Chemical analysis - Te Marua

The following table shows the mean values of chemical analysis of the water supply from the Te Marua Water Treatment Plant, for the year ended 30 June 2018, compared with the maximum allowable value (MAV) or guideline value (GV) for each element as set out in the Drinking Water Standards New Zealand (DWSNZ).

Notes (A) MAV denotes the maximum acceptable value to comply with the Drinking-water Standards. (B) GV denotes the maximum guideline value in the Drinking Water Standards

Parameter

DWSNZ MAV (A) / GV (B)

No of samples

Median value

Max value

Alkalinity - total CaCO3/m3

-

13

28.769

36

Aluminium - total g/m3

0.1 (B)

14

0.021

0.052

Arsenic - total g/m3

0.01 (A)

2

<0.002

<0.002

Boron - total g/m3

1.4 (A)

2

<0.05

<0.05

Cadmium - total g/m3

0.004 (A)

2

<0.001

<0.001

Calcium hardness g CaCO3/m3

200 (B)

13

16.846

20

Chloride g/m3

250 (B)

1

9.99

9.99

Chromium - total g/m3

0.05 (A)

2

<0.001

<0.001

Conductivity at 25oC - mS/m

-

1

10.9

10.9

Copper - total g/m3

2 (A)

13

0.020

0.03

Cyanide g/m3

0.6 (A)

2

<0.005

<0.005

Fluoride g/m3

1.5 (A)

104

0.564

0.86

Hydrogen sulphide g/m3

0.05

1

<0.05

<0.05

Iron - total g/m3

0.2 (B)

13

0.014

0.014

Lead - total g/m3

0.01 (A)

2

<0.005

<0.006

Manganese - total g/m3

0.04 (A)

13

0.021

0.025

Mercury - total g/m3

0.007 (A)

2

<0.001

<0.001

Nickel - total g/m3

0.08 (A)

2

<0.001

<0.001

Nitrate - nitrogen g/m3

50 (A)

2

0.03

0.04

pH

7.0 - 8.5 (B)

14

7.629

7.8

Selenium - total g/m3

0.01 (A)

2

<0.005

<0.005

Silica g/m3

-

2

9.93

10.5

Sulphate g/m3

250 (B)

1

3.27

3.27

Total dissolved solids g/m3

1000 (B)

1

54

54

Zinc - total g/m3

1.5 (B)

13

0.11

0.12