GHD understands the following QA/QC procedures were completed during the field sampling regime: – Rinsing of monitoring equipment between sampling bores with town potable water. – Laboratory quality control, which is detailed in Section 4.3.2. 3.3 Water quality guidelines Toxicant concentration levels for the MMM are compared to the Australian & New Zealand Guidelines for Fresh and Marine Water Quality Guidelines (ANZG, 2018), default guideline values (DGVs) listed in Table 3.2. MMM is located within the Callide Creek catchment of the Dawson River Sub-Basin and the larger Fitzroy Basin. Environmental values (EVs) and water quality objectives (WQOs) for Fitzroy Basin waters are included in schedule 1 of the Environmental Protection (Water and Wetland Biodiversity) Policy – the EPP (Water and Wetland Biodiversity). Specific to the MMM site the WQOs have been detailed in the Environmental Protection (Water) Policy 2009, Callide Creek Catchment Environmental Values and Water Quality Objectives, Basin No. 130 (part), including all waters of Callide Creek Catchment within the Dawson River Sub-basin (EPP Water) (Department of Environment and Heritage Protection, 2011), and the management intent for groundwater is protection of high ecological value aquatic ecosystems. The WQO for aquatic ecosystem protection stipulates that where groundwaters interact with surface waters, groundwater quality must not compromise the identified environmental values or WQOs for those waters. The plan states “ Where groundwaters are in good condition the intent is to maintain existing water quality (20th, 50th and 80th percentiles) ”. The 20 th and 80 th percentiles for the established WQOs are presented in Table 3.3.
Table 3.2
95% species protection levels for freshwater based on EA-listed toxicant indicators – ANZG 2018, default guideline values
Toxicant DGVs
95% Limit (freshwater) mg/L
Aluminium pH >6.5
0.055 0.013
Arsenic (V) Cadmium Chromium
0.0002
0.001 0.001
Cobalt Copper
0.0014 0.0034
Lead
Manganese
1.900 0.011 0.011 0.008 0.007
Nickel
Selenium
Zinc
Total cyanide
GHD | Heritage Minerals Pty Ltd | 12638246 | Groundwater Quality Review 2024 15
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