The sorption of algal organic matter by extracellular polymeric substances: Trade-offs in disinfection byproduct formation influenced by divalent ions.

Disinfection by-products (DBPs), formed from biofilm extracellular polymeric substances (EPS) and organic matter during regular disinfection practices in drinking water distribution systems, poses a potential threat to drinking water safety. However, the diverse DBP formations induced by the intertwined algal organic matter (AOM) and bacterial EPS remains elusive. In this study, we show substantial variations in EPS and DBP formation patterns driven by AOM biosorption with divalent ions (Ca and Mg).

Effects of land use and dissolved organic matter on pCO are dependent on stream orders and hydrological seasonality in a low-order karst river.

Human activities and stream accumulation influence carbon loadings, altering the distributions and characteristics of dissolved inorganic and organic carbon in rivers. It is widely recognized that such alterations affect dissolved organic matter (DOM) components, water environment and river carbon dioxide (CO) degassing, however, the control factors by which land use/land cover (LULC) and DOM components regulate the partial pressure of CO (pCO) are unclear. Here, in the Daning karst river system, an extensive investigation was presented to investigate the role of LULC and DOM components in influencing the spatial and temporal variability of pCO, as well as to investigate the regulating effect of stream order and hydrological rhythm on this influence.

Eutrophication constrains driving forces of dissolved organic carbon biodegradation in metropolitan lake systems.

Dissolved organic carbon (DOC) components can be highly variable in aquatic ecosystems, and play a pivotal role in the global carbon cycles. To comprehend potential effects of nutrient enrichment on portion of DOC biodegradability (%BDOC), we conducted an extensive investigation on 26 urban lakes in a major metropolitan area in subtropical China in a small gradient of trophic levels from mesotrophic to light and middle eutrophic. In addition to field measurements on lake ambient conditions and laboratory analysis of DOC characteristics, we conducted a 28-day temperature-controlled incubation experiment, in which %BDOC of lake waters was determined.

A comprehensive conceptual framework for signaling in-lake CO through dissolved organic matter.

Organic carbon (C) and CO pools are closely interactive in aquatic environments. While there are strong indications linking freshwater CO to dissolved organic matter (DOM), the specific mechanisms underlying their common pathways remain unclear. Here, we present an extensive investigation from 20 subtropical lakes in China, establishing a comprehensive conceptual framework for identifying CO drivers and retrieving CO magnitude through co-trajectories of DOM evolution.

Air pollution control and carbon reduction policies: Assessing effectiveness in alleviating PM-associated mortality in China.

To confront the challenges posed by air pollution and climate change, China has undertaken significant initiatives to develop strategies that address both issues concurrently. However, the health benefits of these initiatives have not been clearly articulated. In this study, the dynamic changes in health impacts under air pollution and carbon reduction actions in China are evaluated by employing the latest concentration-response models and projected PM concentrations under future scenarios.

Algae removal and algal organic matter chemistry modulated by KMnO-PAC in simulated karst water.

In this study, we examined the modulation of algae removal and algal organic matter (AOM) chemistry by potassium permanganate and poly-aluminum chloride (KMnO-PAC) in simulated karst water. Specifically, we verified the compositional changes of AOM sourcing from Chlorella sp. and Pseudanabaena sp.

Drivers of ozone-related premature mortality in China: Implications for historical and future scenarios.

Long-term exposure to ambient ozone (O) poses a severe public health threat in China. However, the drivers of premature mortality caused by O pollution are still poorly constrained, despite being prerequisites for addressing the threat. Here, we demonstrate the contributions of historical and future changes in peak-season O, population size, age structure, and baseline mortality to China's O-related mortality using decomposition analysis.

Riverine nitrate source and transformation as affected by land use and land cover.

A mixed land use/land cover (LULC) catchment increases the complexity of sources and transformations of nitrate in rivers. Spatial paucity of sampling particularly low-resolution sampling in tributaries can result in a bias for identifying nitrate sources and transformations. In this study, high spatial resolution sampling campaigns covering mainstream and tributaries in combination with hydro-chemical parameters and dual isotopes of nitrate were performed to reveal spatio-temporal variations of nitrate sources and transformations in a river draining a mixed LULC catchment.

Land use and hydrological factors control concentrations and diffusive fluxes of riverine dissolved carbon dioxide and methane in low-order streams.

We analyzed the impacts of land use/land cover types on carbon dioxide (CO) and methane (CH) concentration and diffusion in 1 to 4 Strahler order tributaries of the Longchuan River to the upper Yangtze River in China by using headspace equilibration method and COSYS program. Field sampling and measurements were conducted during the dry and wet seasons from 2017 to 2019. The average of calculated CO partial pressure (pCO, mean ± SD: 2389 ± 3220 μatm) by COSYS program was 1.

Dynamics and internal links of dissolved carbon in a karst river system: Implications for composition, origin and fate.

Dissolved carbon (DC) deciphers biotic and abiotic processes in aquatic ecosystems, representing a critical component of global carbon cycling. However, underlying drivers of riverine DC dynamics and internal links have yet to be studied. Here, we investigated fluvial physicochemical characteristics, dissolved inorganic carbon (DIC) species, carbon dioxide (CO) exchange, dissolved organic carbon (DOC) compositions and properties in a karst river system Qijiang, Southwest China.

Ultraviolet humic-like component contributes to riverine dissolved organic matter biodegradation.

Biological degradation of dissolved organic matter (DOM) regulates its structure and fate in river ecosystems. Previous views suggested that labile components were dominantly consumed by microbial metabolism. Here we provide new observations that a part of recalcitrant compounds largely contribute to riverine DOM biodegradation.

Effect of dissolved organic matter and its fractions on disinfection by-products formation upon karst surface water.

In this study, disinfection by-products (DBP) formation from dissolved organic matter (DOM) and its fractions, including both hydrophilic and hydrophobic components, were investigated at a typical karst surface water. The subsequent DBP formation potential was evaluated by deducing chemical characteristics of DOM fractions and representative algal organic matter (Chlorella sp. AOM) under the influence of divalent ions (Ca and Mg) via spectra analysis.

[Dissolved Organic Matter Component and Source Characteristics of the Metropolitan Lakes and Reservoirs in a Typical Karst Region].

In order to explore dissolved organic matter (DOM) components and their origins in metropolitan lakes and reservoirs in the karst region, the typical Hongfeng Lake, Baihua Lake, Songbaishan Reservoir, and Aha Reservoir were investigated in Guiyang City. Surface water parameters, including dissolved organic carbon (DOC), chlorophyll a (Chla), and optical parameters (, , , E2:E3, , FI, , BIX, and HIX) were analyzed. Fluorescence peaks (B, T, A, M, C, D, and N) and three-dimensional matrix fluorescence with parallel factor analysis (EEM-PARAFAC) were employed to explain distinct DOM abundances and proportions.

[Water-air Carbon Dioxide Exchange and Nutritional Controls in a Typical Karst River].

To explore water-air carbon dioxide (CO) exchange and its nutritional controls in karst rivers, water sampling and analyses were conducted in the Furong River as a representative karst river system. Regional hydrometeorological characteristics, carbonate system parameters, total organic carbon (TOC), nutrients and their stoichiometric ratios, and the riverine pressure of aqueous CO (CO) and its couplings to trophic status were analyzed. The results showed that gas transfer velocity of CO () varied between 2.

Seasonal variations of water quality response to land use metrics at multi-spatial scales in the Yangtze River basin.

Land use pattern is increasingly regarded as an important determinant of environmental quality and regional ecosystems. Understanding the correlation between land use metrics and water quality is essential to improve water pollution prediction and provide guidance for land use planning. Here, we examined the land use metrics and water quality parameters (i.

Linking riverine partial pressure of carbon dioxide to dissolved organic matter optical properties in a Dry-hot Valley Region.

The mineralization of dissolved organic matter (DOM) can partially explain riverine carbon dioxide (CO) emissions to the atmosphere. However, little is known about how the DOM origin and composition drive CO partial pressures (pCO). Here, we reveal links between aquatic pCO, DOM optical parameters (a, a and S and S) and nutrients in a subtropical river in China's Dry-hot Valley Region.

[Water-Air Interface CO Exchange Flux of Typical Lakes in a Mountainous Area of the Western Chongqing and Their Influencing Factors].

To examine the mountainous lake CO evasion in Southwest China, partial pressures of carbon dioxide[(CO)] and the CO exchange flux[(CO)] the water-air interface of nine mountainous lakes in Chongqing, China, have been studied in summer using the thin boundary layer model (TBL) and floating chambers. Key water quality parameters were concomitantly measured. The results indicate that the CO in the mountainous lakes in western Chongqing ranges from 2.

Optimization of Malachite Green Removal from Water by TiO₂ Nanoparticles under UV Irradiation.

TiO₂ nanoparticles with surface porosity were prepared by a simple and efficient method and presented for the removal of malachite green (MG), a representative organic pollutant, from aqueous solution. Photocatalytic degradation experiments were systematically conducted to investigate the influence of TiO₂ dosage, pH value, and initial concentrations of MG. The kinetics of the reaction were monitored via UV spectroscopy and the kinetic process can be well predicted by the pseudo first-order model.

Electrokinetic-Fenton remediation of organochlorine pesticides from historically polluted soil.

Soil contamination by persistent organic pollutants (POPs) poses a great threat to historically polluted soil worldwide. In this study, soils were characterized, and organochlorine pesticides contained in the soils were identified and quantified. Individual electrokinetic (IE), EK-Fenton-coupled technologies (EF), and enhanced EK-Fenton treatment (E-1, E-2, and E-3) were applied to remediate soils contaminated with hexachloro-cyclohexane soprocide (HCH) and dichloro-diphenyl-trichloroethane (DDT).

Heavy metals in soils of Hechuan County in the upper Yangtze (SW China): Comparative pollution assessment using multiple indices with high-spatial-resolution sampling.

In order to assess heavy metals (HMs) in soils of the upper Yangtze Basin, a very high-spatial-resolution sampling (582 soil samples) was conducted from Hechuan County, an important agricultural practice area in the Southwest China. Multiple indices including geoaccumulation index (I), enrichment factor (EF), sediment pollution index (SPI) and risk index (RI), as well as multivariate statistics were employed for pollution assessment and source identification of HMs in soils. Our results demonstrated that the averages of eight HMs decreased in the following order: Zn (82.