What is groundwater pollution?
Groundwater is water that accumulates below the ground's surface. Groundwater forms when rainfall and run off, seeps down through the soil surface, filling up the pores between rocks and sand particles until it reaches an impermeable layer. Like all water bodies, groundwater flows downhill and while a lot of groundwater eventually reaches a discharge point such as a wetland, river or the sea, some groundwater pools deep underground and may never reach the surface.
Groundwater, extracted via bores, has long been used for domestic and industrial purposes. Over extraction or contamination of groundwater can have long-term impacts by reducing the volume and quality of groundwater available to the ecosystem. The NSW Department of Primary Industries - Water (DPI-W)is responsible for the management of groundwater resources in NSW. All works connected to a source of underground water and used for water supply, groundwater monitoring, dewatering, or any other purpose must be licensed by the Department.
What is the Botany Sand Beds aquifer?
The Botany Sands Aquifer is a large body of groundwater beneath the dunes that skirt Botany Bay and extends from Botany Bay northwards to Surry Hills and Centennial Park. Groundwater within the aquifer is readily recharged by rainfall and generally flows in a northeast-southwest orientation, from Centennial and Moore Parks into Botany Bay and the Botany Wetlands.
The Botany Sand Beds Aquifer is relatively shallow, often less than 1-2 metres below the ground surface and has been an important groundwater resource for Sydney’s south eastern suburbs for many decades. Water is still pumped from the aquifer by industry, golf courses and residents.
Due to the permeability of the sands, shallowness of the aquifer and a long history of industry in many parts of the aquifer's catchment, the Botany Sand Beds Aquifer has been and continues to be, highly vulnerable to contamination. Over the last 100 or so years tanneries, wool scourers, metal platers, service stations, fuel depots, tips and dry cleaners operated with no environmental controls. As a result, chemicals such as chlorinated hydrocarbons and other solvents, petroleum hydrocarbons (such as petrol and diesel), and some heavy metals (chromium, nickel, lead and arsenic) may have contaminated the aquifer. Legacy pollutants from these industries may still continue to leach into the aquifer. This is a legacy that we are working to manage.
What areas are affected?
There are several groundwater sites in the former Botany Council area which are in the process of being cleaned up or have a site management plan. The NSW Environment Protection Authority (EPA) is the lead agency responsible for managing contaminated groundwater and clean-up strategies for significantly contaminated sites. A list of these sites can be found in the EPA Record of Notices. The NSW Department of Primary Industries - Water assists by supplying technical information, establishing the beneficial use of aquifer systems and restricting the take of groundwater, if necessary.
Groundwater management in Botany Sand Beds aquifer
Given the history of the area, the shallow water table and highly permeable soils, a precautionary approach to managing groundwater use in the area has been taken by the The NSW Department of Primary Industries - Water to ensure public health is not put at risk from exposure to potentially contaminated groundwater. As a number of contaminated sites in the Botany Bay area have resulted in the contamination of groundwater in the aquifer, the NSW Office of Water has developed a management approach for the Botany Bay Sands Aquifer.
Based on the NSW Government’s concerns about contamination in the Botany Bay Sands Aquifer Area, the area has been divided into four groundwater management zones.
In Zone 1, all use of groundwater is prohibited. In Zones 2,3 and 4, all domestic groundwater use is banned and all industrial users must test their bore water annually and provide results to the NSW Office of Water. There is also an embargo on new applications for licences to extract groundwater from the Botany Sands Aquifer.
Contamination at the Orica complex
Orica (formerly ICI Australia) has operated a chemicals manufacturing facility at the Botany Industrial Park since 1942. Poor environmental management and waste disposal practices up until the 1980's, resulted in significant amounts of chemicals contaminating the underlying soil and groundwater. Orica has been in the process of remediating its contaminated sites and groundwater since the 1990's. Bayside Council, in conjunction with NSW Environment Protection Authority continues to monitor the Orica clean up and is a member of the Orica Botany Liaison Committee (OBLC).
Information on the groundwater contamination and remediation projects occurring at the Orica Botany site, can be found at Orica Australia or by calling Orica's Community Hotline 1800 025 138.
Independent review into off-site mercury at Orica Botany
In January 2013, the NSW Environment Protection Authority announced that it would conduct an independent review of all information around historical mercury emissions at Botany.
The comprehensive review is overseen by a steering panel, which includes representatives from:
- NSW Environment Protection Authority
- the community
- Bayside Council
- Randwick Council
- Office of Environment and Heritage
- NSW Health
- an expert toxicologist
The review assesses the potential for health risks to the adjacent community associated with mercury emissions from the former plant. Further Information can be found at the following links.
Other contaminated sites
Although contaminated sites can occur anywhere, they are typically clustered in areas that have been used for industry. Land contamination is significant in parts of Bayside Council, as some places have been heavily used by industry for at least 100 years. Much of this industrial use occurred before any environmental protection controls were in place or even considered necessary. The identification, investigation, clean-up and management of contaminated sites is important to protect our health and our environment. Due to the industrial history of the area there are several properties in the Bayside Council area that are in the process of being cleaned up or have a management plan in place.
The NSW Environment Protection Authority is the agency responsible for formulating guidelines for contaminated land investigation and management, and for managing contaminated land and clean-up strategies for significantly contaminated sites. A list of these sites can be found at the EPA in the Record of Notices. Council is responsible for assessing if a site is suitable for the intended use as part of Development Application process. Council also maintains a register of contaminated sites located within the City.
Contaminated land assessment
In accordance with the State Environmental Planning Policy No 55—Remediation of Land, Council requires contamination assessments to be submitted with all Development Applications where:
- the site is known to have been used for a potentially contaminating use or is otherwise suspected by Council to be contaminated
- where the Development Application is for residential or recreational development on land which has been used for any industrial or commercial purpose
- where the Development Application is for a child care facility or school regardless of site history
If a development requires remediation, a sign off that this has been achieved and a Site Audit Statement, which is an independent review of any or all stages of the site investigation process, may also be required.