Toxic Plume may reach Docklands
The Age
TOXIC sediment in the Yarra stirred up by port dredging could spread as far as upmarket Docklands, the Port of Melbourne's environmental effects statement on channel deepening reveals.
It also emerged yesterday — the day the Port of Melbourne's report went public — that one of the two massive boats owned by the Dutch company hired to dredge Port Phillip Bay was this month involved in a horrendous collision in the Chinese port of Tianjin. The collision, on March 7, will throw out dredger Boskalis' schedule for at least nine months.
And the Port of Melbourne has conceded it could be years before larger ships use the channel, because current trade volumes were too small to warrant larger vessels. Port of Melbourne Corporation chief executive Stephen Bradford yesterday said current trade volumes were too small to warrant larger vessels.
"It's a bit like having a B-double (truck) and only using half the B," Mr Bradford said. "It doesn't make any sense. The channel deepening is a 30-year project, so will the 14-metre draught vessels arrive on day one? No."
A study by PricewaterhouseCoopers predicts container numbers will be the same whether or not the project goes ahead. Either way, trade is expected to jump from 2.1 million containers in 2010 to 7.1 million by 2035.
The Port of Melbourne's 12,000-page environmental effects statement revealed that plumes of contaminated silts in the mouth of the Yarra, stirred up by dredging, would spread as far as the William Street turning basin in the city, and deep into Port Phillip Bay. "I wouldn't really be wanting to own a property at Docklands at the moment," Blue Wedges Coalition spokeswoman Jenny Wharfe said.
Huge amounts of industrial waste from industry were poured into the Maribyrnong and Yarra rivers until the 1970s, and much of the toxic waste remains settled on the bottom of the Yarra River's mouth.
This will be unsettled during dredging, when the port says it will remove 90 per cent of the seabed floor at the river mouth.
Highly toxic spoil being removed from the Yarra will also be dumped in the bay, the channel deepening report says. The report predicted that dredging would turn water murky at beaches as far away as Altona and St Kilda. "And we are going to have fairly murky-looking water from Dromana to Sorrento when they are dredging in the south of the bay," said Ms Wharfe.
A technical report by consultants SKM completed for the report says the dredging will generate vast amounts of sediment and remobilise toxic algal cysts. "These can cause toxic algal bloom," Monash University water studies centre biologist Simon Roberts said. "Paralytic shellfish poisoning is caused by algal bloom. It can kill us, it can kill fish — it is deadly," Dr Roberts said.
The report gives a frank assessment of the effect of the planned dredging next year on Port Phillip Heads, and of trial dredging there in 2005. Falling rock from planned dredging is expected to damage 18 hectares of the reef for up to five years.
Perhaps most strikingly, the report details for the first time the copious amount of loose rock that fell in 2005 onto delicate sea sponges and coral that live at the entrance to the bay.
During the channel deepening trial in 2005, up to 6000 square metres of loose rock fell into the canyon where the sponges and coral live, the report said. In 2005, the Port of Melbourne was embarrassed to admit that just 20 cubic metres of rock had fallen into 30-metre deep water. "If we had continued dredging it would have been much worse," Mr Bradford said. "There will be rock fall during the major project and it will fall into the canyon."
Rocks and rubble will also plunge into the Point Lonsdale National Marine Park, mapping of the planned dredging shows.
Victorian Recreational Fishing yesterday lashed out at the Port of Melbourne. The potential damage to the bay's ecology was "much worse than we had previously anticipated", chairman Bob Pearce said.
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