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As the most abundant element in the atmosphere, nitrogen is a vital nutrient for plant growth. Nitrate is the main form of nitrogen uptake by plants. Although nitrates are relatively low in toxicity, if they accumulate in vegetables can be converted to nitrite and nitrous acids in the human body. This study collected 83 tomato and 40 onion samples cultivated in Fars province; then nitrate concentration was determined by an HPLC, also cadmium (Cd) and lead (Pb) concentration by an atomic absorption instrument. The Cd and Pb in samples were below the detection limits (LOD) of the techniques used. However, the nitrate concentration in tomato and onion samples from Fars province varied from 0 to 154.40 mg/kg and 0 to 317.20 mg/kg, respectively. The mean chronic daily intake (CDI) for tomatoes in children, women and men was 0.1188, 0.0375, and 0.0366, and for onions, 0.1899, 0.0605, and 0.0447, respectively. On the other hand, the 95th percentile hazard index in the probabilistic method for nitrate for children, women, and men were 0.81, 0.26, and 0.21, respectively. Also, nitrate concentration in onion for children and tomatoes in both men and women was identified as the most considerable parameter in assessing the non-carcinogenic risk of nitrate. This study showed that the amount of nitrate in some samples of tomatoes and onions was not within the acceptable international standard limits. Therefore, monitoring the nitrate concentration in these high-consumption vegetables is crucial. [ABSTRACT FROM AUTHOR]

This study aimed to model the dispersion of emitted SO2 from stacks and flares in one of the largest Gas Refinery Companies in the Middle East. Pollutant emission coefficients and air pollution's various sources contributions were determined based on the collected data after measuring SO2 concentrations in a fixed monitoring station (stack) and across different distances from it for a year. The SO2 release pattern was simulated, and annual pollutant concentrations in average periods of 1-hr and 24-hr were predicted using AERMOD 8.9.0. The maximum simulated ambient SO2 were 27,447 and 4592 µg/m3 in average sampling times of 1-hr and 24-hr, respectively. The hazard quotient of 95% percentile for children, teenagers, and adults due to inhalation of SO2 was more than one.The maximum concentration of SO2 in the 1-hour and 24-hour period in the study area was higher than the amount introduced by Iran's clean air standard and the WHO standard. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the concentration and risk of carcinogenic and non-carcinogenic causes due to skin and drinking exposure with water in 27 points of potable water in Shiraz. The total samples were 162 the studied variables included fluoride and heavy metals (HMs). The results showed that the concentration of all parameters in winter was higher than in summer (p value < 0.05). However, the concentration in this study was lower than the standards of Iran, the World Health Organization (WHO), and the United state environmental protection agency (USEPA). The average fluoride (F−) concentration in summer and winter was 462 and 588 µg/L, respectively. The lead concentration in winter (8.91 µg/L) was higher than in summer (5.86 µg/L). So, in 40% of the samples, it was higher than the WHO standard. Zinc (Zn) and cadmium (Cd) concentrations were lower than allowed, and only 70% and 15% of winter samples were above the WHO standard. The chronic daily intake (CDI) for variable was F− > Zn > Cu > Pb > Cr > As > Cd but HQ < 1 for all HMs. The risk of cancer and non-cancer caused by HMs in children due to dermal and drinking exposure has been higher than in other groups. Chromium (Cr) cancer risk (1.84 × 10−4) in children has been 30 times higher than the allowable limit. The highest risk of non-carcinogenic risk was caused by arsenic in the children group. Overall, the best chemical quality of water was in the centre to the west of the city. So that most of the parameters were in optimal condition. However, cancer and non-cancer risk through drinking have been significant, especially in children. [ABSTRACT FROM AUTHOR]

Hazardous organic compounds such as benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene (known as BTEX) found at work and at home can cause adverse health effects of human beings throughout their lives. Biological monitoring, an exposure assessment method, considers all exposed organic and non-organic compounds. Our goal was to perform a systematic review and a statistical analysis (meta-analysis) of peer-reviewed publications to assess urinary concentrations of BTEX biomarkers in both occupationally-exposed population and the general population. Several major electronic databases, including Scopus, Embase, Medline, Web of Science, and Google scholar (grey literature), were searched for biomonitoring studies of BTEX. Overall, 33 studies met the eligible criteria for the systematic review and six met the full inclusion criteria for meta-analysis. For meta-analysis, we included studies in which unmetabolized BTEX compounds were measured in urine samples. Due to insufficient data, studies that measured BTEX metabolites in urine samples and unmetabolized BTEX compounds in blood samples were excluded from the meta-analysis but were analyzed in the qualitative synthesis. Most studies showed increased urinary concentrations of BTEX in exposed individuals (mainly workers) compared to unexposed individuals. The results showed that the highest total BTEX concentrations were recorded in painters and policemen. This study showed that the undoubted associations between lifestyle and environmental factors and urinary levels of BTEX or its metabolites have not yet been confirmed in current biomonitoring studies. This is attributed to the few studies reported in this research area, the lack of homogeneous information, and the disagreement in the published results of the studies. [ABSTRACT FROM AUTHOR]