ABSTRACT
Analyzing municipal wastewater for the presence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) helps to evaluate the efficacy of treatment systems in mitigating virus-related health risks. This research investigates wastewater treatment plants' (WWTPs) performance in the reduction of SARS-CoV-2 from municipal wastewater in Tehran, Iran. SARS-CoV-2 RNA was measured within sewers, at the inlets, and after the primary and secondary treatment stages of three main WWTPs. Within sewers, the average virus titer stood at 58,600 gc/L, while at WWTP inlets, it measured 38,136 gc/L. A substantial 67% reduction in virus titer was observed at the inlets, accompanied by a 2-log reduction post-primary treatment. Remarkably, the biological treatment process resulted in complete virus elimination across all plants. Additionally, a notable positive correlation (r > 0.8) was observed between temperature and virus titer in wastewater. Using wastewater-based epidemiology (WBE) technique and the estimated SARS-CoV-2 RNA shedding rates, the infection prevalence among populations served by WWTPs found to be between 0.128% to 0.577%. In conclusion, this research not only advances our understanding of SARS-CoV-2 dynamics within wastewater treatment systems but also provides practical insights for enhancing treatment efficiency and implementing the feasibility of WBE strategies in Tehran. These implications contribute to the broader efforts to protect public health and mitigate the impact of future viral outbreaks.
ABSTRACT
Fluoride concentration in groundwater resources that used as the source of drinking water in urban areas of Iran was determined. All of the groundwater wells located in urban areas were monitored in 2008. Fluoride concentration of water samples was measured using SPADNS method. The nationwide mean fluoride concentration in the groundwater resources was found to be 0.47 +/- 0.28 (+/- standard deviation) mg/L. Only in Bushehr Province, the provincial mean fluoride level in the groundwater resources was higher than the WHO guideline value of 1.5 mg/L (1.86 +/- 0.86 mg/L). At nationwide level, the portion of extracted groundwater with fluoride concentration lower than the minimum permissible level of 0.5 mg/L, desirable fluoride range of 0.5-1.5 mg/L and elevated fluoride level was 69.2, 29.3 and 1.4%, respectively. In the areas with low fluoride content drinking water, it is recommended that fluoride is absorbed by use of high fluoride content foods and beverages. The recommendations for the circumstances with excessive fluoride content of drinking water are provision of drinking water from alternative sources and defluoridation of drinking water by point-of-use systems, respectively.
