However, biota both need and are vulnerable to other elements that occur in soil, tiny concentrations of elements such as copper, zinc, cobalt, boron or lead. While some, such as copper and zinc, are essential for biological growth and function, others, such as lead, are not.
But if you work in land-use planning and management or for any regional council in a consenting role, how do you know if what’s in the soil is safe or not? If soil concentrations of trace elements have been modified through deliberate or unintentional actions, how do you safeguard its life-supporting capacity?
Manaaki Whenua researcher Dr Jo Cavanagh is working on an Envirolink Tools-associated project that is evaluating the implementation of soil guideline values for a suite of commonly encountered soil trace elements. “There is an intimate link between protecting soil quality, and the management of contaminated land,” she says.
While there are chemically mineralised areas with naturally elevated concentrations of trace elements, contamination follows inappropriate disposal of industrial waste as well as general human activity through industrial, agricultural and residential land use. Increasing regulatory changes and a focus on ecological integrity have raised awareness of the importance of looking after soils through understanding ecological receptors
and protecting them.
Jo started developing soils guideline values to protect terrestrial biota for 11 priority contaminants as part of the Envirolink Tools project in 2014. These Soil Guideline Values (ECO-SGVs) have been refined and updated.
The focus of the work is on understanding how these numbers can be applied, particularly in changing regulatory environments, and with a greater drive to incorporate Māori perspectives.
Jo and Manaaki Whenua’s toi rangahau Māori Garth Harmsworth have been leading workshops with end-users, and central and local government to get feedback into a guidance document they are developing.
“What we’re looking to do within the project is have a tool that can inform land usage under current conditions, but with an eye on the future that will enable us to identify opportunities where we can connect with the future legislation, including the Natural Environment Act,” says Jo. “The guideline values can be used to support contaminated land management, discharge to land activities, usage in agriculture and for state of the environment reporting.”
