Table 1 Water quality rank (according to Environmental Quality Standard for Surface Water of PRC³⁷) and concentration (μg/L) of dissolved elements.

S1

Qingpu

III

I

0.174

I

ND

I

4.386

I

ND

I

0.047

I

0.018

I

2.922

I

0.973

S2

Qingpu

III

I

0.427

I

ND

I

4.345

I

ND

I

0.025

I

0.012

I

0.791

I

1.28

S3

Qingpu

II

I

0.433

I

7.425

I

4.288

I

ND

I

0.021

I

0.026

I

1.372

I

0.742

S4

Qingpu

II

I

0.056

I

1.762

I

5.011

I

ND

I

0.034

I

0.021

I

2.112

I

0.752

S5

Kunshan

II

I

ND

I

ND

I

2.329

I

ND

I

ND

I

0.017

I

1.914

I

0.522

S7

Jinshan

V

I

ND

I

5.135

I

3.743

I

ND

I

ND

I

0.004

I

0.668

I

2.074

S8*

Songjiang

IV

I

ND

I

2.272

I

3.626

I

0.535

I

ND

I

0.011

I

0.831

I

0.6

S9

Songjiang

III

I

0.529

I

3.414

I

3.276

I

ND

I

ND

I

0.023

I

1.205

I

1.33

S10

Kunshan

II

I

ND

I

ND

I

2.359

I

ND

I

ND

I

ND

I

0.457

I

ND

S11

Kunshan

II

I

ND

I

ND

I

2.442

I

ND

I

ND

I

0.005

I

0.642

I

ND

S12*

Kunshan

II

I

ND

I

9.226

I

2.708

I

ND

I

ND

I

ND

I

0.332

I

0.264

S13*

Kunshan

II

I

ND

I

ND

I

2.217

I

ND

I

ND

I

0.004

I

0.646

I

0.113

S14

Kunshan

IV

I

0.275

I

0.72

I

2.712

I

ND

I

ND

I

0.022

I

0.967

I

0.351

S15

Kunshan

III

I

2.07

I

11.143

I

2.309

I

ND

I

ND

I

0.031

I

2.364

I

1.125