Abnormal amount of radon in water results in increasing health risks. Concentrations of 222 Rn in 56 samples of drinking water resources, in villages surrounding ''Rafsanjan fault'' were measured in the fall of 2013.Range radon concentration is 0 and 18.480 BqL -1 , respectively. The maximum annual effective dose for adults and children were 181.5 and 248.95 lSvY -1 , respectively, and the lowest was zero for both groups. Radon concentration is higher on the right side of the fault than the left side. In order to reduce the radon concentration, water ventilation is recommended before use.
Background: Radioac ve substances are water chemical contaminants. In this study, the concentra on of radon was measured in drinking water supplies of Ta villages (part of Dehshir-Ba fault located in central part of Iran) and also Shirkooh area with granite rocks (containing uranium). Materials and Methods: This cross sec onal research was conducted in fall 2013 and winter 2014 on the sources of drinking water and also drinking water network of Ta city of Yazd province. According to the measured radon levels; the annual effec ve absorbed dose was also calculated. Results: Minimum and maximum levels of radon gas were related to sample number 54 (0.88 BqL ). Range of radon concentra ons was 1.88-43.01 BqL -1 in samples of wells in private homes, 0.88-20.36 BqL -1 in supplier wells of public network of drinking water, 1.23-10.29 BqL -1 in aqueducts, 1.23-11.49 BqL -1 in water tap connected to the public network and 12.89 BqL -1 in one measured spring. The annual effec ve absorbed dose through drinking and breathing in an environment that this water is used ranged from 0.00 msv/y (sample No.54) to 0.11 mSv/y (sample No.31). Conclusion: Radon concentra on was lower than the limit set by the Environmental Protec on Agency of United States of America, in 82% of samples. Samples with high radon concentra ons were located around Shirkooh area due to the presence of grani c rocks. Dehshir and Garizat villages located through Dehshir -Ba fault and the Radon concentra on of these samples was less than the permissible limit, probably due to the inac ve Fault.
Background: Fluoride plays an important role in bone and dentin mineralization; however, excess fluoride intake is harmful to mankind. Methods: This study evaluated the performance of bauxite from active Iranian mines in removing fluoride from drinking water. The effects of pH, contact time, adsorbent dose, and fluoride concentration on defluoridation and removal efficiency were determined. Kinetics and adsorption isotherms were studied. Fluoride levels were measured using SPADNS. Data analysis was performed using SPSS16. Results: Bauxite from the Jajarm mine had the lowest adsorbency (20 g/L) and required the shortest contact time (90 minutes) to reach equilibrium compared with the ore from bauxite mines evaluated in another study which had greater efficiency rates in removing fluoride from drinking water (58.15%). The fluoride removal efficiency rates of the other bauxite mines were as follows: Mendon > Sadrabad > Khidabas > Khezri > Shahbalaghi > Tash > Biglar. Bauxite from Shomal-e Yazd, Hasanabad, and Shahid Nilchian mines could not achieve the required efficiency to remove fluoride from drinking water without initial preparation and modification. The removal efficiency rates of actual samples were much lower than the synthetic samples because of confounding factors. Conclusion: As a result of the low cost and abundant availability of bauxite and the fact that its use does not require a particular expertise or sophisticated technology, the removal efficiency of this adsorbent can be increased to desirable levels through the use of corrective methods such as heating, acidifying, particle crushing, or the mixing of two or more removal systems. Keywords: Fluoride, Iran, drinking water, kinetics Citation: Malakootian M, Javdan M, Iranmanesh F. Use of bauxite from active Iranian mines for the removal of fluoride from drinking water.
Background: Although excess fluoride intake is detrimental for humans, but fluoride shortage may cause health problems. This study aimed on evaluation of removal of fluoride from aqueous solution using province Semnan (Tash) bauxite mine. Methods: The study was conducted in laboratory scale, from May to October 2013, on both synthetic and real water sample of Kuhbonan city in the Kerman environmental health engineering research center. The adsorbent was made from Bauxite obtained from Tash bauxite mine in Semnan province. Characterization of bauxite was studied by XRD and XRF. Synthetic samples contained fluoride were considered to determine the effect of pH, contact time, adsorbent dose and initial fluoride concentration on the efficiency of fluoride removal. Experiments on real water samples were done based of optimized adsorption condition. The kinetics and isotherm of the adsorption process were evaluated in order to better understanding the adsorption process. Fluoride measurement was carried out by SPADNS method. Data analysis was done by Excel software. Results: The maximum removal efficiency of fluoride, in synthetic sample, was 68.2% which was obtained at pH=7, contact time of 120 minutes and absorbent amount of 25g/L. The efficiency for real water sample was 61.67%, in optimized condition. Fluoride adsorption was best fitted with the Langmuir sorption isotherm equation (R 2 =0.991) and the second order synthetic model (R 2 =0.985). Conclusion: Bauxite from Tash mine could be initially applied for fluoride removal from groundwater samples with the efficiency of 61.67% which could be used as a low-cost and effective adsorbent.
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