CORAMBIRRA OUTFALL

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Monitoring Results

Indicator Bacteria

Monitoring of faecal coliform bacteria from the pipeline upstream of the outlet indicated that the primary contact recreation criteria are met prior to discharge.

Biological Communities

Found that sewage effluent:

• had a detectable impact on the benthic communities at Corambirra Point with the scale of the effect being variable depending on the species/community considered.

• suggested the cover of Ulva lactuca had increased for the full length of Corambirra Point (approximately 600m)

• reduced the intertidal algal species richness and a change in the pattern of dominance in the animal community inhabiting kelp holdfasts within 400m of the outfall..

• increased the abundance of bivalves (in the kelp holdfast fauna) closer to the outfall, and decreased the abundance of amphipod crustaceans adjacent to the outfall.

• effected the importance of different feeding strategies of organisms with a shift away from generalist feeders (omnivores) to suspension feeders closer to the outfall.

Methods: 

Smith and Simpson investigated the intertidal region focusing on: algal species richness; % cover of Ulva lactuca; and the abundance of herbivorous molluscs. In the sublittoral region they focused studies on kelp holdfast communities

General Findings (not necessarily related to outfall):

• 63% of liver samples contained small traces of dieldrin

• heavy metal residues from 2 locations (Corambirra Point and Arrawarra Headland) showed relatively high muscle zinc concentrations.

Methods:               

Six red morwong (Cheilodactylus fuscus) were collected from 5 locations (Corambirra Point, Muttonbird Island, Look-at-me-now Headland, Woolgoolga Headland and Arrawarra Headland) and examined for organochlorine pesticide and heavy-metal residues.

Outfall Site

Faecal Coliform

Red Morwong

Banacles

Outfall Site

Mollusc

Corambirra

(Cora_7) Last updated May 2000