There are total 3 tables in supplementary of the manuscript.

Table S1 Descriptive statistical summary of heavy metal content in soils

Table S2 Non-carcinogenic risk associated wheat flour assumption

Table S3 Carcinogenic risk associated wheat flour assumption

Table S1 Descriptive statistical summary of heavy metal content in soils

Element / Distribution type / Range
/ (mg kg-1) / Mean concentration /(mg kg-1) / EQSFC
/(mg kg-1) / BVS
/(mg kg-1) / Increased heavy metal content/% / Asympotic significance
(2-tailed)
Hg / LN / 0.024~0.184 / 0.070±0.04 / 1.0 / 0.086 / 19 / 0.076
As / N / 11.3~19.1 / 15.4±1.64 / 25 / 12.7 / 95 / 0.969
Cd / N / 0.10~0.39 / 0.25±0.05 / 0.60 / 0.118 / 99 / 0.548
Cr / N / 54.3~116.5 / 75.5±9.06 / 250 / 65.7 / 80 / 0.062
Pb / N / 19.6~34.2 / 27.2±2.53 / 80 / 16.3 / 100 / 0.409
Cu / N / 19.8~37.9 / 28.1±3.37 / 100 / 23.5 / 91 / 0.838
Zn / N / 58.0~97.3 / 81.1±7.59 / 300 / 65.8 / 97 / 0.953
Ni / N / 27.2~44.8 / 36.6±3.39 / 60 / 30.5 / 94 / 0.956

Note: LN-lognormal distribution; N-normal distribution; Increased heavy metal content=the number of concentration exceed the BVS values/ the number of total samples

EQSFC: Environmental quality standards for farmland in China; BVS: Background values for soils

Table S2 Non-carcinogenic risk associated wheat flour assumption

Item / Adult / Children
Range / Mean / Range / Mean
Hg / 7.79E-03 ~ 3.25E-02 / 1.25E-02 / 1.08E-02 ~ 4.52E-02 / 1.73E-02
As / 1.11E-01 ~ 3.19E-01 / 2.09E-01 / 1.55E-01 ~ 4.44E-01 / 2.91E-01
Cd / 1.91E-02 ~ 1.37E-01 / 4.50E-02 / 2.66E-02 ~ 1.91E-01 / 6.27E-02
Cr / 7.92E-05 ~ 4.48E-04 / 1.62E-04 / 1.10E-04 ~ 6.24E-04 / 2.26E-04
Pb / 1.34E-02 ~ 4.51E-01 / 8.36E-02 / 1.86E-02 ~ 6.27E-01 / 1.16E-01
Cu / 8.76E-02 ~ 2.09E-01 / 1.48E-01 / 1.22E-01 ~ 2.91E-01 / 2.06E-01
Zn / 6.17E-02 ~ 2.78E-01 / 1.79E-01 / 8.59E-02 ~ 3.87E-01 / 2.49E-01
Ni / 2.37E-03 ~ 7.34E-02 / 2.22E-02 / 3.30E-03 ~ 1.02E-01 / 3.09E-02
Total non-carcinogenic risks / 5.40E-01 ~ 8.98E-01 / 7.00E-01 / 7.52E-01 ~ 1.25 / 9.74E-01

Table S3 Carcinogenic risk associated wheat flour assumption

Iterm / As / Cd / Cr / Pb / Total carcinogenic risks
Range / 1.80E-06 ~7.49E-06 / 1.04E-04 ~ 2.99E-04 / 4.91E-06 ~ 3.52E-05 / 2.32E-07 ~ 1.31E-06 / 1.16E-04 ~ 3.13E-04
Mean / 2.88E-06 / 1.96E-04 / 1.16E-05 / 4.75E-07 / 2.11E-04