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Active Chemical Environments

Geochemical Baseline Soil Survey of New Zealand
Element variation of zirconium (Zr) across Southland and southern Otago

Element variation of zirconium (Zr) across Southland and southern Otago

Earth’s surface is chemically, isotopically and physically diverse, reflecting a range of natural and human-related inputs. Geochemical baseline surveys provide data so that we can determine how and why certain elements, isotopes and physical characteristics (e.g. magnetism, mineralogy) are present in the landscape.

This knowledge allows us to understand transport pathways in the near surface (i.e. river transport and deposition), identify input sources (i.e. local rock type weathering, application of fertiliser), to compare between different regions of New Zealand or even overseas, and to monitor change through time. This is useful for environmental, agriculture, human health, land use planning, pollution, mineralisation and forensic studies.

What is happening

We are collecting small (1-5 kg) samples of soil across New Zealand and studying what elements, isotopes and minerals they contain.

This study is national in scale, meaning the results are not specific about the property you live at, but we can compare your area to areas nearby, further afield, or even at the other end of the country.

We use hand-operated augers and shovels (no machines) to dig soil from five holes. The holes are 7 cm-wide and up to 70 cm-deep, which we back fill when finished. Collection of soil from each site (all holes and backfilling) takes only 15 minutes.

Collecting soil with a hand-operated auger on a Southland farm

Collecting soil with a hand-operated auger on a Southland farm

From earlier studies, for example around Southland, we know that element concentration in soils varies across the region. This is for many reasons, including the local soil and rock type, different climates, age of the soil, land-use and distance to a city.

By recording these changes, we will make maps of how elements vary in soil across the country and why. This has not been done across New Zealand before.

Anyone interested in soil can use these data, including for agricultural studies, groundwater information, environmental monitoring, land-use planning, human health research and food traceability studies.