Parker not surprised by contaminants
It’s no surprise that contaminants have been found at the aluminium smelter site at Tiwai Point, Environment Minister David Parker says.
Last week Rio Tinto, which owns New Zealand’s Aluminium Smelter, near Invercargill, released a Detailed Site Investigation, which had been carried out as part of studies to ensure the site was remediated to the required level upon its closure.
The smelter warned that contamination results at the site ‘‘might cause concern to people’’.
Parker said he welcomed the release of the detailed site investigation report.
‘‘It’s no surprise that contaminants have been found at the aluminium smelter site on Tiwai Point.
‘‘The release of the report is a step in the right direction to guide this significant and complex remediation work,’’ he said.
Environment Southland was the responsible authority for leading the cleanup and remediation of the Tiwai Point site, and it has contracted environmental consultants to analyse the detailed site investigation report, Parker said.
The smelter engaged GHD to assess existing information to identify areas of the site most likely to be contaminated, and samples were collected of soil, groundwater, and drain sediment for laboratory analysis.
Samples were gathered across 238 locations, mostly at levels 10cm and one metre below the surface.
In total, GHD found 83 per cent of groundwater samples exceeded guidelines within the New Zealand Drinking Water Standards and Environment Southland groundwater rules.
In May, Rio Tinto confirmed it would remove all spent cell lining, a hazardous by-product produced the aluminium smelting process, from Tiwai Point near Bluff. It has also verbally indicated it would collect all remaining ouvea premix in Southland and return it to Tiwai Point to be stored, and cover the existing shortfall in funding, expected to be $2.5 million, for that to occur, the document says.
In July 2020, Rio Tinto announced it would wind down operations at the smelter, which employs more than 1000 people, by August 2021 because of high energy and transmission costs. However, after it reached an agreement on a new electricity agreement with Meridian Energy, operations were to continue until December 31, 2024.
Aluminium prices have nearly doubled since April last year to trade at a near-record high of $2943 (NZ$4247) a tonne, fuelling speculation that Rio Tinto will seek a new power deal to keep the smelter open beyond 2024.