River Water Research Articles

Dual Recognition Strategy‐Based Transistor Sensor Array for Ultrasensitive and Multi‐Target Detection of Antibiotics

AbstractMulti‐target detection is a notable development direction in the field of analytical methods, boasting significant potential for breakthroughs in complex sample detection. Herein, an extended gate field‐effect transistor (EGFET) sensor array for ultrasensitive and multi‐target detection of antibiotics is developed. To enhance the recognition ability for diverse antibiotics, a dual‐recognition strategy based on tailor‐made molecularly imprinted polymer (MIP) and aptamer is adopted to fabricate the extended gate electrode (sensing electrode). The dual‐recognition strategy‐based EGFET exhibits superior sensitivity, selectivity, and stability compared to single recognition probes due to the synergistic effect of the affinities of MIP and specific aptamer. The developed sensor array can detect three types of antibiotics, including ampicillin, amoxicillin, and kanamycin, at the same time with record‐low detection limit (fM level) and a detection range spanning six orders of magnitude. The practical detection of antibiotics in various samples (tap water, river water, milk, honey, and artificial urine) further validates the feasibility of the sensor array in practical applications. The key advantages of flexibility, high sensitivity and selectivity, and multifunctionality demonstrate the high potential of EGFET sensor array for simultaneous detection of multiple target molecules.

In-Syringe Vortex-Assisted Liquid-Liquid Microextraction Based on Natural Deep Eutectic Solvent for Simultaneous Determination of the Two Anticancer Polyphenols Chrysin and Resveratrol.

The simultaneous determination of multiple anticancer drugs in combination therapy poses a significant analytical challenge due to their complex nature and low concentrations. In this study, we propose an in-syringe vortex-assisted liquid-liquid microextraction (IS-VA-LLME), based on a green natural deep eutectic solvent (NaDES) for the simultaneous determination of two coadministered anticancer drugs (resveratrol and chrysin) prior to the HPLC-UV analysis, for the first time. The key parameters affecting the extraction efficiency, such as extraction solvent, vortex time, pH, and ionic strength were optimized. Under optimal conditions, the method demonstrates good linearity over the range of 0.05-15.0 μg/mL for RVT and 0.50-15.0 μg/mL for CHR with low limits of detection (LODs) of 16.78 and 161.60 ng/mL for RVT and CHR, respectively, confirming the high sensitivity of the method. The interday and intraday precision values, expressed as %RSDs, are below 2.0%, indicating good repeatability and reproducibility. Furthermore, the proposed method could be efficiently applied for the determination of the two drugs in human plasma and river water. The obtained results show satisfactory % recoveries (97.80%-102.04%), highlighting the accuracy and reliability of the developed method. The sustainability of the method was comprehensively evaluated using seven different tools. In conclusion, the developed IS-VA-LLME-NaDES allows for enhanced extraction efficiency, reduced extraction time, and improved recovery of the target analytes. This method holds great promise for applications in clinical and environmental research, enabling the precise quantification of these anticancer drugs in complex matrices.

Investigation of the formation and variability of dissolved inorganic carbon and dissolved organic carbon in the water of a small river (on the example of the Styr River, Ukraine).

This paper presents the results of a study on the dynamics in the concentrations of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) in water samples collected from the Styr River between 2019 and 2022. The concentrations of DIC and DOC were measured using an Elementar liqui TOC II analyzer. The study methodology involved analyzing the changes in DIC and DOC concentrations and their relationship with flow rates, temperature, seasonality, and other indicators such as hydrogen pH levels, total alkalinity (TA), and total dissolved solids (TDS). The purpose of this article is to identify patterns in the formation and changes of DIC and DOC concentrations in the Styr River. The concentrations of DIC and DOC in the samples ranged from 1.55 to 4.93mM and 0.49 to 1.43mM, respectively, with DOC accounting for an average of 22% of the total dissolved carbon content. The highest DOC concentrations were observed in summer, while the highest DIC concentrations were observed in winter. Based on the results, it can be concluded that water flow and temperature have an impact on DOC concentration, while flow, temperature, and pH affect DIC concentration. There was no correlation between DIC and DOC concentrations, but a strong positive relationship (r = 0.9056, p < 0.001) was found between DIC and TA concentrations. Therefore, the main factors influencing DIC in the Styr River are those that affect the carbonate equilibrium, such as leaching of carbonate and silicate rocks, CO2 absorption from the atmosphere, and changes in pH. Additionally, the concentration of DOC is influenced by biological activity and is higher during the warm season. These findings can be used to develop a strategy for managing water resources in the Styr River basin and to assess and predict the ecological state of the river.

Assessing the health risks from flooding and chemical contamination: a scoping review

Abstract Flooding can increase the mobilization of hazardous chemicals in the environment. This scoping review provides an overview of the evidence on how flood events effect our health through chemical contamination and describes the exposure pathways to guide prevention and response measures. Flooding includes surface water flooding, coastal flooding, river flooding, storm surge, monsoon rainfall and high tide. We found 110 papers that looked at the association between flooding and chemicals in the environment, with most studies looking at heavy metals, polyhydroxyalkanoates (PAHs), and arsenic. There was a lack of information on rural populations and studies on mobilisation of pesticides. Very few studies mapped or modelled human exposures, including for high-risk populations (e.g., children), and this remains an important evidence gap. Studies considering climate change highlighted the likelihood of chemical contamination and health risks to be exacerbated. Our results highlighted new pathways by which flood events mobilise chemicals and pose risks to human health (i.e., urban runoff, industrial sources). Although found extensively in the environment, gaps were identified in the evidence for pesticides, microplastics and heavy metals. Limited studies reported response measures to address the chemical contamination linked to flooding despite the health risks likely to increase due to poor infrastructure and management measures despite the extent of contaminated land and landfill sites. A dual risk management strategy (i.e., the coordinated management of both flood-related and chemical release risks is required to address flooding events, chemical releases, and health impacts.

Mercury speciation in environmental samples associated with artisanal small-scale gold mines using a novel solid-phase extraction approach to sample collection and preservation

In artisanal small-scale gold mines (ASGM), mercury (Hg) is known to pollute nearby river waters and sediments where it can be methylated to the highly bioavailable methylmercury (MeHg). The assessment of Hg speciation in water samples has been challenging for many years, with recommended procedures often not adequately allowing for analysis of samples in a suitable timeframe. Using a novel solid-phase extraction (SPE) method for sampling and preservation of Hg species, representative speciation data can be safely and easily collected and retained for up to 4-weeks (MeHg = 115 ± 8% refrigerated and 109 ± 13% unrefrigerated storage; Hg2+ = 100 ± 14% refrigerated and 94 ± 12% unrefrigerated storage). Concentrations of MeHg in environmental water samples and drinking water were below detection limit across two ASGM sites in western Kenya and concentrations of Hg2+ were below drinking water guidelines; however, drinking water sources contribute 20–30% of the tolerable weekly intake of Hg, indicating a need to minimise exposure of Hg from dietary sources to prevent Hg poisoning. Sediments from receiving rivers at ASGM sites showed total Hg concentrations above guideline limits (0.08–1.84 mg kg−1 total Hg) along the length of the river; however, MeHg concentrations fluctuated dependent on the stagnation of the river due to damns and ponds (5.9 ± 14.3 µg kg−1 MeHg). The findings show that SPE can be used as a robust sample collection and preservation approach for Hg speciation, which can better inform mitigation measures, understand ecological and human health implications, and improve environmental monitoring.

Patterns of sperm swimming behaviour depend on male mating tactic and spawning environment in chinook salmon

Many species exhibit alternative mating tactics (ARTs), with larger socially dominant males competing for females and smaller males adopting “sneaker” strategies to exploit fertilisation opportunities without competition or courtship. Females typically prefer larger socially dominant males, but their ability to manipulate mating or fertilisation outcomes is largely unknown. Here, using chinook salmon Oncorhynchus tshawytscha, we examined whether the female’s ovarian fluid (OF) differentially influences the temporal patterns of sperm swimming traits in ejaculates from non-preferred sneaker (‘parr’) and preferred (dominant) males. Results demonstrate that OF improves sperm swimming speed and linearity compared to river water, regardless of male mating tactic. We report a novel tactic-specific difference in sperm linearity in which parr male sperm initially maintain straighter trajectories in river water, compared to dominant males, but then rapidly change to less linear and more circular paths over time. Intriguingly, we show that OF counteracts this change in sperm linearity in parr males so that patterns become indistinguishable from dominants when parr sperm swim in OF. Together, these results show that male chinook salmon exhibit differential sperm trait investment strategies depending on reproductive tactic.

Space–Ground Remote Sensor Network for Monitoring Suspended Sediments in the Yellow River Basin

The Yellow River, China’s second-largest river, is renowned for its high sediment content. In response to the potential impacts of climate change on Yellow River water resources and water environmental management, an advanced monitoring and forecasting system for water and sediment throughout the entire Yellow River basin—from its source to the sea—is urgently needed. In this paper, based on the current status of water and sediment monitoring technologies, we proposed an integrated remote sensing monitoring network that combines satellite remote sensing, drone remote sensing, and ground-based wireless automatic monitoring networks, aiming to achieve the digital monitoring of water and sediment across the entire Yellow River basin, from its upper reaches to its estuary in the Bohai Sea. By utilizing ground-based in situ hyperspectral stations for sediment source areas in the upper reaches, such as the Qingshui River basin in Ningxia, and satellite remote sensing for midstream processes in the Xiaolangdi reservoir before the flood season in 2023, as well as downstream monitoring at the Yellow River estuary, this paper demonstrates the novelty and efficiency of the space–air–ground integrated remote sensing monitoring technology.

Simple solution and paper-based fluorescent aptasensors for toxic metal ions, thallium(l) and lead(ll).

Heavy metal ions, such as thallium(I) and lead(II) are environmental toxicants known to cause a severe threat to human and ecosystem health. This work investigates aptamers and intercalating chromophore-based complexes for the detection of these toxic species. In one method, a selective label-free "turn-on" biosensor was developed using a G-quadruplex-intercalating agent, berberine. Fluorescence, melting temperature (Tm), and circular dichroism analysis confirmed the affinity and selectivity results, illustrating the potential of these aptasensor methods for improving detection limits. These fluorescence assays were found to perform with a detection limit of 3.4 μM for Tl(I) and 0.84 nM for Pb(II). Furthermore, the assays were challenged successfully with Tl(I) and Pb(II) spiked into river water samples. We next developed paper-based fluorescent assays for Tl(I) and Pb(II), where the aptamer/berberine complex was spotted onto the paper test zone. When Tl(I) or Pb(II) ions solutions were spotted onto the top of the test zone and the spot was illuminated with a portable UV light (365 nm), a strong green fluorescence could be easily visualized with the naked eye. The lowest detection limits achieved with these fluorescent paper-based assays for Tl(I) and Pb(II) were 1.1 nM and 1.6 nM, respectively. The two fluorescent approaches presented here have the potential to be the basis of rapid, fast, and cost-efficient screening assays for these toxic species.

Multi-stage ecological pond and reservoir system to enhance river water quality: demonstration study on Periurban River

ABSTRACT Pollution of urban rivers not only destroys the river ecology but also adversely affects the health of residents and urban landscape. In this regard, we selected a certain river in Wuhan for research. In this paper, we utilize the modified bypass multi-stage ecological pond reservoir system, set up the front parthenogenetic pond, aeration and oxygenation pond, ecological purification pond and other processes, supplemented with aeration–bacteriophage coupling, filler-type ecological floating island and other technologies to improve the water quality of the river. Results show that 4 months after the operation of the system, the rate of enhancement in water transparency reached 550%, and with a dissolved oxygen (DO) uplift rate of 322%, in addition, this system achieved 77.98, 77.78 and 74.41% removal of the ammonia nitrogen (NH3-N), total phosphorus (TP), chemical oxygen demand (COD) respectively, and the effluent water quality meets the target water quality standard. The process not only has a good pollutant removal effect, low cost and other characteristics but also can enhance the river landscape and improve biodiversity. It can provide a reference for similar river pollution water quality improvement.

Phenolic Ecotoxins in River Water: Survey on Knowledge and Practices of Road-Side Food Vendors Operating Along River Chania Bank Fringes in Thika Sub- County, Kenya

Purpose: Phenolic ecotoxins consumed in raw surface water from river sources has been implicated in causing diseases of high burden such as cancers, in Kenya. This study was conducted in Thika Sub County, and data collected from roadside food vendors and food hawkers who operate small scale street food business along the fringes and banks of River Chania. The study’s objective was to establish the knowledge on Phenolic ecotoxins present in river water and practices of the study respondents. Methodology: A crossectional descriptive study design was used, in which combined interviews and questionnaire enquiries conducted from, n=341, small-scale road side food vendors and hawkers was analyzed. Findings: Data reveals that none of the respondents had knowledge on Phenolic ecotoxin contaminants and additionally a strongly associated correlation (P&lt;0.001, χ222.6 and df 1), further augments the disclosure that, poor knowledge of raw river water safety and hygiene does result to body harm and ill health. Unique Contribution to Theory, Policy and Practice: There is increased need and effort to scale up the sensitization and awareness on exposure to harmful ecotoxin contaminants from the use of raw river water. Water decontamination mobile units should be considered and introduced especially in urban areas of high population density, transversed by rivers.

Amorphous infrastructure: Contesting the proposed Yuam River water diversion project in the Salween River Basin

Recent studies in human geography and political ecology have examined the anticipatory politics of proposed infrastructure and their effects. Less work analyses how speculation and rumour are mobilised to promote or resist such infrastructures. In this paper, I examine how speculative ideas about long-proposed hydropower dams and transbasin water diversions in the Salween River Basin are strategically deployed by differently placed actors working towards project development or demise. I draw on empirical research on the proposed Yuam River water diversion project in Northwest Thailand and near the Thai–Myanmar border. I develop a conceptualisation of proposed infrastructures as amorphous as they constantly change form and enrol a shifting network of actors, and development plans and imaginaries. The Yuam diversion becomes amorphous through the contested ‘facts’ of the case and over time. I illustrate this using two longitudinal examples. First, infrastructure is made amorphous through protracted development processes for the Yuam diversion and earlier iterations. Second, I examine speculative ideas about how the Yuam diversion is intertwined with proposed dams in the Basin including the Hatgyi Dam in Myanmar. In this case, the lack of confirmed project developers and financiers for the Yuam diversion, and rumours of Chinese actors’ involvement under the Belt and Road Initiative, creates strategic space for project promotion and resistance. What is at stake is not just theorising proposed infrastructures as speculative ideas but how the ‘amorphous’ qualities of infrastructure are deployed strategically, by whom, and to what effect.

Hydrogeochemical Insights into the Sustainable Prospects of Groundwater Resources in an Alpine Irrigation Area on Tibetan Plateau

The Tibetan Plateau is the “Asia Water Tower” and is pivotal for Asia and the whole world. Groundwater is essential for sustainable development in its alpine regions, yet its chemical quality increasingly limits its usability. The present research examines the hydrochemical characteristics and origins of phreatic groundwater in alpine irrigation areas. The study probes the chemical signatures, quality, and regulatory mechanisms of phreatic groundwater in a representative alpine irrigation area of the Tibetan Plateau. The findings indicate that the phreatic groundwater maintains a slightly alkaline and fresh status, with pH values ranging from 7.07 to 8.06 and Total Dissolved Solids (TDS) between 300.25 and 638.38 mg/L. The hydrochemical composition of phreatic groundwater is mainly HCO3-Ca type, with a minority of HCO3-Na·Ca types, closely mirroring the profile of river water. Nitrogen contaminants, including NO3−, NO2−, and NH4+, exhibit considerable concentration fluctuations within the phreatic aquifer. Approximately 9.09% of the sampled groundwaters exceed the NO2− threshold of 0.02 mg/L, and 28.57% surpass the NH4+ limit of 0.2 mg/L for potable water standards. All sampled groundwaters are below the permissible limit of NO3− (50 mg/L). Phreatic groundwater exhibits relatively good potability, as assessed by the entropy-weighted water quality index (EWQI), with 95.24% of groundwaters having an EWQI value below 100. However, the potential health risks associated with elevated NO3− levels, rather than NO2− and NH4+, merit attention when such water is consumed by minors at certain sporadic sampling locations. Phreatic groundwater does not present sodium hazards or soil permeability damage, yet salinity hazards require attention. The hydrochemical makeup of phreatic groundwater is primarily dictated by rock–water interactions, such as silicate weathering and cation exchange reactions, with occasional influences from the dissolution of evaporites and carbonates, as well as reverse cation-exchange processes. While agricultural activities have not caused a notable rise in salinity, they are the main contributors to nitrogen pollution in the study area’s phreatic groundwater. Agricultural-derived nitrogen pollutants require vigilant monitoring to avert extensive deterioration of groundwater quality and to ensure the sustainable management of groundwater resources in alpine areas.

Assessment of Climate Change Impacts on Hydrology Using an Integrated Water Quality Index

Traditional Water Quality Indices (WQIs) often fail to capture the significant impact of flow velocity on water quality, especially under varying hydrological conditions. In this study, an Integrated Water Quality Index (IWQI) was developed by combining water quality parameters and flow rate, providing a more comprehensive assessment under various flow conditions. Compared to traditional indices, the IWQI showed slightly lower correlations in individual parameter performance, but it performed well in evaluating water quality changes associated with flow variations. Parameters such as Total Phosphorus (TP), Total Coliforms (TC), and Fecal Coliforms (FC), which are prevalent pollutants in the Cheongmi River, significantly influenced IWQI scores. River water quality was evaluated using input data simulated under a climate change scenario. When precipitation was abundant, the IWQI score remained relatively stable even with reduced flow rates. However, during periods of insufficient rainfall, water quality deteriorated sharply. While general water quality parameters exhibited approximately a 10% change as flow decreased, TC and FC showed rapid deterioration, with change rates ranging from 20% to 60%. These findings underscore the importance of managing TC and FC, particularly when insufficient rainfall is predicted, as they are major sources of pollution.

Irrigation suitability assessment of urban wastewater for sustainable agriculture: a case study of Musi river, India

In urban areas with dense populations and high water demands, effective management of water resources is crucial for sustainable development. It includes optimizing water usage and recycling wastewater to balance supply and demand. Urban rivers, which now carry sewage year-round due to increased urban water consumption, are increasingly used for irrigation in peri-urban regions. This study aims to assess the suitability of an urban stream for irrigation compared to catchment groundwater, using hydrochemical parameters to evaluate water quality indices. Analysis of major ion distribution from upstream to downstream reveals a significant increase of TDS (r2 = 0.65; p < 0.001) in the surface water and a decrease (r2 = 0.93; p < 0.001) in groundwater samples. The calculated Weighted Arithmetic-Water Quality Index (WA-WQI) indicates that around 85% and 75% of surface water and groundwater samples from the Musi river are classified as very poor to unsuitable for any use, highlighting critical pollution levels. Based on irrigation suitability indices, only 16% of the surface water samples and 60% of the groundwater samples are suitable for irrigation. The nitrate concentration increased from less than 10 mg l−1 in the upstream region to over 100 mg l−1 in the urban stretch. Nitrogen-Phosphate-Potassium (NPK) ratios across the basin are exceptionally higher, representing crops irrigated using the Musi river water might not require fertilizer applications. The adoption of fertilizer application concerning supplied water hydrochemistry, particularly the NPK ratio, might limit the excess usage of fertilizer and benefit farmers. Additionally, this practice may also limits the excess input of nitrate to the groundwater in the Musi river basin.

A temperature tipping point in hypoxic zone size

AbstractTemperature increases will have ubiquitous effects on aquatic food webs, from microbes to consumers, and affect the quality and quantity of carbon flows within and between water layers. A decline in the biological pump moving carbon from surface to lower layers is anticipated. We reviewed 37 years of data on hypoxic zone size and water quality in the northern Gulf of Mexico to determine if air and bottom water temperature increases (0.5°C decade−1) are significantly related to variations in its areal size. There was no significant decline in important river water quality in the 24 years since the national Hypoxia Action Plan was developed to reduce its size. Changes in the ratio of km2 hypoxia per 1000 mt nitrate loading from the Mississippi River from 2000 to 2023 reveals a tipping point in the hypoxic zone size that is driven by ocean warming. Biological factors varying with temperature such as ectotherm growth rates, zooplankton grazing, cell sinking rates, and diatom sequestration of Si or N are apparently more important influences on recent hypoxic zone size than variations in physical factors. This tipping point may be common to similarly warmed and eutrophic coastal waters where warming will likely result in diminished oxygen deficiency (&lt; 2 mgO2 L−1). Hypoxia and food web models assuming a stationary equipoise of nutrient loadings, ratios and food webs will be deficient as coastal waters warm further, coastal storm and hurricane frequency increase and land uses in the watershed are altered with climate change.

Electrospun Nanofiber Dopped with TiO2 and Carbon Quantum Dots for the Photocatalytic Degradation of Antibiotics

Novel photocatalysts were synthesized through the association of carbon quantum dots (CQDs) with commercial (P25) titanium dioxide (TiO2) by sonication. The resulting TiO2/CQDs composite was then incorporated into the polyamide 66 (PA66) biopolymer nanofibers using the electrospinning technique, considering a composite nanoparticles-to-polymer ratio of 1:2 in the electrospinning precursor solution. The produced nanofibers presented suitable morphology and were tested for the photocatalytic degradation under simulated solar radiation of 10 mg L−1 of amoxicillin (AMX) and sulfadiazine (SDZ), in phosphate buffer solution (pH 8.06) and river water, using 1.5 g L−1 of photocatalyst. The presence of the photocatalyst increased the removal of AMX in phosphate buffer solution by 30 times, reducing the AMX degradation half-life time from 62 ± 1 h (without catalyst) to 1.98 ± 0.06 h. Moreover, SDZ degradation half-life time in phosphate buffer solution was reduced from 5.4 ± 0.1 h (without catalyst) to 1.87 ± 0.05 h in the presence of the photocatalyst. Furthermore, the PA66/TiO2/CQDs were also efficient in river water samples and maintained their performance in at least three cycles of SDZ photodegradation in river water. The presented results evidence that the produced photocatalyst can be a promising and sustainable solution for antibiotics’ efficient removal from water.

Metal–organic framework-based SERS chips enable in situ and sensitive detection of dissolved hydrogen sulfide in natural water: Towards a bring-back-chip mode for field analysis

Hydrogen sulfide (H2S) in natural water plays an important role in carbon and sulfur cycles in biosphere. Current detection protocol is complicated, which need to “bring back water” to lab followed by gas chromatograph analysis. In situ, field detection is still challenging. Herein, a portable, sensitive surface enhanced Raman scattering (SERS) chip was proposed for in situ H2S sampling and SERS signal stabilizing, enabling a “bring back chip” manner for lab analysis. The SERS chip was composed of single core-shell gold nanorod-ZIF-8 framework (Au NR@ZIF-8) nanoparticle. Relying on headspace adsorption, evaporated H2S was enriched in the ZIF-8 shell and then reacted with Au NR, resulting in the weakening of the Au-Br bond Raman peak (175 cm−1) and the appearance of the Au-S bond Raman peak (273 cm−1). The SERS signal reached equilibrium in 10 min. The detection range of H2S was 0.1–2000 μg/L and limit of detection was 0.098 μg/L. SERS signal was not interfered by normal volatile gases. Moreover, SERS signal of a reacted chip was stable at an ambient condition, allowing for in situ sampling and bring-back detection. The applicability of the chip was verified by dynamic H2S monitoring during artificial black-odor water evolution, and in-field quantitative analysis of H2S content in river water and sediment. Finally, the chip was sealed in a waterproof breathable membrane device, which realized the detection of vertical profiles of H2S in the river. This work provided a promising tool for field analysis of H2S in natural environments.

Degradation of ciprofloxacin by hydrogen peroxide activated with pyrite under simulated sunlight

Ciprofloxacin (CIP) residues in the environment pose risks to both human health and ecosystems. In this study, we explored the effect of hydrogen peroxide (H2O2) on CIP degradation, activated by pyrite (FeS2) under simulated sunlight. XRD, XRF, EDS, XSP, DRS, and PL tests confirmed the high purity of FeS2 and its photocatalytic properties. With [CIP] = 30 μM, [FeS2] = 0.2 g/L, [H2O2] = 0.2 mM, CIP removal reached 87.6 %. The removal rate of TOC reached 55.3 % after 60 min of light exposure, and hydroxyl radicals (OH) contributed 72.7 % to the process. H2O2 utilization was 67.5 %, and the system operated effectively across a pH range of 2.00 to 8.00. CIP removal in river water reached 87.9 % after 3 h of light exposure, though the degradation was slower than in ultrapure water. Cl−, SO42−, and NO3− had little effect on degradation, whereas H2PO4−, CO32−, and HCO3− significantly inhibited the process as their concentrations increased. In livestock wastewater, the simulated sunlight-FeS2/H2O2 system was less effective, but after diluting the wastewater 100 times, CIP removal reached 87.6 % after 60 min. The degraded solutions showed no significant toxicity. These findings suggest that FeS2, combined with simulated sunlight, can effectively catalyze low concentrations of H2O2 to produce OH radicals, removing antibiotics from livestock wastewater.

Long-term effects of wildfires on river water quality: a comprehensive review of the variability of water quality in South Korea

ABSTRACT After wildfires, the loss of the humus layer leads to increased runoff and ash-related pollutants entering rivers. This study examined the long-term effects of wildfires on river water quality, focusing on 7 years before and after the wildfire events. We statistically analyzed the changes in the water quality of streams surrounding the wildfire area following a major wildfire. We used eight water quality parameters provided by the National Institute of Environmental Research for the analysis. To assess the impact of the wildfires, we employed t-tests and point-biserial correlation analysis to compare the changes in water quality indicators before and after the wildfires. Additionally, an analysis of variance was conducted to evaluate the impact of three wildfires, each occurring in different periods, on the water quality in a single river basin. The results showed increasing trends in hydrogen ion concentration (pH), electrical conductivity, and dissolved oxygen after the wildfire, whereas biochemical oxygen demand, total phosphorus, and total nitrogen exhibited decreasing trends. The impact of wildfires on changes in suspended solids was relatively minimal. It is expected that the results of this study provide valuable insights into developing water quality management and restoration plans following wildfires.

Assessing the Electrochemical Performance of a Novel Low‐Cost Screen‐Printed Electrode Based on Apis mellifera Beeswax Modified with Vulcan@Chitosan Used for Acetominophen Detection

AbstractThe present work reports the development of a highly sensitive electrochemical platform, constructed using screen printed electrode based on Apis mellifera beeswax (SPWE) – employed as substrate, and its application for acetaminophen (AC) detection. The sensor was produced using graphite ink and varnish glass solubilized in acetone. The SPWE was modified with a dispersion of chitosan (0.5% m/v) − functionalized Vulcan XC72R carbon black (Vulcan@Chitosan). Electrochemical characterization was performed using cyclic voltammetry (−0.7 to +0.8 V vs. pseudo‐graphite) and chronoamperometry in 0.1 mol L−1 KCl in the presence of 1.0 mmol L−1 [Fe(CN)6]3−/[Fe(CN)6]4−. Through the application of differential pulse voltammetry (DPV) using 0.1 mol L−1 PBS at pH 6.5, the proposed SPWE/Vulcan@Chitosan sensor was found to exhibit significant improvements in current response relative to the AC electrochemical detection. The sensor exhibited linear dynamic range of 0.05 to 4.0 μmol L−1 (n= 3), with R2= 0.992 and theorical LOD of 0.013 μmol L−1 (RSD= 3.80%). The AC detection was conducted in real matrices of river water, synthetic urine and synthetic saliva using the DPV technique yielded a mean recovery rate of 103% (RSD= 3.52%), exhibiting a high degree of accuracy. The SPWE/Vulcan@Chitosan electrochemical platform demonstrated high stability, good reproducibility and satisfactory repeatability; the current responses were not affected by the reutilization of the beeswax substrate for the production of new electrode. The findings of this study show that the proposed modified electrode is a simple, low‐cost sensing device which has proven to be highly efficient when applied for the AC detection in different matrices.