Zeolitic Erionite in New Zealand: Health Implications for Ground Engineering

Summary Auckland is New Zealand’s fastest growing region, with large infrastructure projects that often include, and have included, tunnelling. The Waterview Connection saw twin tunnels driven through weathered and unweathered Waitemata Group rocks, generating c. 800,000 m3 of spoil. The material was excavated from tunnels, and transferred via conveyor, before being trucked to Wiri Quarry. The City Rail Link (CRL) and Central Interceptor excavations will also generate significant volumes of spoil., some of which is believed to contain erionite. Erionite is a naturally occurring “asbestiform” mineral that belongs to a group of silicates called zeolites. It is listed by the International Agency for Research on Cancer (part of the World Health Organization) as a Group 1 known carcinogen. Studies have demonstrated that erionite is more carcinogenic than asbestos, with similar effects to asbestos, such as malignant mesothelioma (MM). In Auckland, rapid infrastructure and residential development creates a wide number of open excavations in the city, suburbs and region, leaving erionite-bearing Waitemata Group and Waitakere Group rocks exposed. Thus, there is the potential for the exposure of Auckland’s population to erionite-bearing dust, not just in occupational settings, but also in residential and central urban areas, where the material is disturbed, transported, and disposed of.