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Evaluation of heavy metal and total petroleum hydrocarbon contamination of roadside surface soil
Khan, A.B. & Kathi, S.
Abstract
The present study was conducted along three
major highways namely State Highway (SH49), National
Highway (NH66 and 45A) connecting Puducherry (India)
for assessing heavy metals and total petroleum hydrocarbon
contamination from surface soils in close proximity at
a depth of 0–15 cm into automobile repair workshops and
agricultural fields located beside the highways. Contamination
levels of copper, lead, zinc, manganese, cadmium
and chromium were assessed in the surface sediments soil
on the basis of geoaccumulation index, contamination
factors and spatial variability. The results revealed that
sampling sites in the proximity to automobile workshops
were moderately to considerably pollution impacted as
compared to soil from agricultural fields along highways
suggesting a direct influence of anthropogenic activities on
levels of contamination. The concentration of heavy metals
in the surface soil of automobile workshops close to NH66
ranged between 143.07 and 319.28 mg kg-1 copper;
68.72–396.41 mg kg-1 lead; 162.42–284.91 mg kg-1
zinc; 212.72–401.33 mg kg-1 manganese; 0.12–15.41
mg kg-1 chromium; and 0.73–1.06 mg kg-1 cadmium in
dry soil. However, in agricultural fields, the concentrations
varied between 33.68 and 66.62 mg kg-1 copper;
27.22–73.66 mg kg-1 lead; 26.24–75.59 mg kg-1 zinc;
137.88–242.07 mg kg-1 manganese; 0–0.21 mg kg-1
chromium; and 1.04–1.58 mg kg-1 cadmium. Total
petroleum hydrocarbon concentration near automobile
workshops ranged between 90.72 and 121.79 mg kg-1 in
contrast to 44.94–83.4 mg kg-1 in agricultural fields. Total
petroleum hydrocarbon concentration indicated strong
positive correlation with zinc (r = 0.811), copper
(r = 0.761); lead (r = 0.642), Mn (r = 0.571), chromium
(r = 0.530) and strong negative correlation with cadmium
(r = -0.765) at 0.05 significance level. Pearson correlation
indicated a strong association of total petroleum
hydrocarbon with copper, lead and zinc suggesting that the
metal contaminants from roadside surface soil had emanated
from a common source.
Keywords
Agricultural fields; Automobile workshops; Contamination factor; Geoaccumulation index; Total petroleum hydrocarbon; Transportation
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