Assessment of Heavy Metal Pollution Characteristics andEcological Risk in Soils around a Rare Earth Mine in Gannan

Table 1

Criteria for assessment of soil pollution with geoaccumulation index.

The values of	Class	The cumulative degree
< 0	I	Clean
0 ≤  < 1	II	Mild accumulation
1 ≤  < 2	III	Mild-to-moderate accumulation
2 ≤  < 3	IV	Moderate accumulation
3 ≤  < 4	V	Mild-to-heavy accumulation
4 ≤  < 5	VI	Heavy accumulation
≥ 5	VII	Severe accumulation