July 17 (UPI) -- Earthwork construction may pose a significant health risk, according to new research.
During construction, small, needlelike fibers from the mineral erionite can become released from disturbed bedrock. When inhaled, these mineral fibers can cause disease similar to asbestos, scientists warned in a new paper, published Friday in the New Zealand Journal of Medicine.
Earthworks are any construction projects that involve the movement or processing of quantities of soil or unformed rock. Often, earthworks are created for fortification purposes -- to support a new road or prevent flooding, for example.
Though earthworks can offer important benefits, their formation may pose a health hazard.
New Zealand has a greater incidence of abestos-induced malignant mesothelioma than many similar high-income countries. Several studies have looked at the distribution of asbestos, heat-resistant fibrous silicate mineral, among the rocks and soil of New Zealand.
But according to the authors of the latest study, previous research efforts have failed to investigate the prevalence of erionite, a mineral that yields fibers similar to asbestos. Preliminary findings from several U.S. studies suggest erionite fibers have carcinogenic properties.
Researchers found New Zealand has reason to take the U.S. studies seriously. According to the new study, erionite is present in both the Waitemata Group sedimentary rocks and the Waitakere Group volcanic rocks that are ubiquitous in the Auckland region.
"Most of the excavations being done for large construction projects involve the type of rock where erionite can be present, often with waste rock and soil loaded onto trucks and dumped," study co-author Martin Brook, associate professor at the University of Auckland, said in a news release. "Earthworks for residential subdivisions may also be an issue."
"But currently there are no international or New Zealand occupational exposure limits or standard low-cost field sampling and analytical methods for erionite," Brook said.
Because people are often diagnosed with malignant mesothelioma decades after exposure, studying erionite's health effects remains quite difficult.
"This lag between dose and response makes it very difficult to know when, where or how much erionite people might have been exposed to prior to getting ill," Brook said. "In the Auckland region we need to know where this mineral is and how much is present in soils and air before we can quantify the risk it presents to both occupational and public health. We should do this research as a priority."