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Monitoring Results
Nutrients
and Indicator Bacteria
Sampling indicated that 400m offshore
of Red Point concentrations of ammonia and orthophosphate exceeded ANZECC
guidelines and faecal coliform bacteria levels exceeded guidelines for primary
and secondary contact recreation (MHL769 1997). [Note that these latter
results were obtained before the commissioning of the chlorination-dechlorination
system].
Biological
communities
Found that sewage effluent:
-
increased faecal coliform levels at
beaches close to sewage outfalls compared to further away
-
affected Bellambi Beach the most on
the Wollongong coastline with Bellambi Beach and Corrimal Beach (north and
south of Bellambi outfall) having higher levels of coliforms more
frequently than fairy Meadow Beach (several kilometers away).
-
affected Fishermans Beach (north of
Port Kembla outfall) more frequently than Port Kembla Beach (directly
south of the outfall).
Other findings (not necessarily related to
outfall):
-
peak concentrations of chromium,
copper and zinc were found in pipis from beaches near Port Kembla with
lower concentrations of metals in pipis from beaches around Bellambi
outfall. Outteridge (1992) concluded that other sources of pollutants
(e.g. creeks, lagoons, industry, atmospheric fallout and Port Kembla
Harbour) may also have contributed to the observed patterns of trace metal
concentrations. Spatial and temporal variability in the beach fauna was
high and no definitive outfall effects could be inferred.
Methods:
Outteridge (1992) investigated the
effect of sewage outfalls on sandy beach fauna in the Illawarra region. She
analyzed Water Board faecal coliform data (from 9 beaches), independently
collected coliform data, trace metal contamination of pipis (Donax
deltoides) and the community structure and distribution of intertidal
fauna from 6 beaches in the Illawarra region.
Found that sewage effluent:
-
Affected the boulder habitat with
fewer species of cryptic fish at Port Kembla outfall, greater abundance of
rock cale (Crinodus lophodon)
and red morwong (Cheilodactylus
fuscus) and lower abundance of hula fish (Trachinops
taeniatus) and seaperch (Hypoplectrodes
mccullochi).
-
Decreased abundance of sea urchins (Centrostephanus
rodgersii) and increased abundance of Cabestana
spengleri shellfish at the outfall site.
General findings (not necessarily related to
outfall):
-
the fish fauna were dominated by
small mobile fish species.
-
species of economic importance and
tropical origin also occurred in small numbers.
-
the assemblages of macrobenthos were
dominated by macroalgae, kelp (Ecklonia
radiata), turfing and encrusting algae and the sea urchin Centrostephanus
rodgersii.
-
the introduced green alga Caulerpa
filiformis was relatively abundant at Bellambi outfall.
-
few differences between assemblages
of fish from outfall and reference locations, but large, inconsistent
variability within locations. This variability was significant at
individual times for Bellambi and between habitats for Port Kembla.
Methods:
TEL (1994) investigated the fish
communities and macrobenthic assemblages in the Illawarra coastal zone. This
study was specifically targeted at the abundance and species richness of fish
and macrobenthic assemblages at Bellambi and Port Kembla outfalls.
Found that sewage effluent:
-
indicated significant differences
between locations were found for the abundance of some kelp holdfast
invertebrates, however, the abundance often varied between and within
sites at both outfall and control locations.
-
had a small, if any, effect on the
composition of kelp holdfast communities, compared with natural variation.
-
increased some trace metal
concentrations above background levels in P.
stolonifera body and muscle tissue and C.
tramoserica tissue.
-
Significantly increased
concentrations of selenium, zinc and DDT above background concentrations
on one occasion at Port Kembla and concentrations of chlordane and DDE at
Port Kembla and Bellambi on two occasions.
Found no effect on:
-
numbers of taxa at either Bellambi or
Port Kembla (reduced number of taxa often a characteristic of heavily
polluted systems).
-
most kelp holdfast invertebrates
between outfall and control locations (Bass Point and Coalcliff).
General findings (not necessarily related to
outfalls):
Methods:
Roach et al (1995) investigated
differences in kelp holdfast invertebrate communities and accumulation of
metals and organochlorine pesticides by intertidal invertebrates near Port
Kembla (and Bellambi) outfall. They also selected tissue from the limpet (Cellana
tramoserica), the barnacle (Tesseropora
rosea) and muscle and body tissue from the cunjevoi (Pyura
stolonifera) for investigation of organochlorines and trace metals.
Found that sewage effluent:
-
either positively or negatively
affected the abundance or percentage cover of a number of intertidal
species at Bellambi and Port Kembla STPs.
-
Ulva, red turf algae and the limpets Siphonaria
denticulata and S. virgulata
increased their abundance or percent cover while Sargassum
spp. and cunjevoi (Pyura stolonifera)
showed decreased abundance or percent cover.
-
lowered the species diversity around
the outfalls when compared to the reference locations.
-
increased the percentage cover of red
algae and the green alga Caulerpa
filiformis around Bellambi outfall.
-
decreased the percentage cover of
brown algae such as kelp (Ecklonia
radiata) at the Port Kembla outfall.
-
increased the percentage of ‘Brown
Fuzz’ (a mixture of alga, hydrozoa and bacteria that forms a fine
tufting cover over the reef) around Port Kembla outfall.
-
kelp (E. radiata) was absent from the nearshore environment at Bellambi
and Port Kembla (primary treated effluent), however kelp occurred within 5
m of the discharge point at Wollongong (secondary treated effluent).
Methods:
AWT (1998) investigated the effects
of primary treated sewage effluent on intertidal and subtidal rocky reef
communities around Bellambi and Port Kembla ocean outfalls and on the subtidal
communities around Wollongong ocean outfall. Intertidal communities around
Bellambi and Port Kembla ocean outfalls were sampled four times during
1992-1993 and subtidal communities were sampled at four times between
1992-1994. These sites were sampled again in 1998. Subtidal rocky reef
communities were sampled near Wollongong ocean outfall in 1998. A number of
control sites were also sampled. Sampling of intertidal communities was
undertaken using a 50cm X 50cm quadrat. Sampling of subtidal communities was
undertaken using an underwater camera and a 30cm X 40cm quadrat.
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