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Background and Objective: Different coagulants including aluminum sulfate (Alum) and Polyaluminum Chloride (PAC) are used for water clarification process and deposition of colloidal particles. The use of coagulants causes some residual aluminum in water. The residual aluminum higher than 0.2 mg/l, has adverse effects on human health and environment. This study was conducted to determine the amount of residual aluminum by applying Polyaluminium chloride and aluminum sulfate for turbidity removal from turbid water. Methods: In this laboratory study, the experiments were run by using synthetic water having low (10-30 NTU), medium (100-130 NTU) and high (200-230 NTU) initial turbidities. Synthetic turbid water was prepared by adding stock kaolin suspension into distilled water. Samples of 1 liter of water were poured on 6 Jars. After adjusting of pH, coagulant was added into each beaker at various doses and agitated at 100 rpm for 30s. The mixing speed was then reduced to 20 rpm and kept for another 15 minutes. The suspensions were left for sedimentation and after 30 minutes of sedimentation, clarified samples were collected from the top of the beakers. Residual turbidity and residual aluminum was measured. The residual turbidity was measured using a Turbidimeter according to Nephlometric method. The residual aluminum was determined by Eriochrome cyanine R method. Results: Residual alminium in low, medium and high turbidities was 0.006 mg/l, 0.05 mg/l and 0.07 mg/l by applying Polyaluminum Chloride and 0.065 mg/l, 0.15 mg/l and 0.22 mg/l by applying alum, respectively. There was a significant correlation between dosage of Alum and Polyaluminum Chloride with residual aluminium (P<0.05). Conclusion: Polyaluminum Chloride due to low sensitivity to pH variation and less residual aluminum in treated water is more suitable than alum coagulant and could be used as a recommended water coagulant.

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Background and Objective: Nowadays the food contamination is increased and threating human health. This study was done to determine the concentration of cadmium, lead, zinc and copper in tomatoes and cucumber in Northern Iran. Methods: In this descriptive study, 48 cucumber and 48 tomatoes samples were collected randomly from the two sampling stations of Gorgan and Gonbad the two cities in Golestan province of northern Iran during spring and summer of 2012. Cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) concentrations were determined by voltammetry method of 797 Polarography models. Results: Mean±SE of Zn, Cd, Pb and Cu concentration in samples of cucumber in Gonbad was 53.4±7.7, 0.09±0.013, 1.47±0.21 and 4.1±0.66 mg/kg wet weight, respectively. Mean±SE of Zn, Cd, Pb and Cu concentration in samples of cucumber in Gorgan was 60.3±8.7, 0.12±0.017, 1.4±0.2 and 3.7±0.53 mg/kg wet weight, respectively. Mean±SE of Zn, Cd, Pb and Cu concentration in samples of tomatoes in Gonbad was 17.9±2.6, 0.03±0.004, 0.5±0.07 and 0.85±0.12 mg/kg wet weight, respectively. Mean±SE of Zn, Cd, Pb and Cu concentration in samples of tomato in Gorgan was 23.8±3.4, 0.08±0.01, 0.66±0.09 and 1.7±0.24 mg/kg wet weight, respectively. Mean concentrations of Cd and Pb in cucumber and tomatoes samples of Gonbad was up to 2, 14, 0.6 and 5 times and mean concentrations of that in cucumber and tomatoes of Gorgan was up to 2.4, 14.4, 1.6 and 7 times exceed the maximum allowable limits of WHO/FAO. Conclusion: Mean concentration of Cd and Pb in cucumber and tomato samples was exceeded the maximum allowable limits of WHO/FAO and mean concentration of heavy metals in cucumber was more than tomato samples.

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Background and Objective: Raw water is one of the main sources of water supply in some communities. Filteration of surface water resources is a challenging point in the rainy seasons due to the highly turbidity. This study was done to evaluate the removal of turbidity in raw water using chitosan in electrocoagulation process using aluminum electrodes. Methods: In this the descriptive –analytical study, a Plexiglas electrocoagulation reactor in a lab scale to an approximate volume of 6 liter which was equipped with four aluminum electrodes having dimension of 200×20×2 mm was proposed. The effects of operating parameters including pH (5 to 9), applied voltage (10 to 30 V), the initial turbidity (100-600 NTU), initial chitosan concentration (0.5-2 mg/L) and contact time (5 to 30 min) were evaluated. Results: Turbidity removal efficiency was over 100% (pH=7, applied voltage=30 V and initial turbidity concentration of 100NTU) in the application of electrocoagulation with chitosan but in the application of electrocoagulation without chitosan removed 87% of turbidity in the same condition. Conclusion: Chitosan as coagulant aid in low amount can increase turbidity removal efficiency rather than application of electrocoagulation alone.

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Background and Objective: Bioabsorbat is one of the most effective methods for the removal of heavy metals from industrial sewages. This study was done to assess the evaluation of Copper removal from industrial sewages by the Green microalgae Chlorella vulgaris.

Methods: This descriptive-analytic study was done on three samples from Bahonar Kerman copper industry sewage samples and 63 copper biosorption synthetic samples by Green microalgae Chlorella vulgaris at a constant temperature of 25°C, optimum pH 6 and contact time of 60 minutes and adsorbent concentration of 2 g/L. The rate of residual copper was determined using atomic absorption instrument. The adsorption isotherms and metal ions kinetic modeling on to the adsorbent were determined based on Langmuir isotherm, Freundlich and kinetics of type I and II.

Results: The removal efficiency was determined as 82.62% and 91.5 % in Copper real examples and synthetic samples, respectively. Based on the obtained results, copper absorption followed Langmuir model and second order kinetic equation (P<0.05).

Conclusion: Due to high absorption potential of Green microalgae Chlorella vulgaris, this method can be effectively used for copper removal from industrial sewages.

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Background and Objective: Water resident bacteria are potentially important reservoir of antibiotic resistance genes. This study was performed to evaluate the antibiotic resistance in Escherichia coli strains isolated from raw waters of Golestan province, northern Iran.

Methods: In this descriptive study, 26 samples from Ziarat river water (13 samples pre & 13 samples post treatment) and 36 samples from Azadshahr area springs water (18 samples pre & 18 samples post treatment) were collected. 75 numbers of Escherichia coli bacterium samples (50 isolated from river and 25 isolated from springs) identified and isolated from raw waters of Golestan province, northern Iran by MPN method via differential tests. Susceptibility of Escherichia coli strains to 11 antibiotics (Amoxicillin / Clavulanic acid, Ampicillin, Imipenem, Cefalotin, Cefotaxime, Gentamicin, Amikacin, Tetracycline, Nalidixic acid, Ciprofloxacin and Trimethoprim / Sulfamethoxazole) was assayed by disk diffusion Kirby & Bauer’s method.

Results: 14 spring's raw water samples and 12 river raw water samples contained Escherichia coli. All of the river and springs samples assayed free from Escherichia coli post treatment. All of the Escherichia coli strains isolated from samples showed the similar phenotypical resistance against to surveyed 11 antibiotics. The most significance resistance to Ampicillin (river 94% & springs 88%), Amoxicillin / Clavulanic acid (river 76% & springs 80%), Tetracycline (river 14% & springs 16%) and Cefalotin (river 8% & springs 16%) viewed. Resistance to Trimethoprim / Sulfamethoxazole (8%), Nalidixic acid (2%) and Ciprofloxacin (2%) just viewed in river samples. All of the river and spring isolates were sensitive to Imipenem, Cefotaxime, Gentamicin and Amikacin and demonstrated intermediate resistance to others antibiotics.

Conclusion: Treatment of raw water from springs and rivers caused the eradication of Escherichia coli. As regard to observed phenotypical resistance in springs’ raw waters, presumably with lack of treatment springs’ raw water can be caused the transmission of antibiotic resistance to human body.

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Background and Objective: Polycyclic Aromatic Hydrocarbons (PAHs) are the most important organic pollutants that causing multiple side effects including carcinogenic, mutagenic and toxicity. Among the aromatic compounds degrading bacteria, pseudomonas produce board spectrum of degrading enzymes and are used, as biological tools, for decreasing of PAHs. This study was done to evaluate the degradation of polycyclic hydrocarbones anthracene by using Pseudomonas aeruginusa.

Methods: In this descriptive – analytic study, sampling was collected from river estuary sediment and had cultured in Minimal Salt Medium (MSM). Pseudomonas aeruginosa was one of the isolated bacteria from river sediment which identified by molecular technique. In next step, influence of pH (6.5 and 7.5) temperature (25 and 35°C) and concentration of anthracene (150 and 200 ppm) were surveyed on anthracene biodegradation and bacterial growth during zero, 24 and 48 hours by HPLC and spectrophotometry method respectively.

Results: The results showed that the optimized condition for biodegradation included pH=7.5, 35°C and 150 ppm of anthracene. Bacterial degradation of anthracene was increased with prolong of incubation time. Biodegradation efficiency of anthracene in the presence of pseudomonas was 50% within 2 days, which indicates the ability of the bacteria for the enzymes production.

Conclusion: High growth potential of pseudomonas in unsuitable areas and due to the production of degrading enzymes, it can be used as indicator bacteria used to remove anthracene.

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Background and Objective: Leishmaniasis is one of the most important vector-borne diseases which transmitted by sand flies to humans and other animals. This study was conducted to determine the effect of wild rodents control in decreasing zoonotic cutaneous leishmaniasis (ZCL) in Golestan province, north of Iran during 2016.
Methods: In this descriptive-analytic study, rodent control operation was conducted using Zinc phosphide 2.5% in May, July and September 2019 in 45 villages of Gonbad Kavous County in Golestan province, north of Iran during 2016. The stages of operation in each of the villages were scored, as we considered 25 score for each stage of destruction of nests (one stage) and baiting in nests (three stages). Also, incidence rate which is reported in each of the villages was extracted. Finally, the relationship between rodenticide scores in each village with the incidence of disease was compared.
Results: There were rodent’s active burrows around 45 villages. After the end of rodents control operation, 17 villages got 0-25 scores, 8 villages 26-50, 16 villages 51-75 and 4 villages 76-100. The mean incidence rate in these villages was determined 3466.9±2473.5, 2828±1929.1, 4515.4±3478.4 and 636.3±546.6, respectively. There was a significant relationship between the implementation of  rodents control operation and incidence rate of ZCL, so that in villages with a score of between 76-100, the incidence rate was significantly lower than in the villages with a score of between 51 -75 and 26-50 (P<0.05).
Conclusion: Regarding the reduction of the incidence of cutaneous leishmaniasis in villages with high scores in Gonbad-e Kavus County, north of Iran, the implementation of rodents control operation seems to be necessary.

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Background and Objective: Organic aromatic compounds as common environmental pollutants can be existing in the effluent of different industries in concentrations ranging from trace quantities to hundreds of milligrams per liter. Phenol compounds extremely have been used in pharmaceutical, wood industry and paper and dyes industries which introduced to environment via effluents. This study was done to evaluate the efficacy of persulfate activated by Fe²⁺ in the present of UV for removal of phenol from aqueous solutions.
Methods: This photocatalytic degradation experiment was performed in batch mode using a 2.5 L cylindrical reactor equipped with low-pressure Hg vapor lamp of 55 W for wavelength production of 253.7 nm. The effects of operating parameters such as pH of the solution (pH: 3-10), different initial persulfate concentration (10-75 mmol/l), initial Fe²⁺ concentration (5-30 mmol/l) and initial phenol concentration (10-100 mg/l). Concentration changes of phenol were determined using UV–VIS spectroscopy at the wavelength of 500 nm.
Results: Degradation of phenol was significantly decreased with increasing of pH from 3 to 10, whereas the highest phenol removal rate was 82% at pH=3 in 45 min contact time. Also, the phenol removal rate is depending on initial persulfate and Fe²⁺ concentration. The degradation of phenol by this photocatalytic followed first order rate decay kinetics (R²>98%(. Under optimum operational conditions, the removal of TOC was obtained to be 61% in 45 min contact time.
Conclusion: This study indicated that activation of persulfate by Fe²⁺ in the present of UV process could serve as a novel treatment technique for removal of phenol in aqueous solution.
 

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Background and Objective: 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.
Methods: 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.
Results: 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.
Conclusion: 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.

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Background and Objective: 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).
Methods: 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.
Results: 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.
Conclusion: 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.

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Background and Objective: Fish is one of the creatures which have the bio-accumulation of heavy metals. Terapon puta belongs to the order of Perciformes, is a benthic species in the waters of the Persian Gulf. This study was performed to evaluate the bio-accumulation of iron and nickel metals in the muscle of Terapon puta.
Methods: This descriptive-analytical study was performed on 30 pieces of Terapon puta caught in the Jefreh pier area of Bushehr, north of the Persian Gulf during the summer of 2019. Length (mm) and total weight (g) of fish were measured. The concentrations of iron and nickel in fish muscle tissue for human consumption were compared with international standards and calculated according to the US Environmental Protection Agency (USEPA) method for fish consumption, estimated daily uptake (EDI), and pollutant risk index (CR). After preparation, bioassay and, digestion of fish muscle with concentrated nitric acid, the concentration of iron and nickel (mg/kg) in muscle tissue was measured with ICP-OES.
Results: The mean concentrations of iron and nickel in muscle tissue of fish samples were calculated 36.08±15.72 and 0.39±0.13 mg/kg, respectively. There was a significant difference between the concentrations of iron and nickel in the muscle tissue of the Terapon puta in the sampling area (P<0.05) and these values were lower than the standard and meaningless the muscle tissue of the Terapon puta in the sampling area compared to the FDA standard. The highest concentration of metals was observed in the length class of 20-25 cm and weight class of 230-260 g. Linear regression analysis showed that a strong increase (R²=0.9) between the concentration of iron and nickel with the length and total weight of fish. The daily uptake of both metals was obtained by consuming Terapon puta muscle tissue for consumers below the USEPA reference dose. The concentration of iron in the muscle tissue of Terapon puta was lower than the international standards. Nickel concentration was more than allowable limit according to WHO standards. The carcinogenicity risk index for nickel was acceptable.
Conclusion: Concentrations of iron and nickel in Terapon puta were considered acceptable for human consumption in terms of toxicity. The risk index for Terapon puta was less than one; therefore, the consumption of Terapon puta will not cause adverse health effects for consumers.

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Background and Objective: The presence of many synthetic dyes in aqueous solutions can cause carcinogenesis and mutagenicity and affect human health. Reactive Red 198 is one of the types of azo dyes with complex structure, toxic, carcinogenicity, mutagenicity properties, and tolerable in the environment, which is discharged to the environment through the sewage of textile industries. This study was performed to determine the mineralization of 198 reactive red dyes by the hybrid advanced oxidation process UV/US/H₂O₂/O₃ from colored wastewater using central composite design.
Methods: In this descriptive-analytical study several factors affecting on dye mineralization process including the presence of ozone gas and ultraviolet rays (UV) as well as the initial dye concentration, Ultrasound (US), contact time, pH, and hydrogen peroxide were investigated. Experimental design and optimization were performed by design of experiment software using central composite design and its optimal conditions were determined.
Results: The maximum dye degradation efficiency of 100% was performed under optimal conditions including initial dye concentration of 200 mg/L, reaction time of 34 minutes, hydrogen peroxide concentration of 27 mg/L and pH=9 in the presence of ozone gas flow, ultraviolet rays and ultrasonic waves. Also, the influence of factors on dye removal including ozone, UV, initial dye concentration, US, contact time, pH, and peroxide were  58.8%, 19.3%, 2.3%, 1.5%, 1.1%, 0.6 %and 0.2 % ,respectively.
Conclusion: UV/US/H₂O₂/O₃ hybrid process with advantages such as performance and high speed can be recommended for wastewater treatment in various industries.

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Background and Objective: Population growth and pollution caused by the discharge of all kinds of urban, industrial, and agricultural sewage, leachate from landfills, and surface water runoff cause an increase in pollution of water sources. The entry of heavy metals into the environment, especially aquatic ecosystems, due to entering the food chain and jeopardizing human health is one of the concerns of society. This study was conducted to determine the level of heavy metals in muscles of Cynoglossus arel and Pomadasys kaakan fishes in Boushehr coastal waters, north of the Persian Gulf.
Methods: This descriptive study was conducted on twenty pieces of Cynoglossus arel and twenty pieces of Pomadasys kaakan fishes take place from three coastal stations of Boushehr, north of the Persian Gulf, Iran during spring of 2022. The samples were randomly selected from the fish market. After preparation, bioassay, and digestion of fish muscle by concentrated nitric acid, the concentration of heavy metals including nickel, zinc, copper, lead, and cadmium (µg/g) in the muscle tissue was measured by ICP-OES device. The concentration of heavy metals in the fish muscle tissue for human consumption was compared with international standards (FAO, WHO, FDA, NHMRC, and UKMAFF). According to the method of the US Environmental Protection Agency for fish consumption, daily absorption estimates and heavy metal risk indicators were calculated.
Results: The risk potential index for both species was less than one. The daily and weekly absorption of Cynoglossus arel (zinc > copper > nickel > lead > cadmium) and Pomadasys kaakan (copper > zinc > nickel > lead > cadmium) were determined. The mean concentration of heavy metals nickel, zinc, copper, lead, and cadmium in the muscle tissue of the studied species was determined to be 1.88±0.07, 27.16±8.11, 11.55±4.12, 1.14±0.06, and 0.19±0.03 µg/g, respectively. The highest amounts of studied metals in aquatic animals were zinc > copper > nickel > lead > cadmium. The concentration of metals in the analyzed samples was lower than the international standards.
Conclusion: Regarding toxicity, the concentration of metals in Cynoglossus arel and Pomadasys kaakan was evaluated as acceptable for human consumption. In addition, the amount of risk potential and risk index for non-cancerous diseases in adults and children in fish muscle tissue was less than 1, and the consumption of this fish does not cause any problems for human health.