Water quality at Pt Hughes is assessed as being in good, moderate
or poor condition by interpreting water chemistry and algal data.
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Water quality classification for April to September 2006
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Indicator
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|
|
|
|
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Moderate
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NA
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Good
|
|
|
Good
|
NA
|
NA
|
|
|
Good
|
NA
|
NA
|
|
|
Good
|
NA
|
NA
|
|
|
Good
|
Good
|
NA
|
|
|
Good
|
NA
|
NA
|
|
|
Poor
|
NA
|
Good
|
|
|
NA
|
Moderate
|
NA
|
Notes NA = not applicable
Ammonia was classified as moderate at Port Hughes. This is most
likely due to nutrient-rich discharges from sources such as local
stormwater and septic tank overflows. Elevated nutrients promote
algal growth, particularly during the warmer months. The ammonia
(and possibly total nitrogen) concentrations appear to be increasing
recently (see graphs) and this may be due
to increasing development in the Moonta area. Further monitoring
will be required to confirm that a trend is occurring.
Heavy metals were classified as poor (copper and zinc). The source
of the elevated heavy metals is most likely stormwater washing
off roads and galvanised iron roofs into the marine environments
during rain events. In July 2006, a new analytical method for
heavy metals was introduced, which can detect metals at much lower
concentrations in seawater than before. It is now possible to
confidently compare concentrations to National Water Quality Guidelines
for marine waters.
The bacterial (Enterococci) levels were also elevated
for recreational uses (e.g. swimming or incidental contact during
boating activities). Bacterial contamination can be due to stormwater
discharges and septic tank overflows. The South Australian Department
of Health has useful information on the safe
use of recreational waters.
>> Archived results
