Toxic heavy metals — such as arsenic (As), mercury (Hg), cadmium (Cd), and lead (Pb) — are among the most dangerous environmental contaminants. Even low-level exposure can lead to metabolic, neurological, hormonal, and immune disturbances.
The paradox is that blood tests very often do not reveal their presence, even though the body may be chronically burdened by them.
Why does this happen?
And why is ICP-OES considered one of the best methods for detecting exposure to heavy metals?
This article provides the answer — grounded in science, toxicology, and the experience of laboratories using plasma spectrometry.
Why do heavy metals often “disappear” from blood?
Blood reflects the current state of the body, but heavy metals:
- move rapidly into tissues,
- bind to proteins, enzymes, and thiol groups,
- accumulate in bones, hair, and soft tissues,
- often no longer circulate in blood after a few hours or days.
Examples:
- Mercury (Hg) — about 95% is redistributed into tissues within 48 hours.
- Lead (Pb) — accumulates in bones and hair; blood levels are often “falsely low.”
- Arsenic (As) — detectable in blood mainly within 24–72 hours.
For this reason, environmental toxicology has long emphasized:
Blood is not a good indicator of chronic exposure — only of acute exposure.
Hair as a natural biomarker of exposure
Hair grows at approximately 1 cm per month and incorporates into its structure:
- nutritional elements,
- heavy metals,
- products of metabolic processes.
As a result, hair represents 8–12 weeks of exposure — something blood cannot capture.
This is why the WHO, EPA, ATSDR, and toxicology institutes recognize hair as a valuable material in environmental biomonitoring.
Why is ICP-OES ideal for detecting heavy metals?
ICP-OES (Inductively Coupled Plasma – Optical Emission Spectrometry) uses plasma at a temperature of approximately 9,000 K, which atomizes elements and enables their identification through characteristic emission lines.
For heavy metals, this means:
- ✔ very high sensitivity (ppb level)
- ✔ simultaneous multi-element analysis
- ✔ high repeatability and resistance to interferences
- ✔ low risk of biological matrix effects
Unlike AAS and XRF, which:
- offer lower sensitivity,
- analyze single elements,
- perform worse with biological samples.
ICP-OES is considered a benchmark method in toxicology.
How does ICP-OES detect toxins that are invisible in blood?
- Stable binding within the hair structure
Metals are incorporated into keratin — they do not migrate, oxidize, or “escape.” - Cumulative rather than momentary analysis
ICP-OES does not assess the “here and now,” but tissue levels accumulated over recent weeks. - Bypassing the homeostasis problem
Blood must maintain balance — hair does not. - Detection of low-level exposure
Even when blood levels appear “harmless,” hair analysis may reveal:- accumulation trends,
- detoxification disturbances,
- chronic occupational or environmental exposure.
Most common heavy metals detected by ICP-OES
When is it worth performing heavy metal analysis using ICP-OES?
- chronic fatigue, brain fog, nervous tension
- weakness and metabolic disturbances
- hormonal disorders
- suspected occupational exposure
- living in a polluted area
- detoxification problems
- long-term use of low-quality supplements
ICP-OES is one of the best tools for assessing environmental exposure.
Summary
ICP-OES enables the detection of heavy metals that:
- leave the bloodstream within hours or days,
- accumulate in tissues,
- are not detected by standard clinical tests.
For this reason, in toxicology and biomonitoring, hair analysis combined with ICP-OES constitutes the most practical and reliable tool for assessing chronic exposure.
This is precisely the specialization in which Mineralco is building its competitive advantage.
References
- ATSDR Toxicological Profiles (Lead, Mercury, Arsenic, Cadmium).
- WHO (Environmental Health Criteria Series): Heavy Metals in Human Health.
- EPA – Exposure Assessment Tools and Models: Biomonitoring Guidance.
- Harkins, D. K., & Susten, A. S. (2003). Hair Analysis: Exploring the State of the Science. Environmental Health Perspectives.
- Cortés Toro, E., et al. (1993). Hair Analysis as a Means for Assessing Internal Body Burdens of Environmental Pollutants. Journal of Radioanalytical and Nuclear Chemistry.
- Dłuska, E., et al. (2018). Biomonitoring of Heavy Metals Using Hair Samples. Journal of Elementology.
- Taylor, A. (2005). Role of ICP Techniques in Biomonitoring. Clinical Biochemistry.
- González-Muñoz, M. J., et al. (2008). Evaluation of Heavy Metal Exposure Through Hair Analysis. Science of the Total Environment.
- Becker, J. S. (2007). Inorganic Mass Spectrometry: Principles and Applications. Wiley.