ORIGINAL RESEARCH
Evaluating the Heavy Metal Risks of Soil
and Rice from a Farmland in a Nanjing Suburb
through In-vitro Simulation Tests
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1
School of Environment and Ecology, Jiangsu Open University, Nanjing 210036, China
2
School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology,
Zhenjiang 212003, China
Submission date: 2020-06-07
Final revision date: 2020-09-10
Acceptance date: 2020-09-15
Online publication date: 2021-01-29
Publication date: 2021-03-08
Corresponding author
Chenghui Han
School of environment and ecology, Jiangsu Open University, China
Pol. J. Environ. Stud. 2021;30(3):2093-2105
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ABSTRACT
The risks from heavy metals in soil and rice from a farmland in a Nanjing suburb, southeastern
China, were evaluated using the geo-accumulation index, a health risk assessment and an in-vitro
simulation. The concentrations of heavy metals (Pb, Cr, Zn, Cu, Cd, Hg, and As) in the soil and rice were
determined in the present study. The results showed that at the two stages measured, the order of geoaccumulation
index values (except those of Pb and Zn) was Cd>As>Hg>Cu>Cr. Moreover, the heavy
metals with lower Igeo values exhibited lower risks at both stages in the study area. The farmland in the
study area was not polluted by heavy metals, according to the evaluation of the total heavy metal contents
and their chemical speciation. The order of bio-concentration factor was Cd>Cu>Zn>Pb>As>Cr>Hg.
For all heavy metals, the non-carcinogenic doses of the different exposure pathways indicated that
CDIing-nc>CDIdermal>CDIinh-nc for children and adults. The HI values for adults and children from heavy
metals before rice sowing were 0.0984 and 0.634, respectively, indicating that these metals had little
influence on the human body. The HI values for adults and children for heavy metals at the rice
harvesting stage were 0.146 and 0.879, respectively. Before rice sowing, the lifetime carcinogenic risk
values for local adults and children were 5.60 × 10−5 and 8.15 × 10−5, respectively. At the rice harvesting
stage, the lifetime carcinogenic risk values for local adults and children were 3.01 × 10−5 and 4.48 × 10−5,
respectively. At both stages, the order of CF values for adults and children was Cd>Cr>As>Pb. The total
amounts and bioavailable amounts of the heavy metals ingested by adults and children through eating
the local rice did not exceed the tolerable weekly intake values, indicating that there is no health risk
from eating the local rice. However, draining and drying the field at the proper time would improve the
Eh value of the paddy soil.