METALS AND METALLOID IN SOME BASMATI GROWING AREAS AND CHEMICAL REMEDIATION OF METAL POLLUTED SOIL
Loading...
Date
2019
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
DIVISION OF SOIL SCIENCE AND AGRICULTURAL CHEMISTRY ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI
Abstract
Basmati rice is one of the major export commodities in India which has an important
place in the Indian economy. According to European Union (EU) food legislation,
trace toxic metals and metalloid content in rice grain is one of the potential
contaminants, which decides the export quality of rice. Metal and metalloid
contamination in soils is an increasingly urgent problem throughout the world, and
remediation of these soils is costly anddifficult. In India, Haryana is one of the major
basmati ricegrowing states, contributing more than 60% to the total basmati rice
produced in India.However, there is no information about heavy metal and metalloid
status in soils, water and plants in major basmati rice growing districts of Haryana,
like those of other states. The present investigation was therefore, undertaken to
delineate the status of metals and metalloid in soil, water and plants of basmati
growing areas of Karnal district of Haryana.Also, attemptswere made to establish
permissible limits of metals and metalloid in soil of basmati growing areas of Karnal
based on i) solubility of metals and metalloid in soil, ii) metals and metalloid content
in basmati rice grain, and iii) human health hazard associated with intake of metals
and metalloid through consumption of basmati rice grain. The effect of lime
application rates and duration of incubation on release kinetics of metals in metalcontaminated soil was evaluated. The effects of lime, poultry manure and farmyard
manure (FYM) under submergence and alternate wetting and drying moisture
regimes on immobilization of metals and metalloid and their distribution in different
fractions in metal-contaminated soil were assessed. The effectiveness of
amendments and soil moisture regimes was assessed on the basis of human health
risk for dietary intake of metals and metalloid through consumption of rice grown on
metal-contaminated soil.
For the present investigation,field survey work of Karnal district was
conducted on grid (approximately 2×2 km2)basis to assess the status of metals and
metalloid in soil, water and plants in basmati rice growing areas of the district during
October-November, 2018. One hundred and one paired soil and rice plant (straw and
grain) samples were collected from basmati growing areas of Karnal district.
120
Twenty-three irrigation water samples (ground water) were alsocollected. Metals and
metalloid uptake by basmati rice grain was predicted by using simple regression
model and integrated solubility-free ion activity models (FIAM). Riskto human
health for dietary intake of metals and metalloid through consumption of basmati
rice was computed in terms of hazard quotient (HQ) following United States
Environment Protection Agency (US-EPA) protocols.Laboratory incubation study
was carried out to study the effect of lime rates and incubation period on release
kinetics of metals and metalloid. Greenhouse pot experiment was also conducted to
study the effect of lime, poultry manure and FYM under submergence and alternate
wetting and drying moisture regimes on immobilization of metals and metalloid and
their distributionin different fractions affecting availability of metals and metalloid
to basmati rice.
Results indicated that DTPA-extractable Zn, Mn, Fe, Cu and Pb levels in the
soils of the basmati growing areas of Karnal district ranged from 0.32 to 5.66, 0.56
to 17.4, 2.13 to 21.7, 0.08 to 4.22 and 0.82 to 2.80 mg kg-1, respectively. The DTPAextractableNi, Cd and Cr contents in soils varied from 38.3 to 217, 5.07 to 30.9 and
50.7 to 81.9 µg kg-1, respectively. Olsen-extractable As content in the soil varied
from 32.0 to 76.0 µg kg-1. Metal and metalloid contents in soil, water and plants of
basmati growing areas of Karnal district was found within the permissible limits.
Integrated solubility-free ion activity model can successfully predict the uptake of
Zn, Mn, Fe, Cu, Ni, Cd and As by rice grain. The DTPA extractable Pb, Cd, Cr, Ni,
Mn, Fe, Cu and Olsen-extractable As were increased with an increase in duration of
incubation from 0 to 120 days, whereas these were decreased with an increase in the
rate of lime application from 0 to 2.0%. Lime application under alternating wetting
and drying moisture regime was found most effectivefor immobilization of DTPAextractable Pb, Cd, Cr, Ni, Zn, Mn, Fe, Cu and Olsen-extractable As in metalcontaminated soil. Poultry manure and FYM appeared ineffective for immobilization
of Pb, Cr, Ni, Zn, Mn, Fe, Cu and Olsen-extractable As except Cd, in the
contaminated soil. Grain and straw yields were highest with the application of
poultry manure or FYM along with fertilizers. Hence, poultry manure and FYM
could be used under integrated management of contaminated soil.
Description
T-10271
Keywords
null