Residual contamination and environmental effects at the former Vanda Station, Wright Valley, Antarctica
Thesis DisciplineWater Resource Management
Degree GrantorUniversity of Canterbury
Degree NameMaster of Water Resource Management
Antarctica is regarded as a pristine environment, free from anthropogenic impacts. However, environmental contamination in areas of human occupation has occurred and can persist long after occupation ceases. Residual contamination of the land on which the former Vanda Station was built, remained following the stations decommissioning and site remediation in 1994. Since then the level of Lake Vanda has risen flooding most of the contaminated site. A re-evaluation was carried out to determine whether the flooding had allowed contaminants to enter the lake itself. Contamination was not found in the water column of Lake Vanda above the now flooded soils where contaminants had previously been found. Concentrations of trace elements, nutrients and organic compounds measured in the water were all within the natural concentration range in Lake Vanda. Observations of benthic cyanobacteria in affected and control sites indicated slightly enhanced growth at affected sites. Phosphate fertilisation may be contributing to this luxurious growth, and there appears to be no inhibition due to toxic trace elements. This study identified two fuel spills on the remaining unflooded land near the footprint of the former station. These soils contained elevated total petroleum hydrocarbons (TPH 2400-8900mg/kg), and the trace metals Pb (max 98.16 mg/kg) and Zn (max 158.16 mg/kg). These metal concentrations exceed ANZECC sediment guideline values and TPH exceeds the lowest observed effect concentration for Antarctic mosses. Toxicity characteristic leaching procedure (TCLP) results indicate the potential for Pb and Zn leaching from these soils in both acidic and neutral pH waters. While similar levels of contamination were found in Vanda Station soils in 1993 and 1997, and have not resulted in obvious adverse effects, the remediation of former work sites in Antarctica is required under The Madrid Protocol. The opportunity for minor remediation of these exposed soils, and the collection of litter and painted rocks exists. This process is recommended to remove sources of contaminants to Lake Vanda permanently in keeping with The Madrid Protocol.