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

Smith and Simpson (1989, 1990, 1993)

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

FOLLOW-UP STUDIES by Smith et al 1995

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