6. Noosa River DMP Ver0 (Combined)

                                                              Noosa River - Sediment Sampling Report
                                           BMT (OFFICIAL)



All storage containers were chilled on ice immediately following sample collection. Acid Sulfate Soil
samples were frozen at the end of each sampling day to minimise potential oxidation of the sediment
material.

At the end of the sampling campaign, all samples were submitted to the primary and secondary
analytical laboratories. All samples were submitted to the laboratories with Chain of Custody
documentation.

2.6 Laboratory Analysis

Analytical Tests
Primary analysis of sediment samples was conducted by NATA accredited Australian Laboratory
Services (ALS) in Brisbane. A separate Eurofins (Brisbane) was utilised as the secondary (reference)
laboratory for inter-laboratory quality testing.

Samples were analysed according to the SAP (Annex A). 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) at
sites BH11, BH17 and BH5. All remaining samples (Horizon 1 and Horizon 2) were analysed for a
compressive suite of parameters (metals, nutrient and particle size) as per Table 2.1. Horizon 3 (>1.0m)
was sampled for basic characteristics only as per Table 2.1.

A total of 20 samples were analysed for ASS (pH and CRS).

Laboratory Quality Control
Laboratories followed laboratory Quality Control (QC) procedures in accordance with requirements
outlined in Appendix F of NAGD. This included analysis of laboratory blanks, duplicates, certified
surrogate materials and spiked samples.

Validation of all laboratory QC analyses was conducted in accordance with Appendix A of NAGD to
confirm suitable data quality for undertaking a rigorous characterisation of the proposed dredge
material.

Laboratory Blanks
The purpose of this assessment is to monitor potential laboratory contamination of samples due to
potential cross-contamination of samples during laboratory preparation, extraction or analysis. Blank
sample concentrations should be at or near the detection limit of the method used.

Laboratory Duplicates
This assessment refers to a randomly selected intra-laboratory split sample, which provides information
regarding the method precision and sample heterogeneity. Results are presented as Relative Percent
Difference (RPD) values of two sample concentrations for a specific contaminant.

NAGD recommends that duplicates should agree within a typical RPD of the method of ±35 %. This
recommended RPD is typically not adopted by analytical laboratories as it does not account for the
greater uncertainty for contaminant concentrations close to the method’s detection limit. NAGD also
notes that RPDs may not always agree within these limits where sediments are very heterogenous or
vary greatly in grain size.

ALS adopts the following acceptable surrogate and matrix spike recovery limits:

•   Result <10 times LOR – no limit to RPD.



A10342 | 005 | 01                                  13                                        14 April 2022