Ehsan Aghayani, Sakine Shekoohiyan, Ali Behnami, Ali Abdolahnejad, Mojtaba Pourakbar, Hamed Haghnazar, Vahideh Mahdavi, Amir Mohammadi,
Volume 16, Issue 1 (6-2023)
Abstract
Background and Objective: Heavy metals in water can pose risks to human health. Therefore, it is necessary to monitor and measure metals to ensure the health of consumers.
Materials and Methods: This study aimed to measure heavy metals such as arsenic, lead, cadmium, chromium, zinc, and mercury in water resources and urban water distribution networks in spring and summer of 2021 in Maragheh city. Accordingly, 25 samples were taken to investigate the presence of heavy metals. The presence of these metals in water sources was investigated using qualitative maps and finally, by evaluating the health risk caused by the presence of these metals, their effect on the health of consumers has been studied.
Results: Examining the concentration of metals in water resources upstream of the dam shows a relatively high concentration of metals, especially arsenic (13.2 µg/L). Despite this, the amount of arsenic after the water treatment plant and in the distribution network is reduced to an insignificant level. On the other hand, the results show that the amount of zinc metal in the network is higher than in the reservoir of the dam, and its concentration in the dam is equal to zero and in the network, it reaches the highest value of 578 µg/L. Finally, the health risk assessment shows that the calculated THI values for all samples vary between 0.01 and 0.99.
Conclusion: Based on the calculated health risk, there is no threat to the health of consumers regarding heavy metals in Maragheh drinking water. Also, these results double the necessity of additional studies regarding the leakage of zinc metal from the pipes and accessories of the city's drinking water distribution network in the future.
Sakine Shekoohiyan, Mojtaba Pourakbar, Asghar Zohdi Shiran, Farshid Ghanbari, Mostafa Mahdavianpour, Ehsan Aghayani,
Volume 16, Issue 4 (3-2024)
Abstract
Background and Objective: The development of the automobile industry has caused various pollutants to enter the environment, one of which is fluoride. Therefore, this study aims to improve the fluoride removal from wastewater pre-paint units of the automotive industry to achieve discharge standards to surface waters.
Materials and Methods: The study is descriptive and on an applied scale, which has been carried out to compare the efficiency of the chemical coagulation process using lime and alum, as well as the electrocoagulation process using aluminum anodes in the presence of lime to remove fluoride.
Results: The results of real wastewater characteristics showed that the pH of wastewater is in the range of 6.1 to 6.3, and its fluoride concentration is in the range of 45 to 55 mg/L. The results of the experiments show that in the most optimal possible state in the chemical coagulation process, it is possible to achieve fluoride removal efficiency in the range of 76 to 81 percent. However, the removal efficiency in the electrocoagulation process using an aluminum anode at a concentration of 5 mol/L of calcium ions, and current density of 20 A/m2 after reaction time of min 20 to 99% can also be achieved.
Conclusion: Considering the high fluoride removal rate (more than 99%) in the electrocoagulation process in the presence of calcium ions, this process can be introduced as an efficient technology for fluoride removal.
