Even though the water quality in the harbour is much improved,the high levels of dioxins in areas where fish feed means the warning not to eat fish caught west of the Harbour Bridge,and to eat only 150 grams a month of fish caught east of the bridge,will likely remain for decades.
The data,collected by the NSW Department of Environment,Climate Change and Water in 2008,shows that large tracts of sediments in the harbour are more contaminated with dioxins than Tokyo Bay or New York Harbour,and are among the most contaminated in the world.
The department sampled more than 25 sites. They showed that directly outside the remediation area in Homebush Bay dioxin levels were 610 picograms per gram of sediment compared with 2.3 for a relatively pristine estuarine environment.
But there were also readings of 350 picograms 10 kilometres up the Parramatta River and significant readings as far east as Rozelle.