The present study aims at evaluating the risk of Mutagen X (MX) (3-chloro-4-(dichloromethyl)-5-hydroxy-2 (5H)-furanone) and adverse health effects, associated with direct ingestion of chlorinated drinking water in west of Tehran, supplied by chlorinated drinking water from surface and underground water sources. For one year, MX concentrations in tap water samples has been measured for consumers in four different zones in western Tehran. It has been found that average MX concentration in the whole study area is 24.16 ng/L, with the highest concentration being in Zone 1 with a value of 38 ng/L. Also, the role of water sources, seasonal changes, and effective factors such as Total Organic Carbon (TOC) have been evaluated on MX formation. The highest of excess lifetime cancer risk (ELCR), estimated as 0.0037E-05, belongs to Zone 1, which uses surface water to supply drinking water, while the lowest can be seen in Zone 4, being 0.0021E-05. This latter zone utilizes underground water as the water source. In all zones, the highest risk of excessive cancer is related to winter, ranging from 0.0045E-5 in Zone 1 to 0.0023E-5 in Zone 4. The estimated number of cancer cases for Zones 1 to 4 have been 0.012, 0.016, 0.016, and 0.004, respectively, based on their population. The estimated average risk and the number of ELCR, caused by exposure to MX, through direct ingestion of drinking water have been 0.0030E-5 and 0.047, respectively, in the entire studied area for the duration of one year.

Due to the fish are often at the top of the aquatic food chain and may accumulate large amounts of heavy metals from the water, this study was conducted to determine of Cd, Cr, Pb and Ni contents in the muscle of imported tilapia fish marketed in the city of Hamedan in 2017. In so doing, totally, 27 muscle samples from nine different brands of tilapia fish were randomly collected from the market basket of the study area. After preparation and processing the samples in the laboratory, the concentration of metals, was determined using inductively coupled plasma-optical emission spectrometer. The results showed that the mean concentrations (mg/kg) of Cd, Cr, Pb, and Ni in samples were 0.26 ± 0.09, 1.54 ± 0.15, 0.55 ± 0.11, and 0.67 ± 0.20 respectively. Also, the mean contents of Cd and Pb were higher than the maximum permissible levels (MPL) established by the World Health Organization (WHO). The computed health risk index values showed that no potential health risk for adults and children via consuming the muscle of tilapia fish at the current consumption rate for the study area. Based on the results, due to the mean contents of Cd and Pb in the muscle samples of tilapia fish were higher than the MPL, therefore, serious attention to the reduction of the discharge of hazardous substances in the aquatic ecosystems and also periodic monitoring of chemical residue particularly toxic heavy metals in the high-demand food is recommended.

The aim of this study was to determine the levels of Cd, As, Hg, Pb, and Cr in the edible part of eleven most consumed fish species collected from the north-east coast of Persian Gulf, Iran, during 2017. An inductively coupled plasma atomic emission spectroscopy (ICP-AES) instrument was used to measure the concentration of heavy metals. The results were compared within acceptable limits for human consumption set by various health institutions. The order of heavy metals about total accumulation was Cr>As>Pb> Cd> Hg. The mean heavy metals concentrations of fish species muscle decreased in the order of Acanthopagrus latus> Planiliza subviridis> Lutjanus lemniscatus > Alectis indica> Epinephelus areolatus> Otolithes ruber> Epinephelus chlorostigma> Lethrinus crocineus> Euryglossa orientalis > Cynoglossus arel > Grammoplites suppositus. Probably the difference in the concentration of metals between samples depends on fish species, diet, and habitat. These species were declared to exhibit a low probability of causing non-cancerous diseases. The comparison of the accumulation and hazard risk of consuming the five heavy metals existing in the eleven species that were sampled from the coasts of Khuzestan, Maah-shar Harbour, with the WHO and USEPA guidelines showed that although consuming these fish species does not threaten the consumers' health, pregnant women and children should be cautious about consuming them. The HI was calculated for 70 kg body weight of adults and 14.5 kg body weight of children. The amount of optimal consumption is different for different weights of consumers.