Impact
of sewage irrigation on speciation of nickel in soils and its accumulation in
crops of industrial towns of Punjab
M.P.S.
Khurana* and R.L. Bansal
Department
of Soils, Punjab Agricultural University, Ludhiana - 141 004, India
(Received:
March 14, 2006; Revised received: March 03, 2007;? Accepted: March 28, 2007)
Abstract:
Analysis of soil samples collected
from sewage and? tube
well irrigated soils of Ludhiana,
Amritsar,
Jalandhar and Mandi Gobindgarh, revealed that Diethylene
triamine pentaacetic acid
extractable nickel ( DTPA-Ni)? was found
to be higher in sewage fed soils. Sewage irrigation increased? soil?
DTPA-Ni content by 3.04 times over the tube well irrigated soils. The
content of DTPA ?Ni showed decreasing trend with depth. Hydrogen concentration
(pH) was negatively and significantly correlated with DTPA-Ni nickel whereas,
organic carbon and total Ni show positive and significant correlation.
Sequential fractionation was carried out to partition Ni in to fractions namely
exchangeable and water soluble, organic bound, carbonate bound, Mn oxides bound, amorphous Fe oxides, crystalline Fe oxides
bound? and
residual. Plant availability of these fractions is believed to decrease in the
above order. Sequential fractionation? indicated that every extracted
fraction exhibited increase in Ni content with sewage irrigation with most
prominent increases occurring in the organic and oxide fractions. The lowest
amount of Ni in exchangeable and water soluble and? the highest in residual pools testify
that plants grown on these soils may not suffer from Ni toxicity. Though all
the crops irrigated with sewage water had appreciably higher concentration of
Ni as compared to the crops raised with tube-well water, yet raya (Brassica juncea) and toria (Brassica campestris ) accumulated higher content of heavy metals as compared to
other crops, with higher content in roots than shoots. Transport index
suggested that major part?
of? taken up Ni is translocated to top parts of plant.? Based on? values of transport indices, different
crops may be arranged as toria > raya = maize> bajra >lady finger.
As the plants take up nickel readily and there is danger of its excessive
accumulation in plant organs and devaluation of the plant products. This is
topical issue particularly in crops used for direct consumption.?
Key words: ? Nickel, Sewage irrigated soils, Tubewell
irrigated soils
PDF of full length paper is available with author (*khuranamps1@rediffmail.com)
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