By VERONICA ANASSIS
Stormwater debris from suburban gutter and land pollution are destroying Sydney Harbour, smothering marine life and creating uninhabitable areas called “dead zones,” say researchers.
According to the Sydney Institute of Marine Science (SIMS), they’ve found patches of harbour water where no signs of life, not even bacteria, can exist due to low levels of oxygen. These “dead zones” were found in close proximity to litter-laden storm drains, and correlated with excessive organic contaminants.
Sydney Harbour has a very high concentration of microplastics, hostilely taking over of the fragile ecosystem’s food chain. Plastics notoriously never perish – but do break down over time into tiny specs. Ingested by invertebrates, they then get eaten by fish. Plastics sit stubbornly in the gut and accumulate as they’re passed on from predator to predator. Because recreational fishing is not banned in Sydney Harbour, contaminants routinely make their way to human plates from the day’s catch.
According to recycling company TOMRA’s latest information video Sydney Harbour: Above and Below, 37,500 cubic metres of pollution (equivalent to 15 Olympic sized swimming pools) sinks into the harbour bed per year. Two thirds is derived from storm water run-offs.
Below the serene, glistening Sydney Harour, an estimated 900 tonnes of lethal waste lurks in its underbelly. Turtles, seals and birds regularly mistake rubbish for food, clogging their intestines and choking their throats. They get entangled in plastic death-traps of bags and finishing line and cannot get away, resulting in slow and painful fatalities.
Circling the drain
But it’s not just locals in surrounding harbour-side suburbs that are the problem. Litter debris can travel long distances, and just as likely to come from as far away as Sydney’s southern beaches, due to the common direction of prevailing winds. A deluge of pollutants get washed in on “every single rainfall event,” says Dr Katherine Daffornn, Deputy Director of the Sydney Harbour Research Program SIMS, especially when gross pollutant traps are ineffective.
“In inner Sydney suburbs storm drains overflow where there are no gross pollutant traps or nets fail or are damaged,” Dr Daffornn said. “It’s just chocking the waterways with plastics.”
Robert Allen, Lead Networks Programs Scientist for Stormwater and Natural Assets at Sydney Water, says gross pollutant traps (GPTs) are effective at trapping rubbish before they enter major streams, but the problem is lack of maintenance.
“Most organisations [like] Sydney Water have good… programs to clean out the GPT’s properly, but some organisations don’t. This is either due to lack of funding, or lack of knowledge on how to maintain the traps properly.
“They need to be inspected and cleaned out regularly,” Mr Allen added, “otherwise they won’t work properly and can wash out trapped rubbish, especially during rain events.
“Large amounts of rubbish are also moved via the wind, off major roadways. This rubbish doesn’t even have a chance to be caught in a GPT.”
Deep sea striving
All parties can agree the most effective and viable solution is to stop the rubbish entering the environment in the first place. But many are taking clean-up measures in their own hands to rectify the existing damage. Project AWARE runs a ground-breaking program with Manly Dive Centre, which aims to excavate as much plastic as possible in regular deep sea diving expeditions.
Their latest surveys found that one of the biggest source of waste is cigarette butts in the waters. Littered butts release toxic emissions of nicotine and pyrene within one hour of exposure into water as they decompose, toxic to small crustaceans and bacteria.
But Project AWARE said they have seen a reduction of plastic bottle sightings since the introduction of container deposit schemes, such as TOMRA’s ‘Return and Earn’ program. This processed 5,721,464 numbers of containers in NSW for National CleanUp Day on September 21st alone.
Dr Daffornn urges more government support for these initiatives and top-down government policy and incentives, as well as bottom-up decision making.
“On the bottom-up side of things, it needs to become a part of our everyday lives to use metal straws and re-usable cups; make it the norm that cafés aren’t using single-use plastics any more,” she said. “If we don’t stop the use of single-use plastics, it will just continue accumulating. It won’t make a difference unless we stop causing the problem.”
It’s predicted that even if water pollution is stopped now, the effects of the current waste will be felt for decades, or even centuries.