From the 1950s until 2002 the PTA leased railway land to private entities that operated the Three Sisters Service Station. During this time contaminants (from common retail fuel products) leeched into the soil and groundwater. The contaminants are not considered to pose a risk to the community if they remain on site, however they could have adverse affects on human health or the environment if the impacted groundwater was to be used for irrigation from household bores.
The contaminated site (located in Gosnells directly SW of Albany Hwy between Dorothy and Gerald streets adjacent to the railway line and Gosnells Police Station), is currently fenced and vacant.
In October 2014, the PTA started remediation works to treat the ground contamination, through a process called Solvent Enhanced In Situ Chemical Oxidation. This involves pumping organic solvent and oxidants into the soil to convert hydrocarbon contaminants into less harmful products such as carbon dioxide and water.
The works were completed and some additional remediation has been undertaken, involving skimmers and suction trucks to physically remove remnant hydrocarbon contaminants from wells in the soil. The status of the site, and of the plume of dissolved hydrocarbons in the groundwater, are still being monitored.
Removing the soil and groundwater contaminants will reduce the risk of hydrocarbon vapours affecting those in immediate proximity, and will allow the area to be re-classified for possible productive use.