Cadmium is a naturally occurring heavy metal found in low concentrations in air, water, and soils. It occurs naturally in phosphate rock – the main ingredient for superphosphate fertiliser. In response to concerns in the late 1990s about cadmium levels in fertilisers, the fertiliser industry in New Zealand voluntarily adopted a limit for cadmium in fertilisers of 280mg Cd/kg. Testing shows current average fertiliser content of just 180mg Cd/kg.
New Zealand Agriculture and Horticulture Cadmium Strategy
More information on MPI website