شهاب یوسف زاده

In this study, some samples of bed sediments from Rasht rivers were obtained and 19 organochlorine pesticides (OCPs) were determined for specifying the contamination profiles, distribution characteristics, effective factors and hazard of carcinogenic compounds. OCPs as Persistent Organic Pollutants (POPS) haskhown vast distribution, persistence and accumulation in the environment. Their high toxicity to humans and non-target organisms are a significant threat to human health and biodiversity.

Identify and determine the concentrations of organochlorine pesticides analysis were conducted on bed sediment samples by liquid-liquid micro extraction method and then by gas chromatography flame ionization (GC-FID) and via external standard calibration curve drawing.

Based on the analysis, total concentration of OCPs is in the range of 2.6-60.2 ng/g, with an average of 20 ng/g. The main sources of pollution are Heptachlor, HCHs, DDTs and Endosulfans and highest contamination of the dominant pollutant DDE isomers belonges to sediments of Pir Bazar River.

The results are showed that there were various amounts of new and past entries. The analysis shows that the potential source of high levels of DDTs and HCHs residues of pesticides returns to the pastconsumptions.

This article examines a simple and efficient method for extraction and preconcentration at the same time very low values ​​of organochlorine (OCPS) in the river water samples, based on the specific situation of dispersive liquid-liquid microextraction in a long thin tube. The effect of influencing factors in microextraction such as the type and volume of solvents dispersive and extracted and volume of sample aqueous solution was studied and optimized. In the optimized qualification, mixture of 2.5 ml acetone and 0.5 ml n-hexane and toluene (1:1) for 30 seconds to 19 ml water solution is injected into the pipe and formed cloudy solution and toxins transferred to the organic phase and reached the top of the column. Finally, after extraction and cleanup 1 ul of samples injected into gas chromatography flame ionization and compared to standard solutions curve, were determined. Under optimal conditions, the linear range of calibration curves in the range of 0.6 to 1.4 ug/ml and relative recovery of 93.1 to 98.6, relative standard deviation much lower than 5.9% and correlation coefficient of 0.95 was calculated. The limit of detection and quantification limits, respectively, in the range of 0.8 to 1.3 and 3.1 to 3.7 ug/l respectively. The advantage of this method is the simplicity, speed, low cost and high recovery percentage.