6. Noosa River DMP Ver0 (Combined)

                                       Requesting Endorsement of Sediment Sampling and Analysis Plan
                                             BMT (OFFICIAL)



3.4 Core Sub-sampling
Sediment cores will be collected at the selected sites. Cores will be collected to 0.5 m below the full
depth of dredging where possible however vibracoring equipment is not suitable for sampling of stiff
clays, bedrock or sediments with a high content of gravel and cobble material or large shells. If refusal
is met the core length that is achieved will be recorded along with the nature of the material at the point
of refusal (if known). In the event of core refusal, another core will be collected nearby (i.e. 3-4 m away
from original attempt) and if refusal is met again then the core length that is achieved will be recorded
along with the nature of the material at the point of refusal (if known). If repeated refusal occurs at a
site, up to three cores will be attempted with length and refusal recorded for each. The longer of the
three cores will then be logged and sampled for further analysis.

As sediments are mobile and well mixed, it is not expected that there will be major changes in sediment
properties throughout the sediment profile. However, for purposes of this SAP core will be sub sampled
into three horizons for contaminant analysis:

    1) Horizon 1 (0.0m – 0.5m)
    2) Horizon 2 (0.5m to 1.0m)
    3) Horizon 3 (1.0m to maximum/refusal depth)

Section 3.8 defines the sampling and testing methodology for the different horizons.

In addition, where obvious changes in the strata/lithology occur within the lower horizon, additional
subsamples will also be taken up to a maximum of two additional samples.

Cores will be geotechnically logged and photographed.

Cores will also be sub-sampled for field or laboratory pH analysis. pH will be tested every 500 mm
throughout the profile up to the full core length, or refusal, based on guidance on practical sampling
resolutions from NAGD. Where core refusal is met at depths less than the full dredge depth the ASS
results at the refusal point will be assumed to be representative of the remaining core length.

3.5 Field Quality Control

Quality Control Samples
The following field and laboratory quality control samples will be obtained:

•   Field triplicate sample (additional core samples at one sampling location) to determine the small-
    scale variability of the sediment’s physical and chemical characteristics. At the field triplicate sample
    location, three separate cores will be collected.
•   Triplicate split sample at one location where sediments will be thoroughly mixed and split into three
    sample containers set to assess laboratory variation, with one of the three samples sent to a second
    (reference) laboratory for analysis.
•   One trip blank container per sampling day will be filled with inert material (e.g. chromatographic
    sand) to be analysed concurrent with the analysis of volatile organic substances.

3.6 Sample Collection Methodology

Survey Vessel and Field Personnel
The vessel to be used as the platform for the sampling will be a registered commercial vessel and will
be operated by a suitably qualified skipper.



A10342 | 002                                         19                                     15 November 2021