کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4574824 1629547 2008 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of aging process on the fractionation of heavy metals in some calcareous soils of Iran
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Effect of aging process on the fractionation of heavy metals in some calcareous soils of Iran
چکیده انگلیسی

This study was conducted to investigate the effect of time on lead (Pb), zinc (Zn), cadmium (Cd) and copper (Cu) availability in some calcareous soils of Iran. Heavy metals were added to soils at the rate of 500 mg kg− 1 of Pb, Zn, and Cu and 8 mg kg− 1 of Cd as chloride. The samples were incubated for 3 h, 1, 3, 7, 14, 21, and 28 days at 25 °C and constant moisture. After incubation, metals in amended and control soils were fractionated by the sequential extraction procedure. There were changes in the proportional distribution of heavy metals in all five studied soils during 28 days of incubation with spiked heavy metals. In general the proportions of heavy metals associated with the most weakly bound fraction (EXCH) tended to decrease, with corresponding increases in the other five more strongly binding fractions during the incubation. The distribution of added heavy metals into different solid phase fractions appears to be consisted of two phases involving the initial rapid retention followed by a slow continuous retention. Three kinetic equations were used to fit the experimental data. The parabolic equation fits well the data used in this work. The transformation rate of EXCH fraction for soils was estimated by parabolic equation for above incubation periods. There were differences in the rates at which redistribution took place between soils and heavy metals. The constant b in parabolic equation was defined as the transformation rate, which were in the order Cu > Zn ≥ Pb ≫ Cd. The higher proportions of EXCH fraction of spiked Cd in these calcareous soils indicates its higher potential of downward leaching and runoff transport especially at the early stage of pollution.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geoderma - Volume 143, Issues 1–2, 15 January 2008, Pages 26–40
نویسندگان
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