola did not increase with the extension of planting time. The plant height of S. plumbizincicola in lightly Cd contaminated farmland was more than 60 cm at flowering peak period, and its fresh weight of one plant was up to 1.59 kg, and the amount of Cd accumulation in one plant was more than 2.26 mg. The highest Cd content in S. plumbizincicola was found in flowers, and the Cd contents of flowers in moderately and lightly Cd contaminated farmland were 1.60-3.42 times and 1.88-6.53 times of that in other parts, respectively at flowering peak period. There were significant differences in the amount of Cd accumulation in aboveground parts of S. plumbizincicola in moderately and lightly Cd contaminated farmland during the 4 growth periods, and the maximum Cd accumulation was at the peak of branching period and flowering period, respectively. The profile distribution characteristics of soil pH and available Cd content in rhizospheric soil firstly decreased and then increased with the increasing of soil depth and that near the root zone is slightly lower than far from the root zone. The soil pH in moderately Cd contaminated farmland was the lowest at the early branching period, and the soil pH of ＞2-6 cm near the root zone was 4.37-4.43, and the available Cd content was the lowest at the branching peak period, was 0.16-0.31 mg·kg^-1 near the root zone and its coefficient of variation was the lowest (26.5%). The decrease of soil pH is beneficial to the Cd absorption by S. plumbizincicola, and the biomass is the key factor affecting the phytoremediation efficiency of S. plumbizincicola.

Arsenic (As) enters rice roots mainly through the silicon and phosphorus transport channels. Thus, the rational application of silicon and phosphate fertilizers could effectively regulate the uptake and transport of As in rice plants. The effects and molecular mechanism of silicon- or phosphorus-enriched rice seedlings on the As content in brown rice after transplanting to As-contaminated soil were studied. The results show that, in silicon- or phosphorus-enriched seedlings, the total accumulated amounts of silicon or phosphorus in the seedling were increased to 19.6 and 2.3 times that of the control, respectively, without affecting plant growth. Compared with conventionally raised seedlings, the contents of total As, As(Ⅲ), As(Ⅴ) and dimethylated As (DMA) in brown rice of silicon-enriched seedlings were decreased by 31.1%, 32.1%, 58.3%, and 33.5%, respectively. In phosphorus-enriched seedlings, no significant effect was observed on the total As content in brown rice, but the As(Ⅴ) content in brown rice was reduced by 59.2%. The silicon- or phosphorus-enriched seedlings could result in significant increase of the retention of As in the roots of rice plants, and the transfer coefficients between different parts of the rice plant were affected to different degrees. The relative expression levels of As transport-related genes in the roots of silicon- and phosphorus-enriched seedlings were examined. No significant effect was observed on the relative expression of OsLsi1 in silicon-enriched seedlings, but the relative expression level of OsLsi2 was decreased by 26%. The relative expression of OsABCC1 was up-regulated by 203% in silicon-enriched seedlings. The relative expression level of OsPT1 was not significantly affected by the raising of phosphorus-enriched seedlings, but the relative expression levels of OsPT4 and OsPT8 were decreased by 51% and 71%, respectively. The relative expression level of OsABCC1 was up-regulated by 22% in phosphorus-enriched seedlings. In conclusion, the raising of silicon- or phosphorus-enriched seedlings affects the uptake and transport of As in rice plants by regulating the expression of As-related transport genes in the roots, thereby reducing the As content in brown rice. The results provide an important reference for controlling the risk of As contamination in paddy fields.