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In this study, we made the first estimate of the annual dissolved organic phosphorus (DOP) load to Lake Erhai, a typical mesotrophic–eutrophic lake in China. We also evaluated what proportion of DOP was bioavailable using enzymatically hydrolyzable phosphorus (EHP), and further assessed the potential impacts of DOP on lake water quality. We estimated that the annual DOP load into Lake Erhai accounted for nearly 50% of total dissolved phosphorus, while EHP accounted for about 30% of the bioavailable phosphorus (BAP) pool. The DOP load increased and accounted for a greater proportion of total dissolved phosphorus and BAP loads during the wet season, and helped maintain algal blooms. Inflowing rivers were the main source of DOP with high bioavailability to Lake Erhai, especially in the wet season. The EHP concentrations of the inflowing rivers were positively correlated with algal biomass. The observation suggests that, as a significant source of BAP, the contribution of the DOP load to eutrophication of the lake should not be ignored, especially given the low soluble reactive phosphorus concentrations in the lake water during the algal biomass period. Information on the contributions from different pollution sources is needed to support the development of effective P pollution control strategies. Short-term strategies to protect Lake Erhai include better management of the inflowing rivers, especially in the northern part during the wet season, while, over the long-term, strategies to decrease P release from lake sediments should be considered. [ABSTRACT FROM AUTHOR]

Inspired by the mussel adhesion protein, dopamine was used to prepare polydopamine (PDA)-coated polyurethane sponge (PDA-PUS) via self-polymerization reaction. Halloysite nanotubes (HNTs) were grafted with γ -aminopropyltriethoxysilane (APTES). The new organic-inorganic hybrid adsorption material (HNTs@PUS) was fabricated by covalent link of APTES-grafted HNTs and PDA-PUS through Schiff base reaction/Michael addition. The as-prepared HNTs@PUS showed much higher mechanical stability and compressive property than polyurethane sponge (PUS). HNTs@PUS had 7.7, 7.1, 1.7 and 8.5 times adsorption capacity of PUS for Congo red (CR), Methyl orange (MO), Rhodamine 6 G (R6G) and heavy metal ion Cr(VI), respectively. HNTs@PUS had a fast adsorption rate and most of CR, MO, R6G and Cr(VI) were adsorbed by HNTs@PUS within 20 min. In addition, HNTs@PUS maintained 70.3%, 66.5%, 67.3% and 77.4% of its adsorption capacity for CR, MO, R6G and Cr(VI), respectively, after 5 cycles of regeneration. HNTs@PUS could be easily recovered to avoid secondary contamination. Besides, using HNTs@PUS as adsorbents, a continuous flow adsorption device was developed, through which anionic and cationic dyes and heavy metal ion could be continuously and effectively removed from the flowing solution. These results demonstrated that HNTs@PUS had potentially ideal attributes for use as adsorbents in the ultrafast, high efficiency and large-scale removal of anionic and cationic dyes and heavy metal ions from wastewaters. The fabrication strategy not only solved the problem of the poor recyclability and low permeability of HNTs, but also greatly improved the adsorption capacity of PUS, which might accelerate the application of natural "green" HNTs in wastewater treatment. [Display omitted] • HNTs@PUS has been fabricated by covalent link of HNTs and PUS. • HNTs@PUS has more seven times adsorption capacity of PUS for CR, MO and Cr(VI). • Most of CR, MO, R6G and Cr(VI) were adsorbed by HNTs@PUS within 20 min. • HNTs@PUS maintains over 67% of the adsorption capacity for dyes/Cr(VI) after 5 cycles. • HNTs@PUS can be used in a continuous flow system against emerging contaminants. [ABSTRACT FROM AUTHOR]

• P species shifted from TDP dominated in Miju River to TPP dominated in Lake Erhai. • SPM as a sink in rivers and a source in lakes buffered P level during the wet season. • P-buffering effect of SPM was associated with the quality and quantity of SPM. • Increased phyto-SPM enhanced P buffering to maintain algae bloom under DIP-limitation. • For water management, the inner loop among algae-SPM-P should not be ignored. How to maintain harmful algal blooms under phosphate-limitation is still an open question in mesotrophic/eutrophic lakes. Little evidence for the importance of suspended particulate matter (SPM) in mediating phosphorus cycling and contributing to eutrophication has been generated for aquatic ecosystems, especially in coupled river-lake systems. In this study, we examined phosphorus transport and redistribution in a river-lake system in the Lake Erhai basin by establishing the relations between phosphorus distribution and phosphorus sorption behavior on SPM, and predicted how changes in the quality and quantity of SPM might influence phosphorus cycling by laboratory experiments and modeling. During the wet seasons, TP pool shifted from being dominated by total dissolved phosphorus (TDP) in the Miju River and estuary regions (73±5%) to being dominated by total particulate phosphorus (TPP) (74±11%) in Lake Erhai. The detritus-SPM in the Miju River as a P-sink and phytoplankton-SPM in Lake Erhai as a P-source buffered TDP levels during the wet seasons, which attributed to P activity and phytoplankton-POC of SPM. Increasing SPM concentrations could enhance the P-buffering. When C 0 ≤ 5 μmol/L and phytoplankton-SPM ≥ 16 mg/L, P release increased by 50%-300%; when C 0 ≥ 5 μmol/L and detritus-SPM ≥ 16 mg/L, P removal could exceed 30%. This study highlights two distinctive roles of SPM in regulating P cycling during transport from rivers to lakes. Especially the phytoplankton-SPM to buffer phosphate-limitation during algal blooms should not be ignored, which could provide theoretical references for the mechanism of continued algal blooms in mesotrophic lakes. [Display omitted] [ABSTRACT FROM AUTHOR]

A new sediment P release risk index (SPRRI) for "in-situ" phosphorus (P) release risk in lake sediment, is developed based on diffusive gradients in thin films (DGT) technique, DGT induced flux in sediments (DIFS) model and sediment properties. SPRRI includes three sub-indexes, which contain (1) the labile P pool size, (2) resupply constant (r) and desorption rate (Dspt rate) for P transfer and (3) the molar ratio between iron (Fe) in sequential extraction for sediment P by bicarbonate-dithionite (BD) and aluminum (Al) by NaOH (at 25 °C), i.e. BD(Fe)/Al[NaOH25] in sediment solid. The first sub-index considers P release from (i) sediment with NH 4 Cl-P+BD-P pool, i.e. the loosely sorbed P (NH 4 Cl-P) plus iron associated P (BD-P), or (ii) sediment with NH 4 Cl-P pool, respectively. The second and third sub-indexes reflect kinetic P desorption and resupply ability of solid phase, and the effect of P sequestration by Al hydroxide on P release, in turn. The inner relationship between SPRRI and sub-indexes, and their effects on P release risk are elucidated. SPRRI can be used to evaluate sediment P reactivity by five release risk ranks. For Lake Dianchi (China), P transfer dynamics, labile P pool, resupply ability and Al-P in sediment, and "external P-loading" control and affect P release risk in different regions, which is reflected by the spatial distribution map for SPRRI. The present SPRRI can be applied for lakes with (1) pH range varying from moderate acidity to weak alkalinity in waterbody and (2) NH 4 Cl-P or NH 4 Cl-P+BD-P pool in sediment solid. Image 1 • A new sediment P release risk index (SPRRI) for lake sediment has been designed. • DIFS model and sediment properties have been combined to derive SPRRI. • SPRRI considers not only P fraction and Al, but also "in-situ" dynamic P transfer. • P release risk for NH 4 Cl-P or NH 4 Cl-P+BD-P sediment pool can be evaluated. • SPRRI can be applied for pH from moderate acidity to weak alkalinity in water. A new assessment method for P release risk in lake sediment has been developed based on DIFS model and sediment properties. [ABSTRACT FROM AUTHOR]

Selenium (Se), a trace element, is essential for biological growth; however, excess Se in water can harm aquatic organisms, including fish. Thus, increasing attention is being paid to the risk of Se in aquatic ecosystems. However, there has been little research regarding the protection of aquatic organisms from excess Se in China. To comprehensively ensure China's ecological safety, research on the water quality criteria (WQC) of Se is urgently required. Herein, water and fish samples were collected from Taihu Lake and Yellow River estuary to investigate Se distribution characteristics and bioaccumulation factors (BAFs) in aquatic ecosystems. Tissue-based toxicity data and BAFs were used to derive the WQC for Se. Quotient and probabilistic methods were used to assess the ecological risk of Se to aquatic life. The results revealed that the average levels of Se in the water samples were 1.54 and 1.07 μg/L and that the average Se levels in the fish samples were 0.87 and 0.66 mg/kg in Taihu Lake and the Yellow River estuary, respectively. Furthermore, the calculated BAF for Se in fish was 618.69 L/kg, and the calculated WQC for Se to protect aquatic organisms was 0.29 μg/L. The high levels of ecological risk associated with Se in Taihu Lake and the Yellow River estuary indicate that the aquatic risk of Se warrants further attention. This study provides scientific guidance for setting Se water quality standards to protect aquatic organisms and ensure environmental management in China. [ABSTRACT FROM AUTHOR]

• CTRP9 affects the activity of NLRP3 inflammasome during the atherosclerosis development. • CTRP9 exert an atheroprotective effect via AMPK- NLRP3 inflammasome pathway. • CTRP9 could suppress atherosclerosis development in mice, has protective effect on athersocelrosis. C1q tumor necrosis factor-related protein 9 (CTRP9) has been suggested to exert an atheroprotective effect by modulating the inflammation, foam cell formation, endothelia and smooth muscle cell function via Adenosine Monophosphate Activated Protein Kinase (AMPK) pathway. On the other hand, the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome plays an critical role in the atherosclerosis development, which is regulated by the AMPK. However, whether the CTRP9 affects the activity of NLRP3 inflammasome during the atherosclerosis development remains unclear, which would be elucidated in the current study. The macrophage cells were stimulated with the oxidized low-density lipoprotein (ox-LDL) and also treated with the recombinant CTRP9 in the meantime. The activation of NLRP3 inflammasome was determined by measuring the releasing of IL-1β and caspase-1 p10 via ELISA and western blot, respectively. Then the AMPK was inhibited in macrophages by Dorsomorphin. Finally, the CTRP9-AMPK-NLRP3 inflammasome pathway was validated in the mouse model of atherosclerosis. The CTRP9 could down-regulate the expression of NLRP3 protein and also the activity of NLRP3 inflammasome in the ox-LDL activated macrophages. Inhibiting the AMPK significantly restored the activities of NLRP3 inflammasome. In the apolipoprotein E-deficient mice, lentiviral expression of CTRP9 could suppress the atherosclerosis development, which could be abolished by AMPK inhibition. Our data here indicated that the CTRP9 showed atheroprotective function via CTRP9-AMPK- NLRP3 inflammasome pathway. [ABSTRACT FROM AUTHOR]