Evaluating the Heavy Metal Risks of Soil and Rice from a Farmland in a Nanjing Suburb through <i>In-vitro</i> Simulation Tests

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 I geo 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 CDI ing-nc >CDI dermal >CDI inh-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.

Concentration of Heavy Metals in Sediment and Water of Përlepnica Lake, Kosovo

“…Heavy metal pollution has been widely studied because it causes environmental and public health problems worldwide. 29 Among chemical pollutants, heavy metals are of great concern because they are known to inflict several health disorders in humans. 30 Iron (Fe) can initiate cancer mainly by the process of oxidation of DNA molecules.…”

Evaluating the Heavy Metal Risk in Spinacia oleracea L. and Its Surrounding Soil with Varied Biochar Levels: A Pot Experiment

“…The soil samples of 0.2000 g were digested by HNO 3 -HF-HClO 4 (2:2:1) of 100 mL in a polytetrafluoroethylene jar and were heated with a heating plate to determine the heavy metal concentrations of As, Cd, Cr, Cu, Ni, Pb and Zn [21]. Concentrated HNO 3 and HF can destroy the organic structures and silicates in soil, respectively, and concentrated HNO 3 causes the samples to be completely oxidized [21]. The S. oleracea samples were digested by HNO 3 -HClO 4 (3:1) prior to determining their heavy metal contents [22].…”