CLIENT
TfNSW
LOCATION
Tweed Heads, NSW

Our involvement

  • Preliminary Site Investigation (PSI).
  • Sampling Analysis and Quality Plan (SAQP).
  • Detailed Site Investigation (DSI).
  • Remediation Action Plan (RAP).

Project challenges

The Conceptual Site Model (CSM) for the site was complex, of note: fill was historically imported to raise site levels; there had been lack of pavement cover for many years; historical use of antifoul paints with poor environmental controls adopted; and, a tidal influence on the site from Terranora Creek.  Other challenges included time and budget constraints, a pressing need for boat repairs for local businesses, and significant flooding during the investigation phase. The investigations identified antifoul contamination and potential risks to ecological receptors of Terranora Creek.

Our solutions

To assess identified ecological risks to receptors, additional sediment and river water sampling was undertaken and laboratory analysis for Tributyltin (TBT) and other heavy metals using the USEPA Leaching Environment Assessment Framework (LEAF).  This analysis represented tidal action leachate from the contaminated sediment/soil into the Creek. Based on the results of the LEAF analysis JKE recommended a CSIRO subject matter expert be engaged to provide advice. JKE and the CSIRO expert devised and implemented a creek water sampling programme which indicated concentrations of TBT and other heavy metals in the soil/sediments at this site are unlikely to pose a significant impact on the health of the aquatic marine ecosystem if left undisturbed. Consequently, a cap and contain remedial strategy was proposed in the RAP, with a Long-Term Environmental Management Plan (LTEMP) be prepared and implemented following successful remediation.