Industry has been polluting the Botany Sands Aquifer of Sydney, Australia, for a century. More recent contamination with chlorinated hydrocarbons (CHC) led to action by the government of New South Wales, and the Orica corporation since about 2006. A new discovery made in 2011 may help significantly.
This is a lengthy period of time for a "crisis" or "disaster" to unfold, but by nature, the water moves slowly in this aquifer.
Background for the Botany Sands Aquifer Crisis
Captain James Cook named the south-east coastal region of Australia "New South Wales" in 1770. In 1788, the first prisoners were brought here by Britain. Despite Cook's recommendation, Governor Arthur Phillip decided that Botany Bay was not suitable for an agriculture-based prison colony. Sydney is some 20 kilometres north of Botany Bay.
As settlements eventually developed, this area became home to a variety of industries, including dry cleaners, landfills, metal plating factories, service stations and automotive depots, tanneries and wool processors. For many years, no-one paid attention to toxic waste and byproducts.
Hydrocarbons, including CHCs, solvents and heavy metals were accidently leaked or intentionally dumped from these industries. The ICI Australia company is considered most to blame for the recent, severe CHC contamination.
Introducing the Botany Sands Aquifer
The land surrounding Botany Bay is quite sandy. A large aquifer, called the Botany Sands Aquifer, drains water from the surrounding region down to the bay.
Water percolates underground in a south-west direction toward the bay. Traveling under 150 metres per year, it may take a century for all the currently contaminated water to escape or be treated.
The water table is quite shallow in most places, and the sandy ground is very permeable. These factors had made it all too easy to contaminate the aquifer.
Current Safety Measures for the Botany Sands Aquifer
The New South Wales government has issued guidance regarding domestic water use in the affected region. The basic message is, "Do not use the water for anything".
For example, there is a ban on pumping out fairly clean water for watering the lawn. Drawing on the aquifer would speed the underground spread of contaminants.
Current Remediation Measures for the Botany Sands Aquifer
The Orica corporation implemented the Botany Groundwater Cleanup Project to fulfill its mandate to remediate the Botany Sands aquifer. They extract the contaminated groundwater, then treat it to remove the CHC components.
This is an expensive and energy-intensive undertaking, but necessary to keep the pollution out of Botany Bay, the Tasman Sea, and the Pacific Ocean.
New Hope from a Surprising Source
In July 2011, researchers announced that some bacteria, already living in the contaminated aquifer, are able to metabolize some of the pollutants.
The tactic of "look for bacteria already in the toxic site" is reminiscent of other success stories in finding extremophile bacteria in hot springs or oil slicks.
This discovery is especially important for three reasons, although concerns do remain.
Learning from its problems with rabbits and other non-native species, Australia would not favour importing similar toxic-consuming bacteria. They wisely do not wish to set new invaders loose in their territory. However, the new-found bacteria were found right in the aquifer, so they are Australian natives (or at least have been naturalized).
Secondly, it should be possible to inject these bacteria "upstream" of the current processing facility. That would allow the bacteria to clean up the contamination all along the aquifer, rather than only at a downstream location. This may also reduce the total cleanup time.
Finally, any reduction in the time or volume of water to be processed would save money and energy. If the overall time is shorter, then the residents would be able to use their ground water all the sooner.
The major concern at this point is whether the bacteria can deal with all the toxic contamination. They might clean up CHC, for example, but leave the heavy metals in the water.
The Outlook for the Botany Sands Aquifer
The ongoing efforts by the government, by Orica, by researchers and by the community at large makes the long-term outlook hopeful for the Botany Sands Aquifer.
References:
Bob Beale, PhysOrg, "Beer-barrel bacteria breathe toxic brew", Aug. 1, 2011, referenced Aug. 1, 2011.
New South Wales Government, "Botany Sand Beds aquifer", referenced Aug. 1, 2011.
Cathy Dunn and Marion McCreadie, Australian History Research, "The First Fleet", Aug. 27, 2010, referenced Aug. 2, 2011.
Orica, "Botany Groundwater Cleanup Project" and further linked pages within this site, Feb. 28, 2011, referenced Aug. 2, 2011.
Mike DeHaan - Copyright (c) Mike DeHaan, B. Math., of DeHaan Services. Well written and well researched freelance articles; ghost writing for clients.
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