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The presence of organic and inorganic contaminants in drinking water is a global concern. Nitrate and phenol derivatives are examples of pollutants that could be of anthropogenic origin. They are associated with numerous health risks, underscoring the importance of monitoring their presence in drinking water. This study aimed to measure nitrate and phenol derivatives, including 2,4-Dichlorophenol (2,4-DCP), Pentachlorophenol (PCP), 2,4,5-Trichlorophenol (2,4,5-TCP), 2-Chlorophenol (2-CP), 4-Chlorophenol (4-CP), and phenol, in Tehran's water distribution system (WDS). The pollutants in Tehran's WDS were significantly and positively correlated with precipitation. The Hazard Quotient (HQ) and the Excess Lifetime Cancer Risk (ELCR) of the detected pollutants were estimated. The results showed that the regional mean of nitrate and PCP in Tehran's WDS were 35.58+8.71mg L-1 and 76.14+16.93 ng L-1 lower than the guideline values of 50 mg L-1 and 1000 ng L-1, respectively. Some districts exhibited nitrate concentration exceeding the allowable limit by a factor of 1.2 to 2.3. Consequently, the nitrate intake in some districts constituted approximately 50% of the reference dose. While PCP as a phenol derivative with more health concerns was identified in Tehran's WDS, the likelihood of its health effects was determined to be negligible. [ABSTRACT FROM AUTHOR]

TiO2 nanoparticles used in the photocatalytic degradation of pollutants in water treatment processes undergo physiochemical changes; therefore, their toxicological effects may be potentially different from those of the pristine nanoparticles. This study compared the toxic effects of exposure to pristine and photocatalytically used TiO2 nanoparticles in mice. To obtain used TiO2, the nanoparticles were used for photocatalytic degradation of a model pollutant under UV irradiation several times. Two groups of mice were exposed to pristine (PT group) and photocatalytically used TiO2 (UT group) at three different concentrations (5–20 mg/m3) using whole-body exposure chambers (2 h/day, 5 days/weeks, 4 weeks). Exposure to both pristine and used TiO2 increased the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphate (ALP), lactate dehydrogenase (LDH), C-reactive protein (CRP), and creatine kinase (CK-MB) significantly. Both exposed groups showed higher levels of WBC, lymphocytes, platelets, hematocrits, hemoglobin, and mean corpuscular volume (MCV) and lower levels of RBC and mean corpuscular hemoglobin concentration (MCHC) in a concentration-dependent manner. In all analyses, there were small non-significant differences between the PT and UT groups. More pathological changes were observed in the lung, kidney, and brain of the UT group, while the PT group showed more pathological effects in the liver and heart. The histological observations indicated that damage was mostly in the form of vascular endothelial injury. These two types of TiO2 may activate different pathways to promote adverse effects. Further studies are required to evaluate and distinguish the mechanisms through which pristine and used TiO2 induce toxicity. [ABSTRACT FROM AUTHOR]

The paper is focused on the study of controlling the path of ions causing hardness and salinity of water by a combination of electrolysis process and electric and magnetic fields and explaining the mechanism of the process based on magnetohydrodynamic (MHD) and magnetophoretic (MP) forces. The results showed that the highest removal efficiency of total dissolved solids (TDS) was 7.64%, the highest removal efficiency of electrical conductivity (EC) was 38.32% and the highest removal efficiency of total hardness (TH) was 36.04%. The greatest impact occurred when these two forces were applied simultaneously. Moreover, MgSO4 and CaCO3 had the greatest effect on the reduction of ions. This effect was due to the presence of oxygen atoms of MgSO4. Oxygen atoms are considered to be strong paramagnetic particles (magnetic susceptibility of +7,699 × 10–6 m³/mol) due to their unpaired orbitals, which makes them more affected. Besides, the ions that increase the TDS and EC of water (such as NaCl and MgSO4) have a larger rotation diameter or Larmore radius than ions that increase water TH. The circulation of soluble ions around the central electrode was formed by the MHD force that was based on the Lorentz force, and the difference in the concentration of ions in the column was caused by the MP force that was based on the Kelvin force and as a result, more ions were transferred to the spiral paths. [ABSTRACT FROM AUTHOR]

Background and Objectives: Isolating Helicobacter pylori (H. pylori) from wastewater and culturing it using a conventional method has always been a controversial issue because the bacterium converts into a coccoid form when exposed to an unfavourable environment like wastewater. To clarify the cultivability behaviour of the bacterium in fresh wastewater samples, the effect of municipal wastewater dilation on the cultivation of the bacterium using a conventional method was examined., Materials and Methods: Several dilutions of wastewater samples were inoculated with fresh H. pylori suspension (with McFarland's dilution 0.5) to examine the dilution effect of wastewater on the bacterium isolation., Results: The H. pylori growth was found to be possible for a dilution factor from 1/10 6 to 1/10 7 of raw wastewater. In higher dilution factors the growth of fungi was dominant and could prevent the isolation of the bacterium., Conclusion: The optimized technique could be applied in future studies for increasing the chance of H. pylori isolation from fresh wastewater environments., (Copyright © 2022 The Authors. Published by Tehran University of Medical Sciences.)