Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes Report Commissioned by DELWP

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes Report commissioned by DELWP

J.M. Reeves, and A. Trewarn Federation University Australia Mt Helen, Victoria, Australia

1 Executive Summary

This report describes an investigation on the distribution of metal and metalloid contaminants in the upper sediments of the Gippsland Lakes. The results of these analyses can be viewed spatially at: http://www.vvb.org.au/vvb_map.php?map=30.

The results show that the contaminant levels across the lakes system was generally very low. Elevated levels, above the sediment quality guideline low trigger values of mercury are located predominantly in the west of the system at the Latrobe River Mouth, Heart Morass, Lake Wellington and Lake Victoria West. Elevated levels of arsenic were identified at depth in the Latrobe River and Lake Victoria East cores. High concentrations of nickel are common throughout the system and thought to be associated with the local geology. No samples, either in the surface sediment or at depth exceeded high level thresholds.

These data indicate that Risk based on the levels of contaminant in the sediment is currently low, although areas such as the morasses which are susceptible to acid sulfate conditions and methylation require closer attention.

Recommendations include: • a more targeted study on mercury analysis, to improve recovery and provide more accurately quantifiable results; • undertake a laboratory-based mobilisation characterisation assessment to better assess the conditions under which contaminants are likely to become bioavailable; • detailed investigation of the morasses and deep-lake anoxic zones to better understand likely mechanisms for contaminant mobilisation in the field; • examination of the bioaccumulation of mercury through the food chain of the Gippsland Lakes.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 1

TABLE OF CONTENTS Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes ...... 1 Report commissioned by DELWP ...... 1 1 Executive Summary ...... 1 2 Introduction ...... 3 2.1 Background to the issue ...... 3 2.2 Contamination classification for this project ...... 3 2.3 Scope of study ...... 4 3 Methods and Materials ...... 4 3.1 Sampling Strategy ...... 4 3.1.1 Field sampling methods - water ...... 5 3.1.2 Field sampling methods - sediment ...... 5 3.2 Methods for assessment of contaminants ...... 6 3.2.1. iTRAX ...... 6 3.2.2 Total metal analysis ...... 6 3.2.3 Quality Assurance/Quality Control ...... 6 4 Results ...... 7 4.1 Water quality data ...... 7 4.2 Distribution of contaminants in surface sediments ...... 8 4.3 Distribution of contaminants at depth ...... 9 4.3.1 Qualitative ...... 9 4.3.2 Quantitative ...... 11 5 Discussion ...... 13 5.1 Metals of interest ...... 13 5.1.1 Mercury ...... 13 5.1.2 Arsenic ...... 13 5.1.3 Nickel ...... 14 5.2 Potential for risk ...... 14 5.2.1 Morasses ...... 14 5.2.2 Methylation ...... 14 5.3 Future recommendations ...... 15 5 Conclusions ...... 16 6 Acknowledgements ...... 16 7 References ...... 16 8. Appendices ...... 17 Appendix 8.1 Sample Log ...... 17 Appendix 8.2 Water quality data ...... 19 Appendix 8.3 Inter-lab comparative recovery rates on control samples ...... 25 Appendix 8.4 Metal Concentration and Associated hazard quotient (HQ) for surface sediment samples ...... 26 Appendix 8.5 Metal Concentration and associated hazard quotient (HQ) for sediment core samples ...... 28 Appendix 8.6 Qualitative iTRAX on sediment core samples ...... 30

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 2

2 Introduction 2.1 Background to the issue Development of the Gippsland Lakes Ramsar Site Management Plan 1 involved a risk assessment with key stakeholders, through which critical knowledge gaps were identified for inclusion in the plan. One of the identified critical knowledge gaps relates to mercury and other contaminants in lake sediments. Accordingly, Action 6B in the plan is to: Assess the distribution of heavy metals and other contaminants (including mercury) in the Gippsland Lakes and the level of risk (i.e. bioavailability), in the mega-habitats of deep lakes, shallow lakes and estuarine reaches. This project is an initial investigation to address the first part of this action – only distribution (not bioavalability) of the contaminants is required. The remainder of the action may be addressed at a later stage. Historical contaminant studies in the Lakes have shown elevated mercury concentrations in both the lake sediments and biota (fish and dolphin tissue)1. However, it is not known whether the mercury is predominantly in solid form and bound to lake sediments, or whether a significant portion exists as methyl mercury. The latter form is bioavailable and would pose a risk to the health of Gippsland Lakes flora and fauna. In addition, the sediment contaminant records have not been replicated. This initial investigation will contribute to addressing these knowledge gaps in providing an assessment of the presence and distribution of metals in the upper sediments of the Gippsland Lakes to better understanding the risks that heavy metals and contaminants (including mercury) pose to Gippsland Lake ecosystems.

2.2 Contamination classification for this project

The sediments assessed throughout this report have been recorded as either exceeding the low and high trigger values, as determined by the ANZECC/ARMCANZ (2000) Sediment Quality Guidelines (Table 1). The guidelines have been developed to provide a tiered assessment framework for a risk-based approach to metal contaminant toxicity. Sediments that exceed the trigger values (SQGV) require further monitoring and testing, whereas those that exceed the high values (SQGV-high) require further attention and other lines of evidence (such as bioavailability). These guidelines have been recently revised (Simpson et al., 2013) and reviewed (CSIRO, 2016) in a practical guide to sediment quality assessment.

Table 1. ANZECC/ARMCANZ (2000) Sediment Quality Guidelines.

Contaminant Guideline Value (SQGV) SQGV-high Metals (mg/kg dry weight) (mg/kg dry weight) Cadmium (Cd) 1.5 10 Chromium (Cr) 80 370 Copper (Cu) 65 270 Mercury (Hg) 0.15 1 Nickel (Ni) 21 52 Lead (Pb) 50 220 Metalloids Arsenic (As) 20 70

1 Gippsland Lakes Ramsar Site Management Plan, East Gippsland Catchment Management Authority 2015, Bairnsdale

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 3

2.3 Scope of study This study is focussed on the major lake systems of the Gippsland Lakes, including Wellington, Victoria and King. Samples have also been obtained from the fringing wetlands of Heart and Dowd Morasses and channel entrances to the Lakes (Figure 1,2).

Figure 1. Gippsland Lakes catchment (GLMAC, 2013). Sampling area shown.

3 Methods and Materials

3.1 Sampling Strategy The rationale for sampling was following a stratified random approach, to focus on each of the major river systems entering the lakes. The motivation behind this was to attempt to determine the source/s of contaminants entering the Gippsland Lakes system. Additional samples were obtained, where possible, from the depocentres of the major lake basins, to determine the more diffuse accumulation of contaminants in the basin over time. It should be noted that this was a preliminary scoping study and by no means exhaustive. Such a large estuarine system, with strong ecological gradients would require a far more extensive sampling program to determine with confidence the true spatial and temporal distribution of metal/loid contaminants throughout the system.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 4

Figure 2 Sediment sampling locations within the Gippsland Lakes. Note: yellow = core samples only; red = core and grab samples; green = grab samples only.

Sampling was undertaken on two sampling trips 29th October -1st November of 2015 and 25-27th October 2016, utilising vessels deployed from SEAMEC and Gippsland Ports, respectively.

3.1.1 Field sampling methods - water

At each of the sampling sites, water quality assessment were undertaken using an Aquaread AP-2000. Readings were taken at depth and then at one metre depth intervals to a maximum depth of 9 m (where possible). Measurements taken include: • GPS co-ordinates • Depth (m) • Temperature (oC) • pH • Salinity (EC – µS/cm; TDS – mg/L) • Dissolved Oxygen (%, mg/L) • Turbidity (NTU) • Oxidation Reduction Potential (ORP) (mV)

Water samples were taken at the sediment water interface, where possible at each of the sites. Results are presented in the appendix (8.2) for reference. These are not currently considered of relevance to the interpretation for the metal data, however have been included for comparison with future studies.

3.1.2 Field sampling methods - sediment

Surface sediment samples were obtained using a box grab sampler deployed from over the edge of the boat. The sampler typically captures the top 5-10 cm, depending on the softness of surface sediment. Upon retrieval to the surface, overlying water was drained and the sample placed in plastic zip-locked bags, with all possible air excluded. Samples

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 5

were then stored in a chilled esky until returning to shore, where they were kept refrigerated at 4oC.

Core samples were obtained using a Russian D-section corer with extension rods. The device obtains cores at 50 cm depth intervals with little compression. Where possible, cores were taken to refusal. The longest core obtained was 2.5 m from Lake Wellington. Cores of the top 50 cm were also obtained from the morasses. Note: for the purposes of this study, only the top 20 cm will be reported on.

3.2 Methods for assessment of contaminants

3.2.1. iTRAX Sediment core samples were analysed for qualitative elemental trends throughout the top 50 cm sediment core profile using iTRAX scanning X-Ray Fluorescence facilities at the Institute of Environmental Research at Australian Nuclear Science and Technology Organisation (ANSTO) Lucas Heights facilities. Funding for this was provided through an AINSE scholarship awarded to Adam Trewarn.

Core samples were photographed, x-rayed and scanned at 1mm resolution using a molybdenum tube to provide a qualitative trend analysis of the elements within the core profile. Note: this is a non-destructive method and only scans the exposed surface to a maximum depth of 4mm of the sediment. The iTRAX results are recorded as relative counts for a given element within the length of core being analysed. As such, it is best used to identify areas of interest for further quantitative analyses.

3.2.2 Total metal analysis For the sediment cores, subsamples were taken from a representative core from each site. Samples were taken in 5 cm depth segments, down to 20 cm. Thus each core is represented by four depth samples. For the surface grab samples, samples were homogenized and then bulk random subsamples extracted. Further analyses were undertaken on targeted samples identified as being of interest from the iTRAX scans from the Nicholson, Latrobe and Avon River Mouths. These were analysed at the NATA accredited Environmental Analysis Laboratories. These samples were taken at one centimeter depth intervals focused on the areas of interest.

Sample preparation involved drying sediment samples at 40oC. Large material including shells, organic matter and rock fragments larger than gravel size were removed, prior to grinding to below 60µm using a mortar and pestle and homogenized by hand. Determination of total metal concentrations within the sediment samples was carried out at Federation University Australia following method 17C1 from Rayment & Lyons (2010). This method involves block digestion of 0.5g of dried ground sediment with aqua regia. Samples were then analysed at the Federation University environmental analytical laboratories at the Churchill campus, using a high-precision Inductively Coupled Plasma- Mass Spectrometer (Agilent 7900 ICP-MS).

3.2.3 Quality Assurance/Quality Control

Field sampling Prior to sampling being carried out, all sampling equipment was subjected to a DECON 90 clean and nitric acid wash. This was to ensure there was no cross contamination from other sampling locations. Between each sampling location all sampling equipment was rinsed with site water to remove any contaminants from the previous sample site.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 6

Sample storage and preservation During field sampling and post sampling, all samples were kept below 4oC. Samples were kept in airtight containers, sample bags or tightly wrapped to exclude air and reduce oxidation that may affect the samples prior to analysis.

Metals analysis To reduce the chances of cross contamination between samples, all equipment used in sub sampling, preparation, digestion and dilution was subjected to DECON 90 wash followed by a 10% nitric acid wash and rinse with Milli-Q grade water and dried thoroughly. Prior to metal digestion, all samples were ground to <60 micron and homogenised. All samples were analysed in triplicate to ensure the integrity of the data. Any data that fell outside two standard deviations was considered an outlier and excluded from the data. Zinc was excluded from the dataset due to high error in replicate, calibration and method validation. Based on the data recovered, we are confident of <10% margin of error.

Method validation and recovery efficiency To determine recovery rates of Federation University’s facilities, control Samples were tested at NATA accredited Environmental Analysis Labs (EAL) at Southern Cross University. Two control site samples were used, one being high in silts and organics (Control 1 – Avon River) with the other being higher in silicates (Control 2 – Tambo River). These recovery rates have been used to determine the correction factors on the analysed results. The recovery rates and resultant correction factors are presented in Appendix 8.3.Please note that these recovery efficiencies have been applied to the data presented below, taking into consideration the most appropriate sediment matrix. Where analyses are close to or exceed guideline thresholds, these recoveries will be discussed.

4 Results 4.1 Water quality data Fundamental water quality is by no means the focus of this investigation. However, we report here characteristics that may have influence on the metal availability in the sediment. Full results are presented in Appendix 8.2. The water around Lake Wellington all recorded salinities between 1.6-6.3 g/l, with freshest water associated with the Latrobe River. In general, salinity in the 2016 sampling campaign was around half that of 2015, due to the extensive late Winter-Spring rains. pH was circumneutral throughout and dissolved oxygen levels with a healthy range. Turbidity was significant, with much higher levels in the 2015 sampling campaign. Conditions at Dowd Morass were notably different, with 15.8 g/l salinity, pH of 4.34 and dissolved oxygen of 5.57 mg/l.

Lake Victoria showed significant stratification between 3-4m in the West and 5-6 m in the mid-reaches and East, with dysoxic conditions, lower salinity and lower pH below this. Surface waters were between 14.4-20.9 g/l salinity, increasing from west to east and again, significantly fresher in 2016. High turbidity was recorded in 2015.

Lake King was also stratified between 5-6m. Surface waters had salinities of ~20 g/l in 2015, dropping to ~12.5 g/l in 2016. The river Mouths contributing to Lake King had high turbidity and again, much fresher inflow in 2016 to 2015.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 7

4.2 Distribution of contaminants in surface sediments

The distribution of contaminants in surface sediments is based on the analyses of the grab samples that were taken throughout the lakes.

Table 3. Concentration of specific metals across sample site surface sediments.

Highlighted figures are concentrations that exceed ANZECC/ARMCANZ (2000) Sediment Quality Guidelines. SQGV. See table 1.

Year Metal (loid) Sample site Chromium Nickel Copper Arsenic Cadmium Mercury Lead (mg/Kg) (mg/Kg) (mg/Kg) (mg/Kg (mg/Kg) (mg/Kg) (mg/Kg) 2015 15.51 11.67 11.94 4.14 0.04 0.18 9.18 Latrobe River Moutha 2016 31.38 22.95 22.84 7.31 0.07 0.35 17.25 2015 27.99 20.18 18.71 6.16 0.05 0.24 16.47 Avon River Moutha 2016 22.77 16.50 16.41 5.74 0.04 0.20 14.41 2015 41.75 29.58 26.90 11.37 0.05 0.39 19.19 Lake Wellingtona 2016 39.42 27.66 29.07 10.36 0.08 0.24 18.58 McLennan 2015 N/A N/A N/A N/A N/A N/A N/A Strait - Lake 2016 26.99 19.28 17.52 7.87 0.04 0.26 13.06 Victoriaa 2015 35.58 27.08 24.23 9.41 0.09 0.31 16.56 Lake Victoria Westb 2016 32.45 24.00 20.19 11.19 0.06 0.35 17.45 N/A N/A N/A N/A N/A N/A N/A N/A Lake Victoria Midb 2016 26.85 21.56 20.88 7.69 0.09 0.23 16.16 2015 21.22 15.55 12.45 5.83 0.04 0.27 9.32 Lake Victoria Eastb 2016 28.71 22.39 23.26 11.65 0.1 0.19 18.00 2015 N/A N/A N/A N/A N/A N/A N/A Paynesvilleb 2016 18.72 13.34 55.96 7.67 0.09 0.19 22.21 2015 N/A N/A N/A N/A N/A N/A N/A Jones Bayb 2016 23.89 21.83 20.72 11.27 0.07 0.14 18.41 2015 11.71 11.69 8.84 7.60 0.02 0.06 7.33 Nicholson River Mouthb 2016 20.54 18.73 18.59 10.27 0.07 0.12 15.47 2015 5.97 6.48 3.40 2.19 0.01 BD 4.66 Mitchell River Mouthb 2016 11.77 11.08 9.41 4.19 0.05 BD 11.28 2015 6.62 4.36 3.27 2.22 0.01 0.02 4.03 Tambo River Mouthb 2016 N/A N/A N/A N/A N/A N/A N/A 2015 28.91 21.73 24.39 14.61 0.13 0.17 19.65 Lake Kingb 2016 25.99 19.81 21.84 13.48 0.08 0.17 19.85 2015 N/A N/A N/A N/A N/A N/A N/A Shaving Pointb 2016 22.10 15.80 15.86 10.08 0.08 0.12 11.74 2015 N/A N/A N/A N/A N/A N/A N/A Bunga Arm / Back Lakeb 2016 16.28 14.00 22.69 14.38 0.18 0.17 13.15

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 8

Lake Wellington Surface samples from the rivers discharging into Lake Wellington both showed appreciable levels of nickel (Ni) and mercury (Hg). For the Latrobe River, the low trigger levels were exceeded in both samples. The Avon River also returned levels just above the trigger for Hg. The samples from Lake Wellington likewise had levels of both Ni and Hg above the low trigger levels. In addition, there were appreciable levels of arsenic (As), well exceeding those of either of the contributing rivers, although below trigger levels.

Lake Victoria Levels of Ni and Hg were also elevated across Lake Victoria, decreasing generally from west to east, with the highest concentration of Hg offshore Loch Sport. Levels exceeded the lower trigger level for Ni at all levels within the main body of Lake Victoria. All results from Paynesville during the 2016 sampling season were below trigger levels with potentially elevated levels of Hg, considering recovery. However, it is recommended that this site be monitored more regularly due to high traffic and human amenity.

Lake King Contaminant levels in the channels entering into Lake King and Jones Bay generally recorded low levels of contaminants, with the exception of appreciable levels of Ni. However, the sample taken from the deeper section (7 m) of Lake King returned Ni levels well above the low trigger level and also appreciable levels of both Hg and As. The sample taken from Shaving Point, Metung recorded low levels of all contaminants, with Ni being the only appreciable metal. The final sample from Bunga Arm returned all contaminants below trigger levels. However, there were elevated levels of both As and Ni.

4.3 Distribution of contaminants at depth

4.3.1 Qualitative iTRAX analysis was undertaken on a suite of eight cores, focussing on the river Mouths and strait openings from across the catchment. All further cores will undergo this analysis in 2017. The top 50cm of each core was scanned. Note: the iTRAX provides only qualitative counts for contaminants of note and should only be used to guide further analyses. The quantification of the iTRAX results will also be undertaken in 2017. iTRAX scans for the cores are available in Appendix 8.6. Only the strong trends and points of interest are described below.

Lake Wellington The Latrobe River Mouth core shows a low base level of As with a marked spike at 21-23 cm. Hg shows generally low levels through the basal 25 of the core, with a noted spike at 17 cm and 4-5 cm, with a significant peak at 2-3 cm. selenium (Se) peaks are generally coincident with Hg throughout the core. Nickel levels are elevated throughout, but generally consistent. Significant peaks of Zinc (Zn) are present at 30-31, 13-15 and 11-12 cm, with decreased levels toward the surface.

In the Avon River Mouth, As shows some variability below 11 cm, then a steady increase to 3 cm, before dropping off. Chromium (Cr) also shows variability, with a noted spike at 5 cm. Cu values are generally lower in the basal 15cm of the core with broad spikes within 30-35 cm, steadily decreasing above. Hg is variable throughout the core, although at lower counts than in the Latrobe core. The correlation with Se in this core is not clear. High counts of Ni occur consistently throughout the core. Zn shows low levels, with distinct peaks at 25-26 and 4-5 cm.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 9

The core from the centre of Lake Wellington shows variable counts of As, with peaks at 47 cm and 41-42 cm in the basal 15 cm, then higher average counts from 36-17 cm, decreasing from 17-5 cm, then spikes at 4 and 1 cm. Generally low counts of Hg, with a noted spike at 15 cm. There is no relationship with Se variability. Zn is generally low with a peak at 12-13 cm.

McLennan Strait The core taken from the eastern end of Lake Wellington at the McLennan Strait shows elevated levels of As from 40-31 cm, dropping to nominal levels above. Copper (Cu), Hg and Se show variability throughout the core, but low levels. High counts of Zn are recorded from 39-32 cm and 20-1 cm.

The core taken from the eastern side of McLennan Strait shows low levels of As, with peaks at 30, 14 and 4 cm. Cd is generally low, but shows a decreasing trend upcore. Cr also decreases upcore with the exception of a spike at 7 cm. Cu records high counts, but generally consistent with troughs at 31 and 12 cm. Hg are levels are low in the lower 40 cm, with significant peaks in the upper sediments. Ni shows a step-change at 14 cm to significantly higher levels but low variability, in inverse correlation to the pattern of Zn.

Lake King The core from the Nicholson River Mouth shows low levels of As, with peaks at 40 and 23-24 cm. Cr levels are generally low, but show a decrease above 16 cm. Cu shows a step- change drop at 15 cm. Hg levels are generally low. Zn shows increasing trends from 41- 32 cm, 32-15 cm and 15 cm to surface.

A core taken from the Mitchell River Mouth, at the north of the silt jetties shows low levels of As, increasing above 10 cm. Cr is generally low with a marked peak at 32 cm. Hg is generally low with a significant peak at 2 cm. Se is also low, with a spike at 5-6 cm. Zn is consistent, except for a marked change in sedimentology at 23-17 cm.

The Tambo core shows low counts of most metals. Peaks of arsenic are present at 10 and 20 cm, although the counts are still considered low. There is variability along the core, with no clear trends, excepting Zn which is higher in the basal section. The sediments are predominantly fine to coarse-grained sand, which may in part explain the low metal counts.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 10

4.3.2 Quantitative Quantitative analysis was undertaken on the top 20 cm of each core in 5 cm depth segments. In addition to the cores scanned for iTRAX, additional cores were analysed from Heart and Dowd Morass and the Lake Wellington end of McLennan Strait.

Table 4. Concentration of specific metals at depth Metal (loid) Depth Sample site Cr Ni Cu As Cd Hg Pb (cm) (mg/Kg) (mg/Kg) (mg/Kg) (mg/Kg (mg/Kg) (mg/Kg) (mg/Kg) 0-5 41.86 37.53 38.44 11.63 0.40 0.31 40.38 5-10 42.43 39.33 39.29 12.55 0.12 0.15 42.54 Heart Morassa 10-15 43.76 40.03 39.78 13.83 0.10 0.17 43.25 15-20 44.34 41.23 39.79 19.95 0.12 0.17 43.52 0-5 31.05 18.15 17.96 5.20 0.01 0.07 17.51 5-10 24.34 13.97 22.79 7.50 0.03 0.13 12.12 Dowd Morassa 10-15 24.55 16.67 27.82 6.95 0.04 0.09 9.36 15-20 21.33 17.04 30.96 7.83 0.04 0.11 9.08 0-5 4.05 12.47 2.05 6.96 0.04 BD 9.65 Latrobe River 5-10 3.93 14.78 1.67 12.88 0.07 BD 11.24 Moutha 10-15 4.17 20.88 2.01 20.49 0.10 BD 16.70 15-20 3.73 16.51 1.62 26.26 0.07 BD 13.45 0-5 4.53 23.32 2.40 9.17 0.09 BD 20.89 Avon River 5-10 4.32 24.96 2.28 7.92 0.10 BD 22.13 Moutha 10-15 4.33 26.08 2.28 8.17 0.10 BD 23.74 15-20 4.50 27.48 2.28 7.82 0.10 BD 24.67 0-5 35.95 21.99 15.55 9.27 0.04 0.06 11.17 Lake 5-10 41.56 25.53 20.88 22.00 0.04 0.06 13.67 Wellingtona 10-15 44.81 27.87 23.35 20.11 0.04 0.06 16.01 15-20 45.23 28.14 22.86 13.67 0.04 0.06 16.19 0-5 N/A N/A N/A N/A N/A N/A N/A McLennan 5-10 2.65 1.81 1.73 1.14 0.01 BD 1.88 Strait - Lake 10-15 15.19 11.73 10.59 6.66 0.04 BD 9.44 Victoriaa 15-20 19.37 14.59 13.03 6.69 0.04 BD 11.94 0-5 32.15 24.33 21.98 7.76 0.05 0.39 17.77 Lake Victoria 5-10 24.18 18.55 15.94 5.86 0.03 0.41 14.82 Westb 10-15 30.62 23.46 20.78 8.99 0.05 0.56 18.64 15-20 27.61 21.30 20.25 9.02 0.05 0.62 17.84 0-5 36.30 26.21 22.20 16.26 0.06 0.06 19.40 Lake Victoria 5-10 37.11 26.14 22.16 19.42 0.06 0.06 18.96 Eastb 10-15 31.36 23.59 20.95 17.39 0.07 0.06 19.29 15-20 27.99 21.39 18.62 14.71 0.06 0.06 19.12 0-5 2.08 10.72 0.86 6.22 0.02 BD 8.21 Nicholson River 5-10 2.18 12.74 0.91 9.88 0.02 BD 10.25 Mouthb 10-15 2.26 15.50 1.04 12.22 0.03 BD 12.97 15-20 2.75 19.01 1.18 11.15 0.05 BD 15.35 0-5 2.28 9.39 0.83 2.77 0.04 BD 7.24 Mitchell River 5-10 2.38 9.10 0.88 3.00 0.03 BD 6.85 Mouthb 10-15 2.34 8.22 0.70 2.33 0.02 BD 6.60 15-20 2.47 8.18 0.79 2.27 0.03 BD 6.57 0-5 1.45 4.75 0.43 1.85 0.01 BD 4.51 Tambo River 5-10 1.53 4.70 0.44 1.92 0.01 BD 2.26 Mouthb 10-15 1.47 4.49 0.46 2.37 0.01 BD 3.86 15-20 1.55 4.64 0.49 2.48 0.01 BD 3.99 0-5 4.72 20.58 1.92 10.40 0.06 BD 15.10 Lake King 5-10 4.19 21.77 1.50 10.76 0.05 BD 17.40 (2012)b 10-15 4.25 23.74 1.55 12.48 0.05 BD 18.08 15-20 4.74 23.31 1.79 5.90 0.07 BD 12.09

Highlighted figures are concentrations that exceed ANZECC/ARMCANZ (2000) Sediment Quality Guidelines. SQGV. See table 1. a Sample 1 (Avon River) correction value used. b Sample 2 (Tambo River) correction value used. Samples that were recorded as below detection (BD) will be re-analysed for confirmation.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 11

Heart Morass All of the sample intervals from Heart Morass exceeded the lower guideline trigger for Ni and Hg, with the highest concentration of Hg in the uppermost sample Pb also showed appreciable concentrations consistently down core. Most metals increased in concentration downcore, with the exceptions of Cd and Hg, which were highest in the uppermost sample.

Dowd Morass None of the metals from the Dowd Morass core exceed the trigger values, although Ni levels were high. Most of the metals showed variability through the core, with Cu, As and Cd increasing with depth and Pb and Cr increasing up-core. It should be noted, this site had very overlying acidic water (pH 4.34) and showed signs of disturbance from previous activities on the site e.g. stock.

Latrobe River Mouth Metal concentration throughout the Latrobe River core were generally low, with moderate levels of Ni and Zn. However As levels increased downcore, exceeding the trigger level in the lowest two samples. Hg was below detection limits for all depths. The other metals showed no clear trend.

Lake Wellington The Lake Wellington core exceeded the threshold limit for Ni throughout. Appreciable levels of As and Cr were also recorded throughout the core, exceeding trigger levels of As 5-15 cm. Cr, Ni, Cu, Zn and Pb all increased with depth, whereas Hg concentrations were highest in the uppermost sediments, although below trigger values.

Avon River Mouth Ni levels exceeded threshold limits throughout the Avon River core. Concentrations of the other metals was relatively low, with the exception of Zn, As and Pb. Hg was beyond detection. Ni, Zn and Pb all increase with depth, whereas As was highest in the uppermost level.

McLennan Strait – Lake Victoria. All of the metals were below trigger levels for the Lake Victoria end of McLennan Strait. Hg was below detection except for the lowermost site. All metals present increased with depth. For this site there is no data for the 0-5cm as this sample failed during processing.

Lake Victoria West All of the samples from core from the west of Lake Victoria exceeded the low trigger levels for Hg and Ni. Appreciable amounts of Cr, Zn, As and Pb are also present, with low levels of Cu. All of the concentrations are relatively consistent with depth.

Lake Victoria East All of the samples from the core taken at the eastern end of Lake Victoria have above trigger values of Ni and approaching trigger values for As. Appreciable levels of Cr and Pb are also present, with moderate levels of Hg, Cu and Zn. Most metals increased in concentration up-core.

Nicholson River Mouth The Nicholson River core generally had low levels of metals throughout, with Hg below detection. Appreciable levels of Ni, Zn, As and Pb throughout with Ni approaching the low trigger value at 15-20 cm. In most cases, metals increase downcore.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 12

Mitchell River Mouth Generally low levels of metals were found throughout the Mitchell River core. Only Ni and Zn recorded appreciable levels. Hg was below detection. Most of the concentrations were relatively consistent, or increasing slightly up-core. This sample site was high in sand content, indicating a higher flow energy and lower ability to sequester metal contaminants.

Tambo River Mouth Very low levels of metals were found throughout the core from the Tambo River Mouth. Only Zn was recorded at appreciable concentrations and low levels of Ni. Again, Hg was below detection. Metal profiles were fairly consistent throughout the core. This sample site was high in sand content, indicating a higher flow energy and lower ability to sequester metal contaminants.

Lake King This core was collected from Lake King by Perran Cook in 2012 and he has kindly made it available for analysis. The core material was quite dry and sampled at 0.5 cm intervals – hence had to be reconstructed prior to analysis. As such, metal concentrations may not accurately represent fresh sediment. Ni concentrations exceeded threshold values throughout the core. Appreciable levels of As, Zn and Pb were also recovered. Hg was below detection. Most of the metal profiles were relatively consistent, with the lowest levels of As and Pb in the 15-20 cm sample.

5 Discussion 5.1 Metals of interest The distribution of metals in the surface sediments did show some consistent patterns, both in the surface sediments and at depth.

5.1.1 Mercury The highest concentrations of Hg were found in the west of the system, including Heart Morass, the Latrobe River Mouth, the depocentre of Lake Wellington and the west of Lake Victoria. Although Hg was recorded in most of the other sites from Lake Victoria and Lake King, concentrations were significantly lower. A similar pattern is present at depth, with many sites below detection. The iTRAX scans reveal discrete peaks of Hg, all of which occur in the uppermost 15 cm of the cores. Interestingly, there is a clear correlation between Hg and Se in the Latrobe River core, suggesting that this may be a contribution from fly ash from the power station.

Although Hg levels only exceeded trigger values at four sites, it should be noted that the recovery of Hg using these methods was less than 50%, compared with the NATA accredited analysis. It would therefore be wise to treat these values as a minimum and undertaken further analysis with a more refined method targeted at maximum recovery. Hg is a notoriously challenging element to accurately analyse.

5.1.2 Arsenic The highest levels of As in the surface sediments were found in Lake King and Bunga Arm, with appreciable levels in Lake Victoria and Jones Bay, although none exceeded trigger values. High levels were identified at depth in the Latrobe River and Lake Victoria East (exceeding trigger values), and appreciable levels in Lake Wellington. iTRAX scans revealed discrete peaks of As at depth in the Nicholson River and Latrobe River Mouth

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 13

around 20 cm, McLennan Strait – both at Lake Victoria and Lake Wellington sides around 30 cm. The mid-sections of Lake Wellington (15-36 cm) and upper 10 cm of the Mitchell River cores also showed higher counts, although low concentrations may be expected.

Given that most of the As is present at depth, it is most likely associated with historical practices throughout the catchment, which may include mining or wool scours. Some may also be sourced from native arsenopyrite within the catchment. However, with generally low levels and at depth, it is not considered likely to be considered of risk.

5.1.3 Nickel Ni is ubiquitous throughout the Gippsland Lakes and frequently exceeded trigger values. Concentrations of Ni in the top 20 cm of the cores was also fairly uniform. In addition, the iTRAX scans showed high counts of Ni in most cores and a correlation with sedimentology: higher Ni counts correspond to coarser grainsize in several core profiles. Given its consistency and distribution throughout the basins and at depth, and correlation with coarser sediment, it is considered native to the catchment and likely sourced from the local geology.

5.2 Potential for risk

5.2.1 Morasses

The low lying fringing wetlands of Heart and Dowd Morasses provided significantly different environmental conditions to the other sample sites across the catchment. Unlike the other sites, the morasses vary in the water regimes, where the other sites have overlying water constantly, the morasses experience wet and dry periods, associated with seasonal flood pulses and water allocations upstream. In such settings provide ideal conditions for the development of acid-sulfate soils. This is in the red staining of the sediments and flocculants in the waters of the morasses, associated with iron oxidation.

Acid-sulfate soils occur naturally in both coastal and inland settings, particularly in areas of high organic productivity. These soils contain metal sulphide minerals. If left undisturbed these soils are generally harmless, however if drained, excavated or exposed to air the metal sulphides react with oxygen and form sulfuric acid (DSE, 2009). This acid can trigger the release and mobilise other toxic elements (such as heavy metals and other contaminants) and when combined with acid, kills plants and animals and can contaminate drinking water and shellfish. Fish kills are often associated with acid sulfate events, as the acid leaches aluminium from the sediments, which clogs the gills of the fish, causing them to suffocate. Infrastructure may also be impacted as the acid can corrode concrete and steel both in the immediate vicinity and downstream areas. As these morasses could be classed as being in the ‘’upstream’’ part of the lakes, any significant mobilisation event could cause a significant distribution of metals through the major deep lakes.

5.2.2 Methylation

Another area of potential concern is in the deeper anoxic zones of the lakes, such as Lake King and Victoria. In these zones in estuarine systems, sulfate reducing bacteria can have a role in the methylation of any Hg present in the sediment, producing methylmercury (Merritt and Amirbahman, 2009). Methylmercury (MeHg) is a potent neurotoxin that is known to magnify in aquatic foodwebs. Although the concentrations of Hg were below

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 14

trigger in Lake King, levels above the low trigger value were recorded from Lake Victoria West.

In addition to the deep lake environments, methylation is also a potential issue in Heart Morass, particularly in the channel from which this core was extracted. Here there is extensive monosulfidic black ooze and methane degassing. The heightened levels of mercury here are of concern.

5.3 Future recommendations Although this project has proved a valuable pilot study, more targeted investigation is highly recommended. This is in line with the sediment quality assessment guide, which recommends that sediments exceeding trigger levels warrant further investigation, particularly with regards the extractable metals and the bioavailability of contaminants of concern (CSIRO, 2016). Sampling specifically for mercury in the west of Lake Wellington, including Heart and Dowd Morass and around the Latrobe River, as well as the depocentre of the lake is highly recommended. In addition, incubation samples from the deeper stratified lakes will likely verify the methylation process in these regions, which may be providing a significant source for mercury, particularly relating to bioavailability up the food chain.

A mobilisation characterisation assessment will assist in determining the conditions under which the contaminants, including mercury are most likely to be liberated from the sediment. A second phase of analysis should also focus on the bioavailability of the contaminants of interest, and further bioaccumulation up the food chain.

It should be noted that the cores so far obtained do not have a chronology. 210Pb dating on the sediments proved unsuccessful, due to disparate sediment sources and mixing. In addition, the iTRAX scans of the top 50 cm of sediment did not clearly identify base line conditions, such as prior to industrialisation in the region. The chronology of the cores can be obtained by other methods, such as identification of exotic pollen, noting land clearing and replanting during early European colonisation, or changes in the diatom community of the lakes, relating to changes in salinity, such as following the opening of Lakes Entrance. These studies will be forthcoming, as part of a PhD project on the lakes.

The fringing morasses are areas of significant interest, both because they act as sediment sinks for the rivers, prior to entering the lakes and are known to be potential and actual acid sulfate soils. As such, the morasses provide both a significant source for contaminants and conditions under which they may readily mobilise. These are also significant areas for field and game, as well as at the top of the lakes’ system. Therefore, this would be a very worthy area for further investigation.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 15

5 Conclusions This pilot study on the distribution of heavy metal and metalloid contaminants in the Gippsland Lakes has revealed some interesting patterns. • Mercury is present in the sediments of the lakes above the low trigger value of the sediment quality guidelines. Highest concentrations of mercury are found in the west of the system including the Latrobe River, Lake Wellington, Heart Morass and Lake Victoria West. Mercury is present both in the surface sediments and at depth • Arsenic showed elevated concentrations at several sites, but only exceeded trigger values in the Latrobe River and Lake Victoria East. As higher concentrations occurred at depth, a historical source is likely. • Nickel is present throughout the system and consistently through the cores, suggesting a local geological source.

Although this study revealed no immediate areas for concern, further investigations are recommended on particularly mercury mobilisation and bioavailability in the Morasses, Latrobe River and deep lake sites.

6 Acknowledgements We gratefully acknowledge the financial support of DELWP. A. Trewarn is funded by an APA scholarship and an AINSE PGRA fellowship. We also acknowledge the support of Gippsland Ports and SEAMEC for providing vessels and crew for sampling. We are grateful to Alicia Reynolds for laboratory assistance and Rob Milne form CeRDI for the spatial representation of the data. We also thank the support of the Gippsland Lakes Co- ordinating Committee.

7 References

ANZECC/ARMCANZ (2000). Australian and New Zealand guidelines for fresh and marine water quality. Australian and New Zealand Environment and Conservation Council/ Agriculture and Resource Management Council of Australia and New Zealand.

DSE (2009). Victorian Coastal Acid Sulfate Soils Strategy. Dept. of Sustainability & Environment, Melbourne, Victoria.

GLMAC (2013). Gippsland Lakes Environmental Strategy.

Gippsland Lakes Ramsar Site Management Plan (2015). East GIpplsand Catchment Management Authority.

Merritt, K.A., Amirbahman, A. (2009). Mercury methylation dynamics in estuarine and coastal marine environments – A critical review. Earth-Science Review 96: 54-66.

National Environment Protection (Assessment of Site Contamination) Measure (2011). Schedule B: General guidelines for the assessment of site contamination. B1 – Guideline on Investigation Levels for Soil and Groundwater. National Environment Protection Council.

Rayment, G.E., Lyons, D.J. (2010). Soil Chemical Methods – Australia, CSIRO Publishing.

Victorian Best Practice Guidelines for Assessing and Managing Coastal Acid Sulfate Soils (2010). Dept. of Sustainability & Environment, Melbourne, Victoria.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 16

8. Appendices

Appendix 8.1 Sample Log

Samples collected Sample site Latitude Longitude Water depth Water Core sample Grab sample Total metal Qualitative (m) quality depth (m) collection analysis iTRAX depth length Dowds 38° 9.139'S 147° 12.667'E <1 Surface only 50cm N/A 0-20cm 50cm Morass (2016) Hearts S 38 07.964 E 147 10.755 1 N/A 50cm N/A 0-20cm 50cm Morass Latrobe River S 38 06.8970 E 147 14.7986 1.5-2m Surface- 1m 70cm (2015) 2015 &2016 0-20cm 50cm Mouth (2015 &2016) 250cm (2016) Avon River 38° 3.060'S 147° 16.231'E 2m Surface-1m 100cm 2015&2016 0-20cm 50cm Mouth (2015) -2m (2016) Lake 38° 5.843'S 147° 18.481'E 4.2m Surface- 3m 250cm 2015 & 2016 0-20cm 50cm Wellington (2015) – 4m (2016) McLennan 38° 5.387'S 147° 24.900'E 2-3.7m Surface-3m 100cm N/A N/A 50cm Strait- Lake (2015) – 4m Wellington (2016) McLennan S 38 02.9571 E 147 28.5025 1.2m Surface-1m 170cm 2016 0-20cm 50cm Strait - Lake (2015 & 2016) Victoria Lake Victoria S 38 01.3520 E 147 35.2900 7.5-8m Surface-5m 100cm 2015 & 2016 0-20cm N/A West Lake Victoria S 37 59.7264 E 147 37.8607 9m Surface-6m N/A 2016 N/A N/A Mid (2015) – 7m (2016)

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 17

Lake Victoria S 37 56.4257 E 147 43.0764 8.5m Surface-8m 50cm 2015 & 2016 0-20cm N/A East (2015) – 7m (2015) Lake King S 37 52.8073 E 147 48.1240 6.2-7m Surface-6m 2012 2015 & 2016 0-20cm N/A (2015 & 2016) Mitchell River S 37 51.4104 E 147 44.5454 1.5m Surface-1m 45cm 2015 & 2016 0-20cm 45cm Mouth (2015 & 2016) Nicholson S 37 50.9104 E 147 43.8516 1.5-2.3m Surface-1m 150cm 2015 & 2016 0-20cm 50cm River Mouth (2015) – 2m (2016) Tambo River S 37 51.3186 E 147 47.844 1.7-3m Surface- 1m 50cm 2015 & 2016 0-20cm 50cm Mouth (2015) – 3m 2016 Jones Bay S 37 51.3381 E 147 42.9791 3.4 Surface- 3m N/A 2016 N/A N/A (2016) Shaving Point S 37 53.7763 E 147 51.5636 18m Surface-9m N/A 2016 N/A N/A (2016) Bunga Arm / S 37 56.4311 E 147 48.7492 3.7m Surface-3m N/A 2016 N/A N/A Back Lake (2016)

Paynesville S 37 54.6554 E 147 43.7977 N/A 1m (2016) N/A 2016 N/A N/A

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 18

Appendix 8.2 Water quality data

Parameter Year Sample site Depth (m) Temperature DO (% EC (uS/cm Turb pH ORP (REDOX) DO (mg/L) TDS (mg/L) (⁰C) Sat) @25C) NTU 2015 N/A N/A N/A N/A N/A N/A N/A N/A N/A Dowds Morass 2016 Surface 32.4 4.34 306.7 82.8 5.57 24345 15824 N/A Surface 21.5 7.91 141.1 113.3 9.91 5439 3535 182 2015 Latrobe River 1 18.8 7.95 134.7 105.8 9.75 6686 4345 167 Mouth Surface 15.2 7.85 108.2 101.1 10.08 2483 1613 90.9 2016 1 15.1 7.8 106.1 99 9.86 3639 2365 N/A Surface 18.2 7.57 138.9 84.3 7.82 7870 5115 171 2015 1 18.2 7.57 137.8 84.3 7.84 7849 5101 169 Avon River Mouth Surface 15.2 7.82 86.5 107.3 10.63 5085 3305 83.2 2016 1 15.2 7.84 83.1 107.9 10.69 5151 3348 82.1 2 15.1 7.86 31.1 102.4 10.16 5409 3515 N/A Surface 20 7.96 117.7 109 9.73 8660 5629 172 1 19.6 8.07 114.3 111.5 10.06 8528 5543 173 2015 2 18.7 7.91 121.7 100 9.16 9236 6003 175 3 18.1 7.81 122.1 94.4 8.74 9796 6367 186 Lake Wellington Surface 14.8 8.01 85.2 110.4 11.05 4351 2828 87.9 1 14.5 7.89 87.5 109 10.96 4952 3218 88.9 2016 2 14.4 7.82 91.7 101.4 10.2 5775 3753 80.9 3 14.4 7.81 92.4 99.3 9.98 6078 3950 N/A

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 19

Parameter Year Sample site Depth (m) Temperature DO (% EC (uS/cm Turb pH ORP (REDOX) DO (mg/L) TDS (mg/L) (⁰C) Sat) @25C) NTU Surface 20 8.17 103.5 114.6 10.22 9694 6301 197 2015 1 19.6 8.36 106.8 117.9 10.59 9397 6108 197 2 19.2 8.25 115.5 110.8 10.05 9427 6127 196 McLennan Strait- Surface N/A N/A N/A N/A N/A N/A N/A N/A Lake Wellington 1 15.1 8.22 99.5 112.8 11.18 5745 3734 84.9 2016 2 14.9 8.15 101.1 111.6 11.11 5755 3740 83.5 3 14.5 8.11 91.7 98.3 9.84 6899 4484 15.1 Surface 19.2 7.9 127.3 102.6 9.2 12544 8153 195 2015 McLennan strait - 1 19.1 7.75 125.6 80.8 7.04 24088 15657 201 Lake Victoria Surface 15.3 8.16 95.6 106.1 10.2 15488 10067 96.3 2016 1 15.1 8.13 95.4 97.7 9.39 17206 11183 94.2 Surface 19.8 8.26 105.9 119.2 10.22 25491 16569 212 1 19.5 8.3 104.2 119.9 10.35 25573 16622 212 2 19 8.22 106.5 117.3 10.18 27423 17824 215 2015 3 18.2 7.99 110.5 97 8.43 33613 21848 218 4 17.7 7.21 147.9 87.6 7.63 35438 23034 218 5 17.5 6.6 169 62.3 5.44 37478 24360 217 Lake Victoria west Surface 16 8.17 77.3 113.2 10.45 22898 14883 103 1 16 8.17 76.3 113.9 10.52 22849 14851 102 2 16 8.16 75.1 114.1 10.56 22806 14823 102 2016 3 15.8 8.15 74.8 111.9 10.38 22943 14912 103 4 15 7.95 80.8 31.8 2.94 31428 20428 102 5 14.8 7.96 -336.9 4 0.37 39450 25642 69.1

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 20

Parameter Year Sample site Depth (m) Temperature DO (% EC (uS/cm Turb pH ORP (REDOX) DO (mg/L) TDS (mg/L) (⁰C) Sat) @25C) NTU Surface 19.3 8.28 85.8 116.1 10.03 26981 17537 213 1 18.8 8.33 82.2 116.7 10.12 28454 18495 216 2 19 8.3 80.9 119 10.19 32571 21171 217 2015 3 19 8.22 81.9 112.5 9.59 34600 22490 218 4 18.5 7.77 100.2 96.9 8.31 35797 23268 217 5 17.8 7.12 122.5 67.1 5.79 39785 25860 218 6 16.8 6.3 -212.6 17.2 1.49 48174 31313 211 Lake Victoria Mid Surface 16.3 8.23 12.7 111.8 10.27 22075 14348 104 1 16.3 8.23 13.7 112.2 10.31 22077 14350 104 2 16.3 8.23 14.3 112.3 10.32 22105 14368 104 3 15.9 8.22 18.6 110.1 10.19 22868 14864 104 2016 4 15.2 8.2 23.5 99 9.28 24170 15710 104 5 15 8.17 26.7 88.2 8.29 24851 16153 103 6 14.8 8.02 17.2 9.7 0.89 37517 24386 105 7 14.7 8 14.2 6.3 0.57 40683 26443 105

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 21

Parameter Year Sample site Depth (m) Temperature DO (% EC (uS/cm Turb pH ORP (REDOX) DO (mg/L) TDS (mg/L) (⁰C) Sat) @25C) NTU Surface 18.8 8.42 184.2 117.7 10.11 32181 20917 217 1 19.1 8.39 178.5 117.2 10.01 32669 21234 218 2 19 8.37 175.5 116.2 9.88 34224 22245 218 3 19 8.33 170.9 113.1 9.61 35474 23058 218 2015 4 18.9 8.27 169.5 108.1 9.2 35897 23333 218 5 17.6 7.93 163.9 65.5 5.58 46177 30015 219 6 16.9 7.63 165.1 22.4 1.91 51150 33247 220 7 16.8 7.62 161.3 18.6 1.59 51307 33349 220 Lake Victoria East 8 16.8 7.77 -264.8 1.7 0.15 48547 31555 261 Surface 16.3 8.21 16.8 109.5 10.08 21133 13736 105 1 16.3 8.21 18.2 109.6 10.1 21124 13730 104 2 16.3 8.21 18.8 109.8 10.12 21136 13738 105 3 16.3 8.21 19.9 110.4 10.17 21298 13843 105 2016 4 16.2 8.18 22.5 108.4 9.97 22728 14773 105 5 15.4 8.17 28.5 89.6 8.29 27333 17766 105 6 15 8.06 28.1 39.4 3.56 41355 26880 106 7 14.8 8.04 -283.4 21.5 1.94 42948 27916 89.6 2015 Surface N/A N/A N/A N/A N/A N/A N/A N/A Surface N/A N/A N/A N/A N/A N/A N/A N/A N/A Jones Bay 1 17 8.5 40.1 114.9 10.78 7956 5171 2016 2 17 8.14 55.4 108.9 10.17 9944 6463 N/A 3 16 8.16 22.6 86.4 8.01 21330 13864 N/A

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 22

Parameter Year Sample site Depth (m) Temperature DO (% EC (uS/cm Turb pH ORP (REDOX) DO (mg/L) TDS (mg/L) (⁰C) Sat) @25C) NTU Surface 17.3 8.24 79.6 110.9 9.9 30593 19885 219 1 18 8.32 74 112.2 9.79 33535 21797 219 2 18.4 8.34 73.6 112.6 9.69 34591 22484 219 2015 3 18.6 8.35 73.9 112.6 9.65 34740 22581 219 4 18.7 8.31 76.6 111.2 9.49 36277 23580 219 5 18.4 8.15 78.6 99.3 8.44 40418 26271 219 6 18.1 7.94 81.4 81.2 6.84 46102 29966 219 Lake King Surface 15.7 7.81 76.3 104.1 9.87 19167 12458 102 1 15.9 7.81 73.6 103.9 9.82 19174 12463 102 2 15.9 7.8 71.2 103.6 9.79 19646 12769 103 2016 3 15.8 7.82 67.2 104 9.82 20722 13469 103 4 15.8 7.82 66.1 104.1 9.82 20823 13534 103 5 15.8 7.83 65.2 104.2 9.83 20888 13577 103 6 15.1 7.86 13.5 61.5 5.63 39692 25799 93.5 Surface 18.5 8.32 96.3 108.3 9.72 18467 12003 225 2015 1 18.8 8.29 94 107.8 9.6 18869 12264 216 Nicholson River Surface 18 8.33 80.8 89.7 8.3 4935 3207 99.6 2016 1 17.3 8.23 73.3 100.3 9.31 9997 6498 103 2 16.4 8.1 68 84.2 7.76 20127 13082 102 Surface 18.8 8.25 104.9 111.8 9.8 25106 16318 245 2015 1 19.2 8.29 98.3 112.7 9.65 30744 19983 217 Mitchell River Surface 15.2 8.25 52.9 91.3 8.85 10421 6773 102 2016 1 15.4 8.21 51.4 97 9.08 21666 14082 104

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 23

Parameter Year Sample site Depth (m) Temperature DO (% EC (uS/cm Turb pH ORP (REDOX) DO (mg/L) TDS (mg/L) (⁰C) Sat) @25C) NTU Surface 18.1 8.37 86.1 109 9.58 29855 19405 219 2015 1 18.3 8.35 85.4 109.9 9.59 30412 19767 220 Surface 16.6 8.18 62.3 93.8 8.94 4995 3246 92.1 Tambo River 1 16 8.21 53.5 104.4 9.67 21923 14249 106 2016 2 16 8.23 52.8 104.5 9.67 22120 14378 106 3 15.5 8.22 52.6 98.9 9.21 23941 15561 105 2015 Surface N/A N/A N/A N/A N/A N/A N/A N/A Surface N/A N/A N/A N/A N/A N/A N/A N/A 1 15.5 8.06 51.9 102.1 9.68 22646 14719 102 2 15.5 8.06 51.5 101.9 9.67 22618 14701 102 3 15.6 8.04 50.8 102 9.65 22558 14662 103

Shaving Point 4 15.6 8.04 50.4 102 9.65 22644 14718 103 2016 5 15.6 8.02 49.4 100.6 9.49 23711 15412 102 6 15.6 8.02 48.7 99.4 9.32 25137 16339 103 7 15.6 8.01 48.6 98.8 9.26 25352 16478 103 8 15.6 8.01 48 98.6 9.25 25724 16720 103 9 15.5 8.01 45.2 94 8.72 31740 20631 103 2015 Surface N/A N/A N/A N/A N/A N/A N/A N/A Surface 16.5 7.99 -5.3 102.9 9.49 24630 16009 104 Bunga Arm / 1 16.6 8.01 -2.3 102.9 9.47 24614 15999 104 Back Lake 2016 2 16.6 8.02 -1.4 102.9 9.48 24634 16012 104 3 17 8.07 -161.5 98.6 8.96 26202 17031 45.9

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 24

Appendix 8.3 Inter-lab comparative recovery rates on control samples

Sample Lab Cr Ni Cu As Cd Hg Pb mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg Control EAL 27.70 20.40 19.20 7.01 0.07 0.27 16.40 1a Control FedUni 30.34 19.41 12.54 6.25 0.05 0.15 14.54 1a Recoverye 109.52 95.13 65.31 88.91 66.90 54.30 8.64 % Correction 1.10 0.95 0.65 0.89 0.67 0.54 0.89 value

Control EAL 6.62 4.36 3.27 2.22 0.01c 0.02 4.03 2b Control FedUni 8.70 4.70 2.76 2.43 0.01c 0.00d 4.16 2b Recoverye 131.42 107.80 84.40 109.46 100 0 103.23 % Correction 1.31 1.08 0.84 1.09 1 0.48 1.03 value Sample Lab Cr Ni Cu As Cd Hg Pb mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg Control EAL 27.7 20.4 19.2 7.01 0.07 0.27 16.4 1a Control FedUni 30.65 19.2 12.22 5.48 0.05 0.13 14.6 1a Recoverye 110.65 94.12 63.65 78.43 71.43 48.15 89.02 %

Control EAL 6.62 4.36 3.27 2.22 0.01c 0.02 4.03 2b Control FedUni 8.7 4.7 2.76 2.43 0.01c 0.00d 4.16 2b Recoverye 131.42 107.8 84.40 109.46 100 0 103.23 % aAvon River site control sample. bTambo River site control sample, c Sample concentration below detection. dSample concentration below detection, e Recovery based on Federation University versus NATA accredited EAL.

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 25

Appendix 8.4 Metal Concentration and Associated hazard quotient (HQ) for surface sediment samples

Metal (loid) Year Sample site Cr Ni Cu As Cd Hg Pb Cr (HQ) Ni (HQ) Cu (HQ) As (HQ) Cd (HQ) Hg (HQ) Pb (HQ) (mg/Kg) (mg/Kg) (mg/Kg) (mg/Kg (mg/Kg) (mg/Kg) (mg/Kg) Latrobe River 2015 16.99 0.21 11.10 0.53 7.80 0.12 3.68 0.18 0.04 0.03 0.10 0.67 8.14 0.16 Mouth 2016 34.37 0.43 21.83 1.04 14.92 0.23 6.50 0.33 0.07 0.05 0.19 1.27 15.29 0.31

Avon River 2015 30.65 0.38 19.20 0.91 12.22 0.19 5.48 0.27 0.05 0.03 0.13 0.87 14.60 0.29 Mouth 2016 24.94 0.31 15.70 0.75 10.72 0.16 5.10 0.26 0.04 0.03 0.11 0.73 12.77 0.26

Lake 2015 45.72 0.57 28.14 1.34 17.57 0.27 10.11 0.51 0.05 0.03 0.21 1.40 17.01 0.34 Wellington 2016 43.17 0.54 26.31 1.25 18.99 0.29 9.21 0.46 0.08 0.05 0.13 0.87 16.47 0.33 McLennan 2015 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Strait - Lake Victoria 2016 29.56 0.37 18.34 0.87 11.44 0.18 7.00 0.35 0.04 0.03 0.14 0.93 11.58 0.23

Lake Victoria 2015 46.76 0.58 29.19 1.39 20.45 0.31 10.30 0.52 0.09 0.06 0.15 1.00 17.09 0.34 West 2016 42.64 0.53 25.87 1.23 17.04 0.26 12.25 0.61 0.06 0.04 0.17 1.13 18.01 0.36 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Lake Victoria N/A Mid 2016 35.28 0.44 23.24 1.11 17.62 0.27 8.42 0.42 0.09 0.06 0.11 0.73 16.68 0.33

Lake Victoria 2015 27.89 0.35 16.76 0.80 10.51 0.16 6.38 0.32 0.04 0.03 0.13 0.87 9.62 0.19 East 2016 37.73 0.47 24.14 1.15 19.63 0.30 12.75 0.64 0.10 0.07 0.09 0.60 18.58 0.37 2015 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Paynesville 2016 24.60 0.31 14.38 0.68 47.23 0.73 8.40 0.42 0.09 0.06 0.09 0.60 22.93 0.46 2015 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Jones Bay 2016 31.39 0.39 23.53 1.12 17.49 0.27 12.34 0.62 0.07 0.05 0.07 0.47 19.00 0.38

Nicholson 2015 15.39 0.19 12.60 0.60 7.46 0.11 8.32 0.42 0.02 0.01 0.03 0.20 7.57 0.15 River Mouth 2016 26.99 0.34 20.19 0.96 15.69 0.24 11.24 0.56 0.07 0.05 0.06 0.40 15.97 0.32 BD Mitchell River 2015 7.84 0.10 6.99 0.33 2.87 0.04 2.40 0.12 0.01 0.01 BD 4.81 0.10 Mouth 2016 15.47 0.19 11.94 0.57 7.94 0.12 4.59 0.23 0.05 0.03 BD BD 11.64 0.23

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 26

Metal (loid) Year Sample site Cr Ni Cu As Cd Hg Pb Cr (HQ) Ni (HQ) Cu (HQ) As (HQ) Cd (HQ) Hg (HQ) Pb (HQ) (mg/Kg) (mg/Kg) (mg/Kg) (mg/Kg (mg/Kg) (mg/Kg) (mg/Kg) Tambo River 2015 8.70 0.11 4.70 0.22 2.76 0.04 2.43 0.12 0.01 0.01 BD BD 4.16 0.08 Mouth 2016 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 2015 37.99 0.47 23.42 1.12 20.59 0.32 15.99 0.80 0.13 0.09 0.08 0.53 20.28 0.41 Lake King 2016 34.15 0.43 21.36 1.02 18.43 0.28 14.75 0.74 0.08 0.05 0.08 0.53 20.49 0.41 2015 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Shaving Point 2016 29.04 0.36 17.03 0.81 13.39 0.21 11.03 0.55 0.08 0.05 0.06 0.40 12.12 0.24 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Bunga Arm / 2015 Back Lake 2016 21.40 0.27 15.09 0.72 19.15 0.29 15.74 0.79 0.18 0.12 0.08 0.53 13.57 0.27 BD is Below detection limits. Orange highlighted figures are concentrations that exceed ANZECC/ARMCANZ (2000) Sediment Quality Guidelines. SQGV. See table 1. Yellow highlighted figures are concentrations that are within 10%(0.9 HQ) of the SQGV. Hazard Quotient value (HQ) = sample concentration / SQGV

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 27

Appendix 8.5 Metal Concentration and associated hazard quotient (HQ) for sediment core samples

Metal (loid) Depth Sample site Cr Cr (HQ) Ni Ni (HQ) Cu Cu (HQ) As As (HQ) Cd Cd(HQ) Hg Hg (HQ) Pb Pb (HQ) (cm) (mg/Kg) (mg/Kg) (mg/Kg) (mg/Kg (mg/Kg) (mg/Kg) (mg/Kg) 0-5 45.84 0.57 35.70 1.70 25.11 0.39 10.34 0.52 0.27 0.18 0.17 1.13 35.79 0.72 5-10 46.47 0.58 37.42 1.78 25.66 0.39 11.16 0.56 0.08 0.05 0.08 0.53 37.71 0.75 Heart Morass 10-15 47.93 0.60 38.08 1.81 25.98 0.40 12.30 0.62 0.07 0.05 0.09 0.60 38.34 0.77 15-20 48.56 0.61 39.22 1.87 25.99 0.40 12.40 0.62 0.08 0.05 0.09 0.60 38.58 0.77 0-5 34.00 0.43 17.27 0.82 11.73 0.18 4.62 0.23 0.01 0.01 0.04 0.27 15.52 0.31 5-10 26.66 0.33 13.29 0.63 14.88 0.23 6.67 0.33 0.02 0.01 0.07 0.47 10.74 0.21 Dowd Morass 10-15 26.89 0.34 15.86 0.76 18.17 0.28 6.18 0.31 0.03 0.02 0.05 0.33 8.30 0.17 15-20 23.36 0.29 16.21 0.77 20.22 0.31 6.99 0.35 0.03 0.02 0.06 0.40 8.05 0.16 0-5 4.43 0.06 11.86 0.56 1.34 0.02 6.19 0.31 0.03 0.02 BD BD 8.55 0.17 Latrobe River 5-10 4.30 0.05 14.06 0.67 1.09 0.02 11.45 0.57 0.05 0.03 BD BD 9.96 0.20 Mouth 10-15 4.57 0.06 19.86 0.95 1.31 0.02 18.22 0.91 0.07 0.05 BD BD 14.80 0.30 15-20 4.08 0.05 15.71 0.75 1.06 0.02 23.35 1.17 0.05 0.03 BD BD 11.92 0.24 0-5 4.96 0.06 22.19 1.06 1.57 0.02 8.15 0.41 0.06 0.04 BD BD 18.52 0.37 Avon River 5-10 4.73 0.06 23.75 1.13 1.49 0.02 7.04 0.35 0.07 0.05 BD BD 19.62 0.39 Mouth 10-15 4.74 0.06 24.81 1.18 1.49 0.02 7.26 0.36 0.07 0.05 BD BD 21.04 0.42 15-20 4.93 0.06 26.14 1.24 1.49 0.02 6.95 0.35 0.07 0.05 BD BD 21.87 0.44 0-5 39.37 0.49 20.92 1.00 11.46 0.18 8.24 0.41 0.03 0.02 0.03 0.20 9.90 0.20 Lake 5-10 45.51 0.57 24.29 1.16 13.64 0.21 19.56 0.98 0.03 0.02 0.03 0.20 12.12 0.24 Wellington 10-15 49.08 0.61 26.51 1.26 15.25 0.23 17.88 0.89 0.03 0.02 0.03 0.20 14.19 0.28 15-20 49.53 0.62 26.77 1.27 14.93 0.23 12.15 0.61 0.04 0.03 0.03 0.20 14.35 0.29 0-5 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A McLennan 5-10 2.90 0.04 1.72 0.08 1.13 0.02 1.01 0.05 0.01 0.01 BD BD 1.67 0.03 Strait - Lake 10-15 16.64 0.21 11.16 0.53 6.92 0.11 5.92 0.30 0.03 0.02 BD BD 8.37 0.17 Victoria 15-20 21.21 0.27 13.88 0.66 8.51 0.13 6.19 0.31 0.03 0.02 BD BD 10.58 0.21 0-5 42.25 0.53 26.23 1.25 18.55 0.29 8.49 0.42 0.05 0.03 0.19 1.27 18.34 0.37 Lake Victoria 5-10 31.78 0.40 20.00 0.95 13.45 0.21 6.41 0.32 0.03 0.02 0.20 1.33 15.30 0.31 West 10-15 40.24 0.50 25.29 1.20 17.54 0.27 9.84 0.49 0.05 0.03 0.27 1.80 19.24 0.38 15-20 36.29 0.45 22.85 1.09 17.09 0.26 9.87 0.49 0.05 0.03 0.30 2.00 18.42 0.37 0-5 47.71 0.60 28.25 1.35 18.74 0.29 17.80 0.89 0.06 0.04 0.03 0.20 20.03 0.40 Lake Victoria 5-10 48.77 0.61 28.18 1.34 18.70 0.29 21.26 1.06 0.06 0.04 0.03 0.20 19.57 0.39 East 10-15 41.21 0.52 25.43 1.21 17.68 0.27 19.03 0.95 0.07 0.05 0.03 0.20 19.91 0.40 15-20 36.79 0.46 23.06 1.10 15.72 0.24 16.10 0.81 0.06 0.04 0.03 0.20 19.74 0.39

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 28

Metal (loid) Depth Sample site Cr Cr (HQ) Ni Ni (HQ) Cu Cu (HQ) As As (HQ) Cd Cd(HQ) Hg Hg (HQ) Pb Pb (HQ) (cm) (mg/Kg) (mg/Kg) (mg/Kg) (mg/Kg (mg/Kg) (mg/Kg) (mg/Kg) 0-5 2.73 0.03 11.56 0.55 0.73 0.01 6.81 0.34 0.02 0.01 BD BD 8.47 0.17 Nicholson River 5-10 2.87 0.04 13.73 0.65 0.77 0.01 10.82 0.54 0.02 0.01 BD BD 10.58 0.21 Mouth 10-15 2.97 0.04 16.71 0.80 0.88 0.01 13.38 0.67 0.03 0.02 BD BD 13.39 0.27 15-20 3.62 0.05 20.49 0.98 1.00 0.02 12.21 0.61 0.05 0.03 BD BD 15.84 0.32 0-5 2.99 0.04 10.12 0.48 0.70 0.01 3.03 0.15 0.04 0.03 BD BD 7.47 0.15 Mitchell River 5-10 3.13 0.04 9.81 0.47 0.74 0.01 3.28 0.16 0.03 0.02 BD BD 7.07 0.14 Mouth 10-15 3.07 0.04 8.86 0.42 0.59 0.01 2.55 0.13 0.02 0.01 BD BD 6.81 0.14 15-20 3.25 0.04 8.82 0.42 0.67 0.01 2.48 0.12 0.03 0.02 BD BD 6.78 0.14 0-5 1.90 0.02 5.12 0.24 0.36 0.01 2.03 0.10 0.01 0.01 BD BD 4.66 0.09 Tambo River 5-10 2.01 0.03 5.07 0.24 0.37 0.01 2.10 0.11 0.01 0.01 BD BD 4.40 0.09 Mouth 10-15 1.93 0.02 4.84 0.23 0.39 0.01 2.59 0.13 0.01 0.01 BD BD 3.98 0.08 15-20 2.04 0.03 5.00 0.24 0.41 0.01 2.71 0.14 0.01 0.01 BD BD 4.12 0.08 0-5 6.20 0.08 22.18 1.06 1.62 0.02 11.38 0.57 0.06 0.04 BD BD 15.59 0.31 Lake King 5-10 5.50 0.07 23.47 1.12 1.27 0.02 11.78 0.59 0.05 0.03 BD BD 17.96 0.36 (2012) 10-15 5.59 0.07 25.59 1.22 1.31 0.02 13.66 0.68 0.05 0.03 BD BD 18.66 0.37 15-20 6.23 0.08 25.13 1.20 1.51 0.02 6.46 0.32 0.07 0.05 BD BD 12.48 0.25 BD is Below detection limits. Orange highlighted figures are concentrations that exceed ANZECC/ARMCANZ (2000) Sediment Quality Guidelines. SQGV. See table 1. Yellow highlighted figures are concentrations that are within 10%(0.9 HQ) of the SQGV. Hazard Quotient value (HQ) = sample concentration / SQGV

Assessment of Heavy Metals and Other Contaminants of the Gippsland Lakes 29

Appendix 8.6 Qualitative iTRAX on sediment core samples

Latrobe River Mouth – qualitative core scanning analysis