Characteristics of Heavy Metals and Pb Isotopic Composition in Sediments Collected from the Tributaries in Three Gorges Reservoir, China

Table 1

Geoaccumulation Index and classification of pollution degree.

𝐼geo value	Classification	Pollution level
<0	0	Unpolluted
0~1	1	Slightly polluted
1~2	2	Moderately polluted
2~3	3	Moderately to strongly polluted
3~4	4	Strongly polluted
4~5	5	Strongly to extremely polluted
>5	6	Extremely polluted