A general name, specific elements
The term “heavy metals” is used broadly, but reports must identify specific elements. Lead, cadmium, mercury and arsenic are not one substance and do not share all their properties without qualification. Arsenic, moreover, is classified as a metalloid. Precision begins by no longer treating the group as a single figure.
NIST included elements of toxicological interest in its hemp reference material RM 8210. The initiative shows the importance of characterised materials for checking measurements. It is not an estimate of contamination in all products or a certificate for brands that have not been analysed. NIST: hemp reference material and toxic elements
The source may be further along the chain
Raw material is one part of the chain. Equipment, added ingredients, containers and other components in contact with the material may also matter. Attributing an origin requires evidence connecting that source with the finding. An explanation being intuitive or fitting a photograph of the process is not enough.
A 2025 study of cannabis vaping products on the Canadian market found evidence that metal device components contributed to particles in liquids. This investigated a particular pathway and is limited to the products studied. It does not show that every format or market follows the same pattern. Study of metal sources in devices, 2025
One sample does not represent every moment
If an ingredient is analysed before coming into contact with other components, the result does not necessarily describe every later stage. This does not mean a problem will arise; it means the timing of sampling defines the information available. Investigating changes requires consistent comparisons between stages or units.
Imagine a fictional investigation with three samples: raw material, freshly packaged preparation and product after storage. If they differ, the next step would be to check sampling, the method and possible sources. A single value does not justify jumping straight to an accusation against a supplier. Traceability turns a general suspicion into testable questions.
Reading the table without alarmism or complacency
Look at the element, unit, quantification limit and comparison criterion. A positive number should not be interpreted without context, and an ND result needs its limit. The applicable criterion also depends on the category and use; copying a threshold from another country or product can lead to a wrong conclusion.
Responsible reading neither minimises a signal nor dramatises an isolated figure. It describes exactly what was found and what is still needed to interpret it. In a magazine, that precision makes a story about materials and measurement far more interesting than a generic headline about “toxins”: who took the sample, when, what they looked for and which hypotheses the data support.
Take this with you
Detecting an element and explaining its origin are different tasks. The second needs traceability and comparisons between samples.
Sources you can open
The source may be in its original language. English publication does not change the jurisdiction or date discussed.
Follow the thread
Open the cannabinoid encyclopedia
Check the identity, research, uncertainties and documented forms of each compound.