Reactive Phosphate Research Articles

Analysis of Nitrogen and Phosphorus Pollution in Shenzhen Bay over the Past 40 Years

Based on 40 years of routine water quality monitoring data from Shenzhen Bay and special intensive monitoring since 2021, we analysed the spatiotemporal variations in nitrogen and phosphorus pollution. The results indicate serious levels of nitrogen and phosphorus pollution in Shenzhen Bay. Although recent trends show a decline in concentrations of inorganic nitrogen and reactive phosphate—with the annual average concentration of inorganic nitrogen dropping below 1.0 mg/L since 2020 and reactive phosphate levels near the bay mouth decreasing to approximately 0.020 mg/L—the overall water quality still does not meet China’s Class IV seawater quality standards. Additionally, water quality is poorer during the rainy season, with the average summer concentration of inorganic nitrogen being over 25% higher than in spring and autumn. The water quality is primarily influenced by land-sourced pollutants and tidal effects, generally, with the concentration of DIN and DIP decreased from the estuary of the Shenzhen River, the main seagoing river, to the bay mouth. Near the river’s mouth, concentrations of inorganic nitrogen and reactive phosphate are approximately six and four times higher, respectively, than those near the bay mouth. Due to current emission standards and sewage disposal methods, the proportion of nitrate nitrogen in DIN has significantly increased, exceeding 80% since 2020. To improve the water quality of Shenzhen Bay and to reduce pollution inputs, coordinated land and marine development activities are recommended.

Productivity and competitive dominance of freshwater filamentous macroalgal cultivars for nutrient bioremediation of primary municipal wastewater

ABSTRACT Algal bioremediation using macroalgae is a promising approach to wastewater treatment. This study compared the productivity and bioremediation performance of the freshwater filamentous algal cultivars; Klebsormidium flaccidum, Oedogonium calcareum, and Oedogonium sp., in primary municipal wastewater in outdoor high-rate filamentous algal pond mesocosms. K. flaccidum had the highest biomass productivity (3.09 g dry weight m−2 day−1 ± 0.20 SE) and bioremediation performance, reducing total ammoniacal-N by 51% to 14.80 mg L−1 (± 0.81 SE), nitrate-N by 59% to 0.30 mg L−1 (± 0.02 SE), and dissolved reactive phosphorous by 15% to 3.52 mg L−1 (± 0.07 SE). This cultivar achieved the greatest reductions in total suspended solids (54%), carbonaceous biochemical oxygen demand (93%), and chemical oxygen demand (74%). K. flaccidum and Oedogonium sp. reduced Escherichia coli by 98%. Competitive dominance of K. flaccidum and Oedogonium sp. was assessed in bicultures at three stocking densities. By day 12, K. flaccidum's proportion increased from 50 to 64% (± 6.1 SE) and 73% (± 5.0 SE) at a stocking density of 0.25 g and 0.5 g FW L−1, respectively. Based on superior biomass productivity, bioremediation performance, and competitive dominance, K. flaccidum was identified as a target cultivar for bioremediation of primary municipal wastewater.

Innovative approaches for enhanced nutrient (N and P) removal and biosecurity in marine recirculating aquaculture systems using biofloc and ultrafiltration combined systems

Marine recirculating aquaculture systems (marine RAS) are increasingly utilized for their high productivity and minimal environmental impact. However, effective nutrient management and biosecurity measures remain crucial for sustainable operation of marine RAS. This study successfully established a simultaneous nitrification and denitrification (SND) process using a biofloc technology (BFT)–ultrafiltration (UF) combined approach. A stable autotrophic marine nitrification system was rapidly initiated within 23 days using a ceramic ring (CR)–granular activated carbon (GAC)–UF process (CGUF), followed by the substitution of polyhydroxyalkanoates (PHA) for GAC filter to achieve rapid start-up of SND in 24 h (CG/PUF). Soluble reactive phosphate (SRP) was removed in-situ via biofloc adsorption. The co-existence of ammonia-oxidizing archaea (Candidatus_Nitrosopumilus) and denitrifying bacteria (Stenotrophomonas, Ruegeria and Ilumatobacter) synergistic promoted the SND start-up in CG/PUF process. Stenotrophomonas emerged as the keystone species which closely linked to amoA/B/C, hao and nosZ genes (p < 0.05). The CG/PUF process effectively enhanced the biosecurity of marine RAS, with 100 % elimination of potential pathogens (Vibrio and Tenacibaculum). UF membrane could maintain fluxes at 15 L∙ m−2∙ h−1 (LMH) for 180 days, with a 2-day intermittent hydraulic flushing keeping transmembrane pressure below 50 kPa. These findings provide insights for broader application of BFT–UF combined process in marine RAS.

Mesopore-rich La-based metal organic framework derivatives for phosphorus removal from mariculture tailwater

Deep dephosphorization of mariculture tailwater, a typical high-salinity and weakly alkaline wastewater, is difficult but essential for meeting ever-stricter stringent emission standards. Herein, we developed an alkaline-conversion method to prepare lanthanum-based metal organic framework (La–MOF) derivatives for efficient phosphate removal from mariculture tailwater. During the templated alkaline-conversion process, the strong-alkaline regent gradually broke the coordination bonds of La–MOF while maintained its macrostructure, and the La nodes liberated from the framework were then crystallized into La(OH)3. The universality of this conversion method was verified on other La–MOF precursors with different benzoic multicarboxylate ligands. Importantly, numerous mesopores were formed in the derivative interior, increasing the number of exposed active La sites and accessible transfer channels. Therefore, the derivative exhibited superior phosphate-adsorption performance with a high adsorption capacity (Langmuir Q0: 155.7 mg P/g) and a rapid adsorption rate. The obtained La–MOF derivative with stable structure had broad neutral–alkaline pH range adaptability, which was demonstrated satisfactory dephosphorization selectivity and high cyclic performance under different seawater conditions (coexisting anions, cations, H3BO3 and natural organic matter). Finally, the obtained mesopore-rich La–MOF derivative exhibited an excellent deep dephosphorization capacity for actual mariculture tailwaters collected from seven mariculture ponds. The reactive phosphate level was quickly reduced to an ultra-low effluent concentration (<0.05 mg P/L), demonstrating the promising application potential of the La–MOF derivative.

Simulations predict preferred Mg2+ coordination in a nonenzymatic primer-extension reaction center

The mechanism by which genetic information was copied prior to the evolution of ribozymes is of great interest because of its importance to the origin of life. The most effective known process for the nonenzymatic copying of an RNA template is primer extension by a two-step pathway in which 2-aminoimidazole-activated nucleotides first react with each other to form an imidazolium-bridged intermediate that subsequently reacts with the primer. Reaction kinetics, structure-activity relationships, and X-ray crystallography have provided insight into the overall reaction mechanism, but many puzzles remain. In particular, high concentrations of Mg2+ are required for efficient primer extension, but the mechanism by which Mg2+ accelerates primer extension remains unknown. By analogy with the mechanism of DNA and RNA polymerases, a role for Mg2+ in facilitating the deprotonation of the primer 3′-hydroxyl is often assumed, but no catalytic metal ion is seen in crystal structures of the primer-extension complex. To explore the potential effects of Mg2+ binding in the reaction center, we performed atomistic molecular dynamics simulations of a series of modeled complexes in which a Mg2+ ion was placed in the reaction center with inner-sphere coordination with different sets of functional groups. Our simulations suggest that coordination of a Mg2+ ion with both O3′ of the terminal primer nucleotide and the pro-Sp nonbridging oxygen of the reactive phosphate of an imidazolium-bridged dinucleotide would help to pre-organize the structure of the primer/template substrate complex to favor the primer-extension reaction. Our results suggest that the catalytic metal ion may play an important role in overcoming electrostatic repulsion between a deprotonated O3′ and the reactive phosphate of the bridged dinucleotide and lead to testable predictions of the mode of Mg2+ binding that is most relevant to catalysis of primer extension.

Phosphorus starvation response genes and function coupling: A mechanism to regulate phosphorus availability in a subtropical estuary

Phosphorus (P) plays an important role in regulating primary production in estuarine environments. However, knowledge of the P-functional gene composition of microbial communities and the mechanisms of microbial adaptation to changes in available P in estuaries remain limited. This study coupling 16 s rDNA and metagenomics sequencing was conducted to reveal the relationship between P cycling functional genes, microbial interactions, and P availability in the Jiulong River Estuary. The results showed that the relative abundance of P cycling functions genes was highest in winter, and lowest in summer. Spatially, the total relative abundance of P cycling functions genes was higher in the riverward than that in the seaward. P cycling functional microbial interactions and P cycling gene coupling were strongest in summer and in the seaward. Changes in both temperature and salinity had significant direct and indirect effects on P cycling function, and the influence of salinity on P cycling function was greater than that on the microbial community in the estuary. Salinity had significant direct negative effects on inorganic P-solubilization (IP), organic P-mineralization (OP), and P uptake and transport functions (PT). Whereas, salinity had a significant positive effect on P-starvation response regulation (PR) function. Thus, salinity and microbial communities regulate the soluble reactive phosphate concentrations in estuarine environments by strengthening internal coupling among P cycling functions, promoting PR function, and facilitating PT gene expression. PR is the most important predictors, PR, PT, and PR-PT together explained 38.56 % of the overall soluble reactive phosphorus (SRP) variation. Over 66 % of the explained SRP variations can be predicted by the PR, PT, and PR-PT functional genes. This finding improves the knowledge base of the microbial processes for P cycling and provides a foundation for eutrophication management strategies in the estuary.

Evaluating the agronomic efficiency of alternative phosphorus sources applied in Brazilian tropical soils

Understanding the efficacy of alternative phosphorus (P) sources in tropical soils is crucial for sustainable farming, addressing resource constraints, mitigating environmental impact, improving crop productivity, and optimizing soil-specific solutions. While the topic holds great importance, current literature falls short in providing thorough, region-specific studies on the effectiveness of alternative P sources in Brazilian tropical soils for maize cultivation. Our aim was to assess the agronomic efficiency of alternative P sources concerning maize crop (Zea mays L.) attributes, including height, shoot dry weight, stem diameter, and nutrient accumulation, across five Brazilian tropical soils. In greenhouse conditions, we carried out a randomized complete block design, investigating two factors (soil type and P sources), evaluating five tropical soils with varying clay contents and three alternative sources of P, as well as a commercial source and a control group. We evaluated maize crop attributes such as height, dry weight biomass, and nutrient accumulation, P availability and agronomic efficiency. Our results showed that, although triple superphosphate (TSP) exhibited greater values than alternative P sources (precipitated phosphorus 1, precipitated phosphorus 2 and reactive phosphate) for maize crop attributes (e.g., height, stem diameter, shoot dry weight and phosphorus, nitrogen, sulfur, calcium and magnesium accumulation). For instance, PP1 source increased nutrient accumulation for phosphorus (P), nitrogen (N), and sulfur (S) by 37.05% and 75.98% (P), 34.39% and 72.07% (N), and 41.94% and 72.69% (S) in comparison to PP2 and RP, respectively. Additionally, PP1 substantially increased P availability in soils with high clay contents 15 days after planting (DAP), showing increases of 61.90%, 99.04%, and 38.09% greater than PP2, RP, and TSP. For Ca and Mg accumulation, the highest values were found in the COxisol2 soil when PP2 was applied, Ca = 44.31% and 69.48%; and Mg = 46.23 and 75.79%, greater than PP1 and RP, respectively. Finally, the highest values for relative agronomic efficiency were observed in COxisol2 when PP1 was applied. The precipitated phosphate sources (PP1 and PP2) exhibited a similar behavior to that of the commercial source (TSP), suggesting their potential use to reduce reliance on TSP fertilization, especially in soils with low clay contents. This study emphasized strategies for soil P management, aimed at assisting farmers in enhancing maize crop productivity while simultaneously addressing the effectiveness of alternative P sources of reduced costs.

Catalytic Metal Ion-Substrate Coordination during Nonenzymatic RNA Primer Extension.

Nonenzymatic template-directed RNA copying requires catalysis by divalent metal ions. The primer extension reaction involves the attack of the primer 3'-hydroxyl on the adjacent phosphate of a 5'-5'-imidazolium-bridged dinucleotide substrate. However, the nature of the interaction of the catalytic metal ion with the reaction center remains unclear. To explore the coordination of the catalytic metal ion with the imidazolium-bridged dinucleotide substrate, we examined catalysis by oxophilic and thiophilic metal ions with both diastereomers of phosphorothioate-modified substrates. We show that Mg2+ and Cd2+ exhibit opposite preferences for the two phosphorothioate substrate diastereomers, indicating a stereospecific interaction of the divalent cation with one of the nonbridging phosphorus substituents. High-resolution X-ray crystal structures of the products of primer extension with phosphorothioate substrates reveal the absolute stereochemistry of this interaction and indicate that catalysis by Mg2+ involves inner-sphere coordination with the nonbridging phosphate oxygen in the pro-SP position, while thiophilic cadmium ions interact with sulfur in the same position, as in one of the two phosphorothioate substrates. These results collectively suggest that during nonenzymatic RNA primer extension with a 5'-5'-imidazolium-bridged dinucleotide substrate the interaction of the catalytic Mg2+ ion with the pro-SP oxygen of the reactive phosphate plays a crucial role in the metal-catalyzed SN2(P) reaction.

Hydrobiological assessment of two lakes of Jahangirnagar University campus, savar, Bangladesh

The physicochemical and biological parameters of the water in two different lakes on the Jahangirnagar University campus were evaluated between December 2018 and August 2019. The chosen metrics were air and water temperature, Secchi depth, alkalinity, conductivity, pH, total dissolved solids (TDS), dissolved oxygen (DO), soluble reactive phosphate (SRP), soluble reactive silicate (SRS), nitrate-nitrogen (NO3-N) and phytoplankton density (PD). The correlation between all the matrics was done. 37 orders of phytoplankton from lake-1 and 35 orders of phytoplankton from lake-2 were found under 8 classes (Cyanophyceae, Chlorophyceae, Bacillariophyceae, Synurophyceae, Euglenophyceae, Cryptophyceae, Dinophyceae, and Xanthophyceae). According to the principal component Analysis (PCA), 53.8% variation was found among the classes. In addition, Monoraphidium, Oscillatoria, Cosmarium, Actinastrum, Trachlelomonas, Euglena, Pediastrum, Pinnularia, and Synedra were found to be dominant species. It examined the relationships between various environmental factors and dominant phytoplankton species in two lakes and found that the effects of the physicochemical parameters differ depending on the lake and dominant phytoplankton type. The study found negative correlations between various water quality parameters and phytoplankton taxa, suggesting an influence of environmental conditions on phytoplankton communities. Bangladesh J. Bot. 53(1): 159-171, 2024 (March)

Efeito residual de fontes de fósforo na presença e ausência de composto orgânico na produção de beterraba e chicória em cultivo sucessivo de brócolis

ABSTRACT The utilization of organic fertilizer for a short cycle crop may allow planting, in sequence, another short cycle crop, without the need for new fertilizers, reducing the costs of a new fertilization. The objective of this study was to evaluate the residual effect of fertilization applied to broccoli with phosphorus sources in the presence and absence of organic compost, on beet and chicory production in subsequent cultivation. In broccoli cultivation, four sources of phosphorus (thermophosphate, natural phosphate, natural reactive phosphate, and triple superphosphate) (600 kg/ha of P2O5) were evaluated in the presence and absence of organic compost (Visafértil®, 55 t/ha) before planting. After the removal of the cultural remains of broccoli, beet and chicory, seedlings were transplanted in the same plots of the first crop treatments. For each species eight treatments were evaluated, in a 4 x 2 factorial scheme. The first factor were the four sources of phosphorus and the second one was the application or not of organic compost before broccoli (hybrid BRO 68) planting. Treatments with organic compost showed greater production of beet and chicory, compared to the absence of compost. Fertilization with organic compost associated to the phosphorus sources provides necessary residual effect to beet and chicory production. The best P source for beet was triple superphosphate, and for chicory, in the absence of organic compost, triple superphosphate was the best source. In the presence of organic compost, the best sources were triple superphosphate and natural phosphate.

Decadal limnological changes in Lake Beseka, central Rift Valley of Ethiopia

AbstractLake Beseka (Metahara), formerly, an alkaline soda lake in the Central Rift Valley of Ethiopia is recently undergoing unprecedented changes. The objective of this study was to investigate the current status on the plankton composition of Lake Beseka, in relation to the lake's environmental parameters. Samples for physicochemical and biological parameters were taken twice a year during both the rainy and dry seasons at two different sites (open and shore). Temperature, pH, conductivity, dissolved oxygen, alkalinity, salinity, ammonia, silica and soluble reactive phosphate showed significant variation (p &lt; .05) between wet and dry seasons. The physicochemical parameters recorded during this study shows decreasing trend than the previous studies indicating the lakes ecosystem undergone fundamental changes over time. A total of 25 phytoplankton and 13 zooplankton genera were identified. The phytoplankton community of Lake Beseka had previously been dominated by Arthrospira fusiformis, but this time it was completely missing, and diatoms substituted for it. The decrease in pH and salinity of the lake's water could be responsible for these changes. In addition, cyclopoid copepods now predominate over zooplankton in Branchionus dimidiatus during periods of high salinity. Redundancy analysis showed that SRP, ammonia, nitrate and turbidity are important environmental factors that significantly influenced plankton abundance. This study provides new baseline information on the plankton composition of Lake Beseka, in relation to the lake's environmental parameters, which can be used to evaluate future community structure.

Soil Chemical Attributes under Agrosilvopastoral Systems and Pasture

Agrosilvopastoral systems involve the consortium of trees, agricultural crops, and pasture, in the same area, concomitant or sequential, based on agroecological bases and on the cycling of organic matter and nutrients. This research compares soil fertility under pasture and agrosilvopastoral system. The area of 5 ha, is located on the Campus of the Federal University of Viçosa in Florestal city, central region of Minas Gerais state, formed by Urochloa decumbens for about 30 years, in an argisolic dystrophic Red Yellow Latosol. Two agrosilvopastoral systems - in single lines 2 x 10 m and double lines 2 x 2 + 10 m - were compared with pasture without trees. The soil preparation was conventional, with ploughing and leveling grids, in December 2009. Seedlings of the hybrid Eucalyptpus urophylla and E. grandis, clone GG100, were planted in level and subsoiler lines, which received 500 kg ha-1 of reactive phosphate at a depth of 0.5 m. At planting, each seedling received 120 g of N:P:K 10:28:06 + 0.3% B + 0.5% Zn; and 120 g of N:P:K 20:00:20, at 60 days. The corn was sown in the alleys, receiving 360 kg ha-1 of N:P:K 08:28:16 + 0.5% Zn, at planting, and 240 kg of urea ha-1, at 30 days. After the corn harvest, the pasture was formed naturally from the seed bank. At 135 months post-planting, five composite soil samples were collected in each studied area, obtained from ten simple samples of the 0-5 cm layer. The following attributes were analyzed: pH, P, K, Ca, Mg, Al, H + Al, OM, and Prem. The results were submitted to analysis of variance and F test (p,0.05), and the means of the significant treatments were compared by the Scott Knott test (p&lt;0.05). Both APS provided an increase in the levels of OM, P, Ca, SB, t, and H + Al in the soil, keeping unchanged the other attributes analyzed in relation to conventional pasture. No significant differences in fertility were detected between the two agrosilvopastoral systems studied.

Separation of nutrients and acetate from sewage sludge fermentation liquid in flow-electrode capacitive deionization system: Competitive mechanisms of ions and influence of activated carbon

Effective separation of volatile fatty acids (VFAs), ammonia (NH4+-N) and reactive phosphorous (RP) generated from anaerobic fermentation liquid is critically important for efficient resource recovery. Flow-electrode capacitive deionization (FCDI) is proven to be capable of efficient removal of ions, environmentally friendly and cost-effective in operation. The performances of FCDI system in the separation of NH4+-N, RP, and acetate and mechanism of pHs and activated carbon on their performances were investigated. Results showed that a pH of 5.0 promoted the removal of NH4+-N (53.1 %) and RP (39.5 %), and 72.0 % of acetate was retained in the solution, which revealed that removal of NH4+-N and RP, and retention of acetate were evidently affected by speciation of ions. Furthermore, the recovery of NH4+-N and RP was undermined by the adsorption of ions on activated carbon. This study provides a novel insight of ion selective mechanism during the operation of the FCDI system.

Distinct diversity patterns and assembly mechanisms of prokaryotic microbial sub-community in the water column of deep-sea cold seeps

Methane leakage from deep-sea cold seeps has a major impact on marine ecosystems. Microbes sequester methane in the water column of cold seeps and can be divided into abundant and rare groups. Both abundant and rare groups play an important role in cold seep ecosystems, and the environmental heterogeneity in cold seeps may enhance conversion between taxa with different abundances. Yet, the environmental stratification and assembly mechanisms of these microbial sub-communities remain unclear. We investigated the diversities and assembly mechanisms in microbial sub-communities with distinct abundance in the deep-sea cold seep water column, from 400 m to 1400 m. We found that bacterial β-diversity, as measured by Sørensen dissimilarities, exhibited a significant species turnover pattern that was influenced by several environmental factors including depth, temperature, SiO32−, and salinity. In contrast, archaeal β-diversity showed a relatively high percentage of nestedness pattern, which was driven by the levels of soluble reactive phosphate and SiO32−. During the abundance dependency test, abundant taxa of both bacteria and archaea showed a significant species turnover, while the rare taxa possessed a higher percentage of nestedness. Stochastic processes were prominent in shaping the prokaryotic community, but deterministic processes were more pronounced for the abundant taxa than rare ones. Furthermore, the metagenomics results revealed that the abundances of methane oxidation, sulfur oxidation, and nitrogen fixation-related genes and related microbial groups were significantly higher in the bottom water. Our results implied that the carbon, sulfur, and nitrogen cycles were potentially strongly coupled in the bottom water. Overall, the results obtained in this study highlight taxonomic and abundance-dependent microbial community diversity patterns and assembly mechanisms in the water column of cold seeps, which will help understand the impacts of fluid seepage from the sea floor on the microbial community in the water column and further provide guidance for the management of cold seep ecosystem under future environmental pressures.

Computational Study on the Water Corrosion Process at Schreibersite (Fe2NiP) Surfaces: from Phosphide to Phosphates.

Phosphorus (P) is a fundamental element for whatever form of life, in the same way as the other biogenic macroelements (SONCH). The prebiotic origin of P is still a matter of debate, as the phosphates present on earth are trapped in almost insoluble solid matrixes (apatites) and, therefore, hardly available for inclusion in living systems in the prebiotic era. The most accepted theories regard a possible exogenous origin during the Archean Era, through the meteoritic bombardment, when tons of reactive P in the form of phosphide ((Fe,Ni)3P, schreibersite mineral) reached the primordial earth, reacting with water and providing oxygenated phosphorus compounds (including phosphates). In the last 20 years, laboratory experiments demonstrated that the corrosion process of schreibersite by water indeed leads to reactive phosphates that, in turn, react with other biological building blocks (nucleosides and simple sugars) to form more complex molecules (nucleotides and complex sugars). In the present paper, we study the water corrosion of different crystalline surfaces of schreibersite by means of periodic DFT (density functional theory) simulations. Our results show that water adsorbs molecularly on the most stable (110) surface but dissociates on the less stable (001) one, giving rise to further reactivity. Indeed, subsequent water adsorptions, up to the water monolayer coverage, show that, on the (001) surface, iron and nickel atoms are the first species undergoing the corrosion process and, in a second stage, the phosphorus atoms also get involved. When adsorbing up to three and four water molecules per unit cell, the most stable structures found are the phosphite and phosphate forms of phosphorus, respectively. Simulation of the vibrational spectra of the considered reaction products revealed that the experimental band at 2423 cm-1 attributed to the P-H stretching frequency is indeed predicted for a phosphite moiety attached to the schreibersite (001) surface upon chemisorption of up to three water molecules.

Lake morphology as an important constraint for benthic diatoms in temperate, humic forest ponds

Small lakes are among the most threatened ecosystems in the world. Their protection is of crucial importance since they support an unusually high biodiversity relative to their size. The present study aimed at selecting the main drivers, especially the role of the morphological variables, shaping benthic diatom communities in unique, but rarely investigated forest pond ecosystems in the temperate region, using traditional (species-based methods and diversity indices) and novel approaches (trait-based methods and functional diversity indices) of diatom ecology. Therefore, we analyzed the effects of the environmental (temperature, conductivity, colour, shading, pH, nutrient forms, anions) and morphological (surface area, depth) variables of 70 temperate, forest ponds located in two regions of Hungary on the composition (species- and trait-based) and diversity (traditional and functional) of their benthic diatom communities. Based on the multivariate analyses, no regional differences in the environmental and morphological variables were been observed among the ponds. Our results showed that both environmental variables and lake morphology had significant effects on the benthic diatom communities, but they contributed to their variation with different proportions. Environmental variables such as nutrient content (rsoluble reactive phosphate = 0.72) and conductivity (r = 0.65) affected mostly the species composition, and the traditional diversity metrics (rtotal phoshate = −0.42, rconductivity = −0.54). In contrast, morphological features of the ponds were the most important drivers of diatom trait composition. This functional response of diatoms manifested in the selection of species according to their size, shape and lifeforms, moreover, in changing of functional diversity. Overall, this study revealed the complex interplay between environmental variables and lake morphology in shaping the composition of benthic diatom communities. Furthermore, it highlights the necessity to apply different methods to understand the ecology and functioning of these special aquatic ecosystems.

Spatial distribution, source apportionment, and assessment of marine water quality parameters in the Bohai Sea, China

A two–year (2020−2021) survey dataset of six water quality parameters (pH, dissolved oxygen (DO), chemical oxygen demand (COD), dissolved inorganic nitrogen (DIN), soluble reactive phosphate (SRP), and petroleum pollutants) was used to investigate their spatial distribution in the Bohai Sea and quantify their potential sources. There were significant differences in spatial distribution of the parameters. High concentrations of COD, DIN and SRP were found in three bays, with terrestrial input being the main pollution source. Phosphorus–limiting conditions were present in the Bohai Sea. High petroleum pollutant concentrations were identified in port areas, offshore oilfields, and adjacent areas. The pH was above the global oceanic average and there were no signs of acidification. The contribution of the mixed terrestrial inputs, maritime transportation, and offshore oil exploitation sources, oceanic and associated biotic sources, and seawater–atmosphere exchange and atmospheric deposition sources to water quality were 63.4 %, 8.0 %, and 28.6 %, respectively.

The role of reactive phosphate species in the abatement of micropollutants by activated peroxymonosulfate in the treatment of phosphate-rich wastewater.

This study investigated the mechanisms of forming reactive species to degrade micropollutants through the activation of peroxymonosulfate (PMS) by phosphate, a prevalent ion in wastewater. Considering the density functional theory results, the formation of hydrogen bonds between phosphate and PMS molecules might be the crucial step in the overall reactions, which prefers producing ⋅OH and reactive phosphate species (RPS, namely H2PO4⋅, HPO4⋅-, and PO4⋅2-) to yielding SO4⋅-. Besides, in the phosphate (5mM)/PMS system at pH=8, HPO4⋅- was modeled to be the dominant radical with a steady-state concentration of 3.6×10-12M, which was 666 and 773 times higher than those of ⋅OH and SO4⋅-. The contributions of 1O2, ⋅OH, SO4⋅-, and RPS to the micropollutant decomposition in phosphate/PMS were studied, and RPS were found to be selective for micropollutants with electron-donating moieties (such as phenolic and aniline groups). Additionally, the degradation pathways of bisphenol A, diclofenac, ibuprofen, and atrazine in phosphate/PMS were proposed according to the detected transformation products. Cytotoxicity analysis was carried out to evaluate the potential environmental impacts resulting from the degradation of micropollutants by phosphate/PMS. This study confirmed the significance of RPS for micropollutant degradation during PMS-based treatment in phosphate-rich scenarios.

Permeable Pavement in the Northwestern United States: Pollution Source or Treatment Option?

Permeable pavements can be an effective stormwater mitigation technique, but there are concerns that polluted stormwater may contaminate groundwater as stormwater infiltrates through the soil beneath the pavement. This research evaluates the pollutant removal capabilities of pervious pavements using pervious cement concrete (PC) and porous asphalt concrete (PA) cylinders. Stormwater collected from an outfall was used to perform three tests. The influent and effluent were analyzed for metals, semi-volatile organic compounds (SVOCs), phosphorus, and turbidity. Average percent removal for metals were 37–63% except for zinc, which had an average export of 21% for pervious cement concrete and 52% for porous asphalt concrete. Only 10 of the SVOCs tested had an influent concentration above detection levels. Complete removal (below detection levels) was observed for benzo(a)anthracene, benzo(a)pyrene, chrysene, and indeno(1,2,3-cd) pyrene. Average removals for benzo(b)fluoranthene, benzo(g,h,i)perlyne, fluoranthene, phenanthrene, pyrene, and bis(2-ethylhexyl)phthalate were 63–96%. No significant removal was observed for total phosphorus and reactive phosphate. All contaminant concentrations were below drinking water limits except lead, which would likely be removed in the soil layer below the pavement. This study indicates permeable pavements can effectively remove stormwater contaminants and protect groundwater as a drinking water source.

Introducing La(OH)3 nanoparticles into attapulgite for the control of sediments internal phosphorus release: Effectiveness, mechanisms, and microbial community response

In-situ passivation of engineering materials is an economical and effective method to control internal phosphorus load in aquatic systems. However, few studies have simulated aerobic and anaerobic environments to compare the engineering materials control sediment phosphorus release performance with or without sediment re-suspension. In this study, we prepared and optimized lanthanum modified thermally attapulgite (LMTA) for sediment phosphorus immobilization with a maximum adsorption capacity of 97.99 mg/g. An 88-day sediment core cultivation experiment revealed that LMTA reduced the concentration of soluble reactive phosphate (SRP) and total phosphorus (TP) by 89.3% and 79.4% in absence of re-suspension, and by 89.8% and 78.3% with re-suspension, respectively. LMTA also transformed sediment Mobile-P into HCl-P and Res-P, which are inert phosphorus forms. Moreover, high-throughput sequencing showed that Nitrospirae abundance was significantly increased with LMTA, which could promote the water nitrogen cycle. The results confirmed that LMTA effectively controls internal phosphorus release, even under sediment re-suspension conditions.