Programs

Water Quality Targets

The Tamar River estuary has estuarine and marine water quality targets that have been developed in conjunction with the Water Quality Objectives of the Environment Protection Authority (EPA) Tasmania.

Water quality targets provide guidance when assessing water quality parameters, identifying if systems are functioning within the range of these targets. Some of the water quality targets for the Tamar estuary have been developed using data collected from the Tamar estuary and other similar estuaries in Tasmania (see Table 1).

The default water quality values for South-East Australia for physical and chemical stressors in the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000), are applied where insufficient local data exists to derive guideline values (see Table 2). The default national guidelines for toxicants such as metals, non-metal inorganics and organics, are applied to all surface waters, including fresh and marine waters unless site specific toxicity assessments have been done.

The Water Quality Targets for the Tamar estuary are:

Table 1. Local water quality targets.

Parameter

Chl-a

µg/L

TP

µg P/L

TN

µg N/L

Turbidity

NTU

DO

% Sat

pH

units

Estuarine Trigger level

3.4

27.4

384

6.4

Lower- 78.2  

Upper- 102.2

Lower-  7.3

Upper- 8.2

Marine Trigger level

0.7

36

340

5.1

Lower- 91.7 

Upper- 102.2

Lower – 7.9

Upper - 8.4

 

Chl-a = chlorophyll a, TP= Total Phosphorus, TN= Total Nitrogen, NTU= Nephelometric Turbidity Units D.O=Dissolved Oxygen

Lower and upper values are 20th% ile and 80th%ile values of local data.

 

Table 2. Default guideline trigger values for some key metals (µg/L) for the Tamar for ecosystem protection

Metals μg/L

Copper

Lead    

 

Zinc    

Cadmium

Aluminium

Arsenic^

ANZECC Marine Trigger level

1.3

4.4

15

5.5

6*

As (III) 2.3 As(V) 4.5

* Tamar data has been used to derive this value.

^ These guideline values are for two arsenic forms.

Supported by
Tasmania - Explore the possibilitiesLaunceston City CouncilWest Tamar CouncilGeorge Town CouncilNorthern Midlands CouncilMeander Valley CouncilHydro Tasmania

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