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Background: Existence of fluoride in drinking water above the permissible level causes human skeletal fluorosis. Objectives: Electrocoagulation by iron and aluminum electrodes was proposed for removing fluoride from drinking water. Materials and Methods: Effects of different operating conditions such as treatment time, initial pH, applied voltage, type and number of electrodes, the spaces between aluminum and iron electrodes, and energy consumption during electrocoagulation were investigated in the batch reactor. Variable concentrations of fluoride solution were prepared by mixing proper amounts of sodium fluoride with deionized water. Results: Experimental results showed that aluminum electrode is more effective in fluoride removal than iron, as in 40 minutes and initial pH of 7.5 at 20 V, the fluoride removal process reached to 97.86%. The final recommendable limit of fluoride (1.5 mg/L) was obtained in 10 minutes at 20 V with the aluminum electrode. Conclusions: In electrocoagulation with iron and aluminum electrodes, increase of voltage, number of electrodes and reaction time as well as decrease of the spaces between electrodes, enhanced the fluoride removal efficiency from drinking water. In addition the effect of pH and initial concentration of fluoride varied with types of electrodes.

Background: Entrance of heavy metals into the respiratory system has adverse effects on human health. Accordingly, measuring metals concentration in places and times is necessary. Objectives: This study was done to evaluate the non-carcinogenic risk of Pb, Cd, and As in air suspended particles of Baharestan city, in Isfahan, during 2016 -2017. Methods: In order to evaluate the non-carcinogenic risk of heavy metals in air suspended particles (PM10), sampling was performed using a SKC pump with a low volume (1.5 L/min) and 37 mm membrane filter. Sampling was carried out on average every three days during 24-hours finally, the concentration of Pb, Cd, and As was determined using atomic absorption spectrometry (AAS) and hydride generation atomic absorption spectrometry (HGAAS), respectively. The acute and chronic non-carcinogenic risk of heavy metals sorption in the air was evaluated using the EPA method. Results: The highest and lowest Pb concentration belonged to May -June and October -November, with the mean concentration of 0.25 and 0.14 mg/kg, respectively. For Cd it was 0.017 and 0.009 mg/kg, respectively. Similar results were found for the air suspended particles. The highest and lowest Cd non-carcinogenic risk was observed for permanent residents of Baharestan city and the nondormitory students of this city with the mean of 3.1 × 10 -5 and 1.4 × 10 -5 , respectively. Conclusions:The results of this study showed that the non-carcinogenic risk of heavy metals was lower than the standard level during the study years. However, heavy metal accumulation can threaten human health, which needs more consideration.

Morbidity and mortality impacts of particulate matter (PM) are globally important health critical parameters. In this ecologicaldescriptive study, the health impact of PM 10 and PM 2.5 associated with there temporal variations in Dezful city were assessed from 2013 to 2015. AirQ+ software handles the PM air pollutants by addressing impact evaluation and life table evaluation. We used a new method to analysis fine particles feature by using regular daily observations of PM 10 . In this method, relationship between PM 2.5 and PM 10 mass concentrations were analyzed and calculated. The annual average concentrations of PM 10 were 147.1, 114.3 and 158.8 μg/m 3 , and the annual average concentration of PM 2.5 were 57.8, 50.7 and 58.2 μg/m 3 in 2013, 2014 and 2015, respectively. PM 10 also had obvious diurnal variations with highest hourly concentrations in 13:00 and 22:00 but the lowest concentrations often occurred in 05:00 and 16:00. Unexpectedly, in weekends the concentration of PM pollutants appeared to have increased from 18:00 to midnight. The daily based analysis showed that there are 147 dusty days in the study period during which the most severe dusty day occurred in 2014. Over the study period, mean levels of PM 10 and PM 2.5 in both conditions were higher in 2015 compare to 2013 and 2014, which probably is due to higher frequency of dust storms in 2015. Hence, during 2015 and 2013 they're were higher morbidity and mortality compare to 2014 due to exposure to higher polluted air with PMs in all cases except lung cancer (LC).

This study investigates the concentrations of PM 10 -bound PAHs and their seasonal variations in three cities of Ahvaz, Abadan, and Asaluyeh in Iran. The mean concentrations of PM 10 in two warm and cold seasons in Ahvaz were higher and in Abadan and Assaluyeh were lower than the national standard of Iran and the guidelines of the World Health Organization. The Σ16 PAHs concentration in ambient air PM 10 during the cold season in Ahvaz, Abadan and Asaluyeh was 244.6, 633, and 909 ng m − 3 , respectively, and during the warm season in Ahvaz, Abadan, and Asaluyeh was 242.1, 1570 and 251 ng m − 3 , respectively. The high molecular weight PAHs were the most predominant components. The most abundant PAHs species were Pyr, Chr, B [ghi] P, and Flt. The results showed that the total PAHs concentration in the cold and warm seasons was dependent on industrial activities, particularly the neighboring petrochemical units of the city, vehicular exhausts, traffic and use of oil, gas, and coal in energy production. The total cancer risk values as a result of exposure to PAHs in ambient air PM 10 in all three cities for children and adults and in both cold and warm seasons were between 1 × 10 − 6 and 1 × 10 − 4 , and this indicates a potential carcinogenic risk. Therefore, considering the various sources of air pollutants and its role on people's health, decision makers should adopt appropriate policies on air quality to reduce the ambient air PAHs and to mitigate human exposure.