High Total Phosphorus Research Articles

The Bioaccumulation of Heavy Metals in the Water and Tissues of Invasive Fish Carassius gibelio (Bloch, 1782) and Non-carcinogenic Health Risk Assessment from Meriç Delta Wetland, Türkiye.

Meriç Delta, which has a wide variety of ecosystems, is an A Class Wetland and the most significant natural stagnant freshwater ecosystem located in the south-western of Thrace Region of Türkiye. In this research, heavy metals (Cr, Ni, As, Cd, and Pb) were investigated in the surface water and Carassius gibelio (Bloch, 1782) obtained from Meriç Delta lakes (Gala, Pamuklu, Sığırcı, and Dalyan), which are located on an important migration route of water birds. The heavy metals in surface water samples and fish tissues were determined by ICP-MS. Dissolved oxygen, oxygen saturation (%), pH, electrical conductivity, total dissolved solids, nitrite nitrogen, nitrate nitrogen, and total phosphorus parameters were measured in surface waters. High total phosphorus content was detected in the investigated region. The measured As, Cr, and Ni values in water samples were determined to be higher than Türkiye Regulation Standards criteria. Fish were taken from Gala and Sığırcı Lake. The mean concentrations of measured heavy metals were found to be below permissible values in fish muscle and gill. The target hazard quotient (THQ) and total THQ values (HI) of all heavy metals did not exceed the limit value.

Causal feedback loops modify lake chlorophyll a–nutrient relationships over two decades of nutrient reductions and climate warming

AbstractUnderstanding how the causal feedback between phytoplankton and environmental drivers controlling the chlorophyll a (Chl a, as a proxy of phytoplankton biomass)–nutrient relationships are modulated under different ecosystem conditions is a major challenge in aquatic ecology. Using an empirical dynamic model (convergent cross mapping) on a 20‐yr dataset on 20 Danish lakes, we quantified hypothesized causal feedback networks for each lake and related them to lake system properties (e.g., mean water depth, nutrient concentrations and extent of reduction, climate warming) vs. the Chl a–nutrient relationship (estimated from generalized least square models). The results showed prevalent causal feedback across the studied lakes, which demonstrated clear patterns for the tested ecosystem variations. Weaker causal feedbacks were found in deeper lakes and lakes with larger warming trends, while stronger causal feedbacks appeared in lakes experiencing greater reductions of TP (total phosphorus) and TN (total nitrogen). Moreover, these causal feedbacks showed a strong and positive coupled pattern. Most of the causal feedbacks worked as enhancement loops, which promote the sensitivity of phytoplankton to TP, not least in shallow lakes with a high TP reduction, and as regulatory loops, which force a shift in the Chl a–TN relationship from a more negative slope in lakes experiencing a high nutrient reduction and weak warming to a positive slope in lakes with low nutrient reduction and stronger warming. Our findings suggest a mechanistic explanation of how internal feedbacks regulate the Chl a–nutrient relationships across a broad gradient of nutrient reductions, climate warming, and lake morphologies.

Highly efficient phosphorus removal by a novel prolonged stirring pelleting coagulation for sludge water treatment

Sludge water with high total phosphorus (TP) and suspended solids (SS) easily causes the effluent quality to be substandard in wastewater treatment plants. Although the conventional coagulation process can achieve TP removal, higher sludge production occurred due to loose flocs generation. The prolonged stirring pelleting coagulation (PSPC) process, based on one-by-one agglomeration and mechanical syneresis theories, was proposed to achieve compact flocs and reduced sludge production. Compared with the conventional coagulation process, the removal efficiency of TP was improved by >20 %, settling volume was reduced by about 30 %, and the dosages of polyaluminum chloride (PAC) and polyacrylamide (PAM) were saved by 50 % and 30 %, respectively in the PSPC process. The PSPC process produced pellet-like flocs with the d50 of 6.27 mm, settling velocity of 21.07 mm/s, effective density of 0.1411 g/cm3, and three-dimensional fractal dimension (D3) of 2.094 under the optimal conditions of 50 mg/L PAC and 10 mg/L PAM. With the d50 decreased from 38.38 μm to 21.81 μm, fragmentation of primary particles was realized by high-intensity stirring. Therefore, the mechanism of the PSPC process involves reducing voids in primary particles, achieving regular combination of microflocs under appropriate PAC, PAM, and hydraulic control. The PSPC process shows promising prospects for treating high SS wastewater and may have practical implications for enhancing coagulation.

The Fate of Phosphate: Assessing Dietary Intake and Urinary Excretion in Swedish Adolescents

BackgroundA high total phosphorus (P) intake has been proposed to promote endothelial dysfunction and atherosclerosis. A diet rich in foods containing P additives could contribute to an excessive intake, potentially reflected as increased concentration of P in urine. ObjectivesThis study aimed to assess the intake of total dietary P, P additives, and its sources and examine their correlation with urinary P in a cross-sectional national study in Swedish adolescents. MethodsWe constructed a database of P additives and applied it to the foods consumed by 3099 participants in the representative school-based dietary survey Riksmaten Adolescents 2016–17. Intake of total dietary P and P additives were assessed using two 24-h recalls. Urinary P was analyzed in a subsample of 756 participants using inductively coupled plasma mass spectrometry. Spearman rank correlation (ρ) was used to assess the association between dietary P intake and urinary P excretion. ResultsThe mean (SD) intake of total P was 1538 (±667) mg/d. Food containing P additives were consumed by 92% of adolescents and the median (IQR) intake was 49 (22–97; range: 0.01–947) mg/d, corresponding to 5% (1%–6%; range: 0%–50%) of total P. The main contributing food to P additives was cola drinks, while the main contributing food group was sausage dishes. Total P intake was weakly correlated with urinary P (ρ = 0.12; P < 0.01) but not with intake of P additives. ConclusionsNearly, all participants consumed P additives, contributing to an average of 5% of total P intake but ranging up to 50%. The intake of total P, but not P additives, was weakly reflected in the urinary P. Access to more comprehensive information on P additives in foods would improve further evaluation of potential health consequences.

Bottom sediments as an indicator of the restoration potential of lakes—a case study of a small, shallow lake under significant tourism pressure

The study covered a small, shallow lake, intensively used for recreation (sailing, tourist services and port infrastructure). This study aimed to determine the spatial differentiation of bottom sediments and the potential for phosphorus release in five zones, differing mainly in the type of recreation, depth, direct catchment management, shoreline management and macrophyte presence. The results were used to propose protective and restoration measures to improve the water quality of the studied lake. The innovation in the study was the detailed analysis of bottom sediments, which can be a significant source of pollution besides the external load from the catchment and tourist pressure, in the planned management of this ecosystem. Examination of the physicochemical properties of the bottom sediments showed a clear variation in both composition and potential for internal phosphorus loading. The sediments from the profundal zone, where the most boating activity was observed, together with the sediments from the shallow zone where the boats dock (mooring zone), had the highest potential to supply phosphorus to the bottom waters. This fact was demonstrated by the highest total phosphorus (TP) concentrations in sediments (up to 1.32 mgPg−1 DW) and the content of the most mobile fractions (up to 33%). The other zones associated with the marina, fuel zone, tributary and canal were not significant sources of phosphorus to the ecosystem. Based on the above results, a restoration method involving the removal of bottom sediments from the bottom zone was proposed, supported, of course, by protective measures in the catchment (maintaining a buffer zone around the lake and limiting the inflow of pollutants with tributary waters). The proposed measures with sustainable tourist pressure should improve water quality and thus contribute to protecting this valuable natural landscape.

An investigation of cyanobacteria, cyanotoxins and environmental variables in selected drinking water treatment plants in New Jersey

Harmful Algal Blooms (HAB) have the potential to impact human health primarily through their possible cyanotoxins production. While conventional water treatments can result in the removal of unlysed cyanobacterial cells and low levels of cyanotoxins, during severe HAB events, cyanotoxins can break through and can be present in the treated water due to a lack of adequate toxin treatment. The objectives of this study were to assess the HAB conditions in drinking water sources in New Jersey and investigate relationships between environmental variables and cyanobacterial communities in these drinking water sources. Source water samples were collected monthly from May to October 2019 and analyzed for phytoplankton and cyanobacterial cell densities, microcystins, cylindrospermopsin, Microcystis 16S rRNA gene, microcystin-producing mcyB gene, Raphidiopsis raciborskii-specific rpoC1 gene, and cylindrospermopsin-producing pks gene. Water quality parameters included water temperature, pH, dissolved oxygen, specific conductance, fluorescence of phycocyanin and chlorophyll, chlorophyll-a, total suspended solids, total dissolved solids, dissolved organic carbon, total nitrogen, ammonia, and total phosphorus. In addition to source waters, microcystins and cylindrospermopsin were analyzed for treated waters. The results showed all five selected New Jersey source waters had high total phosphorus concentrations that exceeded the established New Jersey Surface Water Quality Standards for lakes and rivers. Commonly found cyanobacteria were identified, such as Microcystis and Dolichospermum. Site E was the site most susceptible to HABs with significantly greater HAB variables, such as extracted phycocyanin, fluorescence of phycocyanin, cyanobacterial cell density, microcystins, and Microcystis 16S rRNA gene. All treated waters were undetected with microcystins, indicating treatment processes were effective at removing toxins from source waters. Results also showed that phycocyanin values had a significantly positive relationship with microcystin concentration, copies of Microcystis 16S rRNA and microcystin-producing mcyB genes, suggesting these values can be used as a proxy for HAB monitoring. This study suggests that drinking water sources in New Jersey are vulnerable to forthcoming HAB. Monitoring and management of source waters is crucial to help safeguard public health.

Management of eutrophication using combined the “flock &amp; sink” mitigation technique and submerged plants restoration: a mesocosm study

Abstract Currently, the issue of eutrophication and cyanobacterial blooms persists in water bodies worldwide, prompting the exploration of various treatment methods. This study conducted a comparative analysis of eutrophic water bodies using ferric chloride-modified zeolite (FMZ) and calcium hydroxide-modified zeolite (CMZ) combined with Elodeanuttallii (E. nuttallii) for removal and purification effects. The results revealed that the addition of E. nuttallii had a sustained inhibitory effect on phosphorus release, maintaining stability with lower Turbidity(Tur) and stabilized pH within the range of 8.5-9. FMZ demonstrated rapid reduction in dissolved phosphorus concentration, achieving a removal rate of 96% within 3 days. The combined plant group of CMZ and FMZ exhibited synergistic effects with E. nuttallii, achieving an impressive total phosphorus (TP) removal rate of 80.13% and a total nitrogen (TN) removal rate of 48.77%. Additionally, chlorophyll a (Chl a) concentration decreased from 100.74 ± 24.72 μg/L to 49.96 ± 2.08 μg/L. The phytoplankton community composition indicated that diatoms thrived in low temperatures and high NH4 conditions. Under the same low Total Nitrogen to Total Phosphorus (TN:TP) ratio, high TP concentrations were associated with cyanobacteria dominance, while green algae dominated in other scenarios. This comprehensive approach demonstrates the potential efficacy of CMZ and FMZ combined with E. nuttallii in addressing eutrophic water bodies and mitigating cyanobacterial blooms.

Evaluation of the Best Management Practices for Reducing Phosphorus Load in a Watershed in Terms of Cost and Greenhouse Gas Emissions

Effective management of water quality in watersheds is crucial because it is directly linked to the sustainability of aquatic ecosystems. In conventional watershed management, best management practices (BMPs) have been instrumental in addressing deteriorating water quality issues caused by non-point source pollution. Greenhouse gas (GHG) emissions have emerged as a global concern, necessitating immediate and diverse environmental actions to mitigate their impacts. This study aims to explore BMPs that maximize total phosphorus (TP) load removal efficiencies, while minimizing costs and GHG emissions within watersheds, using the Soil and Water Assessment Tool (SWAT) and non-dominated sorting genetic algorithm III (NSGA-III). The Yeongsan River Watershed between 2012 and 2021 was selected as the study area. Hydrological and BMP data were analyzed. Applying identical BMPs to the watershed showed that the BMPs with high TP removal efficiency may not be effective in terms of cost and GHG emissions. Therefore, the optimal combination of BMPs for the Yeongsan River Watershed was determined using NSGA-III considering TP removal efficiency, cost, and GHG emissions. This study is the first to consider GHG emissions at the watershed level when applying BMPs and is expected to contribute to the development of BMP implementation incorporating GHG emissions.

Management of Free-floating Aquatic Weeds by Making Compost and Testing its Efficacy against Root-knot Nematode on Tomato

Aquatic weeds are one of the prime pollution causing agents in fresh water bodies of Sri Lanka. In Sri Lanka, free-floating aquatic weeds such as Salvinia molesta, Eichhornia crassipes, Azolla spp and Pistia stratiotes are proliferating quickly and invading rapidly to new water bodies where threatening biodiversity by impeding light penetration and altering BOD and COD of the waterbody. This research was aimed to manage the aquatic weeds by composting and testing its efficacy on root-knot nematodes. Aquatic weeds were collected, mixed with fresh cow dung in 1:1 ratio and allowed for decomposition for 21 days. The recommended dose of prepared different compost was applied to tomato along with garden compost as control. The experiment was conducted in Complete Randomized Design (CRD) with four replicates. The data on nutritional qualities of the compost, plant growth parameters, and gall index were recorded. The data were subjected to ANOVA using SAS 9.1 and Tukey's HSD multiple comparison test was used to determine the best treatment combination at P&lt;0.05. Total Nitrogen (N) content of composts were ranging from 1.42% to 5.6%. The highest significant N value of 5.6% was recorded in the Azolla spp based compost whereas the lowest N value of 1.42% was recorded in control. The highest total Phosphorus (P) content of 3.47% was observed in P. stratiotes based plant sample, whereas the lowest P value of 1.32% was recorded in the E. crassipes based compost. The total Potassium (K) content of this plant sample ranging from 1.3% to 24.4%. The highest K value of 24.4% was recorded in P. stratiotes based compost. The lowest K content of 1.3% was observed in control. Significantly higher shoot height (37.57 cm, 36.53), root length (18.75 cm and 17.5 cm), lower gall index (3.5,1.0), lower goal length (1.5 mm and 1.2 mm) and lower goal diameter (0.95 mm and 0.8 mm) were recorded in the application of S. molesta and Azolla spp based compost, respectively (P&lt;0.05). Considering superiority of N, P and K level, and nematode suppressing efficacy, S. molesta and Azolla spp. based composts are superior than other composts. Therefore, findings conclude that the compost made from aquatic weeds are good source of plant nutrition, and can be substitute to chemical nematicieds to manage the nematodes in organic agriculture. Extensive field studies are needed for recommendation &#x0D; Keywords: Aquatic weeds, Azolla spp., Compost, Root-knot Nematode

Aerobic composting effect of crop straw with biogas residue

This study aims to improve the aerobic composting efficiency and quality of biogas residue. The residue of biogas production from pig manure was mixed with coconut leaves, sugarcane leaves, and sawdust, respectively, for the aerobic composting experiments. The pile temperature, pH, organic matter content, seed germination index, total nitrogen, total phosphorus, and total potassium were measured to evaluate the composting performance of different treatments. The results showed that the aerobic composting treatment of biogas residue mixed with sugarcane leaves had a seed germination index of 107.71%, the highest maturity, and the highest total phosphorus and total potassium. The aerobic composting treatment of biogas residue mixed with coconut leaves maintained high temperatures above 55 °C for the longest time (23 days) and demonstrated the most thorough harmless treatment, with the total nitrogen increase being the highest (75.63%), which indicated the strongest nitrogen retention capacity. Overall, the supplementation of coconut leaves and sugarcane leaves can improve the maturity and nutrient content, thus improving the aerobic composting quality of biogas residue. The findings provide a scientific basis for the harmless treatment and reuse of manure biogas residue and crop straw.

Landscape differentiation of soil bacteria and bacteria-soil-vegetation interactions in desert-oasis ecosystems

Desertification control and oasis management are of strategic importance for the protection of ecological security and the achievement of sustainable development in arid regions. However, the role of soil microorganisms in desertification and oasification has been historically overlooked, especially for the influence of microbial communities on landscape change and the stability of soil-vegetation system in desert-oasis ecosystems. Here, using an environmental sampling approach combined with functional annotation, the landscape differentiation of soil bacterial diversity, community structure and functional traits, as well as the bacteria-soil-vegetation interactions were investigated in desert, oasis and desert-oasis ecotone habitats. The results showed that soil bacterial diversity increased significantly from desert, ecotone to oasis, and the highest spatial differentiation of bacterial diversity was observed in desert. The simplest and unique bacterial composition was detected in desert, which was dominant by Arthrobacter, Streptomyces, Burkholderia, etc. However, the phyla Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, and the genus Candidatus_Nitrososphaera were the crucial biomarkers for distinguishing the composition differences across different landscapes. In terms of bacterial composition shift, it was far more challenging to go from ecotone to oasis than from desert to ecotone. Meanwhile, the most stable functional network was exhibited in oasis, while the simplest network was detected in ecotone rather than in desert. Relatively high soil moisture, total nitrogen, organic carbon, total phosphorus, and silt and clay proportions played decisive roles in improving microbial diversity, community structure and functional service, which would enhance the stability and diversity of desert-oasis ecosystems. Furthermore, increase in the relative abundances of functional genes, which were related to metabolism, environmental information processing, and organismal systems, may be harmful to nitrogen cycling and vegetation growth. These results conclude that the landscape differentiation of soil bacteria in desert, ecotone and oasis identifies the central role of bacterial interactions in ecosystem processes and highlights the importance of landscape stability control, forming a novel perspective of microbial behaviour in controlling landscape stability in desert-oasis ecosystems.

The application of ionization technology to reduce water pollutant level of domestic wastewater

Increased human activity in households leads to an increase in the amount of wastewater. Domestic wastewater comes from organic matter, namely food waste and detergents which contain high total suspended solids phosphorus (TSS), chemical oxygen demand (COD) and biological oxygen demand (BOD). This can reduce environmental quality if the waste is disposed of directly without prior treatment. one of the treatments is by applying ionization. Ionization technology is used in the treatment process by using ions, high energy electrons, and active species to remove color and organic compounds through the flow of direct current (DC) from the anode to the cathode. This series of studies connects ionization technology with contact times of 30 and 60 minutes with an electric voltage of 20 kV which aims to reduce the level of wastewater pollutants in the Tunjungsari 2 Tembalang boarding house. Among the analyzed wastewater parameters, we succeeded in reducing wastewater pollutants, namely TSS removal reached 54.85%, BOD 85.99%, COD 79.45%, ammonia 55.06%, fatty oil 78.77%, total coliform 85.71% and pH conditions increased in value up to 54.38%. For optimal results, it is better to improve the ionization technology series from procedures to analysis.

Agricultural nonpoint source pollutant loads into water bodies in a typical basin in the middle reach of the Yangtze River

Phosphorus and nitrogen pollution from agricultural nonpoint sources heavily burden the water environment, and a scientific calculating system is needed to calculate the pollutant loads under the water pollution treatment. This study established a system to calculate the coefficients of agricultural nonpoint source pollutants into water bodies in the subregion in Poyang Lake basin in the middle reach of the Yangtze River combining with multiple driving factors. Validation results showed that the errors of the typical unit were 30.58% for total phosphorus (TP), 13.43% for total nitrogen (TN) and 33.93% for ammonia nitrogen (NH3-N), respectively. The errors of the subregion were 26.92% for TP, 31.83% for TN and 29.15% for NH3-N, respectively. Besides, there were higher TP and TN loads in the east area of subregion in both units and county scales, which indicated the heavy phosphorus and nitrogen burden on water environment. In contrast, higher NH3-N loads occurred in the north area of subregion. The establishment of coefficient system for agricultural pollutants into water bodies and the pollutant loads calculation would provide enlightenment for water pollution treatment and agricultural nonpoint source pollution controlling.

Biological treatment of agro-processing industrial effluents from tannery, coffee and dairy plants using green algae (&lt;i&gt;Chlorella Ssp&lt;/i&gt;.) cultured in a photo bioreactor

Due to increased environmental pollution as a result of high emission rates from agro-processing industries, the effluents must be cleaned up before being released into the environment. This study outlines the use of green algae for nutrient removal from agro-processing effluents discharged from three agro-industries (namely coffee, dairy, and tannery) in Kenya and how they can be used for the propagation of microalgae for biofuel production. Green algae were grown inside a photobioreactor containing the three agro-industrial effluents as nutrient media for 21 days. Thereafter, the algae were harvested and evaluated for biofuel production. The effectiveness of green algae (chlorella ssp) to extract the cations from the various agro-processing effluents was used to gauge how well they performed. Additionally, the algae growth rate, quantity of lipids, and biomass generated were used to evaluate the strains' effectiveness in producing biofuel. The results indicate that the highest maximum algae growth rate of 14.528 mg/mL occurred in the dairy effluent. The corresponding values for the coffee and tannery effluents were 13.016 mg/mL and 10.866 mg/mL, respectively. Biochemical analysis was done to establish the amount of biomass in the algae. The results showed that there was higher biomass productivity per day of 293.944, 124.849, and 91.997 μg/mL for the dairy, coffee, and tannery effluents, respectively. The contents of linolenic acid in the chlorella strain in the dairy, coffee, and tannery effluents were 13.21, 12.86, and 15.98%, respectively. The values obtained were slightly above the recommended lower limit value of 12% (EN 14214, 2004) for the production of quality biofuels. The results further show that high chemical oxygen demand removal (maximum of 47.7–67.8%) and total phosphorus removal (maximum of 95%) were achieved in all three effluents. Finally, the fatty acid methyl ester profiles produced indicated that the lipid content of the cultivated green algae was appropriate for the production of biofuel.

Assessment of a diel phosphorus pattern's potential to benefit phosphorus retention in the stormwater treatment areas

The Stormwater Treatment Areas (STAs) are constructed wetlands used to reduce the total phosphorus (TP) level in water discharged to the environmentally sensitive areas of the Everglades Protection Area. Analysis of high temporal frequency TP data reveals that TP concentrations discharged from selected STA flow-ways exhibit diel and seasonal cyclic patterns and are most affected by discharge rate and water depth. The objective of this paper is to describe the diel TP pattern and evaluate the possibility of using it to reduce TP in STA discharge. The amplitude of diel TP pattern ranged from 0.7 to 1.5 μg L−1 (3–6% deviation from daily mean) at three flow-ways, peaking in the early afternoon and reaching lowest concentrations between midnight and 4 am. To assess the possibility of further reducing TP concentration discharged from the STAs by increasing the proportion of daily flow discharged at night when diel TP is at a minimum, a General Additive Model (GAM) was created with discharge rate, water depth, year, location, day-of-year, and time-of-day as covariates. While time-of-day was a statistically significant factor in the model (p < 0.001), its average marginal effect was smaller than all other significant model covariates: discharge rate, season, and water depth. Modeling suggests that within specific ranges of discharge rate and water depth, the opportunity exists to provide additional TP reduction in STA outflow by discharging a greater proportion of the daily flow at night when TP concentrations are lower. Further research is needed to quantify the effect of increasing nighttime flow on annual flow weighted mean TP. Additionally, an evaluation of the practicality and logistical cost required to redistribute flow is needed before attempting to take advantage of this natural cyclic pattern to improve STA TP retention.

Understanding the role of land use for urban stormwater management in coastal waterways

A holistic understanding of the quality and quantity of stormwater in the context of catchment land use plays a crucial role in stormwater management. This study investigated the quality and quantity of stormwater from forested, residential, industrial, and mixed land use areas. Water samples were collected from seven sites over two years at different stages of the runoff hydrograph using fixed sampling stations. Analysis of physicochemical and hydrological variables showed different patterns across the four land use types at various flow conditions highlighting the complex nature of stormwater quality influenced by catchment and rainfall characteristics. Mean concentrations of dissolved organic and oxidised nitrogen (DON and NOx-N) and dissolved organic and filterable reactive phosphorus (DOP and FRP) in stormwater from industrial, mixed-use and residential catchment types were statistically different from stormwater originating from a forested catchment. On average, residential, mixed-use and industrial catchments transported over 50 times more NOx-N to the receiving waters compared to forested catchments. Under high flow conditions, total phosphorus, FRP and total suspended solids (TSS) were mobilised, indicating that phosphorous export is directly related to sediment export regardless of the land use. The study outcomes contribute to the formulation of more effective stormwater management strategies to deal with the drivers of nutrients and TSS inputs resulting from modified land use types to minimise the urbanisation impacts on aquatic biota. In particular, the elevated dissolved nitrogen fractions from all the catchment types other than the forested catchment is a concern for receiving waters, as these can potentially impair water quality and impact the ecosystem health of downstream water bodies such as Intermittently Closed and Open Lakes or Lagoons (ICOLL). The stochastic nature of hydrology and corresponding nutrient loads should be prioritised in stormwater management action plans. However, as space limitations hinder the expansion of vegetation cover and retrofitting stormwater management devices, a paradigm shift in stormwater management is required to achieve the desired outcomes. The study outcomes further indicate that a one-size-fits-all approach to stormwater management may not deliver the desired outcomes, and a suite of tailor-made approaches targeting various flow conditions and catchment surface types is needed.

Ameliorative effects of waste decomposer and effective microorganisms on composting of paddy straw

Composting is one of the most eco-friendly methods to manage paddy straw and reduce environmental pollution with added value to the soil. The present work aimed to investigate the effects of different treatments on composting paddy straw and identify the most effective method for managing paddy straw while also reducing environmental pollution and adding value to the soil. The study used a split plot design with ten treatment and three replications over two years, and measured various parameters such as total organic carbon, total nitrogen, total phosphorus, total potassium, and water-soluble carbon to evaluate the quality of the compost produced by each treatment. From the pooled data of the experiment, the lowest total organic carbon of the compost was obtained in M1 (2.58%) and S8 (15.58%). The highest total nitrogen was acquired in M1 (12.04%) and S8 (26.04%). The highest total phosphorus was recorded in M1 (1.23%) and S8 (33.75%). The highest potassium was observed in M1 (25.67 %) and S8 (55.61%). The least water-soluble carbon was recorded in M1 (14.28%) and S8 (14.92%). The results of the study provide insights into the effectiveness of various composting methods and can help inform best practices for managing paddy straw in an eco-friendly manner.

Effect of Watering Number and Inorganic Fertilizers on Accumulation of Total Phosphorus in Above Ground Biomass of Avena in Gray-Brown Soils of Azerbaijan

An assessment of the effect of mineral fertilizers on the accumulation of total phosphorus in the above-ground mass of oat plants on irrigated gray-brown soils of Azerbaijan was carried out. The studies were carried out in 2021. As a result of the work, it was found that, depending on the number of irrigations and the norms of mineral fertilizers on irrigated gray-brown soils of the western region, the yield of the aerial part varied. Various fertilization methods and rates tested. High total phosphorus was observed with double vegetative irrigation with N90P90K60 and triple irrigation with N120P120K90.

Distribution, driving forces, and risk assessment of 2-MIB and its producer in a drinking water source-oriented shallow lake.

Freshwater blooms of harmful cyanobacteria in drinking water source-oriented shallow lakes affect public health and ecosystem services worldwide. Therefore, identifying 2-methylisoborneol (2-MIB)-producing cyanobacteria and predicting the risks of 2-MIB are critical for managing 2-MIB-infected water sources. Previous studies on the potential producers and risks of 2-MIB have focused on reservoirs or have been limited by the ecosystems of phytoplankton-dominated areas. We investigated the producers, distribution, and occurrence of 2-MIB in East Taihu Lake-a drinking water source-oriented shallow lake with macrophyte- and phytoplankton-dominated areas-from August 2020 to November 2021. We observed that Pseudanabaena sp. produces 2-MIB in this lake, as determined by the maximum correlation coefficient (R = 0.71, p < 0.001), maximum detection rate, and minimum false positive/negative ratio exhibited by this genus. Extreme odor events occurred in this lake during late summer and early autumn in 2021, with the mean 2-MIB concentration increasing to 727 ± 426ng/L and 369 ± 176ng/L in August and September, respectively. Moreover, the macrophyte-dominated area, particularly the wetland area, exhibited a significant decrease (p < 0.01) in bloom intensity and 2-MIB production during these extreme odor events. Pseudanabaena sp. outbreak was likely owing to eutrophication, seasonal gradients, and macrophyte reduction, considering that temporal trends were consistent with high water temperature, high total phosphorus levels, and low-light conditions. Moreover, 2-MIB production was sensitive to short-term hydrometeorological processes, with high water levels and radiant intensity enhancing 2-MIB production. The risk assessment results showed that the probability of 2-MIB concentration exceeding the odor threshold (10ng/L) is up to 90% when the cell density of Pseudanabaena sp. reaches 1.8 × 107 cell/L; this risk is reduced to 50 and 25% at densities of < 3.8 × 105 cell/L and 5.6 × 104 cell/L, respectively. Our findings support calls for shallow lake management efforts to maintain a macrophyte-dominated state and control odorous cyanobacteria growth.

Total nitrogen and pH are key variables for functional structure of zooplanktonic communities in an agropastoral landscape

Changes in land use are one of the main impacts on aquatic ecosystems. The conversion of natural areas into agropastoral, such as pasture or monocultures, can affect the limnological characteristics of the water that in turn influence the structure of aquatic communities. But the impact is still unclear, particularly on zooplankton communities. The objective of this study was to evaluate the effect of water parameters from eight reservoirs inserted in an agropastoral landscape on the functional structure of zooplankton. The functional characterization of the zooplankton community was based on four traits: body size, feeding type, habitat type, and trophic group. Functional diversity indices (FRic FEve and FDiv) were estimated and modeled water parameters, using generalized additive mixed models (GAAM). The water parameters investigated were total nitrogen (TN) and total phosphorus (TP), dissolved oxygen (OD), temperature and pH. Moreover, we used RDA to analyze the influence of these environmental variables on the sharing of traits among the sample sites. FRic was high in the reservoirs with low TN concentration and low pH values. FEve was also high in low pH and high TP concentration. FDiv was high with unsharp increases of pH and high concentrations of TN and DO. Our analyses showed pH as a key variable for functional diversity, since it was related to the variation in all indices. Data also pointed out changes in diversity functional with small pH changes. The big and medium size, raptorial-cop and filtration-clad functional traits were positively associated with high concentrations of TN and alkaline pH. The small size and filtration-rot were negatively associated with high concentrations of TN and alkaline pH. Density of filtration-rot was lower in pasture landscapes. In conclusion, our study indicated that pH and TN are key variables for the functional structure of zooplanktonic communities in an agropastoral landscape.