Water Samples Research Articles

Assessment of trace element occurrence in Nile Tilapia from the Rosetta branch of the River Nile, Egypt: Implications for human health risk via lifetime consumption

River pollution can harm human health through direct contact, drinking water, and the consumption of contaminated fish and irrigated agricultural products. Surface water and Nile tilapia (Oreochromis niloticus) samples were collected monthly from July 2022 to June 2023 at three sites (El-Rahawy, Sabal, and Tala) along the Rosetta Nile branch in Egypt to monitor the presence of eight trace elements. The potential human health risks from consuming contaminated fish were also assessed. Iron and manganese were consistently detected in all water samples across most seasons and locations, with concentrations generally below the WHO permissible levels. All 72 analyzed fish muscle samples were found to contain trace elements. The mean concentrations of metals in the fish muscle samples, in descending order, were: iron > zinc > copper > manganese > tin > antimony > lead > mercury. Significant spatial and seasonal variations were observed in both water and fish samples. El-Rahawy was identified as the most contaminated site, with summer exhibiting the highest contamination rate compared to other seasons. Fish samples collected from El-Rahawy demonstrated the highest bioconcentration factor (BCF) values for most elements, particularly mercury, lead, iron, manganese, and antimony. Target hazard quotient (THQ) calculations for the trace elements in Nile tilapia muscles revealed that all trace elements, except antimony, had THQ values below 1, suggesting that consuming Nile tilapia from these sites is unlikely to cause adverse health effects. However, THQ values for antimony exceeded the threshold of 1, indicating a potential health risk for consumers. Although the detected trace elements in the fish were below the permissible toxicity limits, some could pose a future threat to human health, necessitating further studies, ongoing monitoring, and preventive measures.

A new calibration method for radon detector in seismic systems

Radon observation is an important measurement item of seismic precursor network observation. The radon detector calibration is a key technical link for ensuring radon observation accuracy. At present, the radon detector calibration in seismic systems in China is faced with a series of bottleneck problems, such as aging and scrap, acquisition difficulties, high supervision costs, and transportation limitations of radon sources. As a result, a large number of radon detectors cannot be accurately calibrated regularly, seriously affecting the accuracy and reliability of radon observation data in China. To solve this problem, a new calibration method for radon detectors was established. The advantage of this method is that the dangerous radioactive substance, i.e., the radon source, can be avoided, but only “standard instruments” and water samples with certain dissolved radon concentrations can be used to realize radon detector calibration. This method avoids the risk of radioactive leakage and solves the current widespread difficulties and bottleneck of radon detector calibration in seismic systems in China. The comparison experiment with the traditional calibration method shows that the error of the calibration coefficient obtained by the new method is less than 5% compared with that by the traditional method, which meets the requirements of seismic observation systems, confirming the reliability of the new method. This new method can completely replace the traditional calibration method of using a radon source in seismic systems.

Efficient degradation of bisphenol A and amino black 10B by magnetic composite Fe3O4@MOF-74 as catalyst

Metal-organic frameworks (MOFs) exhibit high chemical stability and porosity, and have been widely applied in various fields including selective adsorption and separation, sensors, and catalysis. When combined with Fe3O4, they effectively address issues such as aggregation of Fe3O4 particles and the difficulty in recovering MOFs as catalysts. Therefore, in this study, we used a simple solvothermal method as a catalyst to synthesize a high specific surface area magnetic composite Fe3O4@MOF-74, which was used to catalyze the degradation of bisphenol A (BPA) and amino black 10B in wastewater. We activated Na2S2O8 to generate radicals for oxidizing and degrading BPA and amino black 10B. Experimental results showed that at 35 °C, with Fe3O4@MOF-74 (Fe3O4: MOF-74=1:1) concentration of 0.2 g/L and Na2S2O8 concentration of 2 g/L, the catalytic effect is efficient and economical. Meanwhile, removal rates of BPA and amino black 10B exceeded 95.58 % over a broad pH range (pH 3–9). Furthermore, even after multiple cycles of use, Fe3O4@MOF-74 maintained catalytic degradation rates of BPA and amino black 10B above 93.24 % and 95.01 %, respectively. Additionally, in water samples, removal rates of BPA and amino black 10B exceeded 91.55 %. This study provides a new and efficient catalyst material for wastewater treatment, which is expected to play an important role in environmental remediation.

A novel solid-phase extraction device for the pneumatic cycle pharmaceuticals residues adsorption: A proof of concept study

In this study, a pneumatic cycle device, herein called the air-operated solid-phase extraction (AO-SPE), was designed for the enrichment of pharmaceutical residues. The device consisted of two parts: an air circulation system and an adsorption system. The continuous air flow ensured that the water sample flowed past the adsorbent, completing the adsorption process. One significant advantage of this device is that the air circulation system can generate pneumatic cycle adsorption with the continuous air flow, increasing the interaction between the adsorbent and the target analytes. Additionally, the entire device is easy to install and dismantle, and the adsorbent can be easily replaced, making the AO-SPE suitable for various types of adsorbents materials tailored to specific target analytes. The smart design is aimed at extracting trace analytes in the large-volume water samples. As a proof-of-concept, the AO-SPE was applied to enrich non-steroidal anti-inflammatory drugs in soil. A Ce-based metal organic framework composite was prepared and applied to verify the applicability of AO-SPE, exhibiting the enrichment factor of up to 538. The results showed that AO-SPE exhibited a maneuverable approach with high efficiency and sensitivity for analyzing large-volume samples, indicating has a great potential for extracting of trace analytes.

A Polyacrylate Cotton-based Pipette Tip Micro-solid-phase Extraction Technique Coupled with High-performance Liquid Chromatography for Carvedilol Determination in Aqueous Media

Introduction: In this work, a polyacrylate polymer was synthesized into a pipette tip containing cotton fibers and used to extract carvedilol from water and urine samples. Methods: A high-performance liquid chromatography-ultraviolet detection method was developed, which demonstrated the suitability of the purposed pipette tip micro-solid-phase extraction device. Factors affecting the fabrication procedure and polymer quality were studied and optimized. In the next step, the sample preparation process (including extraction and desorption) was fully optimized, and the optimized method was validated. Results: A coating with suitable mechanical and chemical stability was achieved. Its structure was successfully characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Within-batch and between-batch fabrication reproducibility were obtained at 3.0 and 9.0 %, respectively. The developed method displayed a limit of detection of 1.1 µg L-1 when 1.5 mL of sample was processed, and it was linear in the concentration range of 3.3-350 µg L-1 with LLOQ of 5 µg L-1 . The polyacrylate cotton-based pipette tip was finally used to extract carvedilol from aqueous media with acceptable recoveries of 92-106%. Conclusion: The proposed method is simple and fast and requires low sample volumes. In addition, this method has been evaluated in terms of greenness with three different tools, and the evaluation results with all three tools have shown that this method is one of the green and environmentally friendly methods.

Electroanalysis of bromate at riboflavin impregnated Ketjen black porous electrode via an autocatalytic cycle with finite length diffusion

The emergence of elevated concentrations of bromate, classified as a 2B type carcinogen, in drinking water following the treatment of water supplies with ozonation and other oxidation methods has underscored the importance of developing methods for reliable and rapid screening of drinking water. In this work, we report the use of electro activated riboflavin (RF) impregnated Ketjen black (KB) modified screen-printed electrode (elRF@KB-SPE) for the determination of bromate. The sensing surfaces were subjected to morphological and structural characterization using scanning electron microscopy and Raman spectroscopy. These analyses confirmed the successful modification of the electrode with an extended elRF@KB porous coating. Based on cyclic voltammetry (CV) and electrochemical impedance spectroscopy measurements, the response of elRF@KB-SPE towards bromate can be described through a dual mechanism involving i) an autocatalytic chemical/electrochemical process that predominantly occurs in the finite length pores of KB, and ii) an RF-mediated electrocatalytic process. Notably, the data demonstrated that the advanced electrocatalytic properties of the otherwise electrocatalytically inactive absorbed RF molecules are endowed after a simple electro activation process (three CV scans). Amperometric measurements at −0.05V vs. Ag/AgCl revealed a linear relationship between the current response and the concentration of bromates over the concentration range 0.50−18.0μM, achieving a limit of detection (3σ/slope) of 0.04μM. The interference effect of various electroactive species was investigated demonstrating that elRF@KB-SPE is highly selective to bromate. The analytical utility of the method was evaluated in spiked tap water samples. Recoveries were 91.2 − 106.4%.

Towards a more sustainable hydrogen energy production: evaluating the use of different sources of water for chloralkaline electrolyzers

Water scarcity is becoming a serious threat for the implementation of energy storage devices based on hydrogen in the inland of dry regions, because of the difficulties in finding appropriate sources of water and the important environmental problem associated with the discharge of rejection saline streams produced during the purification of water. This becomes an opportunity for chloralkaline technology in which the quality of water used is lower than the required in other hydrogen production technologies. This work compares the performance of chloralkaline electrolyzers fed with different solutions of NaCl (from brackish water to brines) with that obtained feeding two natural water samples (seawater and porewater) and three processed waters (rejections streams of the electrodialysis, reverse osmosis of the porewater and a real rejection of the reverse osmosis of a vineyard). All tests were made with a lab-scale 3-D printed cell where, in addition, the performance of Ti/RuO2 and Pb/PbO2 anodes were compared, being always better the results obtained in the tests made with the Ti/RuO2 electrode. Results obtained indicate that efficiencies reached using these alternative sources are lower than those which can be reached using synthetic brines that, in turn, were very near to the standards reached in the chloralkaline industry. In the case of hydrogen production, the maximum values were obtained for seawater, reaching efficiencies proximate to 8.0 mg H2 (Wh)-1. Rejection streams of desalination processes were found to be less efficient, attaining values in the range 2 and 4 mg H2 (Wh)-1. Regarding the production of chlorine and caustic soda, better performances were reached again with seawater (161.7 mg Cl2 (Wh)-1 and 0.092 mg OH- (Wh)-1 ) and with the rejection of the electrodialysis, which also reached sound values of 90.4 mg Cl2 (Wh)-1 and 0.107 mg OH- (Wh)-1. Results obtained are promising and indicate a path that must be further worked for the implementation of a greener water management strategy in the hydrogen -based energy storage technology.

Predicting the spread of contamination in water distribution networks laid on sloping terrains

Contamination in domestic and drinking water during the conveyance process is one of the biggest health risks of all time. This is a very common hazard that is expected in the areas where water, sewer, and drainage pipes are laid in trenches near each other. The extent of the contamination spread in the case of intrusion through a pipe leak for water distribution networks (WDNs) laid on sloping terrain is not known. This article deals with the simulation and hydraulic analysis of organic contaminant intrusion in WDNs with significant consideration of the slope of the laid pipes. The source of organic contamination is considered to be the nearby leaking sewer water. The effects of sloping terrain on contaminant spread in the pipe network are studied in detail by injecting contaminant concentrations at eight different critical locations in the network. The results of contamination spread after a particular time at all nodes are compiled, and by using statistical techniques, a relation between the contaminant spread and pipe slope is proposed. The presented model is validated by comparing the actual values of the contaminant in water samples obtained at the site with the calculated ones, and it shows that the values deviate within the range of ±2% only, which is considered a good match. The research proves to be beneficial for the management of water distribution through pipe networks against contaminants to maintaining water quality and public health.

A Reliable and Straightforward Combination of vortex-assisted Dispersive Magnetic solid-phase Extraction with Direct Sorbent Sampling for Highly Sensitive Silver Determination in Water Samples Using Flame and Metal Furnace AAS

A Reliable and Straightforward Combination of vortex-assisted Dispersive Magnetic solid-phase Extraction with Direct Sorbent Sampling for Highly Sensitive Silver Determination in Water Samples Using Flame and Metal Furnace AAS

Study of Escherichia coli, EPEC, ETEC AND STEC, in water offered in schools in a municipality with low human development index in Maranhão State, Brazil

This study examined the EPEC, ETEC and STEC pathotypes in E. coli isolates from water supplied to schools in a municipality in Maranhão, Brazil with a low human development index. For this, 57 bacterial strains isolated from 19 water samples were used. All strains were confirmed as belonging to the E. coli species, by Gram staining and phenotypic tests. From pure cultures of E. coli, DNA was extracted followed by characterization of the isolates by polymerase chain reaction (PCR). This is the first study carried out in the state of Maranhão on the research of the diarrheagenic strains EPEC, ETEC and STEC in water for human consumption offered in schools, with the detection of virulent genes characteristic of enterotoxigenic E. coli (26.31%; n = 15/57) and E. coli producing Shiga toxin (8.78%; n= 5/57). Of the strains identified, 8.78% (n= 5/57) corresponded to combinations of est + stx1 genes. It is concluded that the detection of the diarrheagenic strains ETEC and STEC in E. coli isolates from water samples for human consumption indicates that, in addition to the water being contaminated, it harbors strains with pathogenic potential to cause diarrheal infection in its users. Keywords: ETEC, school environment, STEC.

A comparative study on water quality and microbial conditions of open well and bore well water from a selected area of Kalaburagi city, Karnataka, India

In order to assess the suitability of water sources for human consumption, six water samples were taken from open wells and drinking bore wells in several selected regions in the Kalaburagi district of Karnataka state, India, from December 2020 to January 2022. The analysis found that the local water sources are contaminated. Total dissolved solids, total alkalinity, chloride, calcium, and magnesium levels in the water exceeded the permissible limits. The samples analysed for the presence of microbial contamination indicate a worrying scenario from the point of view of public health. As a result, such studies must be expanded to include open wells and bore wells in individual homes, as well as detailed investigations of the physicochemical and microbiological quality of drinking water sources in Kalaburagi district.

Synthesis of Multifunctional Chemosensors for Naked Eye Detection of Cu2+ and Hg2+; Application in Paper Strips, Water, and Food Sample

AbstractThree chemosensors ISA‐1, ISA‐2, and ISA‐3 were synthesized for the detection of Cu2+ and Hg2+ ions in a 50% H₂O‐DMF solution. ISA‐1 is specifically designed for the detection of Cu2+ ions, while ISA‐2 can detect both Cu2⁺ and Hg2⁺ ions. Upon interaction with Cu2⁺, ISA‐1 undergoes a naked‐eye colorimetric transition from pink to blue. ISA‐2 exhibits a similar pink‐to‐blue color change in the presence of Cu2+ ion, however, colorless when exposed to Hg2+ ion. The detection limits for Cu2+ using ISA‐1 and ISA‐2 are 0.574 ppm and 0.0074 ppm, respectively, both of which are significantly lower than the WHO guideline of ≤1.5 ppm for Cu2+ in drinking water. These chemosensors have also been successfully integrated into paper strips and logic gate systems and applied for the analysis of water and food samples.

Analysis of the physico-chemical relationship between losses of water, soil and soil nutrients in the water of the Farinha River – MA

Brazil has a vast reserve of water resources, but pollution from various sources and the effects of climate change have triggered a crisis in this sector. The as-sessment of water quality indices plays a crucial role in monitoring and unders-tanding this issue, and the country has established its own standards and moni-toring requirements to guarantee water quality. In addition, the physical-chemical relationship plays a fundamental role in the conservation of both soil and water. In this context, a study was carried out in the Farinha river basin, located in Maranhão, in the Cerrado biome, over an area of 55,338.12 hecta-res. Data was collected at ten different points along the river during the rainy and dry seasons. A Van Dorn bottle was used to collect water samples at vari-ous depths, which were analysed for pH, dissolved oxygen, electrical conducti-vity and temperature. Nutrients such as potassium, calcium, magnesium, sodi-um, silicon, nitrate and total phosphorus were quantified using filtration and spectroscopy techniques. The data obtained was tabulated and subjected to analysis of variance, with the means analysed using the Tukey test. This study reveals significant seasonal variations in the physico-chemical parameters of the water in the Farinha River in Maranhão, impacting aquatic life and water quality. This highlights the importance of continuous monitoring and manage-ment of these resources.

Local and Low-Cost Filter Media of Simple Water Filtration

Commonly the Installation of a Drinking Water Supply System (SPAM) in Indonesia consists of Coagulation-Flocculation, Sedimentation, Filtration and Disinfection Processes as a complete Process Unit for surface feed water such as rivers or lakes. Similarly, the clean water treatment process in Banjarbaru, South Kalimantan, Indonesia uses intake water sources from irrigation. The intake water from irrigation used by the local Regional Drinking Water Company has good quality with a low turbidity value below the quality standards set by the central government. Based on these qualities, the right process unit to treat the water is by filtration only. Therefore, it is necessary to conduct evaluation and research to improve the efficiency of the process unit and the economic value of the water treatment. The purpose of this study is to investigate and evaluate irrigation feed water treatment by filtration using local and low-cost filter media. The filter reactor is designed with a rapid media filter type. The media is characterized using energy dispersive X-ray spectroscopy (EDS) and a scanning electron microscope (SEM) which is plugged in with EDS to find out the primary constituents and morphological information and after knowing the characterization of the media, and followed by tested the media placed in the water filter reactor with data collection. The results show that the size of the filter media has great effect on the quality of the processing water, which the smaller the media diameter conducted high selectivity and speed up filtration time. The greatest result obtained from testing feed water with media is 87.64%. Turbidity of the feed water sample process, which was previously 0.34 NTU, could be decreased to 0.02 NTU. Effective size of 0.4 mm and uniformity coefficient of 1.35 mm are the optimal allowable values.

Bacterial Inactivation Studies in Shrimp Pond Water by using Different Disinfectant Agents

Abstract Background Aquaculture water plays an important role in the dissemination of antibiotic-resistant bacteria during harvest of shrimps. Mitigation of bacteria through discharge is essential to prevent dissemination downstream. Chemical disinfection of culture water is feasible compared to other methods of bacterial inactivation. Objective To study the effect of different disinfectant agent’s viz., chlorine, Fenton’s reagent, and hydrogen peroxide (H2O2) on inactivation of bacteria from shrimp pond water Methods The water samples were subjected to treatment with various concentrations of chlorine (0.0, 1.0, 2.5, 5.0 and 10.0 mg L−1), Fenton’s reagent (1:10 mM ratio of Fe2+:H2O2; 2:20, 3:30, 4:40, 5:50) and H2O2 (20, 30, 40 and 50 mM) for different time durations (5 min, 15 min, 30 min and 60 min). Results The results indicated that all the disinfecting agents inactivated both the total heterotrophic bacteria and tetracycline-resistant bacteria with increased concentrations and time. At the end of 60 min treatment with chlorination (2.5 mg Cl2 L−1), Fenton’s reagent (2 mM Fe2+ + 20 mM H2O2) and H2O2 (50 mM H2O2), the total heterotrophic bacterial count in the water samples gradually decreased by 2.35, 2.65, and 1.38 log10 CFU mL−1, and tetracycline-resistant bacteria count reduced by 1.57, 1.66, and 1.43 log10 CFU mL−1, respectively from initial bacterial load. Conclusions The study revealed that disinfection agents can be successfully employed in the inactivation of antibiotic-resistant bacteria discharged through aquaculture water. Among three disinfection agents, Fenton’s reagent has been found effective in inhibiting both heterotrophic bacteria and tetracycline-resistant bacteria from water samples. Highlights Bacterial inactivation studies were carried with Chlorination, Fenton’s reagent, and Hydrogen peroxide. The highest decrease in HPC (2.65 log) and tetracycline-resistant bacterial (1.66 log) was noticed in the water samples treated with Fenton’s reagent. The use of disinfection agents effectively mitigates antibiotic-resistant bacteria from aquaculture wastewater.

Probabilistic human health risk assessment of commercially supplied jar water in Gopalganj municipal area, Bangladesh

Every day, the amount of quality fresh water decreases notably due to contamination of drinking water. As a result, people use commercially supplied jar water in the southern part of Bangladesh as well as in the Gopalganj municipal area. This study aims to investigate the physicochemical parameters, trace elements, and microbial parameters for assessing human health risks from oral ingestion of these elements. This study gathered commercially supplied jar water samples from 15 companies in the Gopalganj municipal area during the post-monsoon season. Temperature, potential of hydrogen (pH), total dissolved solids (TDS), electrical conductivity (EC), and salinity showed significant variation among the samples, and the level was within the national and international standard limits. The concentrations of iron (Fe) and arsenic (As) were measured using a UV–VIS spectrophotometer and atomic absorption spectroscopy (AAS), respectively. The microbial analysis was conducted by the membrane filtration method. The study found that the water samples had an average concentration of 0.16 mg/L in terms of Fe and 0.016 mg/L in terms of As, with the mean value of As exceeding the standard limits. On the other hand, the mean Fe concentration value did not exceed the standards. Probable human health risk from heavy metal in the jar water was determined by hazard quotient (HQ), hazard index (HI), and carcinogenic risk (CR) assessments. A child (HI = 3.5914) is more vulnerable to non-carcinogenic human health risks than an adult (HI = 1.6931). Furthermore, pollution in water samples was found to pose a high carcinogenic risk, with children (CR = 1.6 × 10−3) being more vulnerable to carcinogenic risk than adults (CR = 7.5 × 10−4). In the microbial analysis, 100% of the samples exceeded the total coliform and fecal coliform standard limits, and 80% of the samples exceeded the Escherichia coli standard limits. Among the samples, 7% present high risk, around 47% present medium risk, 26% show low risk, and 20% show no risk based on the E. coli standard limits. This study did not find any samples that exceeded the extremely high limit for E. coli concentration. This study found that drinking jar water samples had inadequate quality, which may increase the risk of water-borne infections such diarrhea as well as heart disease, diabetes, and cancer. As a result, the manufacturer of drinking water in jars must carry out the essential quality control procedures, and the government should regularly monitor the procedures.

Bacteriological Quality Determination of Borehole Water Supply in Hostels of Rivers State University Main Campus, Port Harcourt, Nigeria

Water serves as a vehicle for the transmission of various diseases to man and animals, and have been associated with both acute and chronic health syndromes. This study was carried out to determine the bacteriological quality of borehole water supply in the Hostels of Rivers State University, Port Harcourt, Nigeria. Borehole water samples were collected from six (6) hostels for each study period, and subjected to standard bacteriological Procedures. Results obtained indicated that the highest mean total heterotrophic bacterial count of 3.6±1.7 X 105cfu/ml was recorded in the Hostel C water sample, while the least mean bacterial count of 5.5±0.35 X 104cfu/ml was observed in FCMB Hostel. The total coliform count had the highest value (3.3±3.82 X 104cfu/ml) recorded in Hostel D and the lowest value of 2.0±0.14 X 103cfu/ml was obtained in the Hostel H water sample. The faecal coliform count recorded the highest value in FCMB Hostel (1.5±0.71X 103 cfu/ml) and lowest in Hostel H (8.5±4.95 X 103 cfu/ml). The staphylococcal count was highest in Hostel B (8±9.9 X 104 cfu/ml) and lowest in Hostel C (0.6±0.57 X 104cfu/ml). Six bacterial species were identified, which included Bacillus spp (100%), Staphylococcus spp (100%), Pseudomonas spp (83.3%), Klebsiella spp. (66.6%), Salmonella spp (16.6%) and Escherichia coli (16.6%). Data obtained showed that all the isolates were biofilm producers, albeit at varying percentages, as 52.9%, 55.5%, 60%, 30%, 33.3%, and 100% of Bacillus spp, Staphylococcus spp., Pseudomonas spp., Klebsiella spp., Salmonella spp. and Escherichia coli, respectively were positive for biofilm formation. The hemolysis result indicated that 28.3%, 10%, and 61.7% of the isolates were alpha, beta and gamma hemolytic, respectively. The study indicated the presence of bacteria of public health importance, thereby, making the need for regular monitoring and treatment of these water sources very necessary to check bacterial proliferation and ensure continuous access to safe water in the hostels.

Perfluoroalkyl substances: a risk for the aquatifc environment? A 1-year case study in river waters of central Italy.

Perfluoroalkyl substances (PFASs) are a large class of persistent emerging pollutants, ubiquitous in different environmental compartments. In this study, twenty-one PFASs were determined in seventy-eight water samples collected from six different rivers in the Umbria region (central Italy) during a 13-month monitoring campaign. The sum of the twenty-one target analytes (Σ21PFASs) ranged from 2.0 to 68.5ng L-1, with a mean value of 22.0ng L-1. The highest concentrations of Σ21PFASs were recorded in the warmest months (from June to September) due to reduced river streamflow caused by low rainfall and high temperatures. PFASs with a number of carbon atoms between four and nine prevail over C10-C18 congeners due to their higher water solubility and to their increased use in industry. PFBA, followed by PFPeA, PFHxA, and PFOA, was the most abundant congeners detected in the analyzed river water samples. Finally, the calculation of risk quotients (∑RQs) has allowed to assess the risk for three aquatic organisms (fish, algae, and daphnid) deriving from the exposure to PFASs. The survey showed that the risk for the three aquatic organisms during the four seasons and throughout the year was always negligible. The only exception was a low risk for fish and daphnid in GEN river considering the annual exposure.

POLLUTION OF THE FIFTH CANAL ON THE CRNA RIVER IN THE REGION OF BITOLA

Water is an irreplaceable natural resource. The main goal of this research is to see the pollution of the fifth canal on Crna River in the region of Bitola. As measuring points for sampling for this analysis are: measuring point 1 (Crna River near the village of Novaci), measuring point 2 (fifth canal exit of Bitola), measuring point 3 (fifth canal near the village of Kravari) measuring point 4 (fifth canal before flowing into the Crna River), measuring point 5 (Crna River before being mixed with water from the fifth canal), measuring point 6 (Crna River after mixing with water from the fifth canal) and measuring point 7 (Crna River near the village of Skocivir). Water samples were taken in May and November. To determine the water quality, the following physicochemical parameters were made: turbidity (by turbidimeter), suspended solids, total organic carbon, biological oxygen demand, and dissolved oxygen (determined with UV pastel). From the results, it has been concluded that the highest pollution is in the fifth channel, measuring point 2 for the following parameters in May: turbidity (35.3 mg/L), total organic carbon (210.8 mg/L), suspended solids (77.5 mg/L, and in November164.0 mg/L). Of the measuring points of Crna River, the highest pollution is in measuring point 6 in November: biological oxygen demand (14.5 mg/L), and total organic carbon (13.7 mg/L). That is why it is suggested to purify the wastewater before it is released into the rivers.

Efficient removal of organic matter and nitrogen from municipal wastewater in multi-module biochar filters for onsite wastewater treatment

ABSTRACT Biochar is a promising material for wastewater treatment. This study assessed multi-module biochar filters (MmBFs) as onsite wastewater treatment systems (OWTSs), comprising movable modules filled with biochar to remove chemical oxygen demand (COD), nitrogen, phosphorus, and Escherichia coli (E. coli) in wastewater. The MmBF treats wastewater sequentially through six modules: three aerobic modules (M1-M3) for organic matter oxidation and nitrification, two anoxic modules (M4-M5) for denitrification, and an additional module (M6) for the removal of faecal bacteria using biochar and bark. The experiments ran for 381 days using three identical MmBF pilots with two distinct sampling periods, conducted under conditions relevant to OWTSs using municipal wastewater as influent. Water samples were taken from the influent, final effluent, and effluent of each module to evaluate the removal efficiency of organic matter, nitrogen, phosphorus, and E. coli. During the second sampling period, the results showed a 95 ± 2.1% removal of COD, along with a substantial removal of total inorganic nitrogen (71 ± 6.6%). However, phosphate removal was limited (3.4 ± 30.4%). E. coli removal decreased from 2.63 ± 0.93 log10 removal in the first sampling period to 1.8 ± 0.73 log10 removal in the second sampling period. In summary, the MmBFs showed promising potential in treating organic matter, nitrogen, and E. coli, making it an alternative option for OWTS. However, further exploration is needed to assess long-term performance, micropollutant removal, and biological activities. Design enhancements, especially for phosphorus removal are necessary.