Contaminant Testing for Natural Health Products: Heavy Metals, Pesticide Residue, Residual Solvents, and Aflatoxins

Natural health products can contain ingredients from many different sources, including botanicals, minerals, oils, extracts, and other processed raw materials. Those materials can bring different contaminant risks into a finished product, while manufacturing and extraction can introduce additional considerations of their own

At PPB Analytical, we support NHP companies with testing for a range of chemical contaminants. Understanding where those contaminants can come from and what each test is designed to evaluate can help quality teams build a testing program around the actual risks associated with their product.

Why Contaminant Testing Matters

Health Canada’s Quality of Natural Health Products Guide requires manufacturers and importers to consider the potential for contamination when determining appropriate testing.

The relevant contaminants are not the same for every NHP. A botanical extract, mineral supplement, oil-based product, and multi-ingredient capsule can have very different sources of risk. Contaminant testing is most useful when those risks are understood before the sample reaches the laboratory.

Different contaminant tests answer different questions about consumer safety. The testing selected should reflect the ingredients used, how they were sourced or processed, and the manufacturing steps involved.

Heavy Metals

Heavy metals can be present in raw materials through environmental exposure, including soil and water. This can be particularly relevant for botanical and mineral-based ingredients, where the source material itself may contribute to the product’s elemental profile.

For oral NHPs, Health Canada establishes acceptable daily exposure limits for several elemental contaminants. The limits are based on body weight rather than a single concentration that applies to every product. The current limits include:

• Arsenic: less than 0.14 µg/kg body weight/day
• Cadmium: less than 0.09 µg/kg body weight/day
• Lead: less than 0.14 µg/kg body weight/day
• Mercury: less than 0.29 µg/kg body weight/day

Health Canada also specifies adult daily limits of less than 10 µg for total arsenic, 6 µg for cadmium, 10 µg for lead, and 20 µg for total mercury.

Because these limits are based on daily exposure, the corresponding concentration limit in a finished product depends on the product’s recommended daily intake. For example, a product consumed at a higher daily quantity would need a lower allowable concentration to remain within the applicable daily exposure limit.

For topical NHPs, Health Canada provides concentration-based limits of 3 ppm for arsenic, 3 ppm for cadmium, 10 ppm for lead, and 1 ppm for total mercury in the current guidance.

Testing for metals such as arsenic, cadmium, mercury, and lead helps quality teams evaluate whether those contaminants are within the applicable limits for the product. Additional elemental analysis may also be useful where other metals are relevant to the formulation or raw materials.

Pesticide Residues

Pesticide residue testing can be especially relevant for NHPs containing agricultural or botanical ingredients. Residues may be associated with how a plant was grown, treated, harvested, or handled before the material entered the manufacturing process.

Health Canada does not establish one universal ppm limit for all pesticide residues in NHPs. For applicable products, the current Finished Product Specifications guidance refers to pharmacopoeial or WHO limits, depending on the applicable specification.

For quality teams, pesticide testing provides information about contaminants that may not be apparent from the finished product itself but can still be introduced through the ingredient supply chain.

Residual Solvents

Solvents may be used during extraction, purification, or other processing steps. Residual solvent testing evaluates whether solvents remain in a raw material or finished product after those processes are complete.

Health Canada refers to ICH Q3C or applicable pharmacopoeial limits for residual solvents rather than establishing one universal limit for all solvents. The acceptable level therefore depends on the specific solvent.

This is a good example of why manufacturing information matters. If a quality team understands which solvents may have been used during production or extraction, the testing request can be targeted to the compounds that could reasonably be present.

Mycotoxins

Mycotoxins, such as Aflatoxins, are produced by certain moulds and can be a concern in susceptible agricultural or botanical materials. The risk is tied to the ingredient and to conditions that can allow mould growth before or during storage and processing.

Aflatoxins are a class of chemicals, of which the B1, B2, G1, and G2 molecules are of particular concern. Health Canada identifies aflatoxin testing as appropriate when their presence is likely, including for certain materials such as ginseng and peanuts. The current guidance establishes an acceptance criterion of less than 0.02 µg/g (20 µg/kg or 20 ppb) for total aflatoxins.

Another important mycotoxin to consider is Ochratoxin A (OTA). Health Canada identifies OTA as a potential contaminant of concern for certain natural health product ingredients. For example, an acceptance criterion of less than 20 µg/kg (20 ppb) applies to liquorice root, while a limit of less than 80 µg/kg (80 ppb) applies to liquorice dry extract used for flavouring purposes.

Testing can therefore be particularly important when the raw material has a known susceptibility to aflatoxin contamination.

Choosing the Right Contaminant Testing

A useful starting point is to look at the product from the raw material forward. Ingredient origin, agricultural inputs, extraction methods, processing aids, and manufacturing conditions can all help identify which contaminant risks are relevant.

Providing this information along with the finished-product specifications gives the laboratory a clearer picture of what needs to be evaluated and helps avoid treating every NHP as if it requires the same contaminant panel.

PPB Analytical offers testing for heavy metals including arsenic, cadmium, mercury, and lead, as well as additional elemental analysis, pesticide residues, residual solvents, and Aflatoxins B1, B2, G1, and G2.

See our full list of NHP testing services here:

Let’s Talk Testing

Whether you’re evaluating a new raw material, reviewing finished-product specifications, or reassessing potential contaminant risks, we’re here to help.

Have a testing question? Connect with the PPB Analytical team to discuss your product and testing requirements: