Agricultural activities have often resulted in the addition of heavy metal contaminants, particularly cadmium (Cd) and copper (Cu), to agricultural and horticultural soils. For example, the link between the use of cadmium-containing phosphorus fertilisers and a rise in Cd content in agricultural soils in New Zealand has prompted the development of the government- and industry-led voluntary management strategies for this pollution problem since 2011 (Gray and Cavanagh, 2023). Basically, the fertiliser industry and the government have endorsed the sustainable farming goal (over the next 100 years) with safeguards against the toxic effects of excessive soil Cd on human health. This is thought to be achieved with the soil Cd level not exceeding 1 mg/kg. A soil Cd map in NZ has been established based on the analysis of thousands of soil samples from all over NZ taken from depths of 7.5 cm to 15 cm. Whether there are restrictions on phosphate fertiliser application or not (type of phosphate fertiliser with lower Cd contamination, rates and need for some risk management practices) at a particular rural site is dependent on 5 categories or “tiers” of soil Cd contents (Abraham, 2020). For example, at the tier 0, soil Cd content is less than 0.6 mg Cd/Kg, and there is no restriction to phosphate fertiliser application. At the highest tier (tier 4), soil Cd content has exceeded 1.8 mg Cd/Kg, phosphate fertiliser application is not allowed pending on some further investigations.