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Investigating carbon (C), nitrogen (N) and phosphorus (P) contents and ecological stoichiometric characteristics in leaf litter from tropical rainforests is crucial for elucidating nutrient cycling and energy flow in forest ecosystems. In this study, a 60-ha tropical montane rainforest dynamic monitoring plot in Jianfengling, was selected as the research site and 60 subplots were selected for detailed study. Leaf litter was collected monthly throughout 2016, branches of similar height were placed atthe four corners of each sample square to support a nylon cloth (1 m× 1 m) with 1 mm apertures. The collected plant leaves were sorted,placed into envelopes, labelled, and transported to the laboratory and samples from various plant species were identified, resulting in a total of 107 samples collected and analyzed. For the 31 dominant species, the leaf litter had C, N and P contents of 312.71 ± 28.42, 4.95 ± 0.46 and 0.40 ± 0.03 g/kg, respectively. The C:N, C:P and N:P ratios were 63.61 ± 7.50, 790.91 ± 82.30 and 12.49 ± 1.00, respectively, indicating moderate variability. The C, N and P contents exhibited greater variability among the plant groups, indicating significant heterogeneity among the samples. In contrast, the data from the subplots exhibited less variability, highlighting significant homogeneity. Overall, the mean carbon, nitrogen and phosphorus contents in the leaf litter from tropical montane rainforests were lower than those observed at national and global scales. The N:P ratios in leaf litter below 14 indicated that nitrogen limited litter decomposition in Jianfengling. However, no significant correlations were observed between the C, N and P contents and their stoichiometric ratios in leaf litter and those in soil. The above results provide important reference data and scientific basis for the nutrient cycling and energy flow processes, and in the future, we can explore the limiting role and mechanism of nitrogen in the decomposition process of leaf litter. [ABSTRACT FROM AUTHOR]

Investigating carbon (C), nitrogen (N) and phosphorus (P) contents and ecological stoichiometric characteristics in leaf litter from tropical rainforests is crucial for elucidating nutrient cycling and energy flow in forest ecosystems. In this study, a 60-ha tropical montane rainforest dynamic monitoring plot in Jianfengling, was selected as the research site and 60 subplots were selected for detailed study. Leaf litter was collected monthly throughout 2016, branches of similar height were placed atthe four corners of each sample square to support a nylon cloth (1 m x 1 m) with 1 mm apertures. The collected plant leaves were sorted, placed into envelopes, labelled, and transported to the laboratory and samples from various plant species were identified, resulting in a total of 107 samples collected and analyzed. For the 31 dominant species, the leaf litter had C, N and P contents of 312.71 ± 28.42, 4.95 ± 0.46 and 0.40 ± 0.03 g/kg, respectively. The C:N, C:P and N:P ratios were 63.61 ± 7.50, 790.91 ± 82.30 and 12.49 ± 1.00, respectively, indicating moderate variability. The C, N and P contents exhibited greater variability among the plant groups, indicating significant heterogeneity among the samples. In contrast, the data from the subplots exhibited less variability, highlighting significant homogeneity. Overall, the mean carbon, nitrogen and phosphorus contents in the leaf litter from tropical montane rainforests were lower than those observed at national and global scales. The N:P ratios in leaf litter below 14 indicated that nitrogen limited litter decomposition in Jianfengling. However, no significant correlations were observed between the C, N and P contents and their stoichiometric ratios in leaf litter and those in soil. The above results provide important reference data and scientific basis for the nutrient cycling and energy flow processes, and in the future, we can explore the limiting role and mechanism of nitrogen in the decomposition process of leaf litter. [ABSTRACT FROM AUTHOR]

Hydrobiogeochemical processes governing water quantity and quality are highly variable in space and time. Focusing on thirty river locations in Québec, Canada, three water quality hotness indices were used to classify watersheds as contaminant transport hotspots. Concentration and load data for suspended solids (SS), total nitrogen (TN), and total phosphorous (TP) were used to identify transport hotspots, and results were compared across hotness indices with different data requirements. The role of hydroclimatic and physiographic characteristics on the occurrence and temporal persistence of transport hotspots was examined. Results show that the identification of transport hotspots was dependent on both the type of data and the hotness index used. Relationships between temporal and spatial predictors, however, were generally consistent. Annual transport hotspot occurrence was found to be related to temporal characteristics such as the number of dry days, potential evapotranspiration, and snow water equivalent, while hotspot temporal persistence was correlated to landcover characteristics. Stark differences in the identification of SS, TN, and TP transport hotspots were attributed to differences in mobilization processes and provided insights into dominant water and nutrient flowpaths in the studied watersheds. This study highlighted the importance of comparing contaminant dynamics across watersheds even when high-frequency water quality data or discharge data are not available. Characterizing hotspot occurrence and persistence, among hotness indices and water quality parameters, could be useful for watershed managers when identifying problematic watersheds, exploring legacy effects, and establishing a prioritization framework for areas that would benefit from enhanced routine monitoring or targeted mitigation strategies. [ABSTRACT FROM AUTHOR]

Thayer J, Enloe S, Prince C, MacDonald G, Leary J. 2024. Spatial-temporal shifts in submersed aquatic vegetation community structure resulting from a selective herbicide treatment in Lake Sampson, Florida, USA. Lake Reserv Manage. 40:248–263. Submersed aquatic vegetation (SAV) is a major ecological component of Florida's shallow lake systems. Hydrilla (H; Hydrilla verticillata [L.F.] Royle) is a nonnative, invasive SAV dominating many of these lakes and a high management priority in conservation. Lake Sampson is a shallow 776-ha lake in north Florida dominated by hydrilla since the 1980s, with native Illinois pondweed (P; Potamogeton illinoensis Morong) and American eelgrass (V; Vallisneria americana Michx.) historically represented. In March 2021, an in-water treatment of the herbicide florpyrauxifen-benzyl was administered to the littoral zone covering 46% of the lake surface. Five months after treatment (MAT), H infestations were reduced by 99%, recruitment by 69%, and invasions to cohabitating native populations by 90%. Conversely, total combined P populations increased occupancy from 15% to 23%, while V populations exhibited only a slight decrease in occupancy, going from 19% to 18%. By 17 MAT, hydrilla infestations, recruits, and invasions had all increased, while native populations started to retract from earlier gains. Moreover, surveys revealed a significant shift in SAV communities to shallower depths that were immediate 1 month after treatment and sustained 17 months later with the posttreatment reduction of hydrilla exclusively occupying deeper water. Posttreatment changes in water quality were apparent and possibly influential to SAV community dynamics. Although this in-water herbicide treatment exhibited good selectivity and reduced hydrilla competition, unintended side effects in water quality may have impeded the long-term succession of resilient native SAV communities that could compete with the recovery of hydrilla. [ABSTRACT FROM AUTHOR]

Granular activated carbon (GAC) filtration is a commonly used method for advanced wastewater treatment. Filters can be operated continuously or discontinuously, with continuous operation not requiring feed flow interruption for backwashing and circulation (B/C). This study investigated the influence of B/C on the effluent quality of continuous filters. Two continuous GAC filters were operated for 1.5 years, with analysis of dissolved substances and particulate matter in the influent and effluent. The results indicated that various B/C modes had no impact on the removal of dissolved organic carbon and organic micropollutants (OMP), achieving an OMP removal of over 70% after 5,600 treated bed volumes (m3 treated wastewater per m3 GAC). However, it was evident that continuous B/C over 2–4 h resulted in increased turbidity, total suspended solids over 30 mg/L and total phosphorus concentrations of 1.3 mg/L in the filter effluent. Additionally, the study demonstrated that longer and more intensive B/C processes resulted in GAC size degradation with AC concentrations of up to 6.9 mg/L in the filter effluent, along with a change in GAC particle size. Furthermore, the importance of pre-filtration in reducing particulate matter in the filter influent and decreasing hydraulic head loss could be demonstrated. HIGHLIGHTS Operation of two continuous granular activated carbon (GAC) filters.; Different backwashing and circulation (B/C) modes were investigated.; Dissolved substances removal (DOC and micropollutants) showed no dependence on B/C mode.; Intensive and long-lasting B/C resulted in GAC abrasion and increased particulate matter and activated carbon concentration in filter effluent.; Pre-filtration was necessary for filter operation.;

Phosphorus pollution is a major water quality issue impacting the environment and human health. Traditional methods limit the frequency and extent of total phosphorus (TP) measurements across many rivers. However, remote sensing can accurately estimate riverine TP; nevertheless, no large‐scale assessment of riverine TP using remote sensing exists. Large‐scale models using remote sensing can provide a fast and consistent method for TP measurement, important for data generalization and accessing extensive spatial‐temporal change in TP. Our study uses remote sensing and machine learning to estimate the TP in rivers in the contiguous United States (CONUS). Initially, we developed a national scale matchup data set for Landsat detectable rivers (river width >30 m) using in situ TP and surface reflectance. We used in situ data from the Water Quality Portal (WQP), alongside water surface reflectance data from Landsat 5, 7, and 8 spanning from 1984 to 2021. Then, we used this data set to develop a machine learning (ML) model using different preprocessing methods and algorithms. We found that using high‐level vegetation in the clustering approach and over‐sampling or under‐sampling our training data in the sampling approach improved our model estimation accuracy. We compared XGBLinear, XGBTree, Regularized Random Forest (RRF), and K‐Nearest neighbors ML algorithms and selected XGBLinear as the best model with an R2 of 0.604, RMSE of 0.103 mg/L, mean average error of 0.83, and NSE of 0.602. Finally, we identified human footprint, elevation, river area, and soil erosion as the main attributes influencing the accuracy of estimated TP from the ML model. Plain Language Summary: Phosphorus pollution in rivers is a big problem for the environment and humans. Traditional ways of measuring phosphorus levels in rivers are limited and slow. However, remote sensing can help estimate phosphorus levels on a large scale. But, there hasn't been a study using remote sensing to measure phosphorus levels in rivers on a large scale. We studied the potential of remote sensing and machine learning to estimate phosphorus in the United States rivers. First, we collected data from 1984 to 2021, both on‐site phosphorus measurements from the Water Quality Portal and satellite river data from the Landsat archive, and developed our model. We found that using vegetation data and changing our data volume improved our model's accuracy. Likewise, we discovered that river characteristics like human activity level, elevation, river size, and soil erosion influenced how accurately our model could estimate phosphorus levels using remote sensing. Key Points: We created a national‐level in situ total phosphorus and water reflectance matchup data set for rivers within CONUSWe developed a machine learning model to simulate riverine phosphorus using water reflectance data retrieved from LandsatWe identified river‐specific characteristics that influence the model performance on retrieving riverine phosphorus from satellite data [ABSTRACT FROM AUTHOR]

Copyright of Technology of Water Treatment is the property of Technology of Water Treatment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the context of water quality target management, it is necessary to trace the pollution sources that impact the water quality of rivers and lakes. Taking the Huangshui River basin as an example, pollution sources were classified and quantified as point sources and non- point sources. Based on the pollutant flux contribution tracing method, inventory analysis and output coefficient method were used to calculate the inflowing loads and contribution rates of ammonia nitrogen (NH3-N) and total phosphorus (TP) from point sources and non-point sources. By identifying the magnitude of contribution rates, the main types and locations of point sources were identified, and the non-point source pollution hotspots and key pollution source types were identified at the town scale. The results show that sewage treatment plants and industrial sources contribute the most to NH3-N, while large-scale livestock and poultry farming sources contribute the most to TP. Point sources are mainly distributed in the middle reaches of the Huangshui River and the main urban area of Xining. Point sources have a significantly greater impact on pollutant concentrations during the dry season than the rainy season. As for non-point sources, urban domestic sources in certain townships in the Huangshui River Basin are identified as significant contributors to NH3-N at the Bianqiang Village section. Non-point sources from some townships in the middle and upper reaches of the Huangshui River Basin have an important impact on TP at the Bianqiang Village section, with urban domestic sources and agricultural planting sources being important sources of TP. [ABSTRACT FROM AUTHOR]

This study used water quantity and water quality data to calibrate and verify the runoff and total phosphorus（TP）parameters of the SWAT model to better control non-point source phosphorus pollution in the Fengle River basin. It modeled the spatiotemporal distribution characteristics of TP loads in the basin from 2011 to 2021 and analyzed the reduction effects of best management practices （BMPs）on TP output. The results showed that temporally, the basin′s annual average TP output was 77.58 tons, with the highest TP output （141.65 tons）in 2020, which was 4.3 times that of 2019. TP output was concentrated primarily during the flood season from May to October, accounting for 70.1% of the annual output. Sub-basins with a high proportion of farmland had high TP load intensities, with spatial variations closely related to land use. The correlation coefficients for TP load between farmland and forest land during the flood season and non-flood season are 0.924 7 and 0.419 3, respectively. Reduced fertilization, filter strips, and grassed waterways were effective in reducing TP output. The filter strip had the greatest TP reduction effect among individual BMPs. Comprehensive management practices had the greatest TP reduction in the basin, with annual reduction rates ranging from 43.41% to 61.23%. The output of phosphorus pollution in Fengle River basin is jointly affected by precipitation characteristics and land use, and the output of phosphorus can be effectively reduced by reducing fertilization, establishing vegetation filter strips or grassed waterways, and the results provide a theoretical basis and methodology for the relevant regions to control the source of emission reduction. [ABSTRACT FROM AUTHOR]

Floodplains constitute a vital and integrated component of the riverine network ensuring the connectivity and continuity of the river with the upland watershed areas. However, the sediment trapping efficiency of floodplains has not been well investigated. The purpose of this experimental study was to evaluate the functionality of floodplains to act as either sources or sinks for fine sediments and sediment‐bound nutrients (e.g., total phosphorus) during floods of various return periods. Thus, we hypothesized that (i) soil texture, in terms of topsoil erodibility and (ii) the magnitude of the incoming flood, in terms of the applied shear stress, are the two key parameters govern river floodplains' ability to store or release fine sediments and total phosphorus, during major flood conditions. Topsoil erodibility experiments were coupled with site‐specific flood inundation maps to estimate the eroded fine sediment mass and the total phosphorus release rates per unit area per unit time of each flood condition considered. Results suggested that the floodplain soils of the upstream reaches act as net sources, the floodplains of the midstream reaches have a dual functionality; during low magnitude flood events (up to 10‐year return periods), they act as net sinks, while during higher flood events, they act as sources; and the floodplains of the downstream reaches largely act as sinks. This study results are applicable for watershed managers to identify floodplain areas vulnerable to erosion and sources of nutrient pollution. [ABSTRACT FROM AUTHOR]

Nutrient content fluctuation in dairy production slurry is highly influenced by the various treatment processes applied in the Chinese dairy sector. The dynamic measurement of these contents is critical for the practical and efficient field application of slurry subjected to various processes. In the study, a total of 715 slurry samples were collected from 24 intensive dairy farms in Tianjin subjected to three typical treatment processes. Descriptive statistical analysis, principal component analysis, and partial least square regression were used to investigate the variation in total nitrogen (TN) and total phosphorus (TP) contents, spectral characteristics, and the performance of the prediction model of the slurry under the processes, respectively. Results revealed significant differences in both TN and TP contents along with the spectra for the slurry subjected to different treatment processes. All the inter-process models showed poor performance, and the results were worse compared to the intra-process models. Among the intra-process models for TN, the optimally performing models were the Pac fusion model (R2pred = 0.82; RPD = 2.38) and the single model Pa (R2pred = 0.83; RPD = 2.31). Among the intra-process models for TP, the optimum results were seen for Pab (R2pred = 0.77; RPD = 2.07) and Pa (R2pred = 0.79; RPD = 2.30). Taking different treatment processes into consideration is essential to establish flexible models that can be adaptive for diversified scenarios. This would be helpful to improve the tracking monitor measures, efficiently guide the land application of slurry, and support the sustainable development of animal farming and environmental conversation. [ABSTRACT FROM AUTHOR]

Development of environment-friendly and efficient aquaculture effluent treatment system is crucial for sustainable intensification of aquaculture, in the face of the rapidly increasing environmental pressure in the mariculture industry. In this study, mariculture wastewater was treated by the anoxic-anaerobic-oxic biochemical treatment system (A2O system) with traditional activated sludge replaced by nitrifying bacteria, denitrification bacteria and phosphorus accumulating bacteria absorbed on PBS carrier biofilms suitable for saline/brackish water. The results showed that biofilm-enhanced A2O system can effectively remove pollutants from aquaculture wastewater. The removal efficiencies of CODMn, NH4 +-N, TN and TP in A2O system were approximately 86.3%-90.8%, 97.7%-99.5%, 94.6%-95.2% and 97.0%-98.1%. The results further showed that CODMn, NH4 +-N, and TN were mainly removed in anaerobic tank and anoxic tank, while TP was mainly removed in the anoxic tank and oxic tank. The biofilm-enhanced A2O system by adding nitrifying bacteria and phosphorus accumulating bacteria biofilms using PBS as carriers instead of conventional activated sludge could be applied to the treatment of circulating aquaculture wastewater. This study provides a feasible scheme for enhancing the efficiency of A2O system in the treatment of aquaculture tail water, and provides a reference for the immobilization of microorganisms. [ABSTRACT FROM AUTHOR]

Phosphorus is a key indicator for water quality management due to its role in eutrophication. The variety of phosphorus-containing substances necessitates highly sensitive detection of total phosphorus, particularly through automated methods, to ensure water safety. This study involved the independent development of a sensor featuring an automated in situ detection technique. Utilizing potassium persulfate high-temperature oxidation and phosphorus molybdenum blue spectrophotometry, total phosphorus was monitored in situ via sequential injection technology. Additionally, the detection process and reaction conditions of the sensor were optimized, and a temperature compensation algorithm and turbidity correction were applied to mitigate environmental factors. Under optimal conditions, the sensor demonstrated a detection limit of 1.9 µg/L with a range of 6.5–1000 µg/L in seawater, and 1.2 µg/L with a range of 4.1–2000 µg/L in freshwater. The digestion efficiency for five representative phosphorus-containing substances was found to range from 87.3% ± 1.7% to 103.1% ± 0.6%. Notably, the sensor was deployed for in situ operation at a marine experimental station and online at a river monitoring station. With its integration, low power consumption, and high precision, the sensor enabled long-term unattended monitoring, delivering accurate, stable, and reliable results.

The article presents the results of the first geoarchaeological study of the materials of Christian burials identified in the interior of the Middle Zelenchuk temple of the 10th century in the Nizhne-Arkhyz ancient settlement (Republic of Karachay-Cherkessia). The results of microbiomorphic (phytolith) and total phosphorus content analyses allowed us to reveal previously unknown features of the funeral rites of the multicultural and multi-ethnic Christian population of one of the largest cities of the North Caucasus in the Middle Ages. The differences in funerary practices between the 11th and 13th centuries became evident when studying even a small group of funerary complexes in which people of the same social group – representatives of the social elite of Western Alania – were buried. The geoarchaeological study showed an abundance of plant and animal organic matter in the burials. The complex analysis of archaeological materials and data obtained during the microbiomorphic study allowed us to conclude that members of the urban Christian community had several burial traditions: in stone boxes (tombs), in wooden frames, and a mixed ritual when a wooden structure was placed in a stone box. The presence of wooden bark particles in the burials seems to be related not so much to the material from which the burial structures were made as to the presence in the graves of bark or bast objects (bast caskets or boxes, birch bark amulets, toys, etc.). The tradition known from pagan Alanian burials of placing the head of the deceased on a “stone cushion” (more typical for male burials) was preserved in early Christian burials. In one of the four women’s graves studied, the analysis showed the presence of a “hay pillow.” Probably, before the burial, a ritual of washing the deceased was performed, as evidenced by the presence of diatoms and sponge spicules in the samples.

The research results showed that the water quality of Jiulong River Estuary has been improved in the past 10 years, especially the permanganate index, ammonia nitrogen, total phosphorus and petroleum showed a continuous decline from 2016 to 2020, indicating that the water quality of Jiulong River Basin has been significantly improved during the Thirteenth Five-Year Plan period, however, the total nitrogen exceeded the standard seriously, based on the survey data of surface water of Jiulong River estuary for 10 years from 2011 to 2020. The characteristics of seasonal variation are as follows: In 2020, permanganate index, ammonia nitrogen, total nitrogen, inorganic nitrogen and total phosphorus are relatively low in summer and high in winter; and the chemical oxygen demand is relatively low in winter and high in autumn; and the petroleum is relatively low in autumn and high in spring and winter.Based on the comparative analysis of the water quality of monitoring sections of Jiulong River and other major rivers entering the sea in Fujian Province, such as Minjiang River, Jinjiang River, Longjiang River and Mulan River from 2011 to 2020, the water quality of Minjiang River estuary and Jinjiang River estuary is relatively good, and Longjiang River estuary and Mulan River estuary are relatively poor, and Jiulong River estuary is average. It will provides reference for environmental planning and management of Jiulong River.

Soil nutrient availability and their spatial distributions are strongly related to land use and landscape morphology. This study aims to address the knowledge gap regarding the interaction between these factors and the underlying mechanisms. We selected five land uses (grassland with Artemisia gmelinii, woodland with Robinia pseudoacacia, shrubland with Caragana korshinskii and Hippophae rhamnoides, and apple orchard with Malus pumila) and nine slope positions across hillslopes in the Loess Plateau, China, to investigate their combined effects on the contents and stocks of soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP). Parametric and non-parametric statistical tests were conducted to determine the significant differences in the means or the medians of the soil nutrient variables. Results showed that the SOC and TN contents of shrubland with Caragana korshinskii were statistically significantly greater than those of the grassland (p

A method is presented for predicting total phosphorus concentration in soils from Santander de Quilichao, Colombia, using a UV-VIS V-750 Spectrophotometer and machine learning techniques. A total of 152 soil samples, prepared with varying proportions of P2O5 fertilizer and soil, were analyzed, obtaining reflectance spectra in the 200 to 900 nm range with 3501 wavelengths. Additionally, 152 laboratory results of total phosphorus concentration were used to train the prediction model. The spectra were filtered using a Savitzky-Golay filter. Key wavelengths were identified using Variable Importance in Projection - Partial Least Squares (VIP-PLS) and Random Forest (RF), reducing the spectral bands to 1085. Principal Component Analysis (PCA) further reduced data dimensionality. A feedforward artificial neural network was then trained to predict phosphorus concentration. This method is faster than traditional lab tests by leveraging advanced data analysis and machine learning, offering results in less time. While sample preparation remains consistent with standard spectroscopic analysis, the value added by the proposed method lies in its data processing and interpretation. Currently applied to a single soil type, future improvements will include more soil types and other macronutrients, enhancing nutrient management in agriculture. Accurate macronutrient measurements aid in better fertilizer uses planning.• Filtering spectra and determining relevant wavelengths using VIP-PLS and RF.• Dimensionality reduction with PCA.• Training feedforward artificial neural networks.

We developed a rapid method of total phosphorus (TP) determination in fresh water by optimizing the volumes and concentrations of the oxidant (potassium persulfate), reductant (ascorbic acid), and colorant (molybdate + antimony potassium tartrate). Instead of a UV spectrophotometer, as used in the national standard method (GB 11893-89), we used the iMark Microplate Absorbance Reader to measure the absorbance. The principle of TP determination was identical to that of the national standard method as the water sample was digested under a neutral condition and phosphorus was oxidized to orthophosphate and colored to measure absorbance. In the developed method, we adjusted the volumes of the oxidant and reductant to 80 µL and 0.1 g/mL, respectively, and the concentration of the colorant to 31.00 + 0.32 mol/mL. The water samples collected from Lake Taihu in Maoming, Guangdong, China, were used in the experiment. The feasibility and applicability of the developed method were validated by determining TP in freshwater samples. The results showed that the developed method has excellent accuracy and precision compared with the national standard method. In addition, the national standard method was simplified in terms of the digestion and determination of TP, whereby the volume of chemical reagents and the determination time were reduced. The efficiency of TP determination was improved such that the developed method can be used for monitoring water quality to prevent environmental problems. [ABSTRACT FROM AUTHOR]

Nonpoint source pollution (NPSP) has always been the dominant threat to regional waters. Based on empirical models of the revised universal soil loss equation and the phosphorus index, an NPSP risk assessment model denoted as SL-NPSRI was developed. The surface soil pollutant loss was estimated by simulating the rain-runoff topographic process, and the influence of path attenuation was quantified. A case study in the Yellow River Delta and corresponding field surveys of soil pollutants and water quality showed that the established model can be applied to evaluate the spatial heterogeneity of NPSP. NPSP usually occurs during high-intensity rainfall periods and in larger estuaries. Summer rainfall increased pollutant transport into the sea from late July to mid-August and caused estuarine dilution. Higher NPSP risks often correspond to coastal areas with lower vegetation coverage, higher soil erodibility, and higher soil pollutant concentrations. Agricultural NPSP originating from cropland significantly increase the pollutant fluxes. Therefore, area-specific land use management and vegetation coverage improvement, and temporal-specific strategies can be explored for NPSP control during source-transport hydrological processes. This research provides a novel insight for coastal NPSP simulations by comprehensively analyzing the soil erosion process and its associated pollutant loss effects, which can be useful for targeted spatiotemporal solutions. [ABSTRACT FROM AUTHOR]

Total phosphorus (TP, a non-optical sensitivity parameter) has become the primary pollutant in the Yangtze River, the third largest river in the world. It is strongly correlated with turbidity (an optical sensitivity parameter) in rivers. In this study, we constructed a turbidity-mediated TP retrieval model using Sentinel-2 observations and field-measured daily-scale water quality. The model was successfully applied to estimate the temporal and spatial variations of TP concentration in the middle reaches of the Yangtze River (MYR) from 2020 to 2023. Our results show: (1) the model accuracy of TP concentration retrieval with turbidity is significantly higher (R2 = 0.71, MAPE = 15.78%) than that for the model without turbidity (R2 = 0.62, MAPE = 16.38%); (2) the turbidity and TP concentration in the MYR is higher in summer and autumn than in winter and spring; and (3) the turbidity and total phosphorus (TP) concentration of the Yangtze River showed a significant increase after passing through Dongting Lake (p < 0.05). [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xinjiang University (Natural Science Edition) is the property of Xinjiang University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phosphorous (P) is an essential element for plant growth and development, and its scarcity is a severe crop output constraint. Determination of total P in soil and fertilizers is very important in agriculture as the amount of P is related to crop production. Rock phosphate (RP) is an excellent natural source of P widely used for P fertilizer production. The objective of this study was to compare two different digestion methods, microwave digestion and hot plate digestion, and to evaluate the performance of two analytical techniques, inductively coupled plasma mass spectroscopy (ICP-MS) and colorimetry (UV-VIS), for measuring total P in imported RP samples. The validation of microwave digestion followed by analysis in ICP-MS was performed. Phosphorus has detection and quantification limits of 1 mg L−1 and 5 mg L−1 respectively through ICP-MS analysis. Average P recovery was found 92.12–96.53%. Precision in terms of intra-day (%RSDR = 2.76–5.98 evaluated using ICP-MS) and inter-day (%RSDr = 2.92–6.75) were found to be within the acceptable range (20%), indicating consistency of the proposed method to determine total-P over traditional UV-VIS method. The combination of microwave-assisted digestion and ICP-MS offers superior efficiency in determining both phosphorus (P) and heavy metals, including aluminum, iron, zinc, cadmium, strontium, manganese and chromium, in RP samples. Hence, this method is novel and rapid and is used for the quantification of total P in different RP samples for quality control. [ABSTRACT FROM AUTHOR]

[Objective) The present paper aimed to explore the relationship between soil physical and chemical factors and microorganisms in Chinese Cordyceps producing areas of Qinghai province, in order to provide reference for the further improvement of artificial Chinese Cordyceps culture matrix. [Method) Hualong Hui Nationality Autonomous county (HL) in Haidong city, Henan Mongol Autonomous county (HN) in Huangnan Tibetan Autonomous Prefecture, Xinghai county(XH) in Hainan Tibetan Autonomous Prefecture, Dari county (DR) in Golog Tibetan Autonomous Prefecture, Maqin county (MQ) in Golog Tibetan Autonomous Prefecture, Zaduo county (ZD) in Yushu Tibetan Autonomous Prefecture, and Guoqing Ranch (GQ) in Yushu Tibetan Autonomous Prefecture were selected as the experimental plots. Potassi- um dichromate-external heating method, kjeldahl nitrogen determination method, alkaline fusion method, acid dissolution method, o-phenanth- roline colourimetric method, flame atomic absorption spectrophotometry, flame photometric method and potassium periodate colourimetric method were used for the determination of the physical and chemical properties of the soil. Microbial content and species were determined u- sing high-throughput sequencing technology. (Result) Most of the soil physical and chemical factors were not significantly different in different producing areas. The composition of microorganisms in each producing area was similar, and the diversity and richness of fungal dominant communities were different among different producing areas. In the bacterial community, Proteobacteria, Actinobacteria and Acidobacteria were the dominant bacterial phyla, and Subgroup_6, Pseudomonas and RB41 were the dominant bacterial genera; In the fungal community, Ba- sidiomycota, Ascomycota and Mortierellomycota were the dominant fungal phyla, and Hygrocybe, Sebacina and Mortierella were the dominant fungal genera. Redundancy analysis was performed on soil physical and chemical properties and microbial communities in the production are- a. Results showed that Actinobacteria highly significant positive correlation (P<0.01) with soil pH and elemental iron (Fe), while RB41, Nitrospira and Subgroup_6 significant negative correlation (P<0.05) with elemental total potassium (TK), total phosphorus (TP), organic matter (OM), manganese (Mn) and sodium (Na); The fungus Mortierellomycota was positively correlated with soil total phosphorus (TP), Ascomycota was negatively correlated with soil total potassium (TK), total nitrogen (TN) and organic matter (OM), and soil pH was posi- tively correlated with the dominant fungal community at most genus levels. [Conclusion] The study further confirmed that there is significant correlation between soil physical and chemical factors and microorganisms. Among them, soil pH, organic matter (OM), sodium (Na) and i- ron (Fe) are significantly correlated with most microbial communities in Chinese Cordyceps producing areas (P<0.05), which may be the key driving factors affecting microbial community structure. [ABSTRACT FROM AUTHOR]

Flood events, whose number and intensity are predicted to increase in the Mediterranean region, are difficult to monitor. This causes the number of observations of suspended sediment and total phosphorus concentration (|SS| and |TP|, respectively) during their occurrence to be still scarce. Non-perennial or temporary water bodies, which react more promptly to rainfall events, represent ideal natural observatories. In this study, observations of streamflow, |SS| and |TP|, carried out during some flood events, in the Celone river basin, a temporary river located in south-eastern Italy, are presented. The research examined the correlations between flows, concentrations and loads of sediment and phosphorus and investigated factors that influence sediment and phosphorous dynamics in the river basin. The results show no relationship between the time of the year and the precipitation quantity of each event. The high coefficient of determination of the |SS|–|TP| correlations (R2 = 0.67 on average) proves the importance of soil erosive processes in the delivery of phosphorus to the river. More than 73% of the total suspended sediment load and 83% of total phosphorus load in the period 2010–2011 were transported during the 11 monitored events. In addition to the discharge, |SS| and |TP| also depend on numerous other factors related to land management, such as soil cover and fertilizations. The study, thanks to the improved understanding of the mechanisms governing sediment and phosphorus losses, represents a useful contribution for river basin authorities who have to draw up management plans aimed at preventing eutrophication phenomena and soil fertility reduction. [ABSTRACT FROM AUTHOR]

Phosphorus, an essential rare element in aquatic ecosystems, plays a key role in maintaining ecosystem balance. However, excess phosphorus leads to eutrophication and algal proliferation. To prevent eutrophication, the pretreatment and measuring of the concentration of total phosphorus (TP) is crucial. Compared to conventional TP pretreatment equipment (autoclave), a lab-on-a-chip detection device fabricated using micro-electromechanical system technology and titania (TiO2) as a photocatalyst is more convenient, efficient, and cost-effective. However, the wide bandgap of TiO2 (3.2 eV) limits photocatalytic activity. To address this problem, this paper describes the preparation of a TiO2/Au nanocomposite film using electron-beam evaporation and atomic-layer deposition, based on the introduction of gold film and TiO2 to a quartz substrate. The photocatalytic degradation properties of TiO2/Au nanocomposite films with thicknesses of 1, 2, 3, and 4 nm were assessed using rhodamine B as a pollutant. The experimental results demonstrate that the deposition of gold films with different thicknesses can enhance photocatalytic degradation efficiency through synergetic reactions in the charge separation process on the surface. The optimal photocatalytic efficiency is achieved when the deposition thickness is 2 nm, and it decreases with further increase in the thickness. When the photocatalytic reaction time is 15 min, the lab-on-a-chip (LOC) device with a 2-nm-thick gold layer and autoclave exhibits a similar TP pretreatment performance. Therefore, the proposed LOC device based on photocatalytic technology can address the limitations of conventional autoclave equipment, such as large volumes, long processing times, and high costs, thereby satisfying the growing demand for on-site evaluation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Non-point source pollution (NPSP) significantly affects regional water environments worldwide. Identifying critical source areas (CSAs) and implementing best management practices (BMPs) are essential to prevent and control NPSP. This study used the Soil and Water Assessment Tool model to simulate and evaluate the characteristics of NPSP in the Gongjiang Watershed, a typical, hilly mountainous area in Southern China. The study identified CSAs of NPSP using total nitrogen (TN), total phosphorus (TP), water quality level, and population density factors. The reduction effect of different BMPs on the NPSP load was evaluated, and the cost-effectiveness (CE) of various BMPs was evaluated for the control of NPSP in the watershed. The interannual variation in NPSP load was high from 2013 to 2018, with the largest pollution load in 2016 (wet year) and the smallest in 2018 (dry year). The pollution load fluctuated throughout the year and was related to fertilization and precipitation runoff. The spatial heterogeneity of NPSP was large, with TN and TP losses showing a spatial pattern of high in the south, low in the north, and highest in the center. The CSAs of the NPSP covered 1566.66 km2, representing 9.77 % of the total watershed area. However, TN and TP loads accounted for 19.39 % and 23.53 % of total watershed production. The order of effectiveness of individual management measures in reducing TN was stubble coverage (SC) > vegetative buffer strips (VBS) > terrace engineering (TE) > grassed waterways (GW) > 20 % fertilizer reduction (FR20) > 10 % fertilizer reduction (FR10). The order of effectiveness of TP reduction was SC > VBS > TE > FR20 > GW > FR10. Combined management measures were much more effective in reducing TN and TP than individual measures, with an average increase in TN and TP reduction of 20.59 % and 25.23 %, respectively. Based on the results of the CE evaluation of BMPs, a combination of FR20, GW, and VBS was more effective than individual measures. We suggest a combination of FR20, GW, and VBS measures for effective NPSP prevention and control in Southern China’s typical, hilly mountainous areas.

The Soil and Water Assessment Tool (SWAT) was used to assess total phosphorus concentrations (TOT-P) and fluxes (TOT_P) in the Paraopeba River basin, located in the state of Minas Gerais, Brazil, following the collapse of tailings dam B1 in Brumadinho. The model was calibrated and validated for periods before (2000–2018) and after (2019–2021) the collapse of Brumadinho dam in 25 January 2019, with great accuracy measured by various performance indicators (e.g., R2 ≈ 0.8). The flow of phosphorus-containing sludge from the iron-ore tailings explored in the Córrego do Feijão Mine of Vale, SA, and released after the B1 dam break has impacted the Paraopeba River water through large increments in the TOT-P near the dam site (60–100%, with pre-rupture values varying between 0.06 and 0.1 mg/L). But other major sources were flagged, namely urban sources from the Betim region that raised TOT-P to ≈ 0.9 mg/L periodically during the entire simulation period. The study also revealed controls of TOT-P concentration in the basin, namely the coverage by forests that lowered down the TOT-P at 0.5–0.8 μg/L.km2. The lowering rate was, however, dependent on the occupation by argisols. As per the simulation results, the larger the percentage of argisols in a region the larger the TOT-P will be in the surrounding water courses, meaning that the argisols are prone to erosion and phosphorus leaching. A cluster analysis of input (e.g., terrain slope, soil type) and output (e.g., runoff) variables from the SWAT allowed relating TOT-P with surface- and TOT_P with underground-dominant hydrological processes, respectively runoff and groundwater flow, linking them to specific environmental variables such as argisols and steep slopes in the first case and latosols and smooth landscapes in the second case. The management implications retrieved from this holistic assessment were discussed. Finally, the TOT-P were checked against Brazilian environmental standards. In that regard, the concentration of total phosphorus was compared to limits established in Resolution 454/2012 of the National Environmental Council – CONAMA. Some sub-basins exhibited levels above the legal threshold, and the contamination was viewed as systemic requiring immediate action (e.g., implementation of sewage treatment and best management practices in agriculture), as well as monitoring in the spatial and temporal frames. The existence of extreme rainfall events in the basin was the main cause of SWAT model inaccuracies, namely of overestimated TOT-P.

The Cihampelas River is one of river that crosses the Regency and City of Bandung, West Java, with a length of 8.5 km. This study aims to assess the water quality status of Cihampelas River based on the STORET method and Pollution Index. The research was conducted at four stations based on the level of anthropogenic activity from July to September 2016. Measurements of the physical and chemical parameters of the waters were carried out five times at two-week intervals. Water quality status was assessed using the STORET method and Pollution Index based on the parameters TDS, TSS, pH, DO, BOD, COD, nitrate, nitrite, ammonia, and total phosphorus (TP). Using the STORET method, shows a score of -20 to -46 in the category of moderately to severely polluted waters. Based on the Pollution Index method, the waters of the Cihampelas River show lightly to severely polluted conditions with a score of 1.14 to 44.66. The water quality status of the Cihampelas River shows a decreasing trend from the upstream to the downstream.

Copyright of Journal of Fuzhou University is the property of Journal of Fuzhou University, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Elevated total phosphorus (TP) leads to water eutrophication, affecting aquatic life and ecosystems. Effective control of phosphorus concentration in rivers is vital. Detecting TP and other nutrients is essential for evaluating river health. Establishing real-time TP prediction is key for studying eutrophication and blooms. In this study, we compared the prediction models combined with two different feature selection tools, Pearson and distance correlation coefficient, and evaluated them with four evaluation indicators. It was determined that the assessment outcomes of the distance correlation coefficient yielded heightened precision. Notably, the random forest validation contributed to an impressive 8.3% enhancement in the performance R2 of the model, and the utilization of BP neural network validation resulted in an improvement of 2.7% in the model's performance. A real-time TP prediction model using distance correlation coefficient was eventually created, which reaches an accuracy up to 82.6%. The final model was applied to field data, revealing elevated TP levels downstream of Dongjiang River in China due to high population density and numerous factories. Additionally, the results indicated that the distance correlation coefficient outperformed the Pearson correlation coefficient in predicting the total phosphorus in Dongjiang River. Our findings suggest that combining distance correlation coefficients with machine learning holds promise for more accurate water quality prediction models. These findings establish a foundation for enhancing the efficacy of the water quality prediction model. [ABSTRACT FROM AUTHOR]

The apparent digestibility of dry matter (DM), crude protein (CP), amino acid (AA), crude lipid (CL) and total phosphorus (TP) of CAP was determined for black sea bream (Acanthopagrus schlegelii) and Jian carp (Cyprinus carpio var. Jian) in this study. The test feed consisted of 70% basal feed and 30% CAP containing 0.1% yttrium trioxide as an inert marker. Three hundred and sixty black sea bream with an average body weight of (6.03±0.09) g were divided into 2 groups with 6 replicates per group and 30 fish per replicate. One control group was fed a basal diet, while the experiment group was fed an experimental diet. One hundred and eighty Jian carp with an average body weight of (45.00±0.50) g were divided into 2 groups with 3 replicates per group and 30 fish per replicate. One control group was fed a basal diet, while the experiment group was fed an experimental diet. The results showed as follows: the apparent digestibility of DM, CP, AA, CL and TP of CAP for black sea bream were 99.89%, 100%, 95.16%-100%, 88.60% and 100%. The apparent digestibility of DM, CP, AA, CL and TP of CAP for Jian carp were 78.68%, 95.00%, 96.12%-100%, 52.26% and 100%. On the whole, apparent digestibility of crude protein and amino acids of CAP was at a high level. The results of this study indicate that CAP is a good protein source for black sea bream and Jian carp. [ABSTRACT FROM AUTHOR]

Primary production in freshwater ecosystems is largely a function of light and nutrient availability, both of which have been changing in many lakes and reservoirs in response to anthropogenic pressures. Recent studies focusing on natural lakes have found a hump-shaped response of primary production (sometimes measured as chlorophyll-a) to dissolved organic matter (DOM, measured as dissolved organic carbon, DOC), which has both light-absorbing chromophoric properties and DOM-bound nutrients. We used the United States National Lakes Assessment dataset to integrate reservoirs into this paradigm in comparison with natural lakes and assessed the relative differences in the predicted response's model structure, regression parameter values, and drivers of the chlorophyll-a residuals. We found that chlorophyll-a in reservoirs exhibited a hump-shaped response to DOC, while natural lakes from this dataset were better fit with a linear response, differing from previous studies focused on boreal lakes. Despite this, reservoirs had a greater maximum chlorophyll-a response compared to natural lakes in this study (45.5 versus 33.8 μg L−1), which occurred at a lower DOC concentration threshold (18.3 versus 26.4 mg L−1) when compared using quadratic models. Reservoirs had lower median light:nutrient values compared to natural lakes, and greater median surface area and total phosphorus (TP), that can all influence the light environment and the peak chlorophyll-a responses. In both reservoirs and natural lakes, chlorophyll-a residuals were most strongly influenced by TP, where TP < 25–30 µg L−1 suppressed chlorophyll-a residuals and higher TP amplified them. Light:nutrient values were somewhat important predictors, and patterns with chlorophyll-a residuals supported previous work showing low light:nutrient values amplified chlorophyll-a responses and higher values suppressed them. Quantifying the shape of the response of primary production to DOM quantity and quality as well as the drivers of the residuals, namely TP for lakes and reservoirs in this dataset, will be important for understanding the effects that changes in water quality may have on primary production and freshwater ecosystem processes. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Management practices, such as tillage and cropping diversification, influence soil phosphorus (P) dynamics. The aim was to evaluate the long-term effect of tillage systems (no tillage, NT; vertical tillage, VT; conventional tillage, CT) on total (TP) and extractable (Pe) soil P distribution under different crop sequences (corn-wheat/soybean, C-W/S; wheat/soybean, W/S; corn-corn, C-C; soybean-soybean, S-S). TP and Pe were measured up to 50 cm deep. The TP distribution was associated to soil organic carbon (SOC) (r = .89, p < .01) and tend to increase near soil surface under NT as compared with CT and VT. The Pe was sensitive to the crop residues pattern of accumulation and their quality in the topsoil. Crop sequences that included corn had lower Pe concentration under NT. Conversely, in W/S, Pe concentration was lower under VT with no differences between NT and CT and, in S-S sequence, there were no differences in Pe concentration. However, under NT the increase in the above-ground biomass in sequences without corn (p < .001) increased Pe concentration in 0-5 cm layer, while the opposite occurs in sequences with corn (p < .06). In S-S under NT, the low crop residue input (1.6 Mg of dry matter ha-1) and the high Pe concentration in 0-5 cm layer (40 mg kg-1) might increase the risk of P loss to adjacent ecosystems. Intensified sequences presented more negative P balances than corn/soybean monoculture. This study demonstrates that it's necessary to develop management strategies that improve P supply in synchrony with the crop demand and decrease P loss, while keeping productivity. [ABSTRACT FROM AUTHOR]

W ith the fast growth of human population, socio-economic development and resource exploitation, significant alterations have unfolded within the Poyang Lake ecosystem, thrusting environmental concerns to the forefront. Presently, total Phosphorus levels in the Poyang Lake region surpass established standards, and this concentration continues to surge, bearing witness to the progressive deterioration of the lacustrine biosphere. Designated as a priority demonstration area for national ecological civilization construction and Yangtze River protection and restoration, phosphorus pollution in the Poyang Lake Basin has emerged as a critical and urgent challenge in Jiangxi Province s management of its aquatic ecological environment. Based on the technological method of watershed zoning in the pollution source census, it presents the estimation of the total phosphorus pollution load and the quantitative analysis of phosphorus pollution sources entering the lake. The results show that the total phosphorus pollution load entering Poyang Lake in 2021 reached 14 900 tons, with the primary pollution originating from the land-based input, accounting for 87.73% of its contribution ; in order of contributing weight, the sources of pollution within the lake primarily arose from endogenous releases (5.52%) and soil erosion (4.60%). Our analysis ranks the pollution sources in descending order of contribution weight as follows: Livestock farming (48.63%) > Urban living (20.01%) > Cultivation (9.71%) > Aquaculture (7.37%) > Endogenous r elease (5.52%) > Soil erosion (4.6%) > Industrial enterprises (1.12%) > Rural domestic (0.89%) > Migratory bird droppings (0.46%) > Tourism (0.12%).Notably, livestock farming emerges as the primary contributor to agricultural surface contamination concerning the total phosphorus indicator. Regarding spatial distribution, high-contributing watersheds of total phosphorus load are primarily concentrated in the Ganjiang River Gathering Area and the Binhu Area, with the contribution proportion of 50.67% and 25.92%, respectively, and concentrated production of total phosphorus in the catchment areas of the Fu River and Xinjiang River, with a contribution of 7.64% and 8.34%, the remaining catchment areas generated load into the lake with relatively low intensity, accounting for contributions totaling 7.39%. Moreover, a similar contributing structure of pollution sources in each sub-region is mainly presented as agricultural sources as the main source, with urban sources as a secondary source. Based on the research findings, it is evidenced that the sources of total phosphorus pollution in Poyang Lake exhibit spatial variability. However, the principal control sources for total phosphorus in the lake show similarities across different regions. To effectively address these concerns and enhance the overall ecological well-being of the Poyang Lake Basin, this paper strongly recommends prioritizing the control of high-contributing watersheds, such as the Binhu District and the Ganjiang Watershed. Mitigating phosphorus pollution effectively would require tailored prevention and reduction strategies, especially focusing on agricultural and urban living. Initiatives such as relocating livestock farming to areas with large environmental capacity, emissions reduction measures, and eco-friendly enrichment. Implementing these measures holds the promise of alleviating the issue of total phosphorus pollution and ensuring the sustainable development of Poyang Lake and the stability of its hydro-ecosystem. [ABSTRACT FROM AUTHOR]

Samples of water and bottom sediments of Lake Ladoga, collected in 2021, were studied to determine the concentrations of mineral and total phosphorus as well as ammonium ions. This study was prompted by the significance of Lake Ladoga as a crucial fisheries resource and a vital water supply source. Additionally, being situated in an economically developed region of Russia, the lake is subject to substantial influences from nearby settlements and enterprises. Throughout the research, samples were taken at 23 stations from two or three horizons, depending on the station's depth. The findings revealed that areas of the lake experiencing intense anthropogenic impact, such as Volkhov Bay, near Priozersk, and the mouth of the Burnaya River, exhibited higher values of the investigated parameters. Furthermore, the study identified a correlation between the hydrological features of the lake and the content of phosphorus and nitrogen compounds, indicating that certain biogens reach the central areas of Lake Ladoga, which are distant from direct anthropogenic influence. The study concluded that, on the whole, phosphorus concentrations in Ladoga's waters are at the mesotrophic level, consistent with recent trends. The concentrations of ammonium nitrogen showed no fundamental changes compared to previous years of observations. The accumulation of phosphorus and nitrogen compounds in soils is influenced by both their concentrations in the overlying water layers and the inherent properties of the soils themselves. [ABSTRACT FROM AUTHOR]

The water quality of Nanliujiang River basin, which is an important river entering the sea in the south of Guangxi, has a very important impact on the ecological environment around the surrounding areas of rivers and even the entire Beibu Gulf. Based on measured data, this study analyzed the pollution characteristics that affect the spatio-temporal distribution of the main water quality indicators( i. e., ammonia nitrogen and total phosphorus) in the Nanliujiang River basin. Statistical analysis shows that the total phosphorus is the limiting indicator leading to unqualified water quality, and the primary pollution source is the pollution of livestock and poultry breeding. Meanwhile, the pollution load of pollutants from livestock and poultry breeding sources in Bobai County was much higher than that in other administrative regions. The results of correlation analysis between livestock and poultry production and tributary water quality show that the livestock and poultry activities in Bobai County directly affect the concentration of ammonia nitrogen and total phosphorus in the tributaries of the Nanliujiang River basin. And in addition, the impact of free-range farming activities was greater than that of large-scale farming activities. After the prevention and control of livestock breeding pollution has been promoted, the water quality of Nanliujiang River basin has obviously improved. At the same time, the key areas that need to be focused on and strenghthened in the future are in Bobai County which is a key breeding area in Nanliujiang River basin, with the key tributaries including Xiaobai River, Wudou River, Shuiming River, Yashan River, Zhoucun River, Heshui River, Chunshi River, Dongping River, etc. [ABSTRACT FROM AUTHOR]

Low floodplain wetlands such as the Western Everglades in South Florida are vulnerable to extreme weather events, and their water quality and ecosystem functions vary greatly depending on changes in water levels and discharges. The future (i.e., the mid and late 21st century) climate is projected to result in increased frequency and magnitude of extreme events, which could negatively affect the hydroecological function of the wetlands. Wetland management practices have commonly been implemented to protect wetlands and their functions, but it is not clear whether the current management practices can still be effective in projected climate change scenarios. The main goal of this study was to evaluate the impacts of climate change on the runoff and total phosphorus (TP) of natural (L28 Gap) and managed (L28) wetland watersheds in the Western Everglades. For the assessment, we employed future climate projections made using 29 general circulation models (GCMs) and the Watershed Assessment Model (WAM), a watershed loading model. The WAM was calibrated and validated for the baseline period (2000–2014), and the bias‐corrected climate projections were incorporated into the model to project the runoff discharge and TP loads for the near‐future (2030–2044) and far‐future (2070–2084) periods in two carbon emission scenarios. The modeling results show that the natural wetland watershed would be more vulnerable to projected climate change than the managed wetland watershed. The impact of projected climate change scenarios on daily runoff and TP loads was modulated by water control facilities and practices in the managed watershed, highlighting the significance of watershed management practices for improved water quality under projected climate change. This study demonstrates how the local natural and managed wetland watersheds distinctly respond to the global‐scale changes and emphasizes the role of water management practices in wetland basins, which are expected to help develop effective climate change adaptation plans for improved sustainability of wetland systems. [ABSTRACT FROM AUTHOR]

The Yeşilırmak basin, with an area of 36.114 km², is Türkiye's fifth-greatest area for precipitation. The primary sources of pollution in the basin are population increase, unplanned urbanization, industrial and animal waste, usage of fertilizers and pesticides. In this study, five lakes with high altitude, small surface area, and deep characteristics in the Yeşilırmak Basin (Boraboy, Büyük, Dipsiz, Düden, and Zinav Lake) were assessed by using the phytoplankton indices (PTI and Q) and trophic status index (TSI). Phytoplankton and water samples were collected (April, July, and September 2018), and 85 species were identified. Total phosphorus, total nitrogen, chlorophyll a, and Secchi depth parameters were used to estimate the trophic status of the lakes. Linear regression analysis was performed separately for PTI and Q indices with total phosphorus, the limiting element in lakes. As a result, the Q index correlated with total phosphorus higher (r²=0.75) than the PTI index (p<0.05). The ecological quality statuses produced by the Q index were comparable to the TSI index. Considering the results collectively, the status of Boraboy Lake was assessed as "good/oligotrophic", Büyük Lake as "moderate/oligotrophic", Düden and Zinav Lakes as "moderate/mesotrophic", and Dipsiz Lake as "moderate/eutrophic" in terms of phytoplankton composition and trophic status. As a result, while Boraboy and Büyük Lakes' quality should be maintained, steps should be taken to improve the quality of the Dipsiz, Düden, and Zinav Lakes. [ABSTRACT FROM AUTHOR]

Magnesium, aluminum, and iron electrode were common anodes in electrocoagulation (EC), but there were few studies comparing the influence of operating parameters on the reaction and the effects of these three different anodes in removing total phosphorus (TP) in cattle farm wastewater (CFW). This study used these three different electrodes as the anode of the electrocoagulation method. The operating parameters such as electrode distance (ED), initial pH, and voltage were examined by the Taguchi method and single-factor method. The result of Taguchi analysis shows that voltage has a significant impact on TP removal of magnesium (Mg) and aluminum anode (Al), and ED has a significant impact on TP removal of magnesium and iron anode (Fe). Among the three operating parameters, the first in the order of the impact on the reaction was ED because ED has the greatest influence on the dissolution of the anode. The result of single-factor analysis shows that the optimum conditions of Mg were ED = 3 cm, voltage = 5 V, pH = 7, Al were ED = 3 cm, voltage = 5 V, pH = 5, and Fe were ED = 3 cm, voltage = 5 V, and pH = 7. For Mg and Fe, the voltage and reaction results follow the second-order reaction kinetics, and Al is the first-order reaction kinetics. Through comparison of the three anodes, it was found that Al worked best in actual CFW. It was noted that the conditions obtained by the single-factor method were more economical in the treatment of actual CFW. This work could provide reference for determining the extent of the influence of operating parameters when other contaminants are removed, and provide reference for comparing the other anodes in EC. [ABSTRACT FROM AUTHOR]

Potato starch wastewater, a byproduct of potato processing, is an escalating environmental concern due to its high concentrations of COD (chemical oxygen demand), ammonia nitrogen, and total phosphorus (TP). Addressing this challenge, this research introduced a novel method combining chitosan-modified biochar film (CBC) adsorption with subsequent ultrafiltration. SEM (scanning electron microscope), FTIR (Fourier transform infrared spectral), XRD (X-ray diffractometer), and BET (specific surface area) analyses validated CBC's enhanced surface characteristics, confirming successful chitosan (CS) film impregnation. CBC exhibited superior adsorption capacities, especially 40%wt-CBC, optimizing COD removal at 79.8%, ammonia nitrogen at 93.3%, and TP at 91.2%. Kinetic studies associated the adsorption process with a pseudo-second-order model, highlighting chemical adsorption. Additionally, the Langmuir isotherm model suggested monolayer adsorption with no inter-adsorbate interactions. The treated effluent, post adsorption, was directed through an ultrafiltration membrane, ensuring water quality suitable for reuse. This integrative treatment not only offers an effective solution for potato starch wastewater management but also underscores the potential for sustainable water resource recovery in the food processing sector. [ABSTRACT FROM AUTHOR]

Development of environment-friendly and efficient aquaculture effluent treatment system is crucial for sustainable intensification of aquaculture, in the face of the rapidly increasing environmental pressure in the mariculture industry. In this study, mariculture wastewater was treated by the anoxic-anaerobic-oxic biochemical treatment system (A2O system) with traditional activated sludge replaced by nitrifying bacteria, denitrification bacteria and phosphorus accumulating bacteria absorbed on PBS carrier biofilms suitable for saline/brackish water. The results showed that biofilm-enhanced A2O system can effectively remove pollutants from aquaculture wastewater. The removal efficiencies of CODMn, NH4+-N, TN and TP in A2O system were approximately 86.3%-90.8%, 97.7%-99.5%, 94.6%-95.2% and 97.0%-98.1%. The results further showed that CODMn, NH4+-N, and TN were mainly removed in anaerobic tank and anoxic tank, while TP was mainly removed in the anoxic tank and oxic tank. The biofilm-enhanced A2O system by adding nitrifying bacteria and phosphorus accumulating bacteria biofilms using PBS as carriers instead of conventional activated sludge could be applied to the treatment of circulating aquaculture wastewater. This study provides a feasible scheme for enhancing the efficiency of A2O system in the treatment of aquaculture tail water, and provides a reference for the immobilization of microorganisms.

Lake Toba is one of the largest lakes in North Sumatra Province, Indonesia. Its waters are used for multiple purposes, constituting an important natural and economic resource. Most of the waters of Lake Toba come from the overflow of disposal of agriculture, livestock, fisheries, tourism, households, and other activities. The present study identified water quality based on total nitrogen, total phosphorus, chlorophyll-a and other water quality parameters carried out at 60 sampling sites grouped into 6 observation stations, i.e., control areas (located in the middle and far from direct activities), community floating net cages, company floating net cages, settlement, hospitality, and river mouths. The main water quality components were very dynamic at the monitoring stations in three seasons (rainy, transition, and dry). Total nitrogen concentration tended to be higher in the rainy season than in the transition and dry seasons. However, all stations tended to be classified as mesotrophic or higher in all seasons, with total nitrogen concentrations greater than 12.5 mg L–1. Total phosphorus at the six stations was highly dynamic in all seasons and tended to decrease in the dry season. The concentration of total phosphorus was higher at the settlement and hospitality stations than at the other stations. The total phosphorus of the settlement and hospitality stations reached 0.18 mg L–1 and 0.17 mg L–1, respectively, in the rainy season. In general, total phosphorus concentrations in the waters of Lake Toba were above 0.1 mg L–1, which allowed the lake to be classified as above mesotrophic status.

Abstract Downwelling aeration has become a widely applied approach to cope with the water eutrophication in stratified reservoirs, rivers and lakes. The aeration parameters involving flow rate, flow locations and working periodicity and their impacts on the temperature and dissolved oxygen (DO) distributions of water have been largely unclarified, causing extra time and energy consumptions in practice. In this study, a home-built water tank and an aeration pump are used to model the downwelling aeration processes in stratified water. Temporal influences of aeration parameters on the water stratifications and eutrophicated elements are systemically investigated, with the purpose of searching parametric configurations to enhance the anti-eutrophication efficiency. It is found that the variation rates of temperature destratification and DO distribution in the water body could be saturated and strongly correlated with the flow rate. Based on such experimental saturation rates, we find an optimized working condition from the aspect of energy saving: a 300 rpm pump speed and a 15 cm distance between the flow exit and the sediment surface. In such conditions, the total nitrogen and phosphorus dissolved in the bottom layer of water decrease exponentially with aeration time, and can be reduced by 53.8 and 86% in the first 6 h of aerations, respectively, taking full advantage of the microbial bonding to the sedimentations. The present work provides better understandings for efficient implementations of downwelling aerations.