Following the round of water quality testing conducted in the
Mackenzie and Isaac catchments in October 2008 more extensive
sampling was conducted throughout the Fitzroy Basin from the 16
th
to the 18
th
December 2008, with an additional site sampled in January 2009.
This latest round of water quality testing focused on waterways
identified as sites of potential contamination from local,
industrial land-use. Several reference sites (at relatively low
risk of contamination) were also selected and sampled. One sample
only was collected from each site.
Samples were analysed for a range of ions (salts) and metals by an
independent, nationally accredited laboratory.
Sites sampled as part of FBA’s Ambient Monitoring Program are
indicated in
Figure 1
.
|
Figure 1
|
Results for each site were compared to the 95% protection level for
aquatic ecosystems in the Australian & New Zealand Guidelines
for Fresh and Marine Water Quality 2000 (ANZECC). Where ANZECC
(2000) and Queensland Water Quality Guidelines (2006) do not exist
for certain parameters, data is compared to the Australian Drinking
Water Guidelines (2004).
The results for the last round of sampling at each site can be
viewed
here .
Conductivity / Major anions and cations
Conductivity values were low to moderate (based on Queensland Water
Quality Guidelines, 2006). The observed results were consistent
with values expected for freshwater and within an acceptable limit
for drinking water.
Major anions and cations are within Australian Drinking Water and
livestock water quality guidelines (ANZECC). The results for the
sites sampled indicate that sodium and chloride ion concentrations
occur well below the Australian Drinking Water Guideline values of
180mg/L and 250 mg/L respectively.
pH
The ideal pH range for livestock drinking water and, in general,
ecosystem health is 6.8 to 7.5. Problems may occur when pH falls
below 5.5 and above 8.5; livestock water intake may be reduced with
more alkaline pH (DPI&F). Three sites recorded pH values close
to and slightly above 8.0.
Dissolved metals
Analysis of metals dissolved in water indicated that a number of
metals exceeded the ANZECC guidelines 95% protection level (trigger
value) for aquatic ecosystems. Above trigger value results were
observed for aluminium (11 out of 12 sites), for copper (7 sites),
lead (4 sites), nickel (1 site) and zinc (11 sites).
It is important to note that data on normal background levels for
these metals in Fitzroy Basin waterways is not currently readily
available.
Monitoring by the Queensland Environmental Protection Agency (EPA)
at various sites within the Fitzroy Basin has also found levels of
some metals to be above the 95% trigger value for ecosystem
protection.
Click here for information on EPA monitoring in the Fitzroy Basin
.
According to ANZECC’s recommended upper limits for livestock
drinking water, aluminium concentrations above 5 mg/L (6 sites) may
have implications for livestock in terms of phosphorus absorption.
However it is noted in the these guidelines that much higher levels
of aluminium can be tolerated as long as there is sufficient
phosphorus in the animal’s diet to meet their phosphorus
requirements. Three sites recorded levels of iron above short term
(up to 20 years) trigger values.
Department of Primary Industries and Fisheries advise that the
upper limit for manganese in livestock drinking water is 0.5 mg/L.
Two sites exceed this level and one is very close to this limit.
For more information access a copy of the
“ Australian and New Zealand Guidelines for Fresh and Marine
Water Quality: Volume 3 - Primary Industries - Rationale and
Background Information”
.
In addition you can view a copy of
Queensland Water Quality Guidelines 2006
.
