Load In Water Research Articles

The effect of nano-sized precipitates on stress corrosion cracking propagation of Alloy 718 under constant loads in PWR primary water

The effect of nano-sized precipitates on stress corrosion cracking propagation of Alloy 718 under constant loads in PWR primary water

An Evaluation of Biochar Derived from Agro-Industrial Waste as an Alternative Material for the Elimination of Pathogenic Load from Water

The contamination of water bodies is becoming more frequent due to uncontrolled discharges into them, including those of domestic or industrial wastewater (WW) characterized by the presence of heavy metals, a high pathogenic load, pesticides, and pharmaceuticals, among other pollutants, which represent a risk to both humans and the health of the ecosystem. Consequently, conventional water treatment processes have been implemented. However, they are not efficient enough. In this regard, exploring and analyzing new alternatives and sustainable systems that efficiently degrade the different pollutants found in WW are required, and biochar can be considered as an attractive treatment option, since it is an adsorbent carbonaceous material that allows for the removal of several pollutants. The generation and use of biochar contribute to the promotion of the circular bioeconomy and the achievement of sustainable development goals by enhancing the reuse and recycling of agricultural and agro-industrial waste as raw material for its production. The objective of this work is to evaluate the utilization of biochar as an alternative material for the elimination of the pathogenic load in water.

Seasonal assessment of surface water and sediments pollution in Rachiine River, Northern Lebanon, using multivariate statistical analysis

Urbanization has caused severe negative impacts on intra-urban river water worldwide. In this study, the WHO drinking water standards (2024) were used as reference to assess the physicochemical properties, heavy metals (HMs) content and microbial load in water and sediment samples collected from 25 locations along Rachiine River, located in Northern Lebanon, during wet and dry periods. Multivariate statistical analysis was applied to evaluate the seasonal variations in water and sediment quality, and determine the pollution sources. The microbial load assessment indicated high pollution levels by Escherichia coli, fecal enterococci, total coliform and fecal coliform, which generally increased as the river progressed downstream. Cluster analysis (CA) provided three major clusters in the study region, representing the northern, central, and southern sectors of the river. Principal components analysis (PCA) of water samples generated four principal components (PCs) accounting for 64.3, 11.4, 7.6 and 4.1 % of the total variance, whereas PCA of sediment samples explained 59.1, 16.9 and 11.1 % of the data set variance. These PCs revealed that the quality of water and sediments is significantly impacted by point and diffuse sources, including geological and anthropogenic factors. These findings call for urgent management strategies to limit future deterioration of the aquatic bodies.

Electrolyzed Water Treatment for the Control of the Zoonotic Pathogen Vibrio vulnificus in Aquaculture: A One Health Perspective.

Vibrio vulnificus (Vv) is a bacterial pathogen native to warm and brackish water ecosystems that can cause fatal septicemia (Vv-vibriosis) in humans and various farmed fish species. From a One Health perspective, controlling Vv-vibriosis outbreaks on farms is essential not only for animal but also for human health, as it reduces the risk of Vv transmission to humans. Electrolyzed water (EW) is a sustainable control method, exhibiting transient disinfectant properties due to the formation of hypochlorous acid (HOCl). We hypothesized that EW could effectively reduce Vv populations in aquaculture facilities, preventing outbreak emergence. To test this hypothesis, survival assays in EW were conducted under varying conditions of salinity, pH, and free available chlorine (FAC). The results indicated that an intermediate concentration of FAC had a significant bactericidal effect on Vv populations regardless of the condition and tested strain. Consequently, the strategic use of EW could serve as an eco-friendly preventive and control measure against Vv-vibriosis by significantly decreasing the bacterial load in farm water.

Rapid detection of bactericidal efficacy of nanoparticles coated polyurethane foam by synchronous fluorescence spectroscopy

The ability of right-angled synchronous fluorescence spectroscopy (SFS) was explored to analyse the bacterial load in water treated with green synthesized silver nanoparticles (AgNPs) coated polyurethane foam (PUF). Gram negative (Escherichia coli, Pseudomonas aeruginosa) and Gram positive (Staphylococcus aureus) bacteria cultured in nutrient broth were diluted in autoclaved water containing NPs-coated PUF. The survival rate of S. aureus and E. coli lowered after ten minutes as compared to P. aeruginosa; however, after thirty minutes, the percentage viability dropped and recorded as 3.4%, 0.9%, and 0.1% for E. coli, P. aeruginosa and S. aureus respectively in the treated suspensions. No spectral change was observed in the fluorescence emission from the positive control and treated bacterial suspension owing to the masking effect of the emission from nutrient broth. In parallel, SF spectra recorded for directly picked bacterial colony dissolved in water showed remarkable drop in tryptophan emission after treatment with NPs-coated PUF. The SF data changes were assisted by hierarchical cluster analysis, which also made it possible to distinguish between positive control and treated bacterial suspensions. SFS has shown to be a reliable substitute for the culture plate approach for the quick identification of bacterial contamination in water.

Exploring the Antimicrobial Efficacy of Low-Cost Commercial Disinfectants Utilized in the Agro-Food Industry Wash Tanks: Towards Enhanced Hygiene Practices.

The increase in vegetable consumption has underlined the importance of minimizing the risks associated with microbiological contamination of fresh produce. The critical stage of the vegetable washing process has proven to be a key point for cross-contamination and the persistence of pathogens. In this context, the agri-food industry has widely adopted the use of disinfectants to reduce the bacterial load in the wash water. Therefore, we conducted laboratory-scale experiments in order to demonstrate the antimicrobial activity of disinfectants used in the wash tank of agro-food industries. Different wash water matrices of shredded lettuce, shredded cabbage, diced onion, and baby spinach were treated with sodium hypochlorite (NaClO), chlorine dioxide (ClO2), and per-oxyacetic acid (PAA) at recommended concentrations. To simulate the presence of pathogenic bacteria, a cocktail of E. coli O157:H7 was inoculated into the process water samples (PWW) to determine whether concentrations of disinfectants inhibit the pathogen or bring it to a viable non-culturable state (VBNC). Hereby, we used quantitative qPCR combined with different photo-reactive dyes such as ethidium monoazide (EMA) and propidium monoazide (PMA). The results indicated that concentrations superior to 20 ppm NaClO inhibit the pathogen E. coli O157:H7 artificially inoculated in the process water. Concentrations between 10-20 ppm ClO2 fail to induce the pathogen to the VBNC state. At concentrations of 80 ppm PAA, levels of culturable bacteria and VBNC of E. coli O157:H7 were detected in all PWWs regardless of the matrix. Subsequently, this indicates that the recommended concentrations of ClO2 and PAA for use in the fresh produce industry wash tank do not inhibit the levels of E. coli O157:H7 present in the wash water.

Quality Control of Tap Water and Factors Determining Bacterial Contamination of Households’ Stored Drinking Water in the Town of Aboisso (Côte d’Ivoire)

Piped water must inspire consumer confidence in health and organoleptic terms. In the event of a food poisoning, consumers who have a poor perception of its quality may incriminate it, without taking into consideration that the fact of passing it through a drinking water storage container before consuming it can also cause contamination. The present study carried out in the town of Aboisso aimed to assess the role of water storage in the deterioration of microbiological quality of drinking water, and to identify the predictive factors of the presence of bacteria in stored water. To do this, physicochemical parameters (temperature, pH, conductivity, turbidity and free chlorine) and microbiological parameters (total coliforms, thermotolerant coliforms and <i>E. coli</i>) were measured on water samples taken from taps and storage containers in 94 households. The storage conditions of drinking water were also the subject of a brief household survey. The identification of predictive factors for the presence of total coliforms and <i>E. coli</i> in stored water was done using bivariate analysis and multivariate analysis by binary logistic regression through two models. The first model included the use of a transport container and the storage conditions as independent variables. The second included besides that the values of turbidity and free chlorine. As results, the waters were weakly mineralized and acidic. Free chlorine levels, temperature values, and bacterial loads in tap water were significantly (p < 0.05) higher than those in stored water. While 13.83% of samples taken at the taps were contaminated with total coliforms and 1.06% with <i>E. coli</i>, 50% and 18.09% of those taken in containers were contaminated with total coliforms and <i>E. coli</i>, respectively. In the first model, only the storage duration and the method used to draw water from storage container were statistically associated with the presence of total coliforms while no variable was statistically associated with the presence of <i>E. coli</i>. In the second model, the drawing method and the free chlorine level were significantly associated with the presence of total coliforms while only the free chlorine level was associated with <i>E. coli</i>. These results motivate the need to raise awareness and train populations in drinking water hygiene.

Inclined Tubes Clarifier for Effective Removal of Suspended Solids from Canal Water Prior to Groundwater Recharge

Groundwater recharge, through surplus supplies of canal water, may prove to be an important strategy for replenishing the rapidly depleting groundwater in Punjab and managing sustainably the groundwater resources. However, presence of suspended silt load in the canal water results in clogging of recharge wells and subsequent reduction in recharge rates and capacity of filters. In present study, an inclined tubes clarifier having filtration capacity of 1.8 L s-1 was designed and fabricated to filter the silt-loaded canal water. In the clarifier, tubes of poly vinyl chloride (PVC) media of 1-m length were attached one over the other to form an inclined honeycomb like structure through which canal water enters as inflow from the bottom and the clarified water exits as outflow from the top of the clarifier. Efficacy of the designed clarifier was tested at different total suspended solids ranging from 500 to 3000 mg L-1 in the canal water and at pumping rates varying from 0.3 to 2.1 L s-1. The results revealed more than 85% sediment-removal efficiency of the clarifier at flow rates above 0.8 L s-1. The results further indicated that efficiency of removing total suspended solids (TSS) reduced drastically at inflow rates more than 1.2 L s-1. Also, at all the flow rates, the efficiency was 6% higher for water samples having TSS more than 2000 mg L-1 in comparison to samples having TSS less than 1000 mg L-1. The clarifier makes no significant difference to the values of total dissolved solids, electrical conductivity, total solids and pH of the canal water.

Impacts of on-farm water sanitation practices on microbial hygiene in poultry waterlines and efficacy of sodium hypochlorite-based product on foodborne pathogens

The microbial water quality of poultry water supplies can be correlated to bird health, livability, overall performance, and human food safety. On-farm microbial evaluations were conducted to understand microbial hygiene of poultry waterlines based on water sanitation practices. With on-farm study I, two farms were selected: Farm A and Farm B; that did not practice water sanitation consistently during the flock grow-out period. Prevalence tests for specific pathogens- Salmonella, E coli, Campylobacter, Listeria, and Staphylococcus were performed for both farms by collecting swab samples post bird harvest from waterlines and plating in specific growth media. With the on-farm study II, one broiler farm with four barn units that treated water (Chlorine (Cl)= ∼ 1 ppm) during the flock grow-out period and flushed waterlines between flocks using concentrated chlorine solution (>1000 ppm) was selected. Swab samples (one from each barn, n=4; each sampling occasion) were collected on three occasions-before flushing, after flushing, and at the end of the grow-out period (d 42) to understand biofilm growth nature in poultry waterlines. Additionally, a separate in-vitro study was conducted to understand the efficacy of a commonly used poultry drinking water sanitizer product (sodium hypochlorite, 8.25 %) against specific foodborne pathogens: Salmonella Enteritidis (SE), E. coli and Listeria. Results from the on-farm study I showed that Farm A and Farm B were positive for Listeria and Staphylococcus, whereas these farms were found negative for other species tested. The findings from on-farm study II showed that biofilm reestablished (> 4 log10 cfu/ml) in waterlines by the end of grow-out cycle despite waterline cleaning and consistent water sanitation during flock grow-out period. The in-vitro test showed that the efficacy of chlorine-based water sanitizer at the field application dose rates was affected by pathogen load in water and pathogen types. The overall results from on-farm or in-vitro studies indicated that poultry growers need to emphasize consistent and robust poultry drinking water sanitation practice in their farms to keep the acceptable bacterial levels in poultry water supplies or water systems.

Removal of sulfur and nitrogen pollutants in a sediment microbial fuel cell coupled with Vallisneria natans: Efficiency, microbial community structure, and functional genes

The rapid development of the economy has led to an increase in the sulfur and nitrogen load in surface water, which has the potential to cause river eutrophication and the emission of malodorous gases. A lab-scale sediment microbial fuel cell coupled with Vallisneria natans (P-SMFC) was designed for surface water remediation. The enhancement of pollutant removal performance of P-SMFC was evaluated in contrast to the SMFC system without plants (SMFC), the open-circuit control system with plants (C–P), and the open-circuit control system without plants (C–S), while illustrating the mechanisms of the sulfur and nitrogen transformation process. The results demonstrated that the effluent and sediment of P-SMFC had lower concentrations of sulfide compared to other systems. Furthermore, P-SMFC exhibited higher removal efficiency for COD (73.1 ± 8.7%), NH4+-N (80.5 ± 19.8%), and NO3−-N (88.5 ± 11.8%) compared to other systems. The closed-circuit conditions and growth of Vallisneria natans create a favorable ecological niche for functional microorganisms involved in power generation, sulfur oxidation, and nitrogen transformation. Additionally, metagenomic analysis revealed that multifunctional bacteria possessing both denitrification and sulfur oxidation genes, such as Thiobacillus, Dechloromonas, and Bacillus, may play simultaneous roles in metabolizing sulfur and nitrogen, thus serving as integral factors in maintaining the performance of P-SMFC. In summary, these findings provide a theoretical reference for the concurrent enhancement of sulfur and nitrogen pollutants removal in P-SMFC and will facilitate its practical application in the remediation of contaminated surface water.

Dietary Bacillus species modulate lipid metabolism-related parameters, growth, water quality, and bacterial load in Nile tilapia (Oreochromis niloticus )

This study examined the impact of supplementing Bacillus spp. mixtures at concentrations of 0.2 g/kg (PRO-0.2) and 0.5 g/kg (PRO-0.5) on Nile tilapia (Oreochromis niloticus) for 90 days. Fish groups receiving PRO-0.2 and PRO-0.5 exhibited significantly lower water ammonia levels than the control group, in linear and quadratic patterns. Furthermore, their length and weight increased exponentially over time, peaking at the end of the experiment. After 90 days, the PRO-0.5 group displayed the highest mean weight gain. Additionally, both the PRO-0.2 and PRO-0.5 groups had the lowest food conversion ratios and highest protein efficiency ratios in a linear pattern. They also showed improved liver function, as indicated by lower levels of liver enzyme (aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase) compared to the control group. In terms of the lipid profile, the PRO-0.2 and PRO-0.5 groups had significantly lower serum levels of low-density lipoprotein, triglycerides, in linear and quadratic patterns, and cholesterol compared to the control group, with no significant differences in cholesterol levels. High-density lipoprotein increased significantly in both PRO-0.2 and PRO-0.5 groups after 90 days, following a linear pattern. Hepatic alkaline phosphatase levels decreased in both the PRO-0.2 and PRO-0.5 groups, following a significant linear pattern over time. After 30 days, the expression of hepatic fatty acid binding protein 3 (fabp3) significantly decreased in the PRO-0.5 group. Intestinal cluster of differentiation 36 (cd36) and fabp3 expression markedly increased, with cd36 showing the greatest rise. After 90 days, hepatic cd36 expression became prominent in both PRO-0.2 and PRO-0.5 groups. Expression of fas was significantly downregulated in both the PRO-0.2 and PRO-0.5 groups. Notably, hepatic lipoprotein lipase (lpl) expression significantly increased in the supplementation groups after 30 days but decreased significantly after 90 days. Overall, this study highlights the positive impact of dietary mixtures of Bacillus spp. on various aspects, including water quality, growth performance, feed utilization, survivability, expression of lipid metabolism-related genes, lipid profile, body composition, and bacterial load in both water and fish bodies.

Drainage ditches are significant sources of indirect N2O emissions regulated by available carbon to nitrogen substrates in salt-affected farmlands

Agriculture is a main source of nitrous oxide (N2O) emissions. In agricultural systems, direct N2O emissions from nitrogen (N) addition to soils have been widely investigated, whereas indirect emissions from aquatic ecosystems such as ditches are poorly known, with insufficient data available to refine the IPCC emission factor. In this contribution, in situ N2O emissions from two ditch water‒air interfaces based on a diffusion model were investigated (almost once per month) from June 2021 to December 2022 in an intensive arable catchment with high N inputs and salt-affected conditions in the Qingtongxia Irrigation District, northwestern China. Our results implied that agricultural ditches (mean 148 μg N m−2 h−1) were significant sources for N2O emissions, and were approximately 2.1 times greater than those of the Yellow River directly connected to ditches. Agronomic management strategies increased N2O fluxes in summer, while precipitation events decreased N2O fluxes. Agronomic management strategies, including fertilization (294–-540 kg N hm−2) and irrigation on farmland, resulted in enhanced diffuse N loads in drain water, whereas precipitation diluted the dissolved N2O concentration in ditches and accelerated the ditch flow rate, leading to changes in the residence time of N-containing substances in water. The spatial analysis showed that N2O fluxes (202–233 μg N m−2 h−1) in the headstream and upstream regions of ditches due to livestock and aquaculture pollution sources were relatively high compared to those in the midstream and downstream regions (100–114 μg N m−2 h−1). Furthermore, high available carbon (C) relative to N reduced N2O fluxes at low DOC:DIN ratio levels by inhibiting nitrification. Spatiotemporal variations in the N2O emission factor (EF5) across ditches with higher N resulted in lower EF5 and a large coefficient of variation (CV) range. EF5 was 0.0011 for the ditches in this region, while the EF5 (0.0025) currently adopted by the IPCC is relatively high. The EF5 variation was strongly controlled by the DOC:DIN ratio, TN, and NO3−-N, while salinity was also a nonnegligible factor regulating the EF5 variation. The regression model incorporating NO3−-N and the DOC:DIN ratio could greatly enhance the predictions of EF5 for agricultural ditches. Our study filled a key knowledge gap regarding EF5 from agricultural ditches in salt-affected farmland and offered a field investigation for refining the EF5 currently used by the IPCC.

A Model System to Evaluate the Potential of Floating Treatment Wetlands to Manage Phytophthora species in Recycled Irrigation Water

Highlights A floating treatment wetland (FTW) planted with Pontederia cordata reduced the flow-through of viable zoospores. Bacterial communities associated with FTWs that differed in remediation efficacy were characterized. FTWs have the potential to reduce plant pathogen load in water recycled for agricultural irrigation. Abstract. The increased incidence and severity of drought have reduced reliable access to freshwater irrigation sources for nursery and greenhouse plant producers. Many plant producers are now considering onsite remediation and reuse of water captured from irrigation return flow. However, potential contamination of recycled water with plant pathogens, primarily species of Phytophthora, is the primary concern preventing many growers from reusing their water. Floating treatment wetlands (FTWs) consist of plants established on a buoyant structure that floats on the surface of a water body with roots extended down into the water column. FTWs effectively remediate nutrients in agricultural runoff, but their potential to manage plant pathogens was previously unknown. Therefore, our objective was to investigate the potential efficacy of FTWs to manage species of Phytophthora in recycled irrigation water. Amplicon sequencing was performed to observe how the bacterial communities associated with the roots of plants in the various FTWs differed. The research was conducted using a controlled model system. Each model FTW consisted of a 3-m-long plastic trough that contained no plants, Agrostis alba plants, or Pontederia cordata plants. Nutrient-amended pond water continuously flowed through each trough at a set hydraulic retention time (HRT) of 1 h or 4 h. A standard inoculum concentration of Phytophthora nicotianae zoospores in aqueous suspension was added to influent water entering each trough, and zoospore activity in effluent water leaving each trough at predetermined time intervals was monitored with a baiting bioassay. Results from this study demonstrated that controlled model FTWs containing P. cordata plants effectively reduced the movement of viable P. nicotianae zoospores through a channel of nutrient-amended water at a target HRT of approximately 4 h. Movement of viable zoospores through the troughs was not reduced at the higher flow rate of 1 h HRT or for FTWs containing A. alba plants. Furthermore, the roots of A. alba and P. cordata had enriched bacterial communities that differed from one another. The mechanism by which FTWs containing P. cordata plants reduced zoospore activity was not determined; however, it may be due to interception of zoospores by plant roots, effects from plant root exudates, interactions with the root microbiome, or differences in water quality parameters. This is the first published study evaluating the potential efficacy of floating treatment wetlands to manage plant pathogens in irrigation water. Keywords: Ecological remediation, Horticulture, Microbial community analyses, Pathogens, Water reuse.

Microbiological analysis strategies for detecting pathogens and assessing biosecurity practices in outdoor earthen shrimp farms

The need for rapid and reliable on-farm bacteriological test methods to detect pathogens and assess the success of biosecurity practices in fish and shrimp farms has been increasing. This study compared on-farm and in-laboratory (after refrigerated transportation) analyses for black tiger shrimp (Penaeus monodon) cultured in two outdoor earthen ponds in low-resource settings on the southeastern coast of Bangladesh, using basic bacteriological facilities. Water quality parameters, including temperature, dissolved oxygen (DO), pH and salinity were determined at monthly intervals during summer (April to June). Water temperature in two farms ranged from 26.3°C to 29.3°C (27.7±1.6°C in Farm-1 and 27.4±0.9°C in Farm 2), within suitable limits for shrimp culture. DO levels varied from 5.1±0.2 to 5.4±0.5 mg/l, pH from 7.1±0.2 to 7.1±0.6, and salinity from 14.7±1.2 to 15.7±0.6 ppt, all within optimal ranges for shrimp farming. Bacterial loads showed slight variations between sampling periods. On-farm analyses consistently showed lower bacterial loads in shrimp samples compared to in-laboratory analyses with bacterial counts increasing over transportation time. Water temperature significantly influenced bacterial load as reflected by different sampling periods. The total bacterial load in farm water, sediment and shrimp samples showed notable differences between on-farm and in-laboratory analyses, reflecting the impact of environmental conditions, handling practices and time delays. It is concluded that on-farm microbiological analysis strategy is an effective method for detecting pathogens and assessing biosecurity practices in shrimp farms cultured in outdoor earthen ponds.

Heavy metal load in waters and sediments of Karamana River Basin, southwestern India: A COVID-19 lockdown modulation

Rapid urbanization and industrialization jointly provoked heavy metal contamination in surface water (SW) and channel sediments (CS) of the riverine ecosystem especially in developing countries like India. Water and sediments are to be considered the most vital gears and useful indicators of the level of contamination in an aquatic environment. Furthermore, it is imperative to assess how COVID 19 lockdown, influenced the Karamana River Basin (KRB) waters catering to the quality water needs of urbanites of a city like Thiruvananthapuram, the capital of Kerala. For an insight into this issue, 84 samples (water = 41; sediment = 41) were collected during the pre-monsoon (i.e., January) of 2021 and 2022 and analysed to generate heavy metal concentration levels in the samples. Our estimate of the Heavy Metal Pollution Index (HPI) of water in the KRB in 2021, during the late peak of Covid-19, indicates that though ∼78.89% of the basin (553.78 km2) stayed within the non-contaminated category, and ∼21.11% (or 148.22 km2) was in the contaminated or very poor category. Contrarily, in 2022 after the withdrawal of lockdown restrictions, the non-contaminated area sharply declined to ∼45.04% (316.15 km2) of the basin and the contaminated area rose to 54.96% (385.85 km2). Furthermore, the Inverse Distance Weighted (IDW) modeling strongly supports that Cr and Fe are the leading heavy metal polluters in the Karamana River (KR) waters during 2021 and 2022. Subsequently, estimated Igeo values in sediments indicate that the uncontaminated area has reduced from 88.89% to 83.73%, and the uncontaminated to the moderately contaminated area rose to 5.16%. Therefore, the shutdown of anthropogenic activities, including small- and medium-scale industries as part of the COVID-19 lockdown, improved the surface water quality of KRB for a short-stint of time, but swung back to normality just after the lifting of lockdown restrictions.

Assessment of bacterial loads and water quality parameters of three different types of fish pond

The present study was conducted to determine bacterial loads in the water columns and mud of three different pond systems,includingan overwintering fish fry pond,a brood fish rearing pond, anda recreational fish pond (L-shaped fish pond) situated at the Field Laboratory Complex of the Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh.Three samplings were done atevery 15-day interval. Bacterial loads in water columns and mud were determined using the drop count method. Water quality parameters, including temperature, dissolved oxygen, pH, and ammonia, were also determined. Significantly (p<.001),the highest bacterial loads in three different water columns were observed in the overwintering fish fry pond, and the lowest bacterial loadswere found in the L-shaped fish pondat all sampling points. Bacterial loads in the bottom water were also significantly higher than those in the surface and middle layers of the water in all ponds. Pond mud was significantly (p<.001) richer in bacterial loads than pond water. Bacterial load was strongly correlated with temperature, and the correlation faded with the increase in depth of the water column.

Trace Metal Based Eco-Biological and Health Risk Status of Surface Water and Sediments of Noyyal River Basin, Tamil Nadu, India

ABSTRACT Pollution in the Noyyal river is a well-known and documented issue and recently, heavy metal contamination has become a serious issue requiring immediate attention. So, to understand the severity of heavy metal contamination in the surface water and sediments of the Noyyal river, a comprehensive study was conducted. About 27 surface water samples and 25 sediment samples were collected at different sites along the Noyyal river. The concentrations of heavy metals were determined using inductively coupled plasma mass spectrometry (ICP-MS). The Noyyal river’s surface water showed significant variations with nickel (Ni), copper (Cu), and zinc (Zn) concentrations exceeding acceptable limits for irrigation and aquatic life. Lead (Pb) concentrations were within acceptable limits for irrigation but potentially harmful to aquatic organisms. Noyyal river sediments also contained varying concentrations of chromium (Cr), copper (Cu), nickel (Ni), zinc (Zn), and gallium (Ga). Various assessment indices were employed to assess the eco-biological and human health risks associated with heavy metal contamination. The results highlighted alarming ecological and biological risks due to the accumulation of trace metals. Sediments exhibited high ecological risk (ERI values ranging from 43.81 to 371.43), while surface water samples intended for irrigation and aquatic purposes displayed extreme risks (ERI values exceeding 1200) to agricultural crops and aquatic organisms. The probability of toxicity to aquatic organisms, particularly benthic communities, was over 76% according to the biological risk assessment. The study also identified potential non-carcinogenic risks associated with metals like chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn) in the sediments. Moreover, elevated levels of Cr, Ni, and Cu in both sediments and surface water were likely to pose significant carcinogenic risks to exposed adults. Additionally, the heavy metal toxicity load in both surface water and sediments exceeded permissible limits, highlighting the urgent need for efficient removal strategies.

Numerical study of a novel small waterplane area USV advancing in calm water and in waves using the higher-order Rankine source method

The wave loads and motion responses of an Unmanned Surface Vehicle (USV) in water will directly influence the powering requirement, energy supply design and function of the installed sensors. In the present article, to investigate the wave loads and motions response characteristics of a USV advancing on the free surface, a Higher-Order Rankine Source (HORS) method is proposed. During the discretization of the boundary elements, bi-quadratic B-splines are applied to distribute the velocity potentials on the body surface and free surface. Based on the proposed HORS method, steady state simulation and time-domain simulation approaches are both used for predicting the wave loads and motion responses of a novel Small Waterplane Area (SWA) USV in calm water and regular waves, respectively. The predicted wave loads in calm water and the predicted heave and pitch in heading wave are compared with corresponding model test data. The good agreement found indicates the validity of the proposed HORS method. Finally, the heave and pitch motion responses and the wave components of the USV including diffraction and radiation forces and Froude−Krylov forces are investigated when the SWA USV is running against heading wave under different conditions of wavelength, wave steepness and advancing velocity.

Omicron COVID-19 Case Estimates Based on Previous SARS-CoV-2 Wastewater Load, Regional Municipality of Peel, Ontario, Canada.

We determined correlations between SARS-CoV-2 load in untreated water and COVID-19 cases and patient hospitalizations before the Omicron variant (September 2020-November 2021) at 2 wastewater treatment plants in the Regional Municipality of Peel, Ontario, Canada. Using pre-Omicron correlations, we estimated incident COVID-19 cases during Omicron outbreaks (November 2021-June 2022). The strongest correlation between wastewater SARS-CoV-2 load and COVID-19 cases occurred 1 day after sampling (r=0.911). The strongest correlation between wastewater load and COVID-19 patient hospitalizations occurred 4 days after sampling (r=0.819). At the peak of the Omicron BA.2 outbreak in April 2022, reported COVID-19 cases were underestimated 19-fold because of changes in clinical testing. Wastewater data provided information for local decision-making and are a useful component of COVID-19 surveillance systems.

How phoD-harboring functional microbial populations trigger the release risk of phosphorus in water sediment system of Shijiuhu Lake, China after experiencing the transseasonal shift

Excessive phosphorus (P) enrichment is the critical cause of eutrophication in the lake water. Organic P (Po) mineralization processes induced by alkaline phosphatase (APase) regulated by phoD-encoding microorganisms in the lake ecosystems was still ambiguous due to the transseasonal shift of water temperatures and depths. Different P pools in the water and sediments of Shijiuhu Lake at varied seasons were measured using chemical extraction methods and solution 31P NMR. The alkaline phosphatase activity (APA) in the sediments were assessed together with enzyme kinetic parameters. The abundances and compositions of microbial communities encoding functional gene phoD were also obtained using high-throughput sequencing. The results showed that Po concentrations remarkably increased from winter toward spring when having higher water depths due to the terrigenous input and biomass deposition. Noteworthy elevation in the PO43- concentration was observed in the interstitial water during the spring, particularly at around 5 cm sediment depth with value reaching as high as 0.43 mg/L. The degradation and mineralization of momoesters and diesters with higher concentrations in the sediments of spring aggravated the PO43- load in the interstitial water. Higher APA reaching 91.6 μg/(g·h) in spring was responsible for the mineralization of Po. Remarkably upwards increasing of absolute abundance of phoD-encoding gene in spring reaching up to 2.6 times of that in winter facilitated the generation of APA in spring. Cobetia and Calothrix followed by Aquabacterium and Mitsuaria were the most abundant phoD-encoding genera with relative abundance > 4%. Weakly positive correlation between dominant bacterial genera and APA and P fractions suggested that low-abundance genera was also involved in the APA generation and Po hydrolysis. These results indicate that spring with high water temperature and depth facilitate the mineralization of Po in the sediment and increase of labile PO43− load in the water, further provide valuable information for the management of eutrophic lakes.