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Moanataiari subdivision

Aerial shot of the Firth of Thames, including MoanataiariAbout the Moanataiari project

The Moanataiari subdivision in Thames was built on land reclaimed from the sea using old mine tailings, which can potentially contain elevated levels of heavy metals and other toxic chemicals. A significant cap of “clean fill” was reportedly used to cover the tailings. However, in 2006, while researching potential contamination of sediments in the Firth of Thames near Moanataiari, a Waikato Regional Council scientist identified the need to test surface soils at the subdivision to see if they might be the source of the sediment contamination. The regional council prioritised Moanatairi for further investigation along with other sites, including the Tui Mine, Rotowaro Carbonisation Plant and Cambridge Gasworks.

The council investigates one contaminated site a year and testing of Moanataiari roadside soils took place in October and November 2011. These tests confirmed the presence of elevated levels of arsenic above recommended guidelines for residential soils, as well as concentrations of other chemicals and heavy metals.

On 22 November 2011 a public meeting was held to inform Moanataiari residents about the situation and next steps, and provide health advice on how they should manage risks from potential arsenic exposure.

The Waikato Regional Council is working closely with Thames-Coromandel District Council, Ministry for the Environment and the Waikato District Health Board to carry out further testing on private properties, decide what actions might be needed once the results are known, and let people know about the simple steps they can take to manage any potential health risks.

Fact sheets

The following fact sheets have been put together, and are available for download (in PDF format) from the Thames Coromandel District Council website:

Public health advice

Soil testing and results 

Timeline: History of the subdivision and project

Further information and FAQs


Waikato Regional Council Technical Report 2007/08: Trace elements in sediments of the lower eastern coast of the Firth of Thames

Moanataiari subdivision site investigation report - December 2011 (Pattle Delamore Partners) (10 mb)

Moanataiari subdivision , Thames, scoping report - historical contamination review - June 2010  (9mb)

More information

Visit the Thames Coromandel District Council website for further information on the Moanataiari project.

Find out about soil testing in Thames for all schools and early childhood centres.