Table 7 Comparison of the verification results of this research with previous researches

(Khodakarami et al., 2011)

Conventional kriging and exponential modeling

Zoned the distribution of heavy metals including zinc and copper

Trend results are consistent

Harati et al. (2010)

Simulation of Hydrus model

The findings show a high concentration of lead in the study area

Consistent with the results of this study

Khaledan et al. (2017) as well as Rahimpour et al. (2014)

Conventional kriging and exponential modeling

were reported that the spherical model for the lead element and the exponential model for the copper element was the best fit

Good agreement between them

Barzin M. et al., 2015

Ordinary kriging and exponential modeling

The permissible standard of agricultural soils in Iran has been introduced by the Environment Agency for these three elements are 75, 200, and 110 mg/kg, respectively

Consistent with the results of this study

WHO standards in agricultural soils

Presentation was standard

The concentrations of nickel and copper in study area, shows there is no contamination of these two elements in the area

Agricultural soils of study area for lead, copper, and nickel are less than the maximum permissible levels

Toth G. et al., (2016)

According to the WHO standard

The maximum permissible levels in agricultural soils for lead, copper, and nickel are reported to be 60, 100, and 50 mg/kg

Agricultural soils of study area for lead, copper, and nickel are less than the maximum permissible levels

Fard Samiei et al. (2016)

Remote sensing techniques

Was reported almost uniform concentration of the element nickel in the entire study area

Good agreement between them