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Impact of sewage and mining activities on distribution of heavy metals in the water-soil-vegetation system
Semhi, K.; Al Abri, R. & Al Khanbashi, S.
Abstract
Several samples of groundwater and soils and
plants have been collected from Sohar (Batina region, NE
Oman), which is affected by various activities such as
mining, agriculture, and sewage. To characterize quality of
groundwater, As and Cu concentrations have been investigated
in waters collected from different wells. Comparison
of data with local and international standard values
revealed that groundwater in Sohar region is characterized
by lower concentrations in Cu and As compared with
standards. In soils collected from the same area, concentrations
of heavy metals have been measured in different
fractions in order to investigate the mobility of such elements
and risk of vulnerability in this area. A sequential
extraction procedure has been applied to surface sediments
to determine the partitioning of Zn, Cu, Co, Mn, Fe, Pb, Cr,
Cd and Ni among (1) exchangeable and acid-soluble phases,
(2) Fe–Mn oxides, (3) organic matter and sulphides
and (4) resistant phases. The results showed that the mobile
fraction in the sewage area accounts only for 10 % of the
total concentration in sediments while in the Cu mining
area, the contribution of the mobile fraction may exceed
10 %, especially for Pb, Mn, Cd, Cu and Co. Investigation
of concentrations in As and Cu in plants collected from
mining and sewage areas revealed an important accumulation
of these elements in leaves and may explain
enrichment of As in shallow groundwater relative to deep
groundwater. This investigation also showed that Cu is
more available in sewage area than in mining zone, as
opposed to As.
Keywords
Batina; Arsenic; Arid; Sediments; Standard; Sohar; Mining
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