Sunflowers bloom in landfill
by Kelly Stone
Sunflowers have bloomed on a former landfill site north of Adelaide as part of a joint research project conducted by UniSA, the CRC for Contamination Assessment and Remediation of the Environment (CRC CARE) and the City of Salisbury.
Scientists from UniSA and CRC CARE are using the giant flowers, along with other plants, to remediate the Coleman Road site near St Kilda which closed as a landfill dump in the early 1990s.
They are also examining the potential value of bio-solids, the final product of sewage treatment, in revegetating the site, and say that ultimately the dump could be turned into a park and education resource centre in years to come.
"The main object is to stabilise the site by revegetating the highly acidic soil," said UniSA’s Professor Nanthi Bolan.
"We want to provide vegetative cover, and as part of that we’re investigating whether you need other soil amendments such as bio-solids to successfully achieve a green belt.
"One of the important aspects is using the plants to pump water upwards, to reduce any leaching from the site."
CRC CARE postdoctoral researcher Dane Lamb has been applying bio-solids to sunflowers, Indian mustard and Arundo plants in trial plots at the site.
"The soil has a high pH and there aren’t a lot of nutrients and carbon, so we’re using bio-solids to improve the fertility of the soil," Mr Lamb said.
"We’ve found that when we use bio-solids it improves the soil’s fertility…the sunflowers and Indian mustard have responded well to the higher concentrations of bio-solids used in the plots.
"Sunflowers and Indian mustard are both hyper-accumulators of metals, which means if there’s contamination in the soils, the plant translocates a high amount of metals from the soil to the above-ground shoots. You can then harvest the plants and take away the metals."
Prof Bolan said the research team was pleased the bio-solids were making such a big difference to soil fertility in the trial plots at the site, with bugs and earthworms living in the plots.
"Ultimately we would like to be able to turn the site into a park and have a visitor resource centre on remediation and recycling for school students and the public, but that would be some years away yet," he said.
City of Salisbury’s Manager of Strategic Assessment Management, Andrew Wilson, said the council was pleased to work with UniSA and CRC CARE on the research project.
"There are benefits for the council in terms of remediating the site and there are also community benefits, because we get to work with UniSA and CRC CARE to promote innovation," Mr Wilson said.