a–c Comparison of
residual B[a]P concentration in
single and co-contaminated soil.
Different letters indicate
significant difference (Tukey
HSD, p #0.05). Treatments
C1and C2 represent 50 and
100 mg Cr kg−1; B1, B2, and B3
represent 1, 5, and 10 mg kg−1 of
B[a]P