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Monitoring Results
Biological Communities
Found
that sewage effluent:
-
increased
faecal coliform levels on beaches close to sewage outfalls compared to
beaches further away.
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Bellambi
Beach was found to be the most affected beach on the Wollongong coastline.
Bellambi Beach and Corrimal Beach (north and south of Bellambi outfall)
were found to have higher levels of coliforms more frequently than fairy
Meadow Beach (several kilometers away). Fishermans Beach (north of Port
Kembla outfall) was found to have higher levels of coliforms more
frequently than Port Kembla Beach (directly south of the outfall). Perkins
Beach (4 km south of Port Kembla outfall) had similar faecal coliform
levels to Fairy Meadow Beach [a nominal control site].
General
findings (not necessarily related to outfall):
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increased
concentrations of chromium, copper and zinc in pipis near Port Kembla.
-
lower
concentrations of metals were found in pipis from beaches around Bellambi
outfall (that is, other sources of pollutants (e.g. creeks, lagoons,
industry, atmospheric fallout and Port Kembla Harbour) may 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 9from 9
beaches), independently collected coliform data, trace metal levels in pipis (Donax
deltoides) and the community structure and distribution of intertidal
fauna from 6 beaches in the Illawarra region.
Found
that sewage effluent:
-
increased
trace metal concentrations above background levels in P. stolonifera body and muscle tissue and C. tramoserica tissue at outfall locations.
-
lowered the
rate of recruitment (colonization by living organisms) of algae and
limpets that graze on these algae at the Bellambi outfall location
compared to the control locations (Bulli Point & Towradgi Point)
-
effected
the patterns of colonization of denuded patches at outfall and control
locations.
Found
no effect on:
General
findings (not necessarily related
to outfalls):
-
no
difference in most kelp holdfast invertebrates between outfall and control
locations.
-
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.
-
that the
effects of effluent discharge on the composition of kelp holdfast
communities, if any, were small compared with natural variation.
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No
organochlorines were detected in any of the tissues analysed.
-
concentrations
of selenium, zinc and DDT were significantly higher than background
concentrations on one occasion at Port Kembla and concentrations of
chlordane and DDE were significantly higher at Port Kembla and Bellambi on
two occasions and two control locations (Shellharbour and Bulli), that is,
when contaminants in the body tissue of P.
stolonifera were measured on four occasions at two outfall locations
(Bellambi and Port Kembla).
-
the
accumulation of trace metals and organochlorines above background levels
was small compared to data collected on the accumulation of metals and
organochlorines in similar organisms from other studies of areas affected
by sewage outfalls.
Methods:
Roach et al
(1995) investigated differences in kelp holdfast invertebrate communities,
accumulation of metals and organochlorine pesticides by intertidal
invertebrates (limpet (Cellana
tramoserica), the barnacle (Tesseropora
rosea) and muscle and body tissue from the cunjevoi (Pyura stolonifera) and patterns of recruitment of intertidal
invertebrates near Bellambi (and Port Kembla) outfall.
Found that
sewage effluent:
-
effected
species composition at the outfall compared to control sites
Particular species occurred at two sites near the outfall, but were
absent at the third outfall site and at all control sites.
-
60% of the
difference was due to the occurrence of three species (Chaetomorpha aurea, Polysiphonia
spp. and Ulva lactuca) at the
outfall sites and four species (Corallina
officinalis, Montfortula rugosa,
Laurencia pinnosa and Sargassum
spp.) at the control sites.
Methods:
Banwell
1996 investigated the impact on intertidal flora and fauna of shifting the
discharge from Sydney’s major sewage outfalls (at North Head, Bondi and
Malabar) from shoreline discharge to offshore (deep water) discharge. The
intertidal communities at two of these outfalls (North Head and Malabar) were
compared with the intertidal communities at two other outfalls (Potter Point
and Bellambi) to see if there was any evidence of a recovery once the sewage
at North Head and Malabar was diverted offshore. A number of control locations
were also included in Banwell’s (1996) design.
General
findings (not necessarily related to outfalls):
-
the fish
fauna were dominated by small mobile fish species.
-
species of
economic importance and tropical origin also occurred in small numbers.
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assemblages
of macrobenthos were dominated by macroalgae, Ecklonia radiata, turfing and encrusting algae and the sea urchin Centrostephanus
rodgersii.
-
the
introduced green alga Caulerpa
filiformis was relatively abundant at Bellambi outfall.
-
multivariate
analyses revealed 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.
Found that
sewage effluent:
-
reduced
individuals and species of fish - an absence of Trachinops taeniatus and fewer Parma
microlepis and Parma unifasciata
at the Bellambi outfall site.
-
increased
the percentage cover of Caulerpa
filiformis, reduced the percentage cover of encrusting algae and sea
urchins (Centrostephanus rodgersii),
as well as fewer Australium
tentoriforme shellfish at Bellambi.
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:
-
either
positively or negatively affected the abundance or percentage cover of a
number of intertidal species at Bellambi and Port Kembla STPs.
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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 (AWT 1998).
-
lowered the
species diversity around the outfalls compared to the reference locations.
-
increased
the percentage cover of red algae and the green alga Caulerpa filiformis around Bellambi outfall.
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decreased
the percentage cover of brown algae such as kelp (Ecklonia radiata) at the Port Kembla outfall.
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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.
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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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