The Hidden Connection Between Mould Illness and High Lead Levels

As both a Building Biologist and Naturopath, one of the most important patterns I see—yet rarely talked about—is the link between mould exposure and elevated lead levels.

This is something Nicole Bijlsma (founder of the Australian College of Environmental Studies) has been teaching for years:
 Every mould-affected client should be assessed for lead.
And the more homes I inspect and the more clients I support clinically, the more obvious this connection becomes.

At first glance, mould and lead seem unrelated.
But physiologically and environmentally, they frequently go hand-in-hand.

Let’s explore why.

1. Damp, Mouldy Environments Mobilise Lead Dust
Lead can linger in:

• old paint
• timber window frames
• roof voids
• ceiling dust
• contaminated soil
• plumbing
• carpets and underlay

When a home becomes damp or mould-affected, moisture acts like a solvent, lifting lead particles from surfaces and turning them into fine, inhalable dust.

Humidity—common in mouldy homes—also makes heavy metals more mobile and airborne. This is when the type of vacuum you use in your own becomes crucial to you and you’re families health

2. Mould Toxicity Weakens Detox Pathways Needed for Lead Clearance

From a naturopathic perspective, mould exposure heavily impacts:

• glutathione production
• liver detoxification
• methylation pathways
• bile flow
• antioxidant status

These are the same pathways required to detoxify heavy metals.

When mould disrupts these systems:

• the body retains more lead
• neurological symptoms worsen
• detoxification slows
• sensitivities increase

This is why mould clients often say:

“Since the mould exposure, I react to everything now.”

It’s not psychological — it’s a physiological overload

3. Mould and Mycotoxins Increase Gut Permeability → More Lead Absorption

Mycotoxins irritate and erode the gut lining.

A more permeable gut absorbs:

• more metals from water
• more dust inhaled and swallowed
• more contaminants from cookware
• more toxins from food stored in old containers

Lead that previously passed through the digestive tract now enters the bloodstream more easily.

4. Older, Damaged Homes Are Both Mould-Prone AND High in Lead

Most mouldy homes I assess fall into one or more of these categories (as well as many other factors):

• built before lead paint was phased out
• have water-damaged ceilings
• have rotting windows or timber
• have plumbing leaks or roof leaks
• have damp soil or poor drainage around the foundation

Those structural issues not only create prime conditions for mould growth—they also disturb historic lead sources and release contaminated particles back into the living space.

A wet, mouldy wall covered in old paint becomes a perfect source of inhalable lead dust.

5. Symptoms Overlap — Making Lead Toxicity Easy to Miss

Both mould and lead can cause:

• anxiety
• brain fog
• poor memory
• irritability
• fatigue
• headaches
• insomnia
• neurological changes
• sensory sensitivities
• mood changes

This overlap means many people are diagnosed with “mould illness”
…while also carrying a significant lead burden that’s never tested.

How to Screen for Lead (Naturopathic Perspective)

A complete assessment may include:

✔ Dust wipe sampling

To determine lead dust in the home. The LEAD group Australia offer a range of different testing. 

✔ Soil testing

(and Why It Matters If You Have Chickens)

Soil is one of the most overlooked sources of lead exposure, especially around older homes, renovations, demolished buildings, historic sheds, or areas close to roads. If you keep backyard chickens, soil testing becomes even more important. Chickens naturally peck, scratch, and ingest soil throughout the day, which means any lead present can accumulate in their bodies and end up in their eggs. Recent Australian studies have shown that backyard eggs can contain high lead levels, even when the chickens appear healthy. Testing the soil in your chickens’ foraging area helps identify whether lead is entering the household food chain. The Lead Group are also able to test chicken eggs themselves for lead levels.

Another often-missed exposure pathway is chicken drinking water. Many families use PVC garden hoses to fill chicken waterers, not realising that PVC hoses are commonly stabilised with lead compounds. When left in the sun or used for warm-weather watering, lead can leach into the water. Over time, this can contribute to elevated lead levels in chickens—and again, in their eggs. It’s best to flush hoses thoroughly before use, avoid drinking-grade water being delivered through standard PVC hoses, or use a certified lead-free drinking water hose for animals.

✔ Water testing

If the home has:

• old copper pipes
• brass fixtures (very common with newer tapware)
• rainwater tanks
• bore water

✔ Biological testing (via practitioner)**

• HTMA (Hair Tissue Mineral Analysis) (I find interclinical laboratories the best in the field for this)
• Blood lead (best for very recent exposure)
• Urinary provocation testing (depends on clinical guidance)