Century has several programs in place to minimise and monitor the impacts of its operations on the township of Karumba and surrounding waters.
Sea grass and sediment monitoring
An extensive monitoring regime is in place in the Norman River and surrounding marine environments to ensure that Century’s Port operations are not impacting local fisheries. This regime has been in place for more than 10 years.
The regime includes:
• Routine monitoring of water discharges to the Norman River;
• Sea water, seagrass and sediment sampling; and
• Regular monitoring of commercial fisheries using samples of barramundi, grunter and mud crab.
Samples are frozen and transported to the Charles Darwin University for analysis. This analysis includes comparing metal and arsenic concentrate and lead isotope ratios to the current Food Safety Australia New Zealand Standard (FSANZ, 2009).
Over more than ten years, results have consistently shown that Century’s operations are not impacting on the local marine environment.
Century carefully manages stocks of zinc and lead concentrates stored at its Karumba Port facility prior shipment. This is because, due to its nature, zinc can begin to emit sulphur dioxide emissions under certain conditions, particularly if stored for an extended period.
Sometimes unforeseen circumstances mean that concentrates occasionally need to be stored for longer periods. If this occurs, Century implements additional controls to manage zinc stocks and minimise potential sulphur dioxide emissions. Emissions monitoring is also conducted within the storage facility.
The detection of emissions at certain levels within the facility triggers a community monitoring program, which involves air monitoring at designated locations surrounding the facility.
Residents are also notified of the commencement of the program and readings at designated areas.
It is important to note, however, that it is unusual for emissions to be detected outside the storage shed.
The monitoring program was implemented in 2009 following consultation with residents and other stakeholders.
In addition to zinc, Century also produces quantities of lead concentrate.
Century takes all precautions to limit exposure to lead by its workforce and residents of Karumba. These precautions include specific procedures for the handling of lead and stringent hygiene practices.
Another precaution is monitoring of the in-blood lead levels of employees and contractors.
To give residents and visitors peace of mind, Century also offers members of the community the opportunity to have their lead in-blood levels tested each year. Testing is free and available over several days.
Following analysis by an independent laboratory, individual results are provided to residents. All results also remain confidential.
Water tank monitoring
Rainwater tanks are common in Karumba, which can have periods of low rainfall. While most water from these tanks is used for gardening, some is used as potable water.
Century commissions the sampling of rainwater tanks throughout Karumba prior to and after each wet season. The sampling process tests for total concentrations of arsenic, cadmium, lead and zinc against the Australian Drinking Water Guidelines (ADWG).
As each sample is collected, other information – such as the size of the tank, tank age, volume of water held, use of collected rainwater, cleaning history, the presence of a first flush diversion and construction material – is also obtained.
After testing at an independent laboratory, the results of each sample are provided to participating residents.
Century works with individual residents to determine an appropriate course of action if water in a particular tank is found to exceed ADWG. This occurs even if the exact source of the metal cannot be determined.