Heavy Metals Part 2: Cadmium

In this second part of a 5-part series, Abraxas Labs discusses


Common sources of cadmium exposure in humans can include primarily ingestion of food containing cadmium, well water contaminated by bedrock containing cadmium, mining, and various sources of industrial pollution. Cadmium is dispersed throughout the Earth’s crust and is present at an average concentration of about 0.1 mg/kg [1]. Some of our qualitative observations from the samples tested at Abraxas Labs have included increased readings of heavy metals content found in samples submitted by clients who use sea kelp as a nutritional additive. Namely, levels of arsenic, cadmium, and lead appear to have positive association with the use of sea-based products.

Natural weathering of rock formations can cause substantial changes in the global cadmium cycle. Once these materials from weathering are transported to the Earth’s oceans, or deposited elsewhere along the way, regional increases of cadmium concentration are observed. Higher levels of cadmium can accumulate in sedimentary rocks, and marine phosphates can contain up to 15 mg/kg of cadmium [1]. However, anthropogenic sources account for more cadmium accumulation in soil than do natural weathering processes. These sources include heavy application of phosphate fertilizers and agricultural run-off. Anthropogenic sources account for 8,000-10,000 metric tons of cadmium contamination, which primarily ends up in soils [2].



  1. World Health Organization. "INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY ENVIRONMENTAL HEALTH CRITERIA 134 CADMIUM", 1992. Geneva, Switzerland. Cadmium (EHC 134, 1992) (inchem.org).
  2. Huang X., Duan S., Wu Q., Yu M., Shabala S. Reducing Cadmium Accumulation in Plants: Structure-Function Relations and Tissue-Specific Operation of Transporters in the Spotlight. Plants-Basel. 2020;9:223. doi: 10.3390/plants9020223.