کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6331264 1619792 2014 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Occurrence, behavior and distribution of high levels of uranium in shallow groundwater at Datong basin, northern China
ترجمه فارسی عنوان
وقوع، رفتار و توزیع سطوح بالای اورانیوم در آب های زیرزمینی در حوضه داتون، شمال چین
کلمات کلیدی
اورانیوم، ژئوشیمی، آب های زیرزمینی، حوضه داتونگ،
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم محیط زیست شیمی زیست محیطی
چکیده انگلیسی


- High U groundwater occurs at the alluvial plains of Datong basin.
- Redox state, complexation and adsorption are responsible for U enrichment.
- Carboniferous and Permian sedimentary rocks have higher U contents at Datong.
- Uranyl is preferentially complexed with carbonate in groundwater.
- U in the aquifer sediments may be primarily associated with carnotite.

Geochemical investigations of uranium (U) occurrence in the environments were conducted at Datong basin of northern China. The results suggest that U contents were generally < 1 mg/kg for the igneous and metamorphic rocks, typically 2-5 mg/kg for the Carboniferous and Permian sedimentary rocks and around 3 mg/kg for sediments and topsoil, respectively. U in the Quaternary aquifer sediments may be primarily associated with carnotite from the Carboniferous and Permian coal-bearing clastic rocks around the basin. Shallow groundwater had U concentrations of < 0.02-288 μg/L (average 24 μg/L), with 24% of the investigated boreholes above the WHO provisional guideline of 30 μg/L for U in drinking water. Average U concentration for surface water was 5.8 μg/L. In oxidizing waters, uranyl (UO22 +) species is dominant and strongly adsorbed onto iron (hydro)xides, while it would be preferentially complexed with carbonate in the alkaline groundwater, forming highly soluble uranyl-carbonate complexes at Datong. Under reducing conditions, uranous (U(IV)) species is ready to precipitate or bind to organic matter, therefore having a low mobility. At the study area, high U groundwater (> 30 μg/L) occurs at the alluvial plains due to intermediate redox and enhanced alkaline conditions. The abnormally high levels of U in groundwater (> 100 μg/L) are locally found at the west alluvial plains. By contrast, U co-precipitation with secondary carbonate minerals like Ca2UO2(CO3)3 in the dominant Ca-Mg-Na-HCO3 type groundwater may prevail at the east alluvial plains. Besides, bedrocks such as Carboniferous and Permian sedimentary rocks, especially the coal-bearing strata which have higher U contents at the west mountain areas may also account for the abnormally high levels of U in groundwater.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Science of The Total Environment - Volume 472, 15 February 2014, Pages 809-817
نویسندگان
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