Table 3 Comprehensive pollution index classification standard23.

From: Occurrence, exposure and health risk assessment of heavy metals in green tea samples cultivated in Hangzhou area

Grade

P

Class of pollution

Pollution level

1

P ≤ 0.7

Safe

Cleaning

2

0.7 < P ≤ 1

Warn

Nearly cleaning

3

1 < P ≤ 2

Mild pollution

Began to be contaminated

4

2 < P ≤ 3

Middle level pollution

Moderately polluted

5

3 < P

Heavy pollution

Heavily polluted

  1. Risk assessment estimation.
  2. To determine the degree of risk posed by the detected heavy metals on human health, an exposure evaluation was conducted based on the results of heavy metal monitoring in tea. The Estimated Daily Intake (EDI; mg/kg.bw.d) factor of each metal was calculated according to Eq. (3)21,24,25:
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