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

Table 3

Criteria for assessment of soil pollution with the potential ecological risk index.

The values of	The values of	Pollution levels
< 150	<40	Light pollution
150 ≤  < 300	40 ≤  < 80	Moderate pollution
300 ≤  < 600	80 ≤  < 160	Moderate-to-heavy pollution
600 ≤  < 1200	160 ≤  < 320	Heavy pollution
≥ 1200	≥320	Extreme-intensity pollution