State of the Environment

2006

Indicator: IW-21 Exceedance of pH water quality triggers

Data

Exceedance of water quality guidelines for pH
Major exceedances Significant exceedances Number of monitoring sites assessed
NSW 0 2 2
Vic 1 1 19
Qld 6 3 18
WA 0 1 3
SA 0 0 1
ACT 0 5 5
Total 7 6 43

adapted from Source: National Land and Water Resources Audit 2001, Australian Water Resources Assessment 2000. Surface water and groundwater - availability and quality, Land and Water, Canberra, viewed 5 Dec 2005, http://audit.ea.gov.au/ANRA/water/docs/national/Water_Quality.html, Tables 6-11

The areas with major pH exceedances included tropical Queensland coastal basins within the North-East Coast Drainage Division and the Campaspe basin within the southern Murray-Darling Drainage Division. Several other basins within the southern Murray-Darling Drainage Division and one each within the South-East Coast, South-West Coast and North-East Coast Drainage Divisions also show significant exceedances.

Many of the pH exceedances are in coastal basins and may indicate natural floodplain conditions or the disturbance of in situ acid-sulfate soils.

In one basin of the Victorian section of the Murray-Darling Drainage Division there are increasing pH trends (increasing alkalinity) and decreasing pH trends (increasing acidity) in six basins. In the South-East Coast Drainage Division, decreasing pH trends were identified in four basins and extensive increasing trends in three basins. Two Queensland basins in the North-East Coast Drainage Division also exhibited pH trends - the Brisbane, more acid and the Fitzroy, more alkaline.

Source: National Land and Water Resources Audit 2001, Australian Water Resources Assessment 2000. Surface water and groundwater - availability and quality, Land and Water, Canberra, viewed 5 Dec 2005, http://audit.ea.gov.au/ANRA/water/docs/national/Water_Quality.html.

What the data mean

pH is a major water quality issue in 7 (16%) of assessed basins.

Data Limitations

NLWRA data have not been updated since its report was published in 2001.

Issues for which this is an indicator and why

Inland Waters —Habitat scale influences — Water Quality (for surface and groundwater) - Other pollutants 

Number of exceedences of water quality triggers for pH is a direct measure of the pressure of acid soils and other pollution on inland waters.

Other indicators for this issue:

Key

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