Iranian Journal of

Backgrounds and Objectives: Water contamination by pesticides is considered as an environmentalproblem today. In terms of agricultural development and diversity of plant pests, the use of pesticides has been increasing. Hamedan province has a suitable agricultural condition, it has enjoyed significant development in this respect. Among all the cities of Hamedan province, Hamedan city has the highest rank in tiller crops. Therefore, yearly use of pesticides is increasing in this area which could be a serious threat to water resources of the city. The aim of this survey was determinaton of Organophosphorous and Carbamat pesticides residue in drinking water resources of Hamadan in 2007.
Materials and Methods: In this survey, 126 water samples were collected from 7 drinking water resources of Hamedan during 12 consecutive months in 2007. for determination of these pesticides,two methods (solid- phase extraction and Liquid-Liquid extraction) were adopted .and samples were analyzed by means of HPLC and GC/MS applying standard methods.
Results: Final results showed that the most concentration of Chlorpyrifos and Carbaryl pesticides were found to be about 3.85 ppb (part per billion) and 1.8 ppb in spring and June respectively the maximum concentration of Diazinon was about 36.5ppb in October (autumn).The minimum concentration of the three pesticides was detected in winter. According to the statistical test Two - Way ANOWA there were significant differences among pesticides concentrations in the water samples in different seasons (p<0.05) . However, there wasn't a significant difference in pesticides concentrations in surface and ground water samples(p>0.05).
Conclusion: Different studies have shown that pesticides residue concentration in water samples have a relationship with the amount of pesticides used in an area, physical and chemical refractory properties of pesticides and environmental conditions. Thus, using resistant pollutants such as pesticides will be a serious threat to health of water consumers if they are not properly controlled.

Background & objectives: Aflatoxin M1 and M2 (AFM1 and AFM2) are secondary toxic metabolite of molds excreted into livestock milk and dairy products when animal consume feedstuffs contaminated with AFB1 and AFB2. Considering the importance of taking dairy products in human diet, the present study was carried out to determine AFM1 of pasteurized Kashk (industrial liquid) in Tehran Metropolitan. Materials & Methods: Totally, 32 industrial liquid Kashk samples (eight brands with four different dates of production) were purchased from supermarkets of Tehran and were analyzed using High Performance Liquid chromatography (HPLC) and immunoaffinity columns. Results: In this study, 90.62% of samples (mean: 60.17 ± 75.48 ppt) were contaminated with AFM1. The concentration of AFM1 in 20.68% of samples were higher than Iranian national standard limits (100 ppt). Comparison of different brands showed that brand B with the mean 99.09 ± 158.47 ppt and brand G with the mean 21.27 ± 16.91 ppt had the highest and lowest level of contamination respectively, however, the difference was not statistically significant (P > 0.05). Conclusion: Considering contamination of more than half of the samples with AFM1 and the point that even low level of aflatoxin can be a serious problem for human health, therefore, continuous control of dairy products and preventive proceedings such as avoidance of using moldy feedstuffs for livestock is suggested