فهرست مطالب n. a. najafi

The increasing amount of sewage sludge (SS) and more legislative regulation of its disposal have stimulated the need for developing new technologies including gamma irradiation to recycle SS efficiently.

To evaluate the effects of gamma irradiated and non-irradiated SS (SSGI and SSNI, respectively) on essential oil (EO) content and composition of Ocimum basilicum L.

A greenhouse experiment was conducted with 15, 30, and 60 g kg-1 of SS irradiated with absorbed doses of 5, 10, and 20 kGy gamma-ray and soil without SS and irradiation as the control treatment. The essential oil was isolated by hydro-distillation and analyzed by Gas chromatography and Gas chromatography-mass spectrometry techniques.

The applications of SSGI and SSNI at all levels except 15 g kg-1 significantly enhanced EO content compared to the control. The using of 60 g kg-1 SS in each absorbed dose significantly reduced EO yield relative to the control, while it was significantly increased under 15 and 30 g kg-1 SSNI and SSGI. Also, in 60 g SS kg-1, the restriction effects on EO yield were mitigated with increasing the absorbed dose of gamma-ray, but it was insignificant with increasing absorbed dose to 10 and 20 relative to 5 kGy. The methyl chavicol as a major constituent of EO was significantly increased in SSGI and SSNI as compared with the control. However, the increment in the methyl chavicol content was not significant between the treatments ≥ 30 g kg-1 SSGI or SSNI and 15 g kg-1 SS at absorbed dose of ≥10 kGy.

To improve essential oil content and composition, application of ≤ 30 g kg-1 sewage sludge with 5 kGy absorbed dose of gamma-ray can be suggested at similar conditions.

Due to the proximity of dumping sites for mine tailings to agricultural lands, the migration of contaminants to these lands is possible. In this study, a total of 30 points along a track line of approximately 10 km in downstream of Mazra’eh copper mine (Ahar-East Azarbaijan) covered with a mixture of transferred tailings and bed sediments of Mazra’eh seasonal river were selected. The composite samplings were carried out fromsoils at depths of 0-10, 10-30 and 30-60 cmand fromsurficial sediments. In addition, six non-covered points (controls) with minimum distance from the sampling points were selected. The total concentrations ofcopper in surficial sediments as well as soils were determined using aqua regia method. Then, the relationships between these concentrations and soil properties were assessed. The results showed very high concentrations of copper (1116 mg kg-1, on average) in the surficial sediments. The concentrations of copper in the soil depths of 0-10, 10-30 and 30-60 cm were 105, 86.4 and 79.8 mg kg-1, respectively. Based on results, 13% of 0-10 cm soils, all of 10-30 cm soils and 57% of 30-60 cm soils were very contaminated, medium contaminated and low contaminated, compared to controls (48.4 mg kg-1, on average for three depths), respectively. Soil copper concentration showed significant positive correlations with surficial sediment copper concentration, thickness of surficial sediment and soil cation exchange capacity (CEC) in all three depths of the studied soils.