Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 2.629
Filter
1.
Antonie Van Leeuwenhoek ; 117(1): 97, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38980429

ABSTRACT

A Gram-staining-negative, facultative aerobic, motile strain, designated strain ZSDE20T, was isolated from the surface seawater of Qingdao offshore. Phylogenetic analysis of the 16S rRNA gene of strain ZSDE20T, affiliated it to the genus Photobacterium. It was closely related to Photobacterium lutimaris DF-42 T (98.92% 16S rRNA gene sequence similarity). Growth occurred at 4-28ºC (optimum 28ºC), pH 1.0-7.0 (optimum 7.0) and in the presence of 1-7% (w/v) NaCl (optimum 3%). The dominant fatty acids were summed feature 3 (C16:1 ω7c or/and C16:1 ω6c, 34.23%), summed feature 8 (C18:1 ω7c and C18:1 ω6c, 10.36%) and C16:0 (20.05%). The polar lipids of strain ZSDE20T comprised phosphatidylethanolamine, phosphatidylcholine, lyso-phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol dimannoside, phosphatidylinositol mannosides and two unknown lipids. The major respiratory quinone was ubiquinone-8 (Q-8). The DNA G + C content of strain ZSDE20T was 45.6 mol%. Average nucleotide identity (ANI) values between ZSDE20T and its reference species were lower than the threshold for species delineation (95-96%); in silico DNA-DNA hybridization further showed that strain ZSDE20T had less than 70% similarity to its relatives. Based on the polyphasic evidences, strain ZSDE20T is proposed as representing a novel species of the genus Photobacterium, for which the name Photobacterium pectinilyticum sp. nov. is proposed. The type strain is ZSDE20T (= MCCC 1K06283T = KCTC 82885 T).


Subject(s)
Base Composition , DNA, Bacterial , Fatty Acids , Photobacterium , Phylogeny , RNA, Ribosomal, 16S , Seawater , Seawater/microbiology , RNA, Ribosomal, 16S/genetics , Photobacterium/genetics , Photobacterium/classification , Photobacterium/isolation & purification , Photobacterium/metabolism , Photobacterium/physiology , DNA, Bacterial/genetics , Fatty Acids/analysis , Fatty Acids/chemistry , China , Bacterial Typing Techniques , Nucleic Acid Hybridization , Sequence Analysis, DNA , Quinones/analysis , Phospholipids/analysis
2.
Sci Total Environ ; : 174602, 2024 Jul 08.
Article in English | MEDLINE | ID: mdl-38986709

ABSTRACT

Traditional mining practices not only cause severe environmental issues, but also face the problem of insufficient production capacity of gold to meet its growing demand. The proposed alternative strategies for gold production, such as the extraction of gold from seawater, still keep a formidable challenge due to their strong dependence on adsorbent materials with high capacity, selectivity, and sensitivity, while also needing to meet the demands of being environmentally friendly and cost-effective. In practice, the direct extraction of gold from seawater is limited by its extremely low yield and high energy expenditure. However, if the combination of gold extraction techniques with seawater desalination can substantially reduce the energy consumption, the extraction of gold from seawater will become economical and feasible. In this paper, we evaluate the feasibility of marine gold extraction using reduced graphene oxide membranes (rGOM) during the seawater desalination process. The rGOM can adsorb almost all Au3+ from the solutions with trace concentrations of Au3+ ranging from 10 ppb to 200 ppb. The adsorption quantity is linearly related to the concentration, indicating that the adsorption capacity of rGOM is much higher than the total amount of Au3+ in the solution. Additionally, the rGOM can selectively adsorb 99 % of Au3+ in the mixed solution while hardly adsorbing other common elements in seawater. More importantly, the rGOM exhibits the long-term stability over 30 days when being immersed in the solution, making it directly compatible with the existing seawater desalination processes. These specific properties allow the rGOM to be an ideal candidate for combining the extraction of gold from seawater with seawater desalination processes. Our findings provide a methodology for enhancing the economic efficiency of the extraction of gold from seawater and hold promise for addressing the problem of gold scarcity.

3.
J Colloid Interface Sci ; 675: 429-437, 2024 Jul 04.
Article in English | MEDLINE | ID: mdl-38981252

ABSTRACT

Aqueous sodium-ion batteries (ASIBs) show great promise as candidates for large-scale energy storage. However, the potential of ASIB is impeded by the limited availability of suitable anode types and the occurrence of dissolution side reactions linked to hydrogen evolution. In this study, we addressed these challenges by developing a Bi-coating modified anode based on a sodium titanium phosphate (NTP)-carbon fibers (CFs) hybrid electrode (NTP-CFs/Bi). The Bi-coating effectively mitigates the localized enrichment of hydroxyl anion (OH-) near the NTP surface, thus addressing the dissolution issue. Notably, the Bi-coating not only restricts the local abundance of OH- to inhibit dissolution but also ensures a higher capacity compared with other NTP-based anodes. Consequently, the NTP-CFs/Bi anode demonstrates an impressive specific capacity of 216.8 mAh/g at 0.2 mV/s and maintains a 90.7 % capacity retention after 1000 cycles at 6.3 A/g. This achievement sets a new capacity record among NTP-based anodes for sodium storage. Furthermore, when paired with a cathode composed of hydroxy nickel oxide directly grown on Ni foam, we assembled a seawater-based cell exhibiting high energy and power densities, surpassing the most recently reported ASIBs. This groundbreaking work lays the foundation for a potential method to develop long-life NTP-based anodes.

4.
Water Res ; 261: 122024, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38986282

ABSTRACT

Water quality, critical for human survival and well-being, necessitates rigorous control to mitigate contamination risks, particularly from pathogens amid expanding urbanization. Consequently, the necessity to maintain the microbiological safety of water supplies demands effective surveillance strategies, reliant on the collection of representative samples and precise measurement of contaminants. This review critically examines the advancements of passive sampling techniques for monitoring pathogens in various water systems, including wastewater, freshwater, and seawater. We explore the evolution from conventional materials to innovative adsorbents for pathogen capture and the shift from culture-based to molecular detection methods, underscoring the adaptation of this field to global health challenges. The comparison highlights passive sampling's efficacy over conventional techniques like grab sampling and its potential to overcome existing sampling challenges through the use of innovative materials such as granular activated carbon, thermoplastics, and polymer membranes. By critically evaluating the literature, this work identifies standardization gaps and proposes future research directions to augment passive sampling's efficiency, specificity, and utility in environmental and public health surveillance.

5.
J Colloid Interface Sci ; 675: 515-525, 2024 Jul 06.
Article in English | MEDLINE | ID: mdl-38986325

ABSTRACT

The scarcity of freshwater resources and increasing demand for drinking water have driven the development of durable and sustainable desalination technologies. Although MXene composites have shown promise due to their excellent photothermal conversion and high thermal conductivity, their high hydrophilicity often leads to salt precipitation and low durability. In this study, we present a novel Cellulose (CF)/MXene paper with a Janus hydrophobic/hydrophilic configuration for long-term and efficient solar-driven desalination. The paper features a dual-layer structure, with the upper hydrophobic layer composed of CF/MXene paper exhibiting convexness to serve as a photothermal layer with exceptional salt rejection properties. Simultaneously, the bottom porous layer made of CF acts as an efficient thermal insulation. This unique design effectively minimizes heat loss and facilitates efficient water transportation. The Janus CF/MXene paper demonstrates a high evaporation rate of 1.11 kg m-2h-1 and solar thermal conversion efficiency of 82.52 % under 1 sun irradiation. Importantly, even after 2500 h of operation in a simulated seawater environment, the paper maintains a stable evaporation rate without significant salt deposition and biodegradation due to an antibacterial rate exceeding 90 %. These findings highlight the potential of the Janus CF/MXene paper for scalable manufacturing and practical applications in solar-driven desalination.

6.
Mar Pollut Bull ; 206: 116669, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38991609

ABSTRACT

Dichlorvos (DDVP) is a widely used organophosphorus pesticide (OPP) that has been frequently detected in the marine environment of China. Water quality criteria (WQC) is however not available for this emergent pollutant in the marine environment, which hinders its ecological risk assessment. This study, therefore, screened toxicity values of DDVP and conducted toxicity tests on six marine species to supplement toxicity data. The WQC for DDVP was derived with the species sensitivity distribution (SSD) methodology, based on which the ecological risk of DDVP in the seawater of China was assessed. The results showed that the recommended short-term (SWQC) and long-term water quality criteria (LWQC) for DDVP were 1.47 and 0.0521 µg/L, respectively. Most marine waters of China showed low or negligible risk (HQ < 1, ORP < 2 %), whereas some estuarine waters warrant further concern due to higher risk. This study provides the scientific basis for seawater quality standard formulation and ecological risk management for DDVP.

7.
Sci Total Environ ; : 174683, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38992352

ABSTRACT

The estuary of Huelva is constituted by the common mouth of the Odiel and Tinto rivers, which are extreme cases of acid mine drainage contamination due to the Iberian Pyrite Belt, the world's largest sulfide mineral province. The drained acidic waters are subjected to seawater mixing and thus, to dilution and precipitation processes that drive the load of contaminants entering the oceanic environment. This research reports the distribution of major metal(loid)s present in the highly acidic waters across the entire Tinto and Odiel estuarine systems as they are subjected to acid mine drainage neutralization, until reaching the ocean. The datasets presented are divided in low- and high-flow periods, corresponding to dry/warm and wet/cold seasons, respectively. Iron and Al were almost entirely removed from solution with pH increase at both periods due to their precipitation as schwertmannite and basaluminite, respectively. These mineral phases also, controlled the behavior of As, Cu and Pb, which were removed from solution, with >90 % of their concentration ending up in the particulate phase due to sorption processes. However, at pH >7, As returned entirely to the dissolved phase at both sampled seasons because of desorption, similarly to Cu at the low-flow period. On the other hand, concentrations of Zn, Cd, Mn, Co and Ni in solution decreased only by dilution with seawater, with null partitioning to any sorption processes during estuarine mixing until reaching the Atlantic Ocean.

8.
J Colloid Interface Sci ; 675: 218-225, 2024 Jun 27.
Article in English | MEDLINE | ID: mdl-38968638

ABSTRACT

Converting plastics into organic matter by photoreforming is an emerging way to deal with plastic pollution and produce valuable organic matter. Water shortage can be alleviated by using seawater resources. To solve these problems, we synthesize a ternary heterostructure composite g-C3N4/CdS/NiS. Heterojunctions are formed between graphitized carbon nitride (g-C3N4), cadmium sulfide (CdS) and nickel sulfide (NiS), which effectively improve the problem of fast charge recombination of pure g-C3N4 and CdS. The results of the g-C3N4/CdS/NiS photocatalytic tests show that the hydrogen production rates in seawater and pure water for 5 h are 30.44 and 25.79 mmol/g/h, respectively. In stability test, the hydrogen production rate of the g-C3N4/CdS/NiS in seawater and pure water is similar. This suggests that seawater can replace pure water as a source of hydrogen. While H2 is generated, the lactate obtained by polylactic acid (PLA) hydrolysis is oxidized to form small organic compounds such as formate, acetate and pyruvate. Our study shows that g-C3N4/CdS/NiS can not only use seawater as a hydrogen source to produce H2, but also photoreformate plastics dissolved in seawater into valuable small organic molecules. This has a positive impact on the production and use of clean energy, as well as on plastic pollution and water scarcity.

9.
J Colloid Interface Sci ; 674: 894-901, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38959735

ABSTRACT

The endeavor to architect bifunctional electrocatalysts that exhibit both exceptional activity and durability heralds an era of boundless potential for the comprehensive electrolysis of seawater, an aspiration that, nevertheless, poses a substantial challenge. Within this work, we describe the precise engineering of a three-dimensional interconnected nanoparticle system named SCdoped Co2VO4/CoP (SCCo2VO4), achieved through a meticulously arranged hydrothermal treatment sequence followed by gas-phase carbonization and phosphorization. The resulting SCCo2VO4 electrode exhibits outstanding bifunctional electrocatalytic stability, attributed to the strategic anionic doping and abundant heterogeneous interfaces. Doping not only adjusts the electronic structure, enhancing electron transfer efficiency but also optimizes the surface-active sites. This electrode prodigiously necessitated an extraordinarily minimal overpotential of merely 92 and 350 mV to attain current densities of 10 and 50 mA cm-2 for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, in 1 M KOH solution. Noteworthily, when integrated into an electrolyzer for the exhaustive splitting of seawater, the SCP-Co2VO4 manifested an exceptionally low cell voltage of 2.08 V@50 mA cm-2 and showcased a durability that eclipses that of most hitherto documented nickel-based bifunctional materials. Further elucidation through Density Functional Theory (DFT) analyses underscored that anion doping and the inherent heterostructure adeptly optimize the Gibbs free energy of intermediates comprising hydrogen, chlorine, and oxygen (manifested as OH, O, OOH) within the HER and OER paradigms, thus propelling the electrochemical kinetics of seawater splitting to unprecedented velocities. These revelations unfurl a pioneering design philosophy for the creation of cost-effective yet superior catalysts aimed at the holistic division of water molecules, charting a course towards the realization of efficient and sustainable hydrogen production methodologies.

10.
Chemphyschem ; : e202400397, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38960874

ABSTRACT

Freeze desalination is an appealing method for seawater desalination through freezing seawater. The percentage of ions in the liquid phase, which is termed ion rejection rate, is a critical factor affecting the performance of freeze desalination. Improving the ion rejection rate is an important topic for freeze desalination. In this work, we investigate the effects of electric fields on the ion rejection rate during the freezing of seawater through molecular dynamics simulations.  It is found that the ion rejection rate increases with increasing electric field strength.  The enhanced ion rejection rate is due to the reduction of the energy barrier at the ice-water interface caused by the electric field, which affects the orientation of water molecules and ion-water interactions. However, the electric field hinders the ice growth rate, which affects the productivity of freeze desalination. Nevertheless, the finding in this work offers a new idea to improve the ion rejection rate. Practically, a trade-off needs to be found to optimize the overall performance of freeze desalination.

11.
Chemosphere ; 362: 142780, 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38971437

ABSTRACT

Lipophilic shellfish toxins (LSTs) are widely distributed in marine environments worldwide, potentially threatening marine ecosystem health and aquaculture safety. In this study, two large-scale cruises were conducted in the Bohai Sea and the Yellow Sea, China, in spring and summer 2023 to clarify the composition, concentration, and spatial distribution of LSTs in the water columns and sediments. Results showed that okadaic acid (OA), dinophysistoxin-1 (DTX1) and/or pectenotoxin-2 (PTX2) were detected in 249 seawater samples collected in spring and summer. The concentrations of ∑LSTs in seawater were ranging of ND (not detected) -13.86, 1.60-17.03, 2.73-17.39, and 1.26-30.21 pmol L-1 in the spring surface, intermediate, bottom water columns and summer surface water layers, respectively. The detection rates of LSTs in spring and summer seawater samples were 97% and 100%, respectively. The high concentrations of ∑LSTs were mainly distributed in the north Yellow Sea and the northeast Bohai Sea in spring, and in the northeast Yellow Sea, the waters around Laizhou Bay and Rongcheng Bay in summer. Similarly, only OA, DTX1 and PTX2 were detected in the surface sediments. Overall, the concentration of ∑LSTs in the surface sediments of the northern Yellow Sea was higher than that in other regions. In sediment cores, PTX2 was mainly detected in the upper sediment samples, whereas OA and DTX1 were detected in deeper sediments, and LSTs can persist in the sediments for a long time. Overall, OA, DTX1 and PTX2 were widely distributed in the water column and surface sediments in the Bohai Sea and the Yellow Sea, China. The results of this study contribute to the understanding of spatial distribution of LSTs in seawater and sediment environmental media and provide basic information for health risk assessment of phycotoxins.

12.
Materials (Basel) ; 17(11)2024 May 25.
Article in English | MEDLINE | ID: mdl-38893813

ABSTRACT

Sandwich structures made with fibre-reinforced plastics are commonly used in maritime vessels thanks to their high strength-to-weight ratios, corrosion resistance, and buoyancy. Understanding their mechanical performance after moisture uptake and the implications of moisture uptake for their structural integrity and safety within out-of-plane loading regimes is vital for material optimisation. The use of modern methods such as acoustic emission (AE) and machine learning (ML) could provide effective techniques for the assessment of mechanical behaviour and structural health monitoring. In this study, the AE features obtained from quasi-static indentation tests on sandwich structures made from E-glass fibre face sheets with polyvinyl chloride foam cores were employed. Time- and frequency-domain features were then used to capture the relevant information and patterns within the AE data. A k-means++ algorithm was utilized for clustering analysis, providing insights into the principal damage modes of the studied structures. Three ensemble learning algorithms were employed to develop a damage-prediction model for samples exposed and unexposed to seawater and were loaded with indenters of different geometries. The developed models effectively identified all damage modes for the various indenter geometries under different loading conditions with accuracy scores between 86.4 and 95.9%. This illustrates the significant potential of ML for the prediction of damage evolution in composite structures for marine applications.

13.
J Colloid Interface Sci ; 673: 607-615, 2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38897062

ABSTRACT

Electrochemical seawater splitting is a sustainable pathway towards hydrogen production independent of scarce freshwater resources. However, the high energy consumption and harmful chlorine-chemistry interference still pose major technological challenges. Herein, thermodynamically more favorable sulfion oxidation reaction (SOR) is explored to replace energy-intensive oxygen evolution reaction (OER), enabling the dramatically reduced energy consumption and the avoidance of corrosive chlorine species in electrocatalytic systems of NiFe layered double hydroxide (LDH)/FeNi2S4 grown on iron foam (IF) substrate. The resulting NiFe-LDH/FeNi2S4/IF with superwettable surfaces and favorable heterointerfaces can effectively catalyze SOR and hydrogen evolution reaction (HER), which greatly reduces the operational voltage by 1.05 V at 50 mA cm-2 compared to pure seawater splitting and achieves impressively low electricity consumption of 2.33 kW h per cubic meter of H2 at 100 mA cm-2. Significantly, benefitting from the repulsive effect of surface sulfate anions to Cl-, the NiFe-LDH/FeNi2S4/IF exhibits outstanding long-term stability for SOR-coupled chlorine-free hydrogen production with sulfion upcycling into elemental sulfur. The present study uncovers the "killing two birds with one stone" effect of SOR for energy-efficient hydrogen generation and value-added elemental sulfur recovery in seawater electrolysis without detrimental chlorine chemistry.

14.
Mar Pollut Bull ; 205: 116588, 2024 Jun 17.
Article in English | MEDLINE | ID: mdl-38889666

ABSTRACT

Mariculture stands as a pivotal enterprise aimed at enhancing the quality of human existence. However, the utilization of antibiotics and pesticides in the mariculture process poses threats to both the environment and human well-being. Therefore, it is of great significance to investigate the occurrence, distribution and risk of antibiotics and pesticides in mariculture areas. In this study, 11 kinds of antibiotics and 12 kinds of pesticides were screened in four mariculture areas around Liaodong Peninsula in China. The pollution characteristics of pollutants were investigated in three different mariculture stages. The pollution in the reproduction stage was the most serious, indicating that mariculture may have a potential impact on the surrounding seawater. Health risk assessment results indicate that the pollutants have a significant risk to human health, therefore it is necessary to strengthen the control of chemicals used in mariculture in future.

15.
Sci Rep ; 14(1): 13997, 2024 Jun 18.
Article in English | MEDLINE | ID: mdl-38886202

ABSTRACT

Efficient seawater desalination is an effective way to solve the shortages of fresh water and energy but with limitations of the low fresh water production rate and high cost. Here, a hollow carbon fiber (HCF) wrapped by regular reduced graphene oxide (rGO) wave-like folds (rGO@HCF) is prepared on account of the differences in thermal shrinkage performance between graphene oxide (GO) and willow catkins fiber. Under one sun irradiation (1 kW m-2), the dry and wet surface temperature of the resulting evaporator reached up to 119.1 °C and 61.7 °C, respectively, and the water steam production rate reached 3.42 kg m-2 h-1. Also, for the outdoor experiment, the rGO@HCF exhibits good evaporator performance which reach up 27.8 kg m-2 day-1. Additionally, rGO@HCF also shows good seawater desalination performance and excellent durability for longtime work. DSC results indicate that the evaporation enthalpy of bulk water and adsorbed water decreased from 2503.92 to 1020.54 J g-1. The excellent evaporating performance is mainly attributed to the regular wave-like microstructure surface of the HCF, which can enhance the light absorption, reduced the vaporization enthalpy of the adsorption water. The findings not only introduce a novel approach for agricultural utilization, but also establish a crucial theoretical foundation for the design of regular wave-like microstructures.

16.
Sci Rep ; 14(1): 12970, 2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38839793

ABSTRACT

Chloride-induced steel corrosion is known to be a very common kind of deterioration of reinforced concrete. It is beneficial to bind free chloride ions to reduce the corrosion probability of the reinforcement embedded in the concrete. The binding capacity of the concrete varies according to its cementitious system. This paper investigates the chloride binding capacity of different kinds of supplementary cementitious materials (SCMs): Ground granulated blast furnace slag (GGBFS), Fly ash, and Metakaolin as a partial replacement of Ordinary Portland Cement (OPC). Different properties of concrete after chloride binding are assessed by carrying out the following tests: half-cell potential, accelerated corrosion test, compressive strength, rapid chloride penetration test, sorptivity test, measuring pH value of concrete, and XRD. The results showed that utilizing the SCMs in concrete can enhance the chloride binding capacity, especially those materials that have high quantities of aluminate and calcium in their chemical composition like GGBFS. Based on testing results, it's recommended that the limit of the chloride content in the different codes should be revised regarding the binding capacity according to the type and quantity of the cementitious materials used.

17.
Mar Pollut Bull ; 205: 116547, 2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38875965

ABSTRACT

The shallow hydrothermal vents (HVs) of Kueishan Island are considered as a template for studying the extremes of sulfide-polluted and acidified water. The present study examined the biological and spatiotemporal aspects of mesozooplankton mortality in waters around this extreme HV environment. Zooplankton sample collection was carried out in three monsoonal periods and the results revealed that there was a significant decrease in the mortality of total mesozooplankton with increasing distance from the HVs. The overall mortality of mesozooplankton showed a significant negative correlation with sea surface temperature and pH. Particularly, mortality of copepods showed a significant negative correlation with pH, whereas it was significantly positive correlated with sea surface temperature in the southwest monsoon prevailing period. Overall, the results may imply a situation that zooplankton will encounter in the more acidified environment of a future ocean.

18.
Angew Chem Int Ed Engl ; : e202406043, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38866704

ABSTRACT

Metal atom catalysts have been among the most important research objects due to their specific physical and chemical properties. However, precise control of the anchoring of metal atoms is still challenging to achieve. Cobalt and iridium atomic arrays formed sequentially ordered stable arrays in graphdiyne (GDY) triangular cavities depending on their intrinsic chemical properties and interactions. The success of this method was attributed to multifunctional integration of GDY, enabling selective growth from one to several atoms and various atomic densities. The bimetallic atom arrays show several advantages resulting from reducibility of acetylene bonds, space limiting effect, incomplete charge transfer between GDY and metal atoms, and sp-C hybridized triple bond skeleton. This well-designed system exhibits unprecedented oxygen evolution reaction (OER) performance with a mass activity of 2.6 A mgcat.-1 at a low overpotential of 300 mV, which is 216.6 times higher than the state-of-the-art IrO2 catalyst, and long-term stability.

19.
Chemosphere ; 361: 142559, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38852634

ABSTRACT

This study focused on investigating the concentrations, compositional profiles, partitioning behaviors and spatial variations of organophosphate esters (OPEs) in the Pearl River (PR), South China Sea (SCS) region, to evaluate their environmental risks. ∑OPEs concentrations in the surface water of the PR ranged from 117.5 to 854.8 ng/L in the dissolved phase and from 0.5 to 13.3 ng/L in the suspended particulate matter. In the surface seawaters of the northern and western parts of the SCS, ∑OPEs concentrations were 1.3-17.6 ng/L (mean: 6.7 ± 5.2) and 2.3-24.4 ng/L (mean: 7.6 ± 5.5), respectively. The percentage of chlorinated OPEs in surface water samples from the PR to the SCS was 79 ± 15%. Tripentyl phosphate (TPeP) (average: 28.3%) and triphenylphosphate (TPhP) (average: 9.6%) exhibited significant particulate fraction. A significant negative correlation (p < 0.05) between salt concentration and OPE congeners in seawater suggested that river runoff predominantly introduced OPEs into the coastal waters of the SCS. The findings also showed higher levels of OPEs in the PR and estuary than in offshore waters. The OPE loading from the PR into the SCS was estimated to be ∼119 t y-1. The presence of TCEP (RQmax = 2.1), TnBP (RQmax = 0.48) and TPhP (RQmax = 0.3) in PR water samples pose a high risk to aquatic organisms, whereas OPEs (RQ < 0.1) in SCS water samples do not pose a threat to aquatic organisms. This research emphasizes the environmental fate and impact of OPEs on surface waters of the PR and SCS.


Subject(s)
Environmental Monitoring , Esters , Organophosphates , Rivers , Seawater , Water Pollutants, Chemical , China , Water Pollutants, Chemical/analysis , Rivers/chemistry , Organophosphates/analysis , Seawater/chemistry , Esters/analysis , Risk Assessment
20.
J Hazard Mater ; 475: 134804, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-38880042

ABSTRACT

Microplastics (MPs), omnipresent contaminants in the ocean, could be carried by seawater intrusion into coastal aquifers, which might affect the fate of heavy metals existing in aquifers. Herein, we investigated the release behavior of arsenic (As) in coastal aquifers during MPs-containing seawater intrusion by applying laboratory experiment and numerical simulation. We found that seawater with marine MPs enhanced the release of As in aquifers, especially for dissolved As(V) and colloidal As. Negatively charged MPs competed with As(V) for the adsorption sites on iron (hydr)oxides in aquifers, resulting in the desorption of As(V). In addition, MPs could promote the release of Fe-rich colloids by imparting negative charge to its surface and providing it with sufficient repulsive force to detach from the matrix, thereby leading to the release of As associated with Fe-rich colloid. We also developed a modeling approach that well described the transport of As in coastal aquifer under the impact of MPs, which coupled variable density flow and kinetically controlled colloids transport with multicomponent reactive transport model. Our findings elucidated the enhancement of MPs on the release of As in aquifers during seawater intrusion, which provides new insights into the risk assessment of MPs in coastal zones.

SELECTION OF CITATIONS
SEARCH DETAIL
...