Fremantle Port Inner Harbour and Channel ... - Fremantle Ports

Method
• Sentinel mussels shall be deployed at each site in cages (in triplicate) for collection
and replacement every 6 weeks.
• Cages shall be cleaned of biofouling every 3 weeks (in between collection).
• Collected mussels shall be stored chilled and immediately sent to a NATA-accredited
laboratory for analyses of the concentration of toxicant analytes listed in Table 4.6
(metals, organotins, OC pesticides, PAH, PCBs).
• Toxicant concentration data shall be processed (within 5 days of laboratory receipt
samples) and median analyte concentrations compared against ‘seafood safe to eat’
triggers where available and listed in Table 4.6, to determine the appropriate
management response as listed below.
Contingency Management Measures
• Where a toxicant analyte is determined to be above the trigger level, exceedances in
the first instance will be investigated to determine whether the dredging and spoil
disposal activities were responsible (wholly or in part) for the observed higher levels of
toxicants in mussel flesh. Investigations of possible causes will examine:
o Whether any similar trends were observed at the mussel reference site;
o The location of the dredging and spoil disposal activities in relation to the
o
affected site(s); and
The spatial distribution of affected sites in relation to unaffected sites and the
position of the dredge.
• In the event that it is considered that dredging or spoil disposal has not contributed to
the exceedance/s, then the exceedance/s, together with reasons as to why the
dredging or spoil disposal were not responsible, will be noted in fortnightly reporting
(by the Environmental Monitoring Contractor) to Fremantle Ports and the Office of the
EPA.
• Where a toxicant analyte is determined to be above the trigger level and it is
considered that dredging or spoil disposal has contributed to the exceedance, then:
o
the CEO of the Office of the EPA and DoH will be informed of the exceedance
and proposed management strategies (see below) as soon as practicable and
no later than within 72 hours of detection of the exceedance (i.e. subsequent
to processing of toxicant data);
o if applicable, any management actions already implemented within 72 hours
shall also be reported; and
o all management strategies will be implemented as soon as practicable.
• The exceedance will also be noted in fortnightly reporting (by the Environmental
Monitoring Contractor) to Fremantle Ports and the Office of the EPA;
• If mussel quality is deemed to be an ongoing risk to public health, depending on
location and severity of contamination, and advice from the EPA and DoH,
management measures may include:
o
o
o
o
Signage erected at adjacent areas to warn public that natural mussels in area
may not be safe to eat.
Establish cause of exceedance, e.g. initiation of more detailed monitoring of
water quality to determine (i) source and spatial spread of toxicants, and (ii)
risks posed to environmental and other values (e.g. water quality risks to
crayfish industry utilising water from Rous Head Harbour).
Initiation of sampling and analysis of toxicant levels in naturally occurring
mussels in areas likely to be affected.
Initiation of sampling and analysis of toxicant levels in fish species targeted by
recreational fishermen and/or dolphins in areas potentially affected.
5.3. Sediment Quality
5.3.1. Ecosystem Health Surrounding the Inner Harbour and Rous Head
Frequency
• Monthly during dredging of the Inner Harbour Channel and associated reclamation,
with one sediment survey thereafter (subsequent to Inner Harbour Channel dredging
and conclusion of reclamation return water discharge) (N.B. sufficient baseline
sediment quality data was deemed available within the SAP Implementation Report for
Oceanica: Fremantle Ports: Inner Harbour and Channel Deepening - Water Quality Monitoring Program 29