6. Noosa River DMP Ver0 (Combined)

                                                                Noosa River - Sediment Sampling Report
                                            BMT (OFFICIAL)



•   Result between 10 and 20 times LOR – RPD between 0% and 50%.
•   Result >20 times LOR – RPD between 0% and 20%.

Surrogate and Matrix Spikes
Laboratory Control Samples are either certified reference materials or a blank sample spiked with
known concentrations of the analytes of interest. The purpose of this measurement is to monitor
method accuracy.

Matrix spikes refer to an intra-laboratory split sample spiked with a representative set of target analytes
of known concentration. Matrix spikes are assessed to monitor potential sample matrix effects on
analyte recoveries.

Surrogate spikes are used for organic analytes. Surrogates are known additions to samples which
mimic the compounds of interested and are not normally expected to be present in the sample. For both
surrogate and matrix spikes, a calculation of the percent recovery of the spiked amount against the
returned concentration is performed indicating analytical performance in terms of extraction efficiency.

NAGD states that recovery limits of 75% - 125% are generally acceptable. Analytical laboratories
typically adopt specific surrogate and matrix spike recovery limits for the various contaminant
compound groups. It is also noted that ideal recovery ranges may be waived in the event of sample
matrix interference.

The primary laboratory ALS adopts specific recovery limits for individual compounds as detailed in the
laboratory report in Annex E and Annex F.

Contaminant List
The contaminant list was based on a review of catchment land uses, geology and existing contaminant
data. The catchment does not contain major pollution sources (e.g. industrial uses, large urban areas),
however there are too few existing data to develop a robust contaminant list. Therefore, a conservative
approach was applied to ensure a broad suite of parameters are assessed including metals/metalloids,
various organic compounds and acid sulfate soils (Table 2.1).

A pilot study (20% of sites) was undertaken on hydrocarbons, pesticides and emerging contaminants
such as PFAS for Horizon 1 (0.0m to 0.5m). If concentrations were detected for these parameters,
remaining samples for Horizon 1 and Horizon 2 (0.5m to 1m) were analysed (for those parameters
detected). Horizon 3 (>1.0m) was sampled for basic characteristics only as per Table 2.1.

Laboratory testing of ASS was also conducted on samples taken at 0.5 m intervals along the full length
of the retained core as described in Table 2.1.

Because all dredge material is intended for placement up to and above HAT, a tier 1 assessment was
conducted as per NEPM. Contaminant screening levels are based firstly on the NEPM for public open
space (HIL C). Screening levels based on NAGD (2009) and subsequent updates to it (Simpson et al.,
2013) have also been included.




A10342 | 005 | 01                                   14                                          14 April 2022