The department water sampling program – post-Binary fire incident

The department water sampling program

Since the fire in August 2005, the department has been conducting a water-sampling program in Saltwater Creek and areas affected by contaminated firewater.

About 2.7 million litres of water was used to bring the blaze under control. Firewater contaminated with the chemicals stored in the Binary factory flowed from the site into a nearby tributary of Saltwater Creek.

Quick action by Caboolture Shire Council during the fire contained most of this firewater runoff to a 700m section of a tributary of Saltwater Creek. This firewater was bunded into four containment ponds on State land to prevent the spread of contamination during the 2005/2006 wet season.

However, due to the intensity of the fire, action to bund the contaminated fire runoff water was delayed for approximately four to five hours resulting in some of the firewater flowing into Saltwater Creek.

The day after the fire, the department collected water samples from Saltwater Creek, past the bunded areas, to assess the extent of the contamination in the waterway. This testing covered 175 chemicals.

Since then, the department has continued to collect water samples (grab samples) from a broader range of sites in Saltwater Creek and areas affected by contaminated firewater.

Map of sampling locations (PDF, 330K)*
Full report of grab water sampling (PDF, 1.1M)*

Passive sampling has also been conducted in Saltwater Creek to give an average contaminant concentration over the period of deployment (4 weeks), particularly during significant rain events.

Passive sampling results (PDF, 319K)*

How is passive sampling different from grab sampling?

Grab water samples provide a snapshot of contaminant concentrations at the time of sampling. Passive samplers, which are placed in a waterway over a number of weeks or months, provide an average contaminant concentration over the period of deployment.

Because passive samplers accumulate contaminants out of the water column as it flows past, the passive samplers provide a concentration value. This means that contaminants can be detected at lower concentrations than is possible with grab sampling.

The results of both the grab sampling and passive sampling programs have been compared against the ANZECC Guidelines for the protection of freshwater ecosystems.

What chemicals were tested for and why?

Different sets of chemicals were included for various sampling occasions depending on the purpose of each sampling. For some samplings, the purpose was to ascertain what was in the creek while for others the purpose was to track how far downstream the contaminant plume had spread.

Initial testing after the fire covered 175 chemicals to determine what contaminants were present in the creek. This testing covered all the major classes of chemicals involved in the fire - organophosphates, organochlorines, synthetic pyrethroids, phenoxy herbicides, glyphosate. Both LCMS (liquid chromatography mass spectrometry) and GCMS (gas chromatograph mass spectrometry) analyses were conducted by Queensland Health Scientific Services, which is registered with the National Association of Testing Authorities (NATA) for all these chemicals.

Secondary testing to track the contaminant plume covered the chemicals with the highest concentrations in the creek - glyphosate and 2,4-D.

As the department had some knowledge of the types of chemicals stored in the Binary factory, soil testing for the timber treatment chemical copper chrome arsonate (CCA) was also conducted. Soils and sediments that had been in direct contact with the contaminated firewater were tested for metals, including copper, chrome and arsenic. The testing showed CCA levels were not of concern and no further testing was conducted.

Where were the sampling locations and why were they chosen?

Sampling sites were selected representative of where the contamination may have spread and according to their distance from the point where the contaminated water entered Saltwater Creek.

This resulted in sites being selected in the dry creek bed beside the Binary factory site, then progressively downstream as far as the west end of Jones Street at Rothwell. There were also reference sites selected upstream, away from areas directly affected by contaminated firewater.