Site number

Mean ± standard error (mg∙L−1)

Lead

Cadmium

Chromium

1

0.012 ± 0.000

0.002 ± 0.000

0.029 ± 0.008

2

0.015 ± 0.002

0.002 ± 0.000

0.022 ± 0.005

3

0.018 ± 0.003

0.002 ± 0.000

0.019 ± 0.004

4

0.021 ± 0.001

0.003 ± 0.000

0.036 ± 0.004

5

0.016 ± 0.001

0.003 ± 0.000

0.028 ± 0.004

6

0.016 ± 0.001

0.003 ± 0.000

0.034 ± 0.001

7

0.020 ± 0.003

0.004 ± 0.000

0.048 ± 0.004

8

0.013 ± 0.003

0.003 ± 0.000

0.018 ± 0.003

9

0.014 ± 0.001

0.002 ± 0.000

0.010 ± 0.001

10

0.013 ± 0.002

0.002 ± 0.000

0.024 ± 0.007

11

0.021 ± 0.001

0.003 ± 0.000

0.024 ± 0.006

Safe limit (mg∙L−1)

CPCB*

0.1

2.0

2.0

FAO**

5.0

0.01

0.1

US EPA***

0.065

0.0018

Cr(III)

Cr(VI)

0.570

0.016