Evaluation grading standards of the single contamination index.

Table 1: Evaluation grading standards of the single contamination index.

Index	Quality status of crops
Ii < 1	Uncontaminated corn, cassava and plantain
1 < Ii ≤ 2	Lightly contaminated corn, cassava and plantain
2 < Ii ≤ 3	Medium contaminated corn, cassava and plantain
Ii > 3	Severely contaminated corn, cassava and plantain

Adapted from Hong-gui, et al. [22].