عادل احمدزاده

Solar ultraviolet radiation (UVR) is considered one of the most important biological risk factors in the world. Most health damages from solar ultraviolet radiation at ground level are mainly caused by UVA and UVB spectrums.
The aim of this study was to Measure the solar ultraviolet radiation intensity type A and B in Qazvin city.
In this cross-sectional study, the intensity of solar ultraviolet radiation type A and B was measured in Qazvin on years of 2013-14 (during one year) every monthly at three times, in the morning, afternoon and evening by using a UV Radiometer. Data were analyzed using descriptive statistics.
Findings: The maximum average intensity of UVA and UVB rays during the one year with 28.36±1.88 W/m2 and 0.156±0.035 W/m2 respectively was in Tir month (June 22–July 22) and the minimum average intensity of UVA and UVB rays with 10.36±0.83 W/m2 and 0.041±0.010 W/m2 respectively was in Dai month (December 22–January 20).
With regards to the results, it is recommended that individuals were less exposed to exposure time with direct sunshine and use appropriate protective measures such as; wear appropriate clothing, sunglasses, and sunscreen.

As seasonal turbidity is one of the major challenges in drinking water supply; consequently, take an appropriate method to provide standards range is necessary. This study aimed to determine the effect of Snail shell as a coagulant aid in the removal of turbidity in aqueous environments using electrocoagulation process through aluminum electrodes. This experimental study was investigated at the laboratory scale. The used reactor had a volume of 1 liter whit four aluminum electrodes as a cathode and anode in the form of a direct current power supply. Effects of pH (9-6), initial concentration of turbidity (200 NTU to 800 NTU), reaction time (30 -10 min), the concentration of Snail Shell (0.5-4.5 mg/L) and the potential difference (10-40 V) were examined. The findings indicated that the best performance for turbidity removal obtained at pH 8, reaction time 30 min, potential difference of 40 V, SS 2 mg/L dose of coagulant aid concentration and turbidity 200 NTU. The results suggest that Electrocoagulation process using aluminum electrodes have good performance for removal of high concentration of turbidity and snail shell coagulant aid is a good option to improve the performance of the electrocoagulation process.

fluoride in low concentration is essential for human but in high concentration is very hazardous for human health. The efficacy of Snail Shell (SS) was investigated in this research work as an adsorbent for the elimination of fluoride from aqueous. in this experimental study، the capability of SS to adsorb fluoride ions was conducted using a series of batch tests in a shaker-incubator instrument. For each batch run، 100 mL of solution containing a known initial concentration of Fluoride and with the preferred level of pH was shacked. The effects of selected parameters such as pH (3-11)، reaction time (5–60 min) cyanide concentrations (5-10 mg/L) and the adsorbent dosage (0. 25–2. 5g/L) were investigated on the removal fluoride as a target contaminate. Chemical composition SS were analyzed using a Philips model XL30- scanning electron microscope (SEM) with energy-dispersive X-ray microanalysis (EDX). The concentration of Fluoride in solution before and after treatment was determined using the HACH method. Analysis of the SS component using the EDX technique showed that the main part of it consisted of calcium and its other components were magnesium، aluminum and silicate. The experimental data showed that the maximum fluoride removal occurred at pH of 7، adsorbent dose (0. 5 g/L) and 30 min contact time and 5 mg/lit initial concentration. The kinetic evaluation indicated that the pseudo-second-order kinetic had the best fit to the experimental results predicting a chemisorption process. The equilibrium adsorption of fluoride onto SS was well represented by the Langmuir equation. As a result، SS was revealed as a very efficient and low-cost adsorbent and a promising option for removing fluoride from industrial wastewaters.