KiwiChem data sources and terms

Every number in KiwiChem traces to a document. This page lists them all, says what each contributed, and sets out the terms under which the compiled datasets may be reused. The counts and the reference lists below are generated from the data files themselves when this page loads, so the documentation cannot drift away from the database.

1What is in the database

2The four source files

These are in archive/, unchanged. Everything in data/ is generated from them by the scripts in scripts/.

Soil contaminants — half-lives, K_d and soil guideline values.xlsx

One row per contaminant for soil half-life, K_oc, K_d and mobility class; one row per contaminant × jurisdiction × land-use scenario for the guideline values, across twelve jurisdictions; the jurisdiction key; and the reference list.

Drinking water standards for soil contaminants.xlsx

One row per contaminant × source for the drinking-water values, across nine sources; the soil–water equilibrium screen; the jurisdiction key; and the reference list.

Food safety standards for soil contaminants.xlsx

One row per contaminant × jurisdiction × food group across eight jurisdictions; the coverage summary; the health-based guidance values; the food group key; the jurisdiction key; and the reference list.

national_soil_geochemistry_analyses.csv

GNS Science, Geochemical atlas of Aotearoa New Zealand analytical data by meshblock: 676 topsoil samples at 2–20 cm, 65 elements, mg/kg. Reduced to a distribution per element, nationally and by region. Also in archive/ are the accompanying GNS report (sr_2023-023.pdf) and the full geodatabase (national_soil_geochemistry.gdb.7z), neither of which the application reads.

3Soil guideline values

4Drinking-water standards

5Food safety standards

5bSoil K_d

Five compilations, built into data/kd.js by scripts/build_kd.py. The first three measure the sorption of freshly added element; the last two the partitioning of the element already in the soil. They are kept apart in the data and on the tab, because for the same metal in the same soil they differ by one to two orders of magnitude. Nothing is derived from them except unit conversion and, at a pH between two tabulated values, a log-linear interpolation the tab declares.

5cCorrections to published values

In September 2026 every soil guideline value was read back against the instrument that publishes it. Where the two disagreed the instrument won, and the change is recorded rather than absorbed: scripts/sgv_corrections.py holds each one with the document it was read from, the Sources tab of the application lists them all, and a corrected value is badged corrected with the superseded number in its tooltip. Values compared and found to agree are badged checked.

6The datasets compiled for KiwiChem

The source workbooks carry no periodic table, no plant concentrations, no physicochemical constants and no toxicological reference values. Those four datasets were assembled for this application from the references below.

7Terms

The geochemical atlas

GNS Science 2023, licensed Creative Commons Attribution 4.0 International (CC-BY). Reuse is free with attribution. Cite it as: Martin AP, Turnbull RE, Roudier P, Cavanagh J, Rattenbury MS, Rogers KM, Vandergoes MJ, Reyes L, Gard HJL, Richardson SJ et al. 2023. Geochemical atlas of Aotearoa New Zealand. Lower Hutt (NZ): GNS Science. 247 p. (GNS Science report 2023/23). doi:10.21420/P9BK-7016

The guideline values

These are published standards and guidelines, reproduced here for comparison. Each remains the property of the body that issued it, and each is authoritative only in its own current version — the version in KiwiChem is a snapshot of the compilation date. Where a value matters, go to the instrument.

The application

KiwiChem is part of the KiwiScience suite of postgraduate resources, alongside KiwiFert and MINTEQ Soil. It is offered for teaching and for preliminary assessment.

8Citing KiwiChem

Cite the underlying source for any value you use. If you need to cite the application itself — for the compiled datasets, or for a screening calculation done with it — cite it as a software tool with the version date shown at the head of this page, and say which datasets you took from it.

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