PO Box 162

VIC 3936


Review of Documents (not released in the SEES) which relate to contaminated sediments.


Dredging and disposal of an estimated 3 million m3 of contaminated sediments from the bed of the Yarra River has serious implications for the marine food chain, social impacts, and human health.


The first Planning Panel which assessed the Channel Deepening Environment Effects Statement in 2005, considered the failure of Port of Melbourne Corporation to present a key report on toxicity in the Yarra sediments to be a significant procedural defect. Consequently, this issue was required to be addressed by further studies in the Supplementary Environment Effects Statement (SEES).


The Channel Deepening SEES released for public comment in March 2007 omitted key documents relating to contaminated sediments in the Yarra and associated water quality issues. The public was therefore denied the opportunity to critique these reports in submissions to the Public Inquiry. 


The documents are:


·        Minor Maintenance Dredging Campaign. Water Quality Monitoring in the Dredge and Disposal Plumes. Hale. J. 2006. December 2006


·        Baseline Benthic Fauna Surveys for the Port of Melbourne DMG, SE DMG and Yarra River Estuary. Sinclair Knight Merz. Sept 2006


·        Bioaccumulation Study. Sinclair Knight Merz. April 2006


Blue Wedges is of the view that failure to include these documents in the SEES is a gross breach of public process.


In addition, the documents also contain instances where elevated levels of toxins are overlooked and data is interpreted in a way that casts a more positive light on the Channel Deepening Project than is actually the case.


This paper has been prepared for the benefit of the members presiding over the SEES Public Inquiry to highlight areas relevant to a more proper assessment and to assist their observance of natural justice and proper public process.

The Hale Report


This Report on water quality sampling[1] was relied upon for the Head Reports on Human Health and Social Impacts. The Blue Wedges submission to the Public Inquiry included the following criticism of water quality reporting used to inform the Head Technical Report on Human Health.


In relation to ‘Surface Water Data Set screening and modelling’ Golder 2006 (p. 19) states:


“The surface water data set was derived from Jennifer Hale (2006) as these were measured water quality values resulting from maintenance dredging activities in the Yarra Port area (where sediments are known to be contaminated by a range of chemicals). Water samples were filtered after collection and analysed for metals and a range of other parameters. The reported concentrations are considered to be predictive of dissolved phase chemical concentrations in contaminated areas.”


“It was concluded that the empirical data set derived from maintenance dredging activities (Hale, 2006) was the most representative of the available data of the surface water concentrations representing dredging activities.” 


Hale. J. 2006. Minor Maintenance Dredging Campaign. Water Quality Monitoring in the Dredge and Disposal Plumes. Draft 1. August 2006 is referenced in the bibliography of the Golder Report, but the Minor Maintenance Dredging Campaign report has not been included in the Technical Appendices (neither hard copy or CD form). Nor are there any other reports in the Golder HHRA bibliography relating to “maintenance dredging” and water quality.


When the Hale report was made available (during the course of the Inquiry) it became evident that the water quality sampling was collected during a minor back-hoe dredging operation, as opposed to a major suction dredge operation; and none of the sampling locations were in the Yarra, which is widely regarded as the most toxic area.


The issues raised in the Blue Wedges submission met with the following response from PoMC[2].


304.      There have been various criticisms made of the limitations in scope of the reports done by Hale and Enesar during the trial dredge program.


305.        The Hale report has been provided to the Inquiry. It specifically stated:


There were potential sources of error from sampling and analyses of results, and the decision to omit dissolved fraction analyses for metals and nutrients, although based soundly on the findings of previous investigations, made interpretation of results difficult. Therefore, it is recommended that further investigations of the sediment characteristics in both the north and the south of the Bay be undertaken. This should include elutriate testing of sediments down to the depth of proposed dredging and following EPA (2001) and Environment Australia (2002) guidelines.


In fact, no such statement, or anything remotely like it appears in the Hale Report.

Baseline Benthic Fauna Surveys[3]


A copy of the Baseline Benthic Fauna Surveys for the Port of Melbourne DMG, SE DMG and Yarra River Estuary was handed to Blue Wedges around 3.30pm on the July 24, 2007 by Mr Gobbo SC Counsel for the PoMC after the last public presentation. We note it was made available to the Blue Wedges toxicity team after their last chance to contribute to the inquiry process.


This study is highly relevant to the CDP. Its expressed purpose was “to form part of the Baseline Monitoring Program for the CDP”. The data contained in this study reveals a link between contaminant levels and reduced biota. In particular, high levels of TBT and PAH were associated with reduced species abundance. Despite the important implications for the potential effects of the toxins on marine life, the Study overlooked this association. These effects have not been properly debated due to the failure of exhibition of this document. 


The data relating to the contaminated Yarra sediments are a case in point. Surveys were conducted in 8 locations:


·        TTS1        Williamstown Channel (adjacent Breakwater Pier)

·        TTS4        Williamstown Channel (Gellibrand Swing basin)

·        TTS7        Entrance to Yarra River

·        TTS12      Yarra River (south of Westgate Bridge)

·        TTS13      Yarra River (Swanson Swing Basin)

·        TTS15      Yarra River (entrance to Swanson Dock)

·        TTS19      Yarra River (entrance to Appleton Dock)

·        TTS24      Yarra River (opposite South Wharf 26)   


Figure 2 (below) shows significantly reduced biota at TTS12, TTS13, TTS15, and TTS19.      




Figure 2[4] (above) shows that TTS13 and TTS15 have the lowest number of taxa present. The Study interprets this as follows:


“The lowest abundance of infauna was recorded from Site TTS15 (17 organisms/0.1m2), near the entrance to Swanson Dock, and could be due to the resuspension of sediment caused by frequent shipping movements."


This interpretation totally ignores the probable link between elevated levels of TBT at TTS15 as shown in Figure 11 (below) 


Figure 12 (above) also shows that Site TTS13 (the other site with least abundant organisms) exceptionally elevated levels of Total PAH


However, no mention is made of these contaminants in the Statistical Analysis (p.18). The data is interpreted as follows: 


"No significant correlation was detected between the number of taxa and concentrations of lead, zinc, nickel, mercury or total DDT (P>0.05), suggesting that the differences in numbers of taxa between sites may be related to other factors, such as grain size or other physical factors such as disturbance from shipping."


High levels of toxins were found several kilometres outside the DMG and the predicted dredge plume, indicating:


·        Toxins have spread well beyond the DMG; and

·        The dredge plume modelling significantly understates the actual distance toxins travel from the DMG. 


This has implications for all the plume modelling done for the SEES. It throws into question whether any of the SEES plume modelling can be relied upon.


Figure 1 (below) indicates “Approximate extent of plume boundary based on CLT modelling.” Accompanying data reveals that there are elevated levels of DDT 4km south of the DMG, and around 3 km south of the “extent of plume boundary based on CLT modelling.”


Figure 19 (below) shows elevated levels of PAH recorded 4 km north of the Northern DMG.


Figure 20 (above) shows elevated levels of DDT recorded 4 km south of the Northern DMG, correlating with reduced numbers of organisms at sites to the south of the DMG (indicated in Figure 14, below).


The NODG screening level for Total DDT is 1.6 μg/kg. In Figure 20 (DMG), most values are at or above the screening level, and one (4000S) is way above (100 times). Despite, the obvious correlation at 4,000S between elevated concentrations of DDT and reduced taxa, the Statistical Analysis of the Port of Melbourne DMG samples (p. 19) states:


“None of the three contaminants which consistently exceeded the respective trigger values (ie. Mercury, total PAH’s and total DDT), were reported to be correlated with either the number of taxa or number of individual species, with the exception of total PAH’s and the number of Lubrineridae (P = 0.000, R2 =0.471).”


The discussion of the composition of infauna communities includes the following seemingly conflicting statements.


“Overall, the composition of infauna inside and outside the Port Melbourne DMG were similar.”


“The lowest abundance of infaunal organisms was recorded from the sites along the southern axis where numbers were consistently low across all four sites on the axis.”


“Infauna abundance along the western, eastern and northern axis generally increased with increasing distance away from the perimeter boundary of the DMG. This was particularly evident along the western axis.”


Important evidence relating to the impact on toxins on marine life and the extent of escape of toxins from the dredge material ground has effectively been hidden.

It has been hidden both by the way the data has been interpreted and by the concealment of these documents until after the public submissions and presentations had finished.


Bioaccumulation Study

Bioavailability and bioaccumulation

We note that the Inquiry wrote to the DSE on the July 24, 2007 in response to the presentations given by Blue Wedges on the toxicant issue asking for comments on our submissions “with respect to the bioavailability of the heavy metals and organic compounds identified as being present in the sediments of the Yarra River and Hobsons Bay in the SEES”. You also sought DSE’s advice on the potential for bioaccumulation of any of these materials. 


The purpose of the Bioaccumulation Study was “to Investigate the bioavailability of contaminants from the dredged material'[5] (p 3 and 4 of the bioaccumulation study). The study involved sampling mussels from the South of the Bay for contaminants, then taking them to points around the dredge material ground, leaving them there for six weeks, and then retesting them to see if they had been contaminated by the toxins from the dredge material. We wish to draw particular attention to the data regarding bioavailability of mercury, lead and cadmium.  


“There was a significant increase in the concentration of mercury in all transplanted mussels following the 6 week deployment"[6]


Clearly, the Study shows that mercury contained within the Dredged material is bioavailable and does bioaccumulate in the PPB environment.


“Concentrations of lead were significantly higher along the northern axis"[7]. This fact may be explained by increased concentrations of lead that were found North of the DMG - in the Benthic fauna survey[8] the authors note “Interestingly, lead concentrations tend to decrease with increasing distance away from the DMG along all axes except the Northern axis.” 


It is reasonable to conclude that the lead found at the DMG is also bioavailable and can bioaccumulate in mussels in the PPB environment.


“Cadmium concentrations in the transplanted mussels were generally higher than background”[9] and were “above maximum permissible” levels at two sites. 


It is reasonable to conclude that cadmium is bio-available and can bio-accumulate in the PPB environment.


Once again the authors of the study appear to be blind to the significance of this data. Despite the expressed purpose of the study being “to investigate the bioavailability of contaminants from the dredged material” they didn’t comment on the question of bioavailability in their discussion.


This document ought to have been available for public exhibition, so that the evidence could have been properly scrutinised. 


Blue Wedges submits that public safety cannot be assured by the Human Health Risk analysis as key heavy metals such as lead were excluded from proper analysis on the grounds they do not bioaccumulate. The Bioaccumulation Study shows that lead is bioavailable and does bioaccumulate in mussels in the PPB environment. 


Levels of Contaminants in mussel samples.


Cadmium levels in the transplanted mussels were above maximum permissible levels at two sites. This was after only six weeks of exposure to water in and around the DMG. We also remind the inquiry of the well documented toxicity of this substance, highlighted in Dr Lindsay Swinden’s presentation. 


The authors of the study state “all metal concentrations were well below the relevant food standards (where available), except cadmium. However, we question this, particularly in relation to lead. The MRL for lead according to our tables (sourced from the 2006 EPA fish and eel study[10]) is 0.5mg/kg. This MRL leaves most of the mussel samples taken from in and around the DMG in this study to be above maximum permissible levels. 


The authors of the Bioaccumulation Study used an MRL value of 2mg/kg (p16). We are unsure where the authors get this figure from as it certainly does not correspond with the tables we have. 


There were steep rises in the levels of TBT in the mussels exposed to the water around the DMG (p 20), with levels of TBT in the translocated mussels many times that of the background levels.


There is no permissible level of TBT in mussels (ANZFSC 2006), however the USEPA screening value for TBT is 1.2mg/kg. The levels of TBT in the translocated mussels were over 30mg/kg in one sample-well in excess of the screening value. 


We can therefore conclude that marine life exposed to toxins associated with dredged material can accumulate those toxins to levels exceeding safe levels. In particular lead, TBT and Cadmium are of concern. 


This information relates directly to Human Health and Marine Ecology risk assessments. The fact that this information was not made available in the SEES documents released for public comment is a failure of process of major proportions.


Limits of these studies


Whilst these studies are highly relevant to the inquiry, their limitations are worth noting. Namely:


The mussels were only studied over a six-week time period. In all probability, concentrations of toxins recorded would have been even more alarming had they had been left in the polluted water for a longer period. E.g. Cadmium levels were noted to increase but the increase was considered not statistically significant. If the study period had been longer, to better reflect the lifespan of a mussel, these differences would probably have become statistically significant. 


Contaminants that were found in high concentrations in the sediments at the DMG (in the baseline benthic fauna survey, were not necessarily considered in the bio-accumulation study. E.g. The levels of PAH were found to be very high in one part of the DMG but did not appear to be properly considered in the bio-accumulation study. 


Relevance to the Human Health Risk Analysis


The bioaccumulation study is very relevant to Appendix 60 of the SEES, the HHRA it does not appear to be listed in the reference section of Appendix 60.    Were the authors of the HHRA aware of the study? If not, why not? If they were aware of it, why did they not list it in the reference section?


Why, when the POMC had this information at hand, did they limit the terms of reference of the HHRA to exclude a proper analysis of the human health risks of heavy metal contamination?


Implications for the inquiry


·        Failure of process


·        Implications for Human health and PPB fisheries.


·        We now have evidence that heavy metals such as lead, mercury and cadmium are bio-available and can bio-accumulate in the PPB environment. 


·        Public safety cannot be assured. 


We call on the Inquiry to recommend strongly against the project proceeding.

Yours sincerely,

Blue Wedges Inc

[1] Hale. J. 2006. Minor Maintenance Dredging Campaign. Water Quality Monitoring in the Dredge and Disposal Plumes. December 2006

[2] Submissions In Reply for the Port of Melbourne Corporation. Minter Ellison Lawyers. July 2007

[3] Baseline Benthic Fauna Surveys for the Port of Melbourne DMG, SE DMG and Yarra River Estuary. SKM Sept 2006

[4] Baseline Benthic Fauna Surveys for the Port of Melbourne DMG, SE DMG and Yarra River Estuary. SKM Sept 2006 (p. 12)

[5] p 3 and 4 Bioaccumulation Study. Sinclair Knight Merz. April 2006

[6] p 25 Bioaccumulation study

[7] p 25 Bioaccumulation study

[8] p 23 Bioaccumulation study

[9] p 13 Bioaccumulation study

[10] Maribyrnong and Yarra estuaries: investigation of contamination of fish and eels, EPA, 2006.