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

• If water quality does not improve and is deemed to be an ongoing environmental risk,
the following hierarchy of management measures shall be implemented as soon as is
practicable:
o Where relevant to each particular analyte for which an exceedance has
occurred, further testing of water samples may be conducted to ascertain the
‘bioavailable’ fraction or potential ecotoxicity of the analyte, for comparison
with relevant guidelines as per ANZECC/ARMCANZ (2000a), EPA (2005a)
and/or appropriate alternate guidance.
o The cause of any exceedance shall be investigated and the spatial extent of
exceedance estimated, including:
• water quality sampling at an increased frequency;
• water quality monitoring for toxicants at additional sites with crossreference
to aerial imagery depicting plume extent at the time of
exceedance; and
• the potential for vertical stratification of toxicant concentration within
the lower Swan River estuary, i.e. sampling of surface and bottom
waters).
o The volume of contaminated material remaining to be dredged shall be
characterised.
o The dredge program may be re-designed to better mix contaminated with
uncontaminated material.
o Dredging shall be re-located from the contaminated area, until a sediment
removal and remediation plan is in place, in agreement with the Office of the
EPA.
Toxicants within Return Water Plume
Frequency
• Baseline prior to discharge of reclamation water, then weekly during return water
discharge, and one week thereafter or until water quality meets HEPA criteria.
Location
• Six sites including one site within the reclamation pond, one site within the weir box,
three ‘dynamic transect’ sites within the return water plume (at distances 10 m,
200 m and 500 m from silt curtain) and two ‘static reference’ sites within the
Cottesloe Reef Fish Habitat Protection Area, as shown in Figure 3.1 (N.B. ‘mock’ sites
at the same distances of separation along a transect offshore of the return water
discharge outlet / weir box, shall be used for (i) baseline sampling and (ii) water
quality sampling in the week subsequent to conclusion of return water discharge).
Method
• Collect a single integrated-depth water sample from each location, every week.
• Store chilled and send samples to a NATA-accredited laboratory for analyses of the
concentration of toxicant analytes listed in Table 4.5 (metals, organotins, OC
pesticides, PAH).
• Toxicant concentration data shall be processed (within 5 days of laboratory receipt
samples during dredging and reclamation of the 300,000 m 3 of potentially
contaminated sediment; within 10 days thereafter) and compared against moderate
and high protection triggers as applicable and where available and listed in Table 4.5,
to determine the appropriate management response as listed below.
Contingency Management Measures
• Where a toxicant analyte is determined to be above the trigger level, then:
o the CEO of the Office of the EPA 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;
22 Oceanica: Fremantle Ports: Inner Harbour and Channel Deepening - Water Quality Monitoring Program