[version 1; peer review: 1 not approved]
No competing interests were disclosed.
This study investigates chloride concentrations in tap water samples from Gimba city administration, using the argentometric method to assess water quality. Chloride levels are a key indicator of water treatment effectiveness, particularly the adequacy of chlorination, which is critical for preventing waterborne diseases.
Chloride concentrations in tap water samples from various locations in Gimba city administration, were determined using the argentometric titration method. Silver nitrate (AgNO₃) was employed as the titrant to precisely quantify chloride ions. The water samples were collected from different sites in Gimba, and chloride levels were measured to evaluate the adequacy of water treatment processes.
The chloride concentrations across all samples ranged from 52.8 mg/L to 71.9 mg/L, well below the World Health Organization’s recommended limit for drinking water. Significant variation in chloride levels was observed, with Dembesh exhibiting the highest concentration and Medera the lowest.
The low chloride concentrations suggest insufficient chlorination at the sampling sites, which may compromise the effectiveness of water disinfection and contribute to the prevalence of waterborne diseases in the region. The study underscores the need for enhanced water treatment and disinfection practices in Gimba city to ensure safe drinking water and reduce health risks.
Water is a vital natural resource, essential for life and human development. Its quality directly impacts public health, economic stability, and environmental sustainability. In many urban areas, ensuring safe and clean drinking water has become increasingly important due to rising population growth, industrialization, and agricultural expansion.
Gimba City Administration, located in Legmbo Woreda, South wollo, Ethiopia, has been grappling with water quality concerns due to a combination of natural factors and human activities, including urbanization and municipal discharge. As the city continues to grow, monitoring the quality of drinking water has become crucial to safeguarding public health. Chloride contamination, often a consequence of sewage infiltration, industrial activities, or saltwater intrusion, is one of the parameters that needs consistent monitoring.
The argentometric method, a widely used titrimetric technique, provides an accurate and reliable means of determining chloride ions in water. This method involves the titration of chloride ions with silver nitrate, forming a precipitate of silver chloride. The endpoint of the titration is detected by the use of a suitable indicator, and the concentration of chloride is calculated based on the volume of silver nitrate used. Its simplicity, precision, and cost-effectiveness make it an ideal choice for evaluating the chloride content in water.
This study focuses on assessing the chloride content in drinking water sourced from various locations within Gimba City Administration, employing the argentometric method. By evaluating chloride concentrations in different water sources, the study aims to provide a comprehensive understanding of the water quality in the city, compare the results with established international standards, and highlight potential risks to public health. The findings of this research was contribute to water quality monitoring programs and support decision-making for improved water management in the town.
Gimba is a town located in the pastoral area of the Ethiopian Highlands, within the Legambo district of South Wollo. It is situated approximately 79 km southwest of Dessie, 22 km northeast of Akesta, and 52 km south of the town of Tenta. The town is positioned at geographical coordinates 10°59′8″N latitude and 39°16′17″E longitude, with an elevation of 3,224 meters (10,577 feet) above sea level. Gimba is characterized by a cold climate, typical of the highland regions, and experiences the Belg season, a short rainy period that usually occurs between March and May.
Drinking water samples were collected from five sites in Gimba city administration, namely Dembesh, Chiro, Medera, Segno, and Yerma, during December 2024 (dry season). The samples were gathered in plastic polyethylene bottles and transported to the laboratory, ensuring that they were kept in cool conditions to prevent any alteration in water quality parameters. Prior to sampling, the polyethylene bottles were thoroughly washed, cleaned, and rinsed with distilled water. The collection and preservation of the samples followed standard methods.
The aim of the sampling process was to obtain samples that accurately represented the water quality parameters at each site. The sample sizes were kept as small as possible while still being sufficient for analysis. Efforts were made to handle the samples carefully, ensuring that their characteristics remained unchanged. Grab samples were taken from each site following the procedures outlined in the Standard Methods.
The reagents chemicals used in the experiment were 8.4935 g of Silver Nitrate was purchased from Merck, Darmstadt, Germany; 5 g of Potassium Chromate from Sigma-Aldrich (St. Louis, MO, USA); and 0.584 g of Sodium Chloride from Merck, Darmstadt, Germany, along with distilled water. All chemicals used were laboratory-grade and were used without further purification.
Beakers, graduated cylinder, Conical flask, burette, filter paper, pipette, pipette filler, volumetric flask, digital balance, Titration setup (stand, clamp, and funnel) and Stirring Rod were taken from our chemistry laboratories for this experiment.
All the glass apparatus first washed with tap water and then rinse thoroughly with distilled water. Rinse the burette with silver nitrate solution and fill it with the same solution up to zero mark. Pipette out 20 ml of standard sodium chloride solution into a clean 250 mL conical flask and add 1 mL of potassium chromate indicator. Titration of the above solution with silver nitrate solution taken in the burette until the first appearance of permanent red brown colour is formed. The faint reddish brown colour should persist permanently. Repeat the titrations for concordant values. From the titration values calculate the strength of silver nitrate solution.
In this experiment, 200 mL of a collected water sample is pipetted into a clean 250 mL conical flask. To this, 1 mL (approximately 4-5 drops) of potassium chromate indicator is added. The solution is then titrated with a silver nitrate solution, which is placed in the burette, according to the procedure outlined in Part 1. After completing the titration, the concentration of chloride ions in the water sample is calculated using the formula provided by,
Where:
35.5 = Molar mass of chloride ion
1000 = Conversion factor
The results were subjected to an analysis of variance (ANOVA), which was performed using an online ANOVA calculator with some modifications. Mean comparisons were carried out using the Least Significant Difference (LSD) method at a significance level of P<0.05. Descriptive statistics, including the mean, standard deviation (SD), minimum, and maximum values, were used to evaluate the water quality parameters.
In this study, chloride concentration in the sample was determined using argentometric titration. The titration was performed at a pH range of 7 to 10, as chromate ions are the conjugate base of weak chromic acid. at pH values below 7, the chromate ion becomes protonated, and chromic acid predominates in the solution. As a result, in more acidic solutions, the concentration of chromate ions is too low to form a precipitate at the equivalence point. Conversely, when the pH exceeds 10, silver hydroxide forms, resulting in a brownish precipitate that interferes with detecting the endpoint. A suitable pH was maintained by saturating the analyte solution with sodium bicarbonate.
The most familiar Mohr’s method in which alkaline or alkaline earth chlorides react with silver nitrate in presence of indicator potassium chromate solution as indicator a simple and accurate method for chloride ion determination. The significance of chloride (Cl
-) ion present in the water is known to everyone. But the presence of higher concentration (> 250 ppm) leads to unwanted toxic problem, corrosion in the industry and etc. In the present investigation, the water samples were we collected from Gimba city administration and analysed for chloride ion concentration. The amount of chloride (Cl
-) ion determined in the collected water sample was reported in
| Sampling sites | Concentration (mg/L) | WHO Standard | ES Standard | EPA Standard |
|---|---|---|---|---|
| Medera | 52.8±3.7 | 250 mg/mL | 250 mg/mL | 250 mg/mL |
| Dmbesh | 71.9±7.1 | |||
| Chiro | 61.8±6.4 | |||
| Segno | 59.2±6.4 | |||
| Yerma | 58.9±6.3 | |||
| LSD, α = 0.05 | 11.1 |
In the present study, laboratory analysis of chloride concentrations in drinking water samples revealed a range from a minimum value of 52.8 mg/L to a maximum of 71.9 mg/L, with a median value of 59.2 mg/L, indicating significant variation in chloride levels across the different sampling sites. The chloride concentration trends followed the order: Dembesh > Chiro > Segno > Yerma > Medera (
Additionally, the table showed that the mean chloride concentrations between Dembesh and Medera, Dembesh and Segno, and Dembesh and Yerma were statistically different (p<0.05). This suggests that the disinfection or chlorination mechanism at the Dembesh site may be more effective than at the other four sites. But there is no significant mean difference between the other sites.
A similar trend was observed in a study conducted by Tadesse et al.,
The estimated daily chloride intake for adults is 2,300 mg, with approximately 530 mg lost per day through perspiration. This loss is recommended to be compensated through both diet and daily water intake.
In general, all the values are well below the 250 mg/L threshold, meaning the chloride concentrations in these sources are within the acceptable range for drinking water. Chloride at high levels can lead to unpleasant taste and, in extreme cases, can have adverse health effects, particularly for people with certain conditions like hypertension. However, since the chloride levels in all these water sources are much lower than the maximum acceptable limit, they are generally considered safe for consumption and domestic use in terms of chloride content. This indicates that the water from these sources does not pose a significant risk regarding chloride contamination and is safe for drinking, cooking, and other household activities.
The study revealed significant variation in chloride concentrations across different sampling sites in Gimba city administration, with Dembesh exhibiting the highest chloride levels and Medera the lowest. The observed chloride concentrations were well below the ES, EPA and WHO recommended limits, with all sites having concentrations below 72 mg/L. This indicates potential issues with water disinfection and the need for improved chlorination practices. Chlorine, as a key disinfectant, is essential for ensuring water safety, and the low levels found in Gimba’s potable water suggest that the disinfection process may be inadequate, which could contribute to the prevalence of waterborne diseases in the region.
All the authors are contributed equally in this manuscript and also both authors read and approved the final manuscript.
Ethics and consent were not required.
Figshare: Argentometric Determination of Chloride content in Tape water at Gimba city Administration, South wollo, DOI:
The project contains the following reporting guidelines:
Raw data of chloride concentration (ppm) in each sampling sites Average concentration of chloride ion in drinking water samples Analysis of Variance Results
Data are available under the terms of the
Title: Argentometric determination of chloride content in tap water at Gimba city administration, South wollo, Ethiopia
The authors brought an interesting case study to examine the chloride levels in tap water samples at Gimba city administration. The average concentration of chloride ranges from 52.8 to 71.9 mg/L. The findings provide realistic data points for chloride levels in Gimba city administration and encourage further studies to investigate the water quality in that area. However, some imbedded experimental design deficiency, mis- or over-interpretation of the experimental results, along with lack of deep discussion on some findings hurdle the effective message delivered to the general science community. Some writing and formatting issues were also observed in this manuscript.
Table 1. Please provide sample numbers for each sample site. Also, make sure to update the units for all the standard levels which are 250mg/L instead of 250 mg/mL. Section Results and Discussion – 5
th/6
th paragraphs. Please note that the statement of natural and human impacts on the chloride levels are weak. The authors are supposed to provide more in-depth analysis to clearly show the trends/correlations of natural/human activities to chloride levels. Section Results and Discussion – 6
th paragraphs. Here is a major logic chain issue. How would the authors directly correlated that the low chloride levels to the low chlorine levels? Have the authors taken any samples to actually compare their correlations? Note the dosed chlorine levels are typically less than 5 mg/L which is very small comparing to the measured chloride levels in this study. Including line numbers so reviewers can make comments based on that specific location. Also please add section numbers and make sure the numbering system is consistent across the paper. Section 1.1. “Chlorides are naturally occurig ions in water that, while not typically harmful in small quantities but have an effect if its concentration exceeds 250 ppm.” Please note this sentence indicates that chloride has a negative impacts to human health which may not be true as the only shown negative impacts for chloride are on the corrosivity. The authors are supposed to specify the health impact for elevated chloride levels. Section 1.1. “Elevated chloride levels in drinking water can affect its taste, corrosiveness, and in certain cases, pose health risks, especially to people with pre-existing conditions like hypertension.” After reviewing the referenced papers, the hypertension is mainly associated with sodium/potassium but not chloride. Please update the references to show the negative health impacts of chloride. Section 1.1. The authors shall add more existing conditions for the Gimba city regarding the levels of chloride. This will help the audience to understand if this is a first-ever study to measure the chloride levels in the area. Section Method – Sample collection. “The sample size were kept as small as possible while still being sufficient for analysis”. Please include the sample size as XXmL. Section Method – Chemicals. Across the paper, please make sure be consistent on the digits after decimals. Section Method – Solutions and reagents – Silver nitrate solution (0.05M). Instead of saying “Dissolve 8.4935 g of AR grade silver nitrate in 1000 mL conical flask with distilled water and homogenize.”, please clarify it as “…silver nitrate in 1000 mL of distilled water in a conical flasks and homogenize”. Section Method – Determination of Chloride Concentration in Water samples – there is no “Part I” section, please modify. Section Results and Discussion – 4
th paragraph. “the table showed that the mean chloride concentrations between Dembesh and Medera, Dembesh and Segno, and Dembesh and Yema were statistically different (p<0.05)”. There are too many “and” here. Please break it down to smaller pieces so it’s much easier to digest.
Is the work clearly and accurately presented and does it cite the current literature?
Partly
If applicable, is the statistical analysis and its interpretation appropriate?
Partly
Are all the source data underlying the results available to ensure full reproducibility?
Yes
Is the study design appropriate and is the work technically sound?
Partly
Are the conclusions drawn adequately supported by the results?
Yes
Are sufficient details of methods and analysis provided to allow replication by others?
Yes
Reviewer Expertise:
Water chemistry; Environmental Engineering
I confirm that I have read this submission and believe that I have an appropriate level of expertise to state that I do not consider it to be of an acceptable scientific standard, for reasons outlined above.