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Detection sensitivity of aquatic species using environmental DNA (eDNA) generally decreases in turbid water but is poorly characterized. In this study, eDNA detection targeted delta smelt (Hypomesus transpacificus), a critically endangered estuarine fish associated with turbid water. eDNA sampling in the field was first paired with a trawl survey. Species-specific detection using a Taqman qPCR assay showed concordance between the methods, but a weak eDNA signal. Informed by the results of field sampling, an experiment was designed to assess how turbidity and filtration methods influence detection of a rare target. Water from non-turbid (5 NTU) and turbid (50 NTU) estuarine sites was spiked with small volumes (0.5 and 1 mL) of water from a delta smelt tank to generate low eDNA concentrations. Samples were filtered using four filter types: cartridge filters (pore size 0.45 μm) and 47 mm filters (glass fiber, pore size 1.6 μm and polycarbonate, pore sizes 5 and 10 μm). Prefiltration was also tested as an addition to the filtration protocol for turbid water samples. eDNA copy numbers were analyzed using a censored data method for qPCR data. The assay limits and lack of PCR inhibition indicated an optimized assay. Glass fiber filters yielded the highest detection rates and eDNA copies in non-turbid and turbid water. Prefiltration improved detection in turbid water only when used with cartridge and polycarbonate filters. Statistical analysis identified turbidity as a significant effect on detection probability and eDNA copies detected; filter type and an interaction between filter type and prefilter were significant effects on eDNA copies detected, suggesting that particulate-filter interactions can affect detection sensitivity. Pilot experiments and transparent criteria for positive detection could improve eDNA surveys of rare species in turbid environments.

Arctic fjords are inherently vulnerable to global warming, particularly because of the substantial freshwater influx resulting from the melting of glaciers. In this study, precipitation, river water, surface ice, and seawater samples from Kongsfjorden were collected to identify the main sources of freshwater. The dual water isotope (δ18O and δD) results and temperature–salinity profiles revealed that between 0% and 7% freshwater contributed to the fjord's water. Furthermore, different freshwater sources for surface and deep water were identified by the dual water isotope analysis. Turbidity profiles confirmed the alter in particle discharge associated with surface runoff and subglacial discharge. Our study highlighted the sensitivity of water isotope analysis in elucidating the hydrological processes within the fjord system and demonstrated its potential for investigating the impact of meltwater on biological processes in the Arctic. [ABSTRACT FROM AUTHOR]

The environment-species relationships can be mediated by functional traits. In this study we investigated how the functional traits of periphytic community respond to environmental variation in streams along a gradient of anthropically modified landscapes in the Brazilian Cerrado. We expect the association of traits with flow gradients, turbidity, productivity, and nutrients directly impacted by changes in land cover around streams. We use the RLQ analysis to test this hypothesis. The first RLQ axis revealed a gradient associated with variation in the local physical and chemical characteristics, nutrients and productivity of the streams, while the second axis was associated with a gradient of impact on land use and nutrients related to the trophic state. The main traits associated with the first axis of RLQ (physical and chemical, and productivity gradient) were life form, substrate adherence, and active mobility, while size, life form, and substrate adhesion were associated with the second axis of RLQ (land use, primary productivity, and orthophosphate gradient). Our results highlight the importance of the trait-environment approach to predict community composition. Furthermore, they suggest that functional traits can be used to predict the responses of periphytic communities to environmental changes at local and landscape scales. [ABSTRACT FROM AUTHOR]

In this study, an acoustic Doppler current profiler (ADCP) operating at 600 kHz was installed on an ocean data buoy in the Qigu waters, Taiwan, to gather real-time sound echo intensity data. These data were then correlated with turbidity measurements obtained by a turbidimeter mounted on the buoy's mooring line at a water depth of 13 m. The data buoy operated from 6 June to 16 August 2017. During this period, turbidity measurements were recorded from 6 to 21 June 2017. This study established a calibration between the sound echo intensity measured by the ADCP and the turbidity measured using the turbidimeter; a strong linear correlation was discovered between these two variables. This correlation enabled the conversion of echo intensity data into a continuous time series of turbidity measurements, facilitating real-time and long-term monitoring of coastal water turbidity through the deployment of a buoy equipped with an ADCP. The relationships between turbidity and environmental factors such as rainfall, tides, current speeds, and wave activity over an extended period were then investigated. The results revealed that stronger tides and currents in the Qigu waters often lead to higher turbidity, suggesting that these two factors are the primary driving forces for sediment transport in the Qigu waters. Additionally, sampling of water in the Qigu area revealed sediment particles of size ranging from 2 to 120 μm. [ABSTRACT FROM AUTHOR]

The ocean, with its intricate processes, plays a pivotal role in shaping marine life, habitats, and the Earth's climate. This study addresses issues such as beach erosion, the survival of propagules from species like Posidonia oceanica, and nutrient distribution. To tackle these challenges, we propose an innovative sensor that quantifies hydrodynamic velocity by measuring the output voltage derived from detecting changes in light absorption and scattering using LEDs and LDRs. Our results not only demonstrate the effectiveness of the sensor but also the accuracy of the processing algorithm. Notably, the blue LED exhibited the lowest mean relative error of 7.59% in freshwater, while the yellow LED was most precise in chlorophyll-containing water, with a mean relative error of 6.80%. In a runoff simulation, we observed similar velocities with the blue, green, and white LEDs, 6.89 cm/s, 6.99 cm/s, and 7.05 cm/s, respectively, for nearly identical time intervals. It is important to highlight that our proposed sensor is not only effective but also highly cost-efficient, representing less than 0.43% of the cost of a Nortek Vector 6 MHz and 0.18% of the Teledyne Workhorse II 300 kHz Marine. This makes it a key tool for managing marine ecosystems sustainably. [ABSTRACT FROM AUTHOR]

To address the issues of image blurring and color distortion in hazy conditions, an image restoration method based on a parametric analytical modulation transfer function model is proposed under turbid atmospheric conditions. A source database is established using a numerical radiative transfer method based on discrete ordinate. Through multivariate nonlinear fitting and linear interpolation, the quantitative relationships among critical spatial frequency, turbid atmospheric MTF, and key atmospheric optical parameters—such as optical thickness, single scattering albedo, and asymmetry factor—are examined. A fast and efficient parametric analytical MTF model for turbid atmospheres is developed and applied to restore images affected by fog. The results demonstrate that, within the applicable range of the model, the model's maximum mean relative error and the root mean square error are 7.16% and 0.0454, respectively. The computational speed is nearly a thousand times faster than that of the numerical radiative transfer method, achieving high accuracy and ease of application. Images restored using this model exhibit enhanced clarity and quality, effectively compensating for the degradation in image quality caused by turbid atmospheres. This approach represents a novel solution to the challenges of image processing in complex atmospheric environments. [ABSTRACT FROM AUTHOR]

Turbidity is commonly monitored as an important water quality index. Human activities, such as dredging and dumping operations, can disrupt turbidity levels and should be monitored and analysed for possible effects. In this paper, we model the variations of turbidity in Dublin Bay over space and time to investigate the effects of dumping and dredging while controlling for the effect of wind speed as a common atmospheric effect. We develop a Vector Auto-Regressive Integrated Conditional Heteroskedasticity (VARICH) approach to modelling the dynamical behaviour of turbidity over different locations and at different water depths. We use daily values of turbidity during the years 2017–2018 to fit the model. We show that the results of our fitted model are in line with the observed data and that the uncertainties, measured through Bayesian credible intervals, are well calibrated. Furthermore, we show that the daily effects of dredging and dumping on turbidity are negligible in comparison to that of wind speed. [ABSTRACT FROM AUTHOR]

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Tigecycline is widely used to treat infections in intensive care units. Drugs often need to be delivered to critically ill patients feeding by parenteral nutrition (PN). Before two preparations are administered in the same infusion line, the safety of this combination should be established. The objective of this study was to determine the compatibility of tigecycline with selected multichamber bag PN (MCB‐PN). Methods: Tigecycline was diluted in 0.9% sodium chloride solution and 5% glucose solution to obtain two 0.5 mg/ml solutions. Then the solutions were combined with selected MCB‐PN in appropriate proportions. The samples were visually assessed, and pH, osmolality, turbidity, particle size, and zeta potential were measured. These measurements were made immediately after combining the solutions and after 4 h of storage at 23°C ± 1°C. Results: It was determined that the pH values of the mixtures after combining with tigecycline changed by ≤0.1 unit. An increase in zeta potential was recorded, excluding one combination of tigecycline with the mixture. For all samples tested, the particle size distribution was within the acceptable range immediately after combination and after 4 h of storage. The difference in osmolality did not exceed ±3%, whereas the zeta potential decreased for only one combination. The turbidity of none of the samples exceeded a critical value. Conclusion: The physical compatibility of the tigecycline with five MCB‐PN was proved. They can therefore be administered to patients in one infusion line using the Y‐site. [ABSTRACT FROM AUTHOR]

Measurements by volunteer scientists using participatory science methods in combination with high resolution remote sensing can improve our ability to monitor water quality changes in highly vulnerable and economically valuable nearshore and estuarine habitats. In the Chesapeake Bay (USA), tidal tributaries are a focus of watershed and shoreline management efforts to improve water quality. The Chesapeake Water Watch program seeks to enhance the monitoring of tributaries by developing and testing methods for volunteer scientists to easily measure chlorophyll, turbidity, and colored dissolved organic matter (CDOM) to inform Bay stakeholders and improve algorithms for analogous remote sensing (RS) products. In the program, trained volunteers have measured surface turbidity using a smartphone app, HydroColor, calibrated with a photographer's gray card. In vivo chlorophyll and CDOM fluorescence were assessed in surface samples with hand-held fluorometers (Aquafluor) located at sample processing "hubs" where volunteers drop off samples for same day processing. In validation samples, HydroColor turbidity and Aquafluor in vivo chlorophyll and CDOM fluorescence were linear estimators of standard analytical measures of turbidity, chlorophyll and CDOM, respectively, with R2 values ranging from 0.65 to 0.85. Updates implemented in a new version (v2) of HydroColor improved the precision of estimates. These methods are being used for both repeat sampling at fixed sites of interest and ad-hoc "blitzes" to synoptically sample tributaries all around the Bay in coordination with satellite overpasses. All data is accessible on a public database (serc.fieldscope.org) and can be a resource to monitor long-term trends in the tidal tributaries as well as detect and diagnose causes of events of concern such as algal blooms and storm-induced reductions in water clarity. [ABSTRACT FROM AUTHOR]

This paper proposes an embedded Internet of Things (IoT) system for bioreactor sensor integration, aimed at optimizing temperature and turbidity control during cell cultivation. Utilizing an ESP32 development board, the system makes advances on previous iterations by incorporating superior analog-to-digital conversion capabilities, dual-core processing, and integrated Wi-Fi and Bluetooth connectivity. The key components include a DS18B20 digital temperature sensor, a TS-300B turbidity sensor, and a Peltier module for temperature regulation. Through real-time monitoring and data transmission to cloud platforms, the system facilitates advanced process control and optimization. The experimental results on yeast cultures demonstrate the system's effectiveness at maintaining optimal growth, highlighting its potential to enhance bioprocessing techniques. The proposed solution underscores the practical applications of the IoT in bioreactor environments, offering insights into the improved efficiency and reliability of culture cultivation processes. [ABSTRACT FROM AUTHOR]

Particle size evolution in seeded semibatch emulsion polymerization is monitored by two real‐time monitoring techniques: online turbidity spectroscopy (TUS) and inline photon density wave spectroscopy (PDWS). An automatic dilution system that withdraws a sample from the reactor and upon dilution transfers to the measurement cell is used for the online TUS analysis. A PDWS probe is immersed in the reactor and collects inline the scattered light directly from the reacting latex. The particle sizes retrieved from TUS and PDWS are compared to offline dynamic light scattering (DLS) values. The particle size obtained by TUS is close to the intensity‐average particle size obtained offline by DLS, while the particle size obtained by PDWS lies closer to the number‐average particle size from DLS. [ABSTRACT FROM AUTHOR]

To evaluate the effect of glyphosate, 2,4-D, and their combination on daily dissolved oxygen saturation percentage (DO%) in freshwater, two separate outdoor mesocosm experiments were performed. The experiments were conducted under contrasting conditions: one in clear mesotrophic status lasting 23 days, and the other in organic turbid eutrophic conditions lasting 21 days. Single concentrations were applied as commercial formulations at two levels. Samples of phytoplankton (micro + nano, picoeukaryotes, picocyanobacteria), mixotrophic algae, and heterotrophic bacteria were analyzed at four sampling dates. Increases in DO levels were consistently observed in both clear and turbid systems treated with glyphosate, either alone or in combination with 2,4-D, suggesting that DO is a sensitive indicator. DO increased in all glyphosate treatments. DO increases reflected different changes in phytoplankton communities, increasing with micro + nano phytoplankton abundance in the clear experiment but with increased picocyanobacteria in the turbid. In contrast, 2,4-D reduced DO levels, but only in the turbid system, where micro + nano phytoplankton abundance decreased. The clear system showed greater resilience by restoring DO levels before the turbid one. Mainly additive effects of the herbicide mixture were observed on dissolved oxygen levels (DO%), but a distinct synergistic decrease was detected within turbid systems, underscoring the importance of considering turbidity as a contributing factor in the freshwater impacts of herbicides. [ABSTRACT FROM AUTHOR]

Groundwater is becoming increasingly important as surface water is decreasing and becoming more and more polluted. In particular, rural areas in the arid region of Central Asia face problems with both water quantity and quality. In view of this, we investigated the drinking water quality in the Maysky district in the Pavlodar region, Kazakhstan. The organoleptic properties, together with microbiological indicators, as well as organic and inorganic substances of drinking water before and after treatment, and tap water were studied and compared to recommended levels. The bacteriological indicators of the drinking water, especially, showed that the water represents health risks since the presence of bacteria of the genus Pseudomonas aeruginosa was confirmed. Water treatment reduced the total microbial count (TMC) indicator by 3.6 times. However, TMC still exceeded permissible levels in the tap water, indicating that the drinking water is sanitary and epidemiologically not acceptable. Pathogenic contamination of drinking water can severely affect weaker individuals and children. It has been estimated that the infant mortality rate in Kazakhstan is six times higher as compared to the EU and less than 30% of Kazakhstan's population have access to safe water. Also, 50% of the population drink water that does not comply with the international standards, e.g., bacteriological levels. Thus, it is important to continuously monitor the groundwater quality to minimize health risks and work towards access to safe drinking water, in line with the UN SDGs. [ABSTRACT FROM AUTHOR]

This study aims to analyze the cost of using lime and alum in the treatment of acid mine drainage at Settling pond 03, Pit Paku, PT. Rimau Energy Mining. Acid mine drainage, formed through chemical reactions between sulfide minerals and water, requires specialized treatment to mitigate its environmental impact. The use of lime and alum is intended to increase pH and reduce turbidity levels in the acid mine water. Through laboratory experiments with various doses of lime and alum, this research identified the most effective doses to neutralize acid mine drainage, raise pH levels, and reduce turbidity in accordance with established environmental standards. Additionally, the study analyzed the costs associated with each dose combination tested, revealing that the optimal lime and alum dose combinations resulted in more cost-effective treatment compared to previously employed methods. he effective dose to neutralize acid mine water is 1 gram of lime and 2 grams of alum per liter, which successfully increases the pH from 3.88-4.13 to 8.10-8.40, and reduces turbidity from 498-522 NTU to 144.9-196.1 NTU. [ABSTRACT FROM AUTHOR]

In tropical islands, calcareous sand with poor engineering properties usually needs to be treated before it can be used as building materials. Considering the scarcity of freshwater in these areas, this study proposes seawater-based enzyme induced carbonate precipitation (EICP) technology to enhance the properties of calcareous sand. It is to induce calcium carbonate crystals to bond calcareous sand particles together using the seawater-based crude soybean enzyme and cementation solution (i.e., urea and calcium chloride). In this study, the crude soybean urease extraction test was firstly carried out using seawater and it was also investigated what components of seawater had a greater effect on the soybean urease extraction. Afterwards, the solution test was conducted to explore the ability of the extracted urease in inducing calcium carbonate through analyzing the variation of concentration of calcium ions and pH of the solution. Finally, the biocementation effect of EICP treated calcareous sand using the seawater extracted urease solution was evaluated by the unconfined compressive strength (quc) and microscopic analysis. Test results show that the turbidity of the seawater-extracted soybean urease solution can be reduced by 66.7% compared to that of deionised water extracted urease, with only a slight reduction in urease activity. Among all the components of seawater, NaCl, MgCl2, CaCl2, NaHCO3 and KBr can significantly reduce the turbidity of soybean urease solution. The lower turbidity can effectively avoid bioclogging and contribute to the homogeneity of the EICP-treated calcareous sands, and thus improve the biomineralization efficiency and strength enhancement. Seawater-based EICP treatment will be a great promising technology in freshwater-scarce tropical islands, because it can directly use seawater for biomineralization treatment of calcareous sand, and meanwhile effectively avoid local clogging of biocementation. [ABSTRACT FROM AUTHOR]

This study explored the synthesis of potash alum from disposed aluminum cans for water purification. The effect of the labels on the cans on the yield of alum was also investigated as it is economically beneficial for industry. Single crystals of potash alum were obtained and characterized by powder X-ray diffraction (P-XRD) and Fourier transform infrared (FTIR) spectroscopy. Through a series of jar test experiments, the characterized alum samples were used to purify river water samples. Some of the parameters investigated include; pH, turbidity, total suspended solids (TSS), total dissolved solids (TDS), electrical conductivity (EC) and chemical oxygen demand (COD). The results show that the alum samples were able to reduce the turbidity by 100 % and substantially decrease the TSS, TDS and COD over the five-hour period of study. However, there were slight increases in acidity and EC which could be corrected by other methods [ABSTRACT FROM AUTHOR]

Socio-economic activities along the Citarum River basin in Indonesia can induce ecological disturbances in the structure of the benthic macroinvertebrate community. This research aims to (1) identify the environmental factors responsible (2) describe the ecological disturbances using biological measurements; (3) and to develop local biocriteria using a multi-metric conceptual approach. An inventory of benthic macroinvertebrates was carried out at eight stations over a sampling period of 3 months, along with water quality monitoring. The results confirm the change in the structure of benthic macroinvertebrate communities, explained by seven environmental parameters: dissolved oxygen (DO), ambient habitat quality, turbidity, nutrient enrichment, conductivity, temperature, and embeddedness percentage. The changes were then assessed using six biological measurements. Only four have been shown to be capable as alternatives to existing biocriteria. Their implementation enabled the development of local biocriteria compatible with the multimetric concept known as the cumulative biotic index (CBI). [ABSTRACT FROM AUTHOR]

This work aims to study the spatio-temporal variability of turbidity in Lake Chascomús using 34 years (1987–2020) of Landsat (TM, ETM + , and OLI) and Sentinel-2-MSI optical data and to understand this variability in terms of environmental variables. A semi-analytical algorithm, using reflectance in the red and near-infrared bands, was calibrated for Landsat and Sentinel-2 bands and tested using in situ turbidity measurements. The best performance was found using only the near-infrared band with 12.84% median accuracy and -12.84% bias when comparing in situ radiometric measurements and field data. When satellite-derived turbidity was compared to in situ values, the median accuracy was 31.8% and the bias 13.22%. Monthly climatological turbidity maps revealed spatial heterogeneity in Lake Chascomús, with differences observed between the north-west and south-east regions, particularly in summer and winter. Turbidity showed marked seasonal dynamics, with a minimum in autumn and a maximum in spring. Annual climatological turbidity maps showed significant inter-annual variability. Generalized linear models showed turbidity was positively associated with wind speed and photosynthetic active radiation (26.2% of the variability explained). Remote sensing was found to be a fundamental complement to traditional field-based methods for monitoring water quality parameters and allowing a better description of their spatio-temporal variability. [ABSTRACT FROM AUTHOR]

Aluminium is an important metal that find application in various areas ranging from simple kitchen utensils to construction and packaging materials. Due to its versatile uses, aluminium wastes are frequently generated. The aim of this research was to recycle waste aluminium foil papers used for barbequed fish packaging into useful potash alum. The method used explored the amphoteric nature of aluminium to react with both acid and alkali to form a double salt. 1.20g of the waste aluminium foil pieces was first reacted with 25ml of 3 M KOH to form a colourless solution. Further addition of 3M H2SO4 to the solution led to the precipitation of a double salt of potash alum. The percentage yield of the synthesized potash alum obtained from 1.20g waste aluminum foil was 76%. The alum also recorded 45% water of crystallization. The efficiency of the synthesized alum in water purification was also tested. Results gave 90.81% reduction in turbidity of muddy water sample from initial turbidity of 1639 NTU to 169 NTU. Thus, the potash alum synthesized from waste aluminium foils was able to coagulate fine suspension of mud from the water, therefore effective in water purification. [ABSTRACT FROM AUTHOR]

Picophytoplankton are important primary producers, but not always adequately recognized, for example, due to methodological limitations. In this study, we combined flow cytometry and metabarcoding to investigate seasonal and spatial patterns of picophytoplankton abundance and community composition in the Elbe estuary. Due to the mixing of freshwater and seawater and the tidal currents this ecosystem is characterized by typical estuarine features such as salinity gradients and high turbidity. Picophytoplankton (mostly picoeukaryotes such as Mychonastes and Minidiscus) contributed on average 70% (SD = 14%) to the total phytoplankton counts. In summer picocyanobacteria (e.g., Synechococcus) played a more significant role. The contributions of picophytoplankton to the total phytoplankton were particularly high from summer to winter as well as in the mid estuary. However, at salinities of around 10 PSU in the mixing area of freshwater and seawater, the proportion of picophytoplankton was comparably low (average 49%, SD = 13%). Our results indicate that picophytoplankton prevail in the Elbe estuary year‐round with respect to cell counts. Picophytoplankton could occupy important niche positions to maintain primary production under extreme conditions where larger phytoplankton might struggle (e.g., at high or low temperature, high turbidity, and in areas with high grazing pressure) and also benefit from high nutrient availability here. However, we did not find evidence that they played a particularly significant role at the salinity interface. Our study highlights the importance of including picophytoplankton when assessing estuarine phytoplankton as has been suggested for other ecosystems such as oceans. [ABSTRACT FROM AUTHOR]

Water quality is essential for a healthy life, so it is necessary to look for technologies to measure its parameters in real time and automatically. The purpose of this study was to implement and determine the reliability of an automated system to evaluate the organoleptic water quality intended for human consumption, in the urban distribution network of the district of Daniel Hernandez (Peru), using a programmable logic controller (PLC) and Simulink. The study was carried out from January to March 2024, corresponding to the rainfall season. In the process of the research, a data acquisition and processing algorithm was implemented in a Simatic S7 1500 PLC with analog input module; using the national sanitation foundation water quality index (NSF-WQI) methodology. The work focused on five key water parameters: potential hydrogen (pH), electrical conductivity (EC), turbidity, free chlorine (FCL) and temperature. The methodology included programming in contact language (KOP) of the algorithm for calculating subscripts for each parameter, according to the functions established by NSF-WQI. Measurements were performed with 4-wire sensing devices with 4–20 mA current signals, ensuring data accuracy. The interface to visualize the parameters and the water quality index was implemented in Simulink, communicating via OPC UA with the PLC server, facilitating the graphical representation of the organoleptic water quality index. The overall equipment efficiency (OEE) or automated system implemented was 90.56%, indicating its acceptable reliability for evaluating water quality. By performing the measurements, with the sensors of the five parameters immersed in tap water, at each of the three established sampling points (Dwelling_1, Dwelling_2 and Dwelling_3) along the water distribution network, the system facilitated the automated and real-time evaluation of the quality, resulting in an average NSF-WQI of 83.08%, classifying the water as good for human consumption. This information is important for water quality management and can guide future treatments to achieve better quality. [ABSTRACT FROM AUTHOR]

Accurate monitoring of estuarine turbidity patterns is important for maintaining aquatic ecological balance and devising informed estuarine management strategies. This study aimed to enhance the prediction of estuarine turbidity patterns by enhancing the performance of the multilayer perceptron (MLP) network through the introduction of stochastic gradient descent (SGD) and momentum gradient descent (MGD). To achieve this, Sentinel-2 multispectral imagery was used as the base on which spectral radiance properties of estuarine waters were analyzed against field-measured turbidity data. In this case, blue, green, red, red edge, near-infrared and shortwave spectral bands were selected for empirical relationship establishment and model development. Inverse distance weighting (IDW) spatial interpolation was employed to produce raster-based turbidity data of the study area based on field-measured data. The IDW image was subsequently binarized using the bi-level thresholding technique to produce a Boolean image. Prior to empirical model development, the selected spectral bands were calibrated to turbidity using multilayer perceptron neural network trained with the sigmoid activation function with stochastic gradient descent (SGD) optimizer and then with sigmoid activation function with momentum gradient descent optimizer. The Boolean image produced from IDW interpolation was used as the base on which the sigmoid activation function calibrated image pixels to turbidity. Empirical models were developed using selected uncalibrated and calibrated spectral bands. The results from all the selected models generally revealed a stronger relationship of the red spectral channel with measured turbidity than with other selected spectral bands. Among these models, the MLP trained with MGD produced a coefficient of determination (r2) value of 0.92 on the red spectral band, followed by the MLP with MGD on the green spectral band and SGD on the red spectral band, with r2 values of 0.75 and 0.72, respectively. The relative error of mean (REM) and r2 results revealed accurate turbidity prediction by the sigmoid with MGD compared to other models. Overall, this study demonstrated the prospect of deploying ensemble techniques on Sentinel-2 multispectral bands in spatially constructing missing estuarine turbidity data. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Environmental & Social Management Journal / Revista de Gestão Social e Ambiental is the property of Environmental & Social Management Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Coln is an ecologically sensitive river in a limestone dominated catchment with no major tributaries. Three in‐line turbidity sensors were installed to monitor changes in the dynamics of suspended sediment transport from headwaters to the confluence. The aims were to (i) provide estimates of yield (t km−2 year−1) and likely drivers of suspended sediment over ~3 years and (ii) assess turbidity dynamics during storm events in different parts of the catchment. In addition, the sensor installation allowed a novel wavelet analysis based on identifying groups of turbidity peaks to estimate transport times of suspended sediment through the catchment. Yearly suspended sediment yields calculated for the upper catchment were typically less than 4 t ha−1 year−1 being similar to other UK limestone or chalk‐based rivers. Time series autoregressive integrated moving average models including explanatory variable regression modelling indicated that river discharge, groundwater level and water temperature were all significant predictors of turbidity levels throughout the year. However, high model residuals demonstrate that the models failed to capture random turbidity events. Five parts of the time series data were used to examine sediment dynamics. Plots of scaled discharge verses turbidity demonstrated that in the upper catchment, after initial suspended sediment generation, sediment quickly became limited. In the lower catchment, hysteresis analysis suggested that sediment dilution occurred, due to increasing base flow. The novel wavelet analysis demonstrated that during winter 'sediment events' identified as groups of turbidity peaks, took ~18 h to pass from the first sensor in the upper catchment to the second sensor (10.3 km downstream of sensor 1) and 24 h to the third sensor (23.3 km from sensor 1). The work demonstrates the potential for using multiple turbidity sensors and time series statistical techniques in developing greater understanding of suspended sediment dynamics and associated poor water quality in ecologically sensitive rivers. [ABSTRACT FROM AUTHOR]

Copyright of Ingeniería del Agua is the property of Universidad Politecnica de Valencia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A low-cost carwash wastewater reclamation unit comprising a lamella settler and filtration unit was designed and fabricated in the laboratory. A newly designed lamella settler, Reflux Lamella Settler (RLS), consisting of two inclined sections, was incorporated for the first time in the reclamation unit with the objective of enhancing the sedimentation process. Furthermore, organoclay was employed as a component of the filtration unit to remove oil contents. The analysis of the reclaimed water demonstrated a notable reduction in the Total Suspended Solids (TSS), from 821 mg/L to 98 mg/L, in turbidity from 253 Nephelometric Turbidity units (NTU) to 2.70 NTU, and in the oil content from 26 mg/L to zero. This implies a substantial removal of the above substances of 88%, 98.9%, and 100%, respectively. Similarly, the concentration of hardness was reduced by 62.8%, from 321.6 to 120 mg/L, that of Chemical Oxygen Demand (COD) by 65.3%, from 274 mg/L to 95 mg/L, that of total solids by 65%, from 1590 mg/L to 543 mg/L, and that of total dissolved solids by 47.9%, from 769 mg/L to 400 mg/L. These results indicate that the reclaimed water was suitable for car washing. Moreover, a study on the RLS demonstrated a reduction in turbidity from 253 NTU to 175 NTU, 150 NTU, 130 NTU, and 10 NTU, respectively, after 0.5, 1, 1.5, and 24 hours. The RLS is an effective method for the removal of solid particles/sludge as a primary treatment step in carwash reclamation. [ABSTRACT FROM AUTHOR]

Understanding the spatial and temporal patterns of sediment loading in water bodies is crucial for effective water quality management. Remote sensing (RS) has emerged as a valuable and reliable tool for monitoring turbidity, which can provide insights into sediment dynamics in water bodies. In this study, we investigate the potential of turbidity data derived from RS to explain simulated spatial and temporal sediment loading patterns in the Lake Tana basin, Ethiopia. Utilizing existing RS lake turbidity data from Copernicus Global Land Service (CGLS) and simulated seasonal and multiyear trends of river sediment loadings into Lake Tana from the Soil and Water Assessment Tool (SWAT + model), we estimate correlations at different river inlets into Lake Tana. The results reveal a strong positive correlation (R2 > 0.66) between the multiyear monthly average sediment load from inflow rivers and RS lake turbidity at most river inlets. This indicates that the simulated river sediment loads and lake turbidity at river inlets exhibit similar seasonal patterns. Notably, higher turbidity levels are observed at the river inlet with the highest sediment load export. These findings highlight the potential of RS turbidity products in characterizing temporal and spatial patterns of sediment loadings, particularly in data-scarce regions, contributing to a better understanding of water quality dynamics in such areas. [ABSTRACT FROM AUTHOR]

With the sustained popularity of hazy IPAs, brewers have explored multiple approaches to maximizing stable haze that will remain in suspension throughout the shelf life of the beer. Our recent investigations into yeast-dependent haze have uncovered specific brewing yeast strains that promote the formation of haze in heavily dry-hopped beer styles. These brewing strains have been termed "haze-positive" and furthermore, the timing of dry hop additions has been found to be another key factor in producing this stable haze. Classical genetics have identified YIL169C (herein referred to as HZY1) as both necessary and sufficient for the haze-positive phenotype in the yeast strain most widely used for Hazy IPAs. HZY1 encodes a candidate glycoprotein and our recent findings suggest it is localized to the cell wall through a GPI anchor. Surprisingly, using long-read sequencing data we uncovered extensive genetic variation in HZY1 across brewing strains. The haze-positive phenotype correlates with an expansion in the N-terminal serine-rich region. We propose that the Hzy1 glycoprotein is a critical component to yeast-dependent colloidal haze and the genetic variation in this locus contributes the range of haze phenotypes observed across industrial brewing strains. [ABSTRACT FROM AUTHOR]

The present study deals with the assessment of different physicochemical parameters (pH, electrical conductivity (E.C.), turbidity, total dissolved solids (TDS), and dissolved oxygen) in different surface water such as pond, river, and canal water in four different seasons, viz. March, June, September, and December 2023. The research endeavors to assess the impact of a cationic polyelectrolyte, specifically poly(diallyl dimethyl ammonium chloride) (PDADMAC), utilized as a coagulation aid in conjunction with lime for water treatment. Employing a conventional jar test apparatus, turbidity removal from diverse water samples is examined. Furthermore, the samples undergo characterization utilizing X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The study also conducts correlation analyses on various parameters such as electrical conductivity (EC), pH, total dissolved solids (TDS), turbidity of raw water, polyelectrolyte dosage, and percentage of turbidity removal across different water sources. Utilizing the Statistical Package for Social Science (SPSS) software, these analyses aim to establish robust relationships among initial turbidity, temperature, percentage of turbidity removal, dosage of coagulant aid, electrical conductivity, and total dissolved solids (TDS) in pond water, river water, and canal water. A strong positive correlation could be found between the percentage of turbidity removal and the value of initial turbidity of all surface water. However, a negative correlation could be observed between the polyelectrolyte dosage and raw water's turbidity. By elucidating these correlations, the study contributes to a deeper understanding of the effectiveness of PDADMAC and lime in water treatment processes across diverse environmental conditions. This research enhances our comprehension of surface water treatment methodologies and provides valuable insights for optimizing water treatment strategies to address the challenges posed by varying water sources and seasonal fluctuations. [ABSTRACT FROM AUTHOR]

Climate change and human activities, for example, dam construction, largely affect hydrologic and hydrodynamic processes of river‐lake system, and hence exerted serious pressure on its aquatic ecology. It's challenging to restore its ecological environment without systematic investigation and knowledge about the features of hydrodynamics, water quality, and aquatic ecology. This study conducted field surveys of hydrodynamic, water quality, and fish distribution in the Yangtze‐Poyang system, the largest river and largest fresh lake in China, to investigate the effects of hydrologic and hydrodynamic variations on fish population dynamics, especially the extreme drought and its effects were largely concerned. In two surveys, discharge decreased from 12,000 m3/s to less than 1,000 m3/s. Distinct differences on fish density, species composition, and populations connectivity between two surveys were observed. During high‐water, connecting channel secured effective transition of river‐lake habitats, its strong hydrological connectivity and flow heterogeneity supported great biodiversity and bidirectional populations connectivity. Limited flow space and elevated turbidity during low‐water confined fish to a few channel units with sufficient depth and width, increasing fish density up to 7 times greater than during high‐water, and seriously weakening ecological connectivity of the system. Furthermore, species interaction was intensified due to limited environmental capacity, periodic strategists were favored while opportunistic strategists visibly diminished, leading to a dramatic decline in species by nearly half. In the future with increasingly frequent extreme climate, engineering measures, for example, effective ecological project regulation, are needful to alleviate the drought problem, being of great significance for maintaining ecological connectivity within the river‐lake system. Key Points: Field surveys of hydrodynamics, water quality and fish population dynamics in the largest river‐fresh lake system in China were conductedStrong hydrological connectivity and flow heterogeneity during flood season promoted bidirectional fish connectivity and species diversityLimited flow space, turbid environment and intensified species interaction during dry season weakened fish connectivity and biodiversity [ABSTRACT FROM AUTHOR]

Processes determining the amount and spatial distribution of dissolved oxygen in the ocean have been a focus of intense research over the last two decades. Anomalies known as Oxygen Minimum Zones (OMZs) have been attracting growing attention, in particular because their growth is believed to be a result of the global environmental change. Comprehensive understanding of factors contributing to and/or controlling the emergence and evolution of OMZs is still lacking though. OMZs are usually thought to result from an interplay between the oxygen transport through the water column from the ocean surface and variable oxygen solubility at different water temperature. In this paper, we suggest a different, novel mechanism of the OMZ formation relating it to the oxygen production in phytoplankton photosynthesis in a stratified ocean. We consider a simple, conceptual model of the coupled phytoplankton-oxygen dynamics and show that the model predictions are in qualitative agreement with some relevant field observations. [ABSTRACT FROM AUTHOR]

A comprehensive multi-year field campaign, the North Passage Channel Measurements (NP-ChaM), was designed and executed to enhance our understanding of the hydro- and sediment dynamics in the North Passage, the primary navigation channel of the Changjiang Estuary, China. The NP-ChaM campaign comprised eight observational sites and spanned 50 days, distributed over four years, including two dry seasons and two wet seasons. A series of tripod systems, equipped with multiple instruments, were deployed on the seabed to monitor near-bed physical processes reliably. The resulting dataset comprises: (i) fluid motions, encompassing pressure, flow velocity and direction (at the bottom and throughout the entire water column), and wave patterns; (ii) near-bed environmental conditions, including temperature, salinity, and turbidity (at the bottom and across a near-bed 1-meter range); (iii) supplementary meteorological data sourced from credible providers; (iv) preliminary results from post-processing showcasing the practical application of the data, such as lateral flows and turbulent kinetic energy characterizations. This dataset is especially valuable due to its extensive temporal and spatial coverage, and the high concentrations characterizing many of the observations (from several g/L to tens of g/L). Conducted annually from 2015 to 2018, the NP-ChaM campaign facilitated detailed observations of seasonal variations in environmental conditions and associated physical processes. The eight observational sites, positioned on either side of the deep channel, enables quantifications of channel-shoal exchanges, along-channel flow dynamics and saltwater intrusion. This dataset is suitable for advancing our understanding of along-channel and cross-channel dynamics in a channel-shoal system, and for calibrating numerical models. The dataset has undergone rigorous quality control to ensure reliability and accuracy. [ABSTRACT FROM AUTHOR]

Remote sensing for water quality evaluation has advanced, with more satellites providing longer data series. Validations of remote sensing-derived data for water quality characteristics, such as chlorophyll-a, Secchi depth, and turbidity, have often remained restricted to small numbers of water bodies and have included local calibration. Here, we present an evaluation of > 100 water bodies in Germany covering different sizes, maximum depths, and trophic states. Data from Sentinel-2 MSI and Sentinel-3 OLCI were analyzed by two processing chains. Our work focuses on analysis of the accuracy of remote sensing products by comparing them to a large in situ data set from governmental monitoring from 13 federal states in Germany and, hence, achieves a national scale assessment. We quantified the fit between the remote sensing data and in situ data among processing chains, satellite instruments, and our three target water quality variables. In general, overall regressions between in situ data and remote sensing data followed the 1:1 regression. Remote sensing may, thus, be regarded as a valuable tool for complementing in situ monitoring by useful information on higher spatial and temporal scales in order to support water management, e.g., for the European Water Framework Directive (WFD) and the Bathing Water Directive (BWD). [ABSTRACT FROM AUTHOR]

Due to observed impacts of sea level rise, many sediment management strategies in coastal settings are seeking ways to beneficially use locally dredged sediment in restoration, nourishment, and construction projects. The placement of sediment in shallow, near-marsh areas is a promising application of dredged material to both increase accretion and provide protection to marshes and intertidal flats in back bay areas. However, dredged material in these areas often include fine-grained (<63 mm) sediments (FGS), that frequently raise questions concerning dispersion, stability, and environmental impact of the placement project. In 2020, approximately 30,500 m³ of FGS from the New Jersey Intracoastal Waterway (NJIWW) was placed along the southern edge of Gull Island, New Jersey to evaluate the feasibility of using FGS for beneficial use projects in near marsh environments. Gull Island was experiencing extensive marsh edge erosion through margin collapse. The placement was unconfined and resulted in the formation of two intertidal muddy berm-like features up to 0.7 m thick along more than 500 m of marsh. Bathymetric surveys showed that approximately 60-70% of the berm volume remained 36 months after placement, however maximum berm thickness reduced to ~0.5 m. Field monitoring performed during construction found that turbidity plumes were localized to within 100 m of the placement site and sediment cores collected in June 2022 did not show systemic winnowing from the berm surface. Laboratory and field observations indicated that the berm material was cohesive in nature and produced large aggregates upon erosion, limiting the dispersal of FGS. Observations of current velocities and waves in the area indicate a low energy system such that the cohesive berm was largely resistant to erosion and that reduction in berm volume was largely due to consolidation and compaction. This suggests that shallow water features can be constructed with FGS in similar low energy environments with limited dispersal during and following construction, while being robust enough to help stabilize the marsh edge and improve marsh survivability against sea level rise. [ABSTRACT FROM AUTHOR]

Climate-driven changes in freshwater inputs have been shown to affect the structure and function of coastal ecosystems. We evaluated changes in the influence of river runoff on coastal systems of Northwestern Patagonia (NWP) over recent decades (1993–2021) by combined analysis of long-term streamflow time series, hydrological simulation, satellite-derived and reanalysis data on sea surface conditions (temperature, turbidity, and salinity). Significant decreases in minimum streamflow across a zone spanning six major river basins were evident at weekly, monthly, and seasonal scales. These changes have been most pronounced in mixed-regime northern basins (e.g., Puelo River) but appear to be progressing southward to rivers characterised by a nival regime. In the adjacent two-layer inner sea, reduced freshwater input corresponds with a shallower halocline and increased surface temperatures across northern Patagonia. Our results underscore the rapidly evolving influence of rivers on adjacent estuarine and coastal waters in NWP. We highlight the need for cross-ecosystem observation, forecasting, mitigation and adaptation strategies in a changing climate, together with corresponding adaptive basin management of systems that supply runoff to the coastal marine waters. [ABSTRACT FROM AUTHOR]

The current study included the Al-Buwair drinking water station located northwest of Mosul City in Nineveh Governorate/Iraq with the aim of evaluating the station's performance efficiency compared to the Iraqi standard specifications. Samples were collected starting from October 2023 until July 2024. Some physicochemical and biological properties were measured, including acidity (pH), electrical conductivity (EC), turbidity concentration (Turb.), total hardness (T.H), total basicity (Alk), total dissolved solids (TDS), sulfate ions (SO4-2), chloride (Cl-), and nitrate (NO3) in addition to the total bacterial count (T.P.C). The results of the current study showed that all the studied properties conformed to the Iraqi standard specifications. [ABSTRACT FROM AUTHOR]

Diclofenac (DCF, C14H11Cl2NO2) is a widely used non-steroidal anti-inflammatory drug, with a significant occurrence in waste effluents. DCF is especially persistent and difficult to degrade, with numerous toxic effects on aquatic fauna and humans. In 2015, DCF was identified as a priority pollutant (EU Directives on water policy). In this work, UV irradiation and its combination with hydrogen peroxide only or catalyzed by iron salts (photo-Fenton) are analyzed to find the most efficient alternative. DCF aqueous solutions were treated in a stirred 150 W UV photocatalytic reactor. Depending on the case, 1.0 mM H2O2 and 0–5.0 mg/L Fe2+ catalyst, such as FeSO4, was added. During the reaction, DCF, pH, turbidity, UVA at 254 and 455 nm, dissolved oxygen (DO), and TOC were assessed. The degradation of DCF yields a strong increase in aromaticity because of the rise in aromatic intermediates (mono-hydroxylated (4-hydroxy-diclofenac and 5-hydroxy-diclofenac) and di-hydroxylated products (4,5-dihydroxy-diclofenac), which subsequently generate compounds of a quinoid nature), which are very stable and non-degradable by UV light. Thus, only if H2O2 is added can UV completely degrade these aromatic colour intermediates. However, adding ferrous ion (photo-Fenton) the aromaticity remains constant due to iron com-plexes, that generates maximum colour and turbidity at an stoichiometric Fe2+ : DCF ratio of 3. As a result of the study, it is concluded that, with UV light only, a strong yellow colour is generated and maintained along the reaction, but by adding H2O2, a colourless appearance, low turbidity (<1 NTU), and [DO] = 8.1 mg/L are obtained. Surprisingly, photo-Fenton was found to be unsuitable for degrading DCF. [ABSTRACT FROM AUTHOR]

The search for eco-friendly materials has greatly evolved ahead of basic requirements encompassing sustainable practices. The selection of such sustainable material requires procedural systematic screening tests to facilitate decision-making. Water and wastewater treatment processes involve several chemicals, and they need to transition from commercial to natural materials owing to their environmental and economic concerns. The present study aimed to select and screen natural coagulants for wastewater treatment. The criteria assessment factors for the present study were easy availability, economic value, turbidity removal efficiency, and reduced sludge generation with high dewaterability. A standard jar test apparatus was used for the coagulation experimental runs. The physicochemical parameters were analyzed using standard methods. The results presented positive insights into the efficiency of tested natural coagulants, with the least turbidity removal of 83.3% by rice husk at 1gm/500ml and the highest being 96.4% by onion peel at 1gm/500ml. The sludge obtained after treatment with natural coagulants has presented an excellent dewaterability, with the least being 29.17% by tamarind seeds at 1gm/500ml and the maximum being 90.2% by coconut fibre at 1gm/500ml. From the study, was concluded that the screening method promoted the selection of the best coagulant type and dose and reduced the efforts and time needed to eliminate the non-performers. [ABSTRACT FROM AUTHOR]

New coagulant Polvak 15/72 consisting of aluminum hydroxychloride with a pure Al2O3 content of at least 15.3 wt % was investigated as a possible highly effective agent for discoloration, clarification, and cleaning the natural freshwater to produce high-quality drinking water. Water was taken from the river of Dnipro during the winter-summer period of 2022. A 20 mg dm-3 coagulant concentration showed sufficient water cleaning effectiveness, and brought its chromaticity, turbidity, permanganate oxidizability, aluminum and iron contents within the sanitary limits. This result has been achieved using a coagulant that does not consist of Fe (for which the toxicity is higher than that of Al) and less Al than in the widely used Polvak-68. The effectiveness of removing trihalomethanes (THM, mostly chloroform) by Polvak 15/72 is insufficient, and additional non-polar adsorbent or the use of a chlorine-free water disinfection technology is required to keep the content of THM within the sanitary limits. [ABSTRACT FROM AUTHOR]

The gross encephalic morphology of representatives from 17 genera within the Geophagini tribe is comprehensively characterized, compared, and analyzed into a previously proposed phylogenetic hypothesis. Our morphological investigation highlights the prominence of the visual center within the cichlid encephalon. Notably, constrained phylogenetic analysis reveals probable convergent adaptations in two genera, Cichla and Saxatilia, characterized by diminutive gustatory lobes. In contrast, Retroculus, known for its sediment-shifting habits among Geophagini species, exhibits well-developed gustatory lobes. Previous research has established that species engaging in sediment sifting exhibit modifications in their pharyngeal apparatus and frequently adopt benthivorous feeding strategies, features that appear to be orchestrated by the gustative center in the encephalon. Furthermore, our findings underscore a putative relationship between encephalon morphology and factors such as feeding behavior, environmental conditions (including turbidity and depth), and their association with the studied cichlid species. The neuroanatomical characters proposed in this study hold promise as valuable phylogenetic markers for future analyses and contribute to our understanding of the complex interplay between neuroanatomy, behavior, and ecology within this diverse group of cichlids. [ABSTRACT FROM AUTHOR]

Defatted wheat germ is a highly nutritious protein, which contains about 30% protein. In this study, defatted wheat germ (DWG) protein was used to form coacervate with apple pectin. Structural transition during coacervate formation was evaluated by ζ-potential, spectrophotometry, and light scattering as a function of pH (2.0-6.0), protein to polysaccharide ratio (DWG protein-Pectin, R=1:1, 2:1 and 4:1) and total biopolymer concentration (0.5 and 1%). Furthermore, the phase changes of DWG protein-pectin complex coacervate was studied by checking the turbidity during the time. The best ratio of DWG protein/pectin for complex coacervation was found 4:1 (Pr:Ps). The critical pH affiliated with forming of soluble and insoluble complexes (respectively pHc and pHf1) at the optimum DWG protein/pectin ratio were found 6.0 and 4.9, respectively. The most interaction, the most turbidity, was found at pH=4.0. The inconsistency and liquidation of DWG protein/pectin complex coacervates initialized at pH=2.0. Particles size of DWG protein/pectin (R=4:1, CT=1 %) measured by dynamic light scattering (DLS) at critical pH values, provided further insight into the segregate and associative processes during complex coacervation. The findings can be contributed to the development of DWG protein/pectin complex coacervates as delivery systems for volatile aromas, or bioactive compounds. [ABSTRACT FROM AUTHOR]

Surface waters are essential for meeting the needs of the world. In many regions, stream water quality is a major concern due to contamination from multiple sources. Stream water is also susceptible to climatic events and land-use practices influencing its catchment. Understanding the impact of such events on stream water quality is crucial for managing and protecting aquatic ecosystems and providing safe drinking water to communities that rely on these streams. Hence, monitoring and evaluating stream water quality holds significance in identifying potential hazards and implementing suitable management strategies. In this paper, a novel effort was made to determine the relative feature importance of a set of watershed characteristics (precipitation, temperature, urban land use, agricultural land use, and forest land-use factors) on four important water quality parameters (WQPs): fecal coliforms (FC), turbidity, pH, and conductivity of the Upper Green River watershed, Kentucky, USA. Random forest (RF), an ensemble learning method, was used to predict the WQPs from the causal parameters and determine the feature importance characteristics of the four WQPs previously mentioned. This model demonstrated that precipitation and temperature are the most influential factors on FC, turbidity, and pH. Forest land use and temperature are the two most important factors for conductivity. The novel feature importance factors of the RF model have likewise been confirmed for each WQP. In modeling stream WQPs, the developed the RF model outperformed the artificial neural network (ANN) model. Using the RF model, we obtain regression coefficients of (0.93, 0.74, and 0.94) for pH in training, testing, and overall. We obtain regression coefficients of (0.60, 0.64, and 0.61) using the ANN model. ⁠⁠⁠⁠⁠⁠⁠Overall, the RF model was more effective than the ANN model in modeling stream WQPs. The model identified precipitation and temperature as the most influential factors on FC, turbidity, and pH, while forest land use and temperature were the most important factors in determining conductivity. It is also found that land use factors are important to improve the accuracy of WQPs predictions from climate variables. The results of this study can be used by authorities to better understand and control pollution at the watershed scale. [ABSTRACT FROM AUTHOR]

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The measurement of turbidity serves as a key indicator of water quality and purity, crucial for informing decisions related to industrial, ecological, and public health applications. As existing processes require both additional expenses and steps to be taken during data collection relative to photography, we seek to generate accurate estimations of turbidity from underwater images. Such a process could give new insight to historical image datasets and provide an alternative to measuring turbidity when lower accuracy is acceptable, such as in citizen science and education applications. We used a two-step approach to a machine vision model, creating an image classification model trained on image data and their corresponding turbidity values recorded from a turbidimeter that is then used to generate continuous values through multiple linear regression. To create a robust model, we collected data for model training from a combination of in situ field sites and lab mesocosms across suspended sediment and colorimetric profiles, with and without a Secchi disk for visual standard, and binned images into 11 classes 0–55 Formazin Nephelometric Units (FNU). Our resulting classification model is highly accurate with 100% of predictions within one class of the expected class, and 84% of predictions matching the expected class. Regression results provide a continuous value that is accurate to ±0.7 FNU of true values below 2.5 FNU and ±33% between 2.5 and 55 FNU; values that are less accurate than conventional turbidimeters but comparable to field-based test kits frequently used in classroom and citizen science applications. To make the model widely accessible, we have implemented it as a free and open-source user-friendly web, computer, and Google Play application that enables anyone with a modern device to make use of the tool, the model, or our repository of training images for data collection or future model development. [ABSTRACT FROM AUTHOR]