Jane MacDonald - Save Ralphs Bay

More documents

Recommendations

Info

in sediments and levels resulting from elutriate tests” but, instead, the surprisingly high levels of mercury found in Ralphs Bay biota, especially flathead, whilst the mercury levels in Ralphs Bay sediments and water are not correspondingly elevated to the same degree. The importance of this is that mercury in Ralphs Bay may be in an especially bioavailable form, and, whatever form it is in, it is entering the food chain and bioaccumulating at high levels. A higher proportion of flathead from Ralphs Bay contain mercury at levels above the Food Standards Australia and New Zealand (FSANZ) guideline than at other sites sampled in the estuary (fig. 4.63 on p. 162, Nyrstar Triennial EMP 2007‐08 and fig. 4.76 on p. 146 of the Nyrstar 2008‐09 EMP Annual Review). These fish are not suitable for human consumption. The most significant reason to be concerned about environmental pollutants is if they are toxic or otherwise harmful to living organisms. Thus the high levels of mercury entering the food chain in Ralphs Bay are a matter of significant concern. A precautionary approach to disturbing Ralphs Bay sediments would help to ensure that, whilst Ralphs Bay mercury in flathead levels are already high, remobilised mercury resulting from sediment disturbance would not exacerbate the problem. Table 4.19 on page 164 of the Nyrstar Triennial EMP 2007‐08 provides a statistical review of mercury levels in flathead for the five monitoring regions, between 1991 and 2007 (table reproduced on the following page). It is significant to note that, • In the 17 years’ worth of data presented, mercury levels in Ralphs Bay flathead were at or above the ANZFA guideline (0.5mg/kg) in 13 of the 17 years. • Mercury levels were higher at Ralphs Bay than at all other sites in 8 of the 17 years, including in 4 of the 5 most recent years for which data is reported. • Ralphs Bay provided 3 of the 5 highest ever levels of mercury in flathead shown in the 17 year data set, and the 3 rd highest figure was a runner‐up to the Ralphs Bay level, in 1994. • This is in spite of the fact that environmental monitoring shows higher levels of mercury in sediments and water at the “Above Tasman Bridge” location, as would be expected. Jane MacDonald, submission on DIAR Page 10
Table 4.19 Statistical review of mercury levels in flathead for the five monitoring regions, 1991–2007. (units are mg/kg) Returning to the DIAR, Dr. Treloar’s statements reported on page 18 give further cause for concern: “Dr Treloar noted that the CSIRO figures show a net export of sediment from Ralphs Bay and that modelling of sediment movement from construction and the resuspension of sediments from the finished development indicate that the changes would be very local. Nevertheless, Dr Treloar conceded that there could be a significant impact on sediment transport in Ralphs Bay although it was very unlikely such sediments would reach the handfish colonies.” Whilst visible sediments may (or may not) be transported over short distances, the continued transport of metals in soluble forms over longer distances remains an issue. Considering that heavy metals in Ralphs Bay have travelled many km from the zincworks and the paper mill, it is a significant concern that such pollutants could affect handfish colonies and, indeed, travel around the South Arm Peninsula to have an impact on aquaculture operations in Pipeclay Lagoon. (See fig. 6, General circulation pattern for coastal waters in southeast Tasmania, Bruny Bioregion Background Report, RPDC). It is believed that the Derwent is the source of high metal levels found in oysters as far away as Pittwater. Jane MacDonald, submission on DIAR Page 11
Page 1 and 2: Jane MacDonald November 22 2009 Sub
Page 3 and 4: 3.1.2 Strategic planning generally
Page 5 and 6: a significant impact on the species
Page 7 and 8: I believe that the visual impact of
Page 9: I fully concur with the Panel’s c
Page 13 and 14: “development” might travel to t
Page 15 and 16: Australia have been weather related
Page 17: Based on the evidence presented, I

Jane MacDonald - Save Ralphs Bay

Create successful ePaper yourself

Delete template?

Save as template?