جستجوی مقالات مرتبط با کلیدواژه "کیفیت آب" در نشریات گروه "پزشکی"

Access to safe drinking water sources is a very important and vital issue that every year 1.1 billion people in the world do not have access to safe drinking water sources. Water softeners play a significant role in providing the water needed by communities, and due to the increase in water consumption and the decrease in natural fresh water resources, this role becomes more prominent day by day. The purpose of this study is to investigate the drinking water quality of Gonabad water desalination devices in 2019 and to compare the quality of its output water with national and WHO drinking water standards.

This study was performed by sampling inlet and outlet water of desalination plants working process in Gonabad during 3 times in 2020. Total hardness, electrical conductivity (EC), total dissolved solids (TDS), temperature, pH, fluoride, nitrate, chloride, sulfate, sodium, calcium, magnesium, potassium and microbiological parameter HPC were investigated. Data analysis was performed by Excel version 2016.

Chloride, total hardness, TDS was less than optimal and fluorine was lower than Iranian or WHO guidelines in both centers. And the concentration of other chemical and physical parameters studied was within acceptable limits. In desalinated water, most of the studied quality parameters were reduced by about 65.50, 53.43 and 68.90% compared to the incoming water in the three centers, and the output values were within the standard range.

Desalination plants have a high efficiency in providing safe drinking water based on qualitative standards.

 The release of organics and heavy metals from drinking water distribution pipes can adversely affect consumers' health. The aim of this study was to investigate the impact of water quality and pipe diameter on the release of organic compounds and heavy metals in polyethylene pipes.

 The experiments were performed in three different cycles of 72, 144, and 216 hours. The effect of water temperature, pH, hardness and remaining chlorine concentrations, as well as pipes diameter on the release of organics and some heavy metals were investigated. Ethical considerations were all observed during the study.

 The release of TOC increased with increasing the contact time of water to the pipe; however, the concentration of released zinc decreased by increasing time. Concentrations of lead, cadmium, and nickel in all samples were lower than the detection limit (LOD). The odor threshold number in all samples was lower than the allowable limit. The results indicated that increasing pH and hardness resulted in the decreased concentrations of TOC and zinc in water. Additionally, with increasing temperature, the concentration of TOC sharply escalated. Nevertheless, the released amounts of both TOC and zinc decreased by increasing pipe diameter.

 The results of the study revealed that the existing pipes do not pose a health threat in terms of the release of heavy metals into water. In relation to the release of TOC in water, although these values are low, thorough research should be conducted to determine their types and subsequently assess the risk of released hydrocarbons on the health of individuals.

Oral and dental health is crucial to public health. The primary indices used to assess oral and dental health are DMFT and CPITN indices. This study aimed to evaluate the oral and dental health status of 11 to 13-year-old students in Mashhad City and its relationship with their water consumption and other related factors.  This cross-sectional analytical study was conducted in 2021 on 1,232 students. Sampling was done from all hand-dug wells, semi-deep wells, deep wells, and qanats (underground channels) in the Mashhad region in 2021. All drinking water parameters were measured according to the standards outlined in "Standard Methods for the Examination of Water and Wastewater." Data were analyzed using SPSS software version 20. The mean DMFT index among Mashhad students was 0.98. The average fluoride content in drinking water was 0.38 milligrams per liter(mg/L), lower than the permissible fluoride level in drinking water. According to the relevant statistical tests, there was a significant relationship (p<0.05) between the DMFT index and daily water consumption, fluoride content in drinking water, and daily flossing. Furthermore, a significant relationship (p<0.05) was found between the CPITN index and toothbrush usage.     Given the significant association between fluoride content in drinking water and daily flossing with the DMFT index, it is essential to maintain fluoride levels in drinking water within the standard range. Moreover, oral health care practices, such as flossing and toothbrushing, should be taught to students.

Nitrates have long been considered indicative of drinking water quality and a critical concern for human health. The evolution of advanced models for water quality management has spurred decision-makers to incorporate artificial intelligence technologies into water quality planning. This study aims to employ the AdaBoost model, one of the cutting-edge models in water quality management, to predict nitrate concentrations in groundwater using pH and EC (Electrical Conductivity) as input variables.

Initially, the study analyzed the Pearson correlation matrix and subsequently determined the input variables for multiple AdaBoost models with varying hyperparameters. A sensitivity and dependence analysis of the model's input variables was conducted to assess their impact on nitrate prediction.

The results obtained from the AdaBoost model reveal R-squared (R2) values of 0.915 for the training dataset and 0.924 for the test dataset. Additionally, the Mean Squared Error (MSE), Root Mean Squared Error (RMSE), Mean Absolute Error (MAE), and Mean Absolute Percentage Error (MAPE) scores for the training dataset were recorded as 1.02, 1.01, 0.823, and 7.3%, respectively. For the test dataset, these metrics were observed in the order of 0.228, 0.477, 0.375, and 3.2%. The model's sensitivity analysis identified the pH variable as the most influential factor in nitrate prediction.

The model analysis demonstrates that the proposed method performs well in predicting nitrate concentrations. This approach holds significant potential for implementation as an intelligent system for forecasting water quality parameters.

Saveh plain, which is one of the semi-arid regions of the country.There is a demand for underground water resources due to extensive agriculture and also the existence of the country's largest industrial city, and the limitations of surface water resources are high. The purpose of this study is the impact of short-term rainfall on the amount of changes in the quality of underground water in this region.

Materials and Methods :

This is a cross-sectional descriptive study to evaluate the impact of rainfall on the chemical quality of water in the underground water resources of Saveh Plain in the period (2016-2018). Necessary information was collected from Iran's specialized mother company of water resources and the results were analyzed using DIC (Drought Indices Calculator) software and Chemistry software, and Wilcox and Shuler charts were used to determine drought years.

 The results showed that in the water year of 2016-2017, a severe drought prevailed in the Saveh Plain catchment area, but in 2017-2018, more rains occurred in this area, so it is considered a water year. The occurrence of successive droughts along with over-harvesting has caused the water in 74% of wells and 43% of aqueducts to be of unfavorable quality for agricultural purposes. For drinking purposes, the situation is better and 30% of wells, 53% of aqueducts and 93% of springs are in good and acceptable range for drinking purposes.

The results showed that the physical and chemical quality of underground water resources including wells, aqueducts and springs are affected by the amount of rainfall and the impact on underground water sources which are springs and aqueducts is more than short-term rainfall changes compared to wells in the region. Therefore, for optimal management, there is a need for proper planning in order to manage the consumption of water resources, change the pattern of cultivation and reduce unnecessary harvests in the mentioned plain.

Controlling biological parameters is a crucial aspect of disinfecting drinking water. As such, a study was conducted in 1400 to examine the changes in the concentration of residual free chlorine at the point of consumption and distribution network of drinking water in Parehsar city, as well as the factors that influence it.

This study was conducted in Parehsar City, taking samples daily from 10 different points. In this cross-sectional study, according to the population of the city and based on the existing guidelines, sampling was done daily from 10 points in the city. Samples were taken during one season, one week every month, and daily, with ten samples from the point of consumption and ten samples from the distribution network (10 points in the city). A total of 420 samples were taken, and the parameters of residual free chlorine, temperature, turbidity, pH, and coliform were measured according to the standard method. Data analysis was also done using SPSS software.

The minimum and maximum concentration of residual free chlorine at the point of consumption and distribution network were measured, 0.2-0.5 and 0.5-1 mg/liter, respectively. It was determined by the analysis that there is no significant relationship between the residual free chlorine concentration at the consumption point and the distribution network. The changes in the concentration of residual free chlorine at the point of consumption and in the distribution network were independent of changes in temperature, turbidity, coliform, and pH (distribution network). There was only a positive relationship between the concentration of residual free chlorine at the point of consumption and pH at the point of consumption.

Out of the 210 cases measuring residual free chlorine concentration, only one case at the consumption point and ten cases in the distribution network did not meet the standards. However, all other residual free chlorine concentration measurements, temperature, turbidity, and pH were within the standards and guidelines.

Swimming is one of the most fun sports, however, swimming pools are a good place for disease transmission. The importance of water quality in water environments that are chosen for swimming is mostly related to their microbial and chemical quality. Nowadays, due to the poverty of sports per capita as well as the dispersion of the population in the country, some natural ecosystems of the country are inevitably chosen as a place for sports and recreational activities. This is while in special circumstances there is a possibility that prominent athletes and national champions will also use such environments for the preparation period before professional competitions and start training in them. Like the national team of rowing, rafting, swimming, and multiple competitions. Also, spending free time is another use of this type of natural ecosystem. Lakes, lagoons, rivers, reservoirs, etc. are of interest to users as natural places for recreational and sports activities. The important thing is that such spaces, in addition to not cost much for users, do not include time limits. But on the other hand, atmospheric conditions as well as their physical-chemical and biological parameters can affect the health and performance of athletes and users. 26 cases of disease outbreaks involving 1363 people have been reported to the Centers for Disease Control in the United States since 1988 due to the use of water in recreational and swimming centers. In this research, an attempt is made to investigate the physical, chemical, and biological quality of water in natural swimming pools in the northern provinces of the country (Mazandaran and Gilan), which are known as sports and recreational environments. In principle, the researcher seeks to investigate the measurement of health and wellness indicators in recreational and sports swimming pools.

TThis study is descriptive-cross-sectional, and in this study, from all existing swimming pools in Sari city (6 swimming pools including one indoor swimming pool for men and women and 5 outdoor swimming pools (once every 10 days during the maximum number of swimmers 14-16) Microbial and chemical sampling was done. The total number of samples collected was 36 samples for microbial tests and 36 samples for chemical tests. In the sampling, first, based on pre-designed questionnaires, the general characteristics of the pool such as pool ownership, sampling date, sampling time, Atmospheric condition, type of pool, type of water purifier, pool area, pool volume, the maximum number of swimmers per day, number of lifeguards, number of showers, number of toilets, number of changing rooms, type of chlorination system, were recorded through interviews with pool operators. Microbial sampling was done using sterilized glasses with a volume of 300 ml and according to the standard method, and after this step, the samples were sent to the laboratory in the vicinity of ice for 2-6 hours. In this study, in addition to determining the general characteristics of the pools through interviews, Chlorine parameters in the case laboratory were measured and recorded in the relevant forms. Water sampling was done once every 10 days during the maximum number of swimmers (14-16). The residual chlorine pH at the sampling site and other parameters were determined in the laboratory. After collecting the data, the obtained values were compared with the existing standards using SPSS software.

 According to the collected information, there are a total of 6 active swimming pools in the city of Sari, which are 5 outdoor swimming pools and one indoor swimming pool. The total area of the existing pools is about 2044 square meters and there are a total of 32 showers, 16 toilets, and 39 changing rooms. Except for one pool, the rest of the pools are of the type of circulating system with closed circuits and equipped with a water purification device (sand filter). A mechanical chlorination system was observed only in two pools and the rest of the pools did not have this system. One of the important microbial parameters of water is the amount of Streptococcus. In none of the samples taken, the amount of this bacteria did not exceed the standard and the water of the pools was evaluated as safe for swimming. The obtained data indicate severe contamination with this bacterium. Of course, in the indoor pool, this contamination was not observed in all sampling stages, but in the other 5 outdoor pools, this contamination was observed many times. The results of the research show that the amount of residual chlorine in 61.1% of cases is lower than the standard (less than and only in Sari and women's indoor swimming pools by the existing standards.

 The lack of a proper chlorination system, incompleteness of water purification systems, and lack of knowledge of the pool operators about the optimal conditions of the pool have caused the pH and residual chlorine to be not optimal in most cases. According to the existing standards in swimming pools, a certain required level is considered for each swimmer, and then the capacity of the pools determines the maximum number of swimmers in each shift, so the larger the area of ​​the pool, the greater the capacity to accept swimmers, and this issue can be Wrong monitoring and management can cause water pollution in swimming pools. Statistical tests have also confirmed this issue because based on the results obtained from the Pearson correlation coefficient, a significant inverse relationship has been obtained between the area of ​​the pool and the amount of total coliform, which shows that due to the large area of ​​the pools, the index of microbial contamination of water is by the existing standards. From these results, it can be concluded that the main reason for the reduction of microbial contamination of water during the research period is the lack of swimmers and the reduction of microbial contamination. Of course, water disinfection has played a positive role in this regard, but this issue does not apply to all swimming pools.

Oral and dental health is one of the most important health indicators in the society. Decayed Missing Filled Teeth (DMFT) index and Community Periodontal) Index of Treatment Needs (CPITN) are the most important indicators used in oral health evaluation. The aim of this study was to evaluate the oral health status of 12-years-old students of Gonabad and Bejestan and its relationship with their drinking water and some related factors. This cross-sectional analytical study was performed on 760, 12 years old students of Gonabad and Bejestan in during the educational years of 2018- 2019. Demographic information, eating and drinking and health habits were collected by a questionnaire and oral health status was recorded in a checklist by a clinical examination. Fluoride and calcium parameters of drinking water were measured 2351 and 8652, according to the standard of Iranian Institute of Standards and Industrial Research.Data were analyzed by SPSS softwareV.20. The mean DMFT index of students in Gonabad and Bejestan were 0.89±1/26 and 0.86±1/12.The mean drinking water fluoride of Gonabad and Bejestan were 0.39±0/298 mg/L and 0.21±0/042 mg/L. The mean calcium of drinking water in Gonabad and Bejestan were 12.86±9/42 mg/L and 10.26±1/07 mg/L. According to the statistical tests, there was a significant relationship between DMFT index and amount of drinking water per day, drinking water fluoride and dental floss usage (P-value <0/05(.There was also a significant relationship between CPITN with toothbrush (P-value <0/05). As drinking water fluoride and dental floss that among the day are associated DMFT index, drinking water fluoride should be kept within the standard range and oral health care techniques such as using toothbrush and dental floss must be taught to students.

The importance of drinking water resources and their infrastructure for human health has made these resources one of the most vulnerable targets of terrorist attacks. The present study aimed to identify and assess the risks posed to drinking water facilities in Taleghan, Iran, using the failure modes and effects analysis(FMEA) method.

This descriptive-analytical study was conducted in all water facilities in Taleghan, Iran, in 2020. The types of potential hazards and threats of water facilities were identified by reviewing the necessary documents, field visits, observation, interviews, and opinion polls of water supply experts in Alborz province. Thereafter, risk assessment was performed, risks were prioritized, and necessary solutions to reduce the risks were presented using the FMEA technique.

The present study identified 40 potential risks. The majority of risks belonged to water wells (37.5%). The identified risks were 7.5%, 40%, and 52.5%, respectively, related to the quantity, quality, as well as exploitation and maintenance of water facilities. The highest risk priority number were 576, 392, and 343, respectively, related to the critical threats caused by point source pollution around water wells, poor protection and security of the pumping station,  as well as fluctuations in water flow in the distribution network and reservoirs. Furthermore, 42.5, 35, and 22.5% of the risks were at the critical, moderate, and non-critical levels.

Ad evidenced by the obtained results, water infrastructure in terms of exploitation and maintenance in the supply, treatment, and distribution sectors is vulnerable to various identified threats; therefore, it is necessary to make the needed adjustments based on the set priorities to prevent possible incidents.

Nowadays, the increase in population growth rate and followed by anthropogenic activities such as urbanization, industrialization, mining and agriculture practices continuously increase the amount of heavy metals in the environment especially groundwater resources. Therefore, qualitative assessment of groundwater resources is of great importance for maintaining public health and for this reason, this study was conducted to qualitative assessment of groundwater resources of Asadabad Plain using WQI, Cd, HPI, HEI, PoS and MI indices in 2018.

In this descriptive cross-sectional study, 120 groundwater samples were collected from 20 stations in the spring and the summer seasons and their temperature, pH and EC values were measured on-site. In the laboratory, the values of physicochemical parameters were determined according to the standard methods. Also, the content of heavy metals was determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). All statistical analyses were performed using SPSS software.

The results showed that the average concentrations of Na, PO4-, Cl-, Ca, Mg and NO3- (mg/L) in samples of the spring season were 21.8, 0.230, 0.170, 69.0, 21.1 and 19.3, respectively; and in the summer season were 8.14, 0.190, 0.160, 75.3, 15.6 and 19.8, respectively. Also, the average concentrations of As, Fe, Zn, Pb, Cd, Cr, Cu, Mn and Ni (μg/L) in samples of the spring season were 5.10, 1.61, 0.970, 7.82, 0.230, 1.25, 3.58, 0.360, and 1.30; and in the summer season were 21.4, 1.62, 1.24, 7.63, 0.200, 1.00, 6.73, 0.430, and 1.01, respectively, and except for As in samples of the summer season, the average concentrations of all elements in groundwater samples of both seasons were lower than the maximum permissible concentration (MPC) established by WHO for drinking water. In addition, water quality index (WQI), pollution index (Cd), heavy metal pollution index (HPI), heavy metal evaluation index (HEI), quality index (PoS) and heavy metal index (MI) of samples of the spring season with values of 18.2, -7.53, 9.86, 1.64, 298 and 1.64, respectively, indicate the quality of groundwater were categorized in "excellent and very good", "low pollution", "low pollution", "low pollution", "low pollution" and " slightly affected" classes and in the summer season with values ​​of 17.9, -5.94, 9.86, 3.05, 602, 3.05, respectively, were categorized in "excellent and very good", "low pollution", "low pollution", "low pollution", "high pollution" and "moderately affected" classes.

Although only the average values of As in groundwater samples of the summer season were higher than the MPC, management of the use of agricultural inputs such as pesticides, chemical and organic fertilizers and municipal wastewater for irrigation to maintain the quality of groundwater resources of the study area is recommended.

With the increase in recent droughts and shortage of drinking water resources led to planning to desalinate water and set up mobile stations. The purpose of this study is to determine the microbial and physicochemical quality of water discharged from desalination plants and tankers in Qom.

This descriptive cross-sectional study was conducted for one year with monthly sampling of water from domestic water purifiers and mobile tankers. Samples were analyzed for microbial contamination and physicochemical quality (pH, TDS, turbidity and chlorination) according to standard methods. The data were analyzed using SPSS and Excel software and compared with the standards.

Positive values of fecal coliform contamination was 13.34% in tankers and 4.35% in domestic water purifiers. The pH, TDS, turbidity was in accordance with the national and WHO standards. T-TEST statistical analysis showed, microbial quality of water had a significant relation with variables of dewatering containers (P<0.021), tank washing (P<0.001), outlet valve contamination (P<0.011), contact with dust (P<0.014), the personal health of the distributor (P<0.026), temperature (P<0.033), water retention time (P<0.019) and environmental sanitation (P<0.003). ). . But there was no significant difference in the distribution of water between tankers and desalination plants (P < 0.068).

By preventing secondary pollution, the water quality of these places can be considered desirable. Therefore, periodic and regular water evaluation and training on maintenance and health issues should always be considered

Pre-ozonation in water treatment is used for various purposes such as; improving the coagulation process, reducing the production of trihalomethanes, color removal, removal of iron and manganese, control of microorganisms, and removal of organic matter. The main objective of this paper is to investigate the effects of pre-ozonation on the physical, chemical, and biological properties of drinking water.

This study on a real scale was conducted on the pre-ozonation unit of the Koohsabz drinking water treatment plant for 6 months. In this study, sampling of raw water entering the pre-ozonation unit and ozonized water was done randomly with glass sampling containers. 4 samples per month and a total of 24 samples were taken to evaluate the trends of changes in the parameters. The necessary tests according to the method presented in the standard method book (twentieth edition) on the samples have been done to investigate the effects of pre-ozonation on the physicochemical and biological parameters.

The studies showed that the turbidity and TOC (Total Organic Carbon) removal efficiency in the pre-ozonation process of the Koohsabz drinking water treatment plant was about 62% and 18. 83%, respectively, and it has no effect on pH. Also, the removal rate of Fe and Mn in the pre-ozonation process was 91.5 and 82%, respectively. Evaluate the effectiveness of pre-ozonation in watercolor removal showed that, by increasing the dosage and the concentration of ozone injection, significant changes did not occur on further reduction of color and color precursors and the removal rate of color precursor compounds, such as the chlorophyll a, is about 21%.

The results indicated that ozone could not change any physical parameters such as pH and color, but it has a significant effect on the chemical properties and reduced biological parameters by about 21%.

Water quality is important for preparation of dialysis solution due to its direct relationship with blood of patients with renal failure. The aim of this study was to evaluate the chemical and microbial quality of inlet and outlet water of dialysis devices in hospitals of East Azerbaijan province.

This study was a descriptive-analytical study in which the water of dialysis ward of three hospitals affiliated to East Azerbaijan University of Medical Sciences was investigated. The results of physicochemical (45 cases) and microbial (163 cases) of dialysis water were extracted from the relevant archives in two stages before and after reverse osmosis treatment during 2014-2016. Independent t-test and one-way ANOVA were used for statistical analysis while extracting descriptive statistical parameters. Data analysis was done using Excel and SPSS 23 software.

Evaluation of the efficiency of reverse osmosis system showed that there was a significant difference between water quality, before and after the system. Except for calcium, magnesium, fluoride and nitrate, the concentrations of other cations and anions in 100% of samples were lower than the European Pharmacopoeia standard. Incoming water samples to dialysis machine in 4.9% of cases had total coliform contamination and there was no fecal coliform in any of the samples. The frequency and frequency of tests in hospitals are not observed and despite the risk of heavy metals, heavy metals tests are not performed on dialysis water for the health of dialysis patients.

The need to develop a national standard for controlling dialysis water, testing all quality parameters of dialysis water according to standards in regular times and timeframes, informing hospital managers and environmental health experts about the importance of dialysis water quality in health and increasing life expectancy of dialysis patients is felt.

The use of packaged drinking water is on the rise nowadays in most countries, including Iran. Currently, more than 100 different brands of packaged drinking water are produced and distributed in Iran. This study was done to evaluate the quality of Iranian, foreign packaged drinking waters and municipal drinking water in Golestan Province, north of Iran.

This descriptive-analytical study was done on 56 packaged drinking waters of different Iranian and foreign brands, eight brands produced in Golestan province and a number of municipal drinking water samples were collected from Gorgan and Gonbad Kavous cities in northern Iran. To assess the quality of packaged drinking water and drinking water, their physicochemical parameters were compared with National Iranian Standards 1053 and WHO. Stiff and Piper diagrams were plotted to determine the type and hydrochemical facies of water samples. Gibbs and Schoeller diagrams were used to determine the water chemistry controlling factors of water samples and their water quality for drinking, respectively.

The concentrations of physicochemical parameters (except bicarbonate) were within the range of national drinking water standards 1053 and WHO. The average nitrate concentration in all packaged drinking and drinking water was within the standard range. The fluoride concentration of all packaged drinking waters and drinking water was within the range of WHO standard. However, only 14 samples of all packaged drinking and drinking water samples are within the range of 1053 National Iranian Water Standard. The total concentration of soluble solids and the total hardness of packaged drinking water were within the range of 1053 NW. There was also a significant difference (P<0.05) between the chemical parameters of magnesium, sodium, chloride and nitrate in packaged drinking water produced in Golestan province with the municipal drinking water samples.

The amount of fluoride in drinking water in this study was less than desirable and required fluorination. The quality of packaged drinking water in Golestan province is better than the municipal drinking water.

The increasing development of agricultural and aquaculture activities along the rivers has reduced the quality of running water. The aim of this study was to evaluate Chehel-chai River water quality with national sanitation foundation water quality index (NSFWQI), Iran water quality index for surface water (IRWQISC), Canadian water quality index (CWQI).

This descriptive-analytical study, was performed on all of 7 sampling stations based on standard factors such as availability, land use type, geology and dispersion along the river, 12 water quality parameters including dissolved oxygen, fecal coliform, pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), temperature, organic phosphate, nitrate, ammonium, turbidity, total soluble solids and electrical conductivity and 5 cations (sodium, calcium and magnesium) and anion (chloride and sulfate) along the river for summer and autumn seasons 2018 (42 sample) with the standard method was measured.

The amount of phosphate and turbidity increased from station 2 to downstream due to the existence of fish ponds and agricultural drainage. BOD, COD and fecal coliform values at station 6 have increased significantly with due to urban effluent output. River pollution in the summer has increased due to reduction of river flow and after station 3 (promenade) to the downstream, which is due to the entry of agricultural fertilizers and urban wastewater discharge. According to the average of IRWQISC and NSFWQI, the water quality of Chehel-chai River in the sampling station in the area of Minoodasht city (station 6) is in bad class. The CWQI index showed that the water of the Chehel-chai River is suitable for drinking and aquaculture at the border of the class, for agriculture in the bad class, and in terms of recreation and livestock use in the higher class.

The mean values of the above indices indicate high pollution quality class, and since this river is used for water supply for agricultural and aquaculture, management strategies are necessary.

One of the most important water-related issues is the pollution of water resources, which is mainly due to human activities and currently threatens many water resources in the world. Therefore, the use of appropriate tools to manage surface water quality seems necessary. This study was conducted to determine the potential risks of pollutants in Sabalan Dam using a WRASTIC model.

WRASTIC evaluation model and GIS software were used to assess the risk of Sabalan Dam pollution accidents. To determine the level of pollution risk, the catchment area of Sabalan Dam was divided into 8 sub-basins. Then, in each sub-area, pollution source maps including various indicators of industrial effluents, agriculture, housing, recreation and transportation accidents were prepared in GIS software environment. Then scoring for each indicator was performed based on the potential intensity of pollutant sources. Finally, based on the obtained data, sub-basins were classified in terms of risk.

The results showed that based on the model used in terms of health and environmental pollution risk, the average risk of water pollution for the catchment area of Sabalan Dam was 48.29. Classification of the level of pollution risk in the sub-basins of Sabalan Dam showed that sub-basin S1 had a high level of risk and the level of risks in sub-basins S2 and S4 were moderate.

The use of WRASTIC model in determining the risk level of Sabalan Dam pollution accidents showed that the most important indicators of Sabalan Dam catchment was the entry of domestic wastewater and effluents of aquaculture and agricultural activities and mineral hot springs. The results of this study indicated the desirability of using the WRASTIC model in determining the pollution risk of the Sabalan dam catchment.

Using available water resources, protection and monitoring of water resources is essential and vital. The aim of this study was to investigate the changes in water quality in Lake of Kalan Malayer Dam in Hamedan province during the year 2017-2018.

Using GIS software and land use maps, sampling locations in the dam lake were selected. In samples was carried out on 5 occasions, pH, EC, Ca, Mg, Cl, SO4, PO4, NO3, TDS, TSS, DO, BOD, COD, TOC, Turbidity and concentration of common pesticides used in the area were measured.

The results showed that according to WHO guidline, turbidity in May and electrical conductivity, BOD and COD in all sampling times, limit the consumption of drinking water. The average concentration of BOD and COD was higher in the primary stations and decreased from the average concentration in the lake and stations near the dam wall, that be related to the discharge and route of pollutants upstream of the river, which increases the amount of biochemical and chemical oxygen demand. Nutrient concentrations (NO3, Cl, SO4 and Na) in all samples were within the allowable range determined by WHO.

Water in winter was of better quality due to increased river flow and water stored behind the dam, lowering the temperature and reducing agricultural activities.

Monitoring water quality is so important so as to decide about using them. So, this research was conducted to evaluate Khuzitan’s river water quality.

The rivers were studied consist of Dez, Karkheh, Maroon, Karoon and Zohreh. Data collecting was applied during 2018 for each river from specified stations. So, water quality standard of Iran, WHO and Canadian council of ministers of the environment, and Shoeller diagram and Wilcox diagram were used. In addition, IRWQIsc and NSFWQI standards were used to categorize river water quality.

The results showed that Dez water was industrially corrosive, while other rivers had sedimentary water for industrial use. The water quality of Dez was better than other rivers in Khuzestan province, but this river also had high magnesium, hardness and chlorine based on the Shoeller diagram. The quality of this river was better for agricultural purposes rather than the others. Karun River was moderately better than other rivers, and water quality is better upstream than downstream. According to IRWQIsc index, the water quality variations of Dez, Karkheh, Karoon, Maroon and Zohreh were 71-83, 41-52, 39-55, 33-41 and 25-32, respectively. The results of NSFWQI index for Dez, Karkheh, Karoon, Maroon and Zohreh rivers showed that the values of these rivers varied between 65-77, 55-70, 58-68, 52-60 and 36-48, respectively.

Thus Dez River was in relatively good condition. Karoon and Karkheh rivers were in moderate condition and other rivers were in relatively poor condition. According to all indices, water quality of Zohreh River was in poor condition and Dez River was in good condition. Other rivers had medium quality.

Zarrinehrud River is one of the most important permanent and water-rich rivers in West Azerbaijan province located in the catchment area of Lake Urmia. In this study, to evaluate the quality of the Zarrinehrud River, with a length of 57.5 kilometers from the outlet of Noroozlou to the drainage dam to the Lake Urmia, QUAL2K computer simulation model was used.

The selected parameters of the model included: flow, dissolved oxygen (DO) and biochemically required oxygen. The selected time for the simulation was May 2016. Model calibration was performed by determining the oxidation coefficients of carbonaceous materials and the re-aeration coefficient of the river, using the mean square root of error (RMSE)

The results show that the water quality of the river downstream of the Noruzlu regulatory dam has caused significant changes in the quality parameters of the river due to receiving wastewater from slaughterhouses, sugar factories, urban, rural and agricultural drains.

Due to the high self-purification capacity of the river, the amount of dissolved oxygen is appropriate and the amount of BOD has reached an acceptable level despite a sudden increase. In terms of matching the observational data with the output diagram of the model, there was a good fit in other parameters except flow rate. In the case of non-compliance of the observed flow data with the simulation diagram, it may be due to unauthorized withdrawals from the river for agricultural purposes.

Increased untreated wastewater and unsustainable development of agriculture has deteriorated water quality of rivers. The aim of this study was to determine the quality of water in Gorganrud River basin using NSFWQI IRWQISC and Liou Pollution Index and compare them with the global standards. To do this, GIS software.was used

In this study, 5 sampling stations were selected based on standard criteria including land use type, accessibility and standard distributions along the river. 12 water quality parameters including dissolved oxygen, fecal coliform, pH, biochemical oxygen demand, chemical oxygen demand, temperature, organic phosphate, nitrate, ammonium, turbidity, total dissolved solids and electrical conductivity in river for one year were measured from June 2019 to May 2019 follwoing standard methods.

The amount of phosphate and turbidity was increased along the river from station 2 to the mouth of the river. This was due to the presence of agricultural and municipal sewage. There was a significant difference in BOD, fecal coliforms and nitrates with those of the standard values. Water quality indicators showed the great effects of urban wastewater and human waste in the river area. The best quality was observed in Station 1 (75; Good Quality), which was less exposed to human activity and development. Based on the conformity of the results of the indicators with the terrestrial reality, the results of the IRWQIsc index (Iranian surface water quality) showed the best results due to compatibility to the land uses and the trend of variables.

The presence of urban sewage and unsustainable agricultural in the city of Gonbad Kavous is the most important reason for the decline in water quality (poor quality class). In this regard, a comprehensive management in water resources and environmental impact assessment is needed.