maryam farajzadeh

The overall purpose of this study was to estimate the health risk of nitrate (NO3-) concentration in the drinking water of Tabriz County.

This research is a descriptive cross-sectional study that was performed on Tabriz drinking water in 2016-2017. The concentration of NO3- in one hundred - ninety drinking water samples was determined in the water and wastewater laboratory of the provincial health center using spectrophotometry.

The results showed that the average levels of NO3- (as nitrate ion) in drinking water of urban and rural districts were 14.6 ± 12.8 and 13.1 ± 12.8 mg/L, respectively, which are lower than the national standard of Iran and WHO guidelines. The average hazard quotient (HQ) for four age groups of infants, children, teenagers, and adults was less than one in both urban and rural zones. However, HQ values for the children were more than 1 in 15.20% of urban and 10.7% of rural samples.

The non-carcinogenic risk of NO3- in drinking water does not threaten the exposed population, but the children presumably are at risk of NO3-. Hence, the continuous control of the concentration of NO3- was recommended to prevent its possible risk for water consumers, especially children.

The aim of this study was to evaluate the concentration and the Non-carcinogenic risk associated with nitrate in the drinking water of Bostanabad city over different age groups. In this descriptive cross-sectional study, nitrate concentration was measured in 98 drinking water samples (18urban samples and 80 rural samples). Also, Non-carcinogenic risk assessment was determined using the indicators of the Environmental Protection Agency. The mean concentration of nitrate in the drinking water of urban and rural areas of Bostanabad was 10.56 and 14.65 mg/L, respectively. Nitrate concentration in 95.91% of the samples was lower than the standard. The mean Hazard Quotient )HQ( values due to nitrate in drinking water for the four age groups of infants, children, teenager and adults both urban and rural areas were less than one. However, HQ values was more than 1 in 5.5% of urban water samples and in 11.25% of rural water samples over age group of children. According to the results, in most cases, the concentration of nitrate in drinking water was less than the national standard of Iran and the World Health Organization. However, age group of children are at Non-carcinogenic risk from drinking water nitrate.

The purpose of the present study is to investigate the relationship between information asymmetry and mispricing of accruals in Tehran Stock Exchange. Hence, we hypothesize that there is a significant positive relationship between the level of information asymmetry and mispricing of accruals. We implement Mishkin test and classification of portfolios method to respectively investigate whether there is any mispricing of accruals and its relationship with information asymmetry. Furthermore, the indirect balance sheet approach and bid-ask spread have been utilized to measure respectively accruals and information asymmetry. Thus, information of 82 entities during the time span of 5 years between 2008 to 2012 have been analysed to test our hypothesis. The results depict that as the level of information asymmetry enhances, the difference between coefficients of predictions and evaluation of accruals in the Mishkin test increases. In other words, as the level of information asymmetry increases, the mispricing of accruals intensifies.

The purpose of this research is to examine both the relationship between accounting conservatism and level of investment under the need or no need of financing conditions and the impact of ultimate ownership on this association. The statistical society of the present research contains 103 companies selecting from all companies listed in Tehran Stock Exchange using removal method over the time span of 2006-2010. Combined data method with fixed effect has been used in order to test the research hypothesis. The result depicts that the association between conservatism and investment is significantly negative when a firm do not need external financing. Nonetheless, this association is significantly positive in companies which need external financing. Furthermore, we find that the relationship between conservatism and investment in the companies whose ultimate ownerships controller is governmental or semi governmental firms is significantly negative. Thus, when the agency problem is enhancing, conservatism acts as a mechanism to decrease this problem and engenders reduction in investment cost