Spectrophotometer Sensing of Heavy Metals – OligoScan
Sources of heavy metal exposure
Heavy metal ions can severely impair human health and negatively impact the environment and ecosystem. The following exposures to heavy metals have been identified in a report by Jarup (2003). Cadmium, found in cigarette smoke, household waste (E.g. batteries), and even food, can damage the kidneys and weaken the bones. The general population is exposed to mercury mainly via food and dental amalgams. Mercury is toxic to the nervous system, and is especially a concern for the fetus; pregnant mothers are advised to avoid fish highly contaminated with mercury, such as swordfish and tuna. Although dental amalgams have been listed, the author Jarup (2003) states that no studies to date have proven any direct correlation between dental amalgams and ill health. Lead exposure occurs via food and air, petrol emissions have contributed significantly to air pollution. Children are particularly susceptible to the neurotoxic effects of lead due to higher gastrointestinal uptake and a more permeable blood-brain barrier (Jarup, 2003). Lead is also found in lead-based paints, and glazed food containers, where the potential exists for lead to leach into food (Jarup, 2003). Arsenic exposure is typically via food and drinking water, and long-term exposure is associated with increased risks of skin cancers, as well as other cancers, as well as other skin lesions such as hyperkeratosis and pigmentation changes. Occupational exposure via inhalation is causally associated with lung cancer. A clear exposure-response relationship and high health risks have been observed with arsenic (Jarup, 2003).
As illustrated, heavy metal accumulation in the human body can severely impact health. Thus, it is important to develop simple, sensitive, and accurate methods for testing levels of human exposure. New technologies are being developed in this area, and although it is early stages, it is expected these technologies will rise, given the increasing worry of human exposure to heavy metals via environmental pollution. According to Yantasee et al., (2007), microanalytical based sensors that work with biometrics, such as blood, urine, or saliva, are currently being developed and validated.
Current heavy metal analysis methods
Much of current analysis for detecting lead levels in the body relies on blood biometrics, as lead is sequestered in the bone, and remains here long-term, thus, steady concentrations of lead in the blood are used to determine the total body burden of lead (Yantasee et al., 2007). Although this method has remained the preference, a correlation between lead blood levels and adverse health outcomes has not always been found. Thus, researchers recognize that there is a substantial need for the development of an alternative lead biomarker, such as plasma/serum/tissue, saliva, bone teeth, feces, and urine biometrics, all of which may provide a better correlation between lead and ill health effects (Yantasee et al., 2007).
Yantasee et al., (2007) investigated the use of a portable metal analyser (based on a mercury-free film electrode). To test this device, researchers obtained 10 blood samples from individual adult males. However, it should be noted that no information was available concerning the individuals’ environmental or occupational exposures to lead. Blood samples taken from the portable metal analyser were compared with blood samples taken from the ICP-MS (Inductively Coupled Plasma – Mass Spectrometry), an instrument commonly used to detect mineral and heavy metal contamination. Yantasee et al., (2007) found that results obtained from the portal metal analyser yielded background blood results similar-to the state-of-the-art ICP-MS.
Since 2007, newer devices have appeared on the market that analyze samples at the intracellular tissue level. These devices are based on spectrophotometer technology, which currently has its largest application in the world of medical bio-optics. Other medical applications for spectrophotometer devices include microbiology labs to measure DNA/RNA samples, the growth of bacterial cultures, and melanoma analysis in pathology labs (Health Blog, 2013). However, we are now seeing that this technology has further uses outside of the realm of medical optics.
The OligoScan: a portable spectrophotometer
A spectrophotometer works by propagating a beam of light through a diffraction grating, which works like a prism and separates the light into different wavelengths. The grating is constructed in that only specific wavelengths reach each exist site located on the grating framework. The wavelengths of light interact with the sample, and a detector within the portable spectrophotometer device measures the transmittance and absorbance of the sample. Put simply, transmittance refers to the amount of light that will completely pass through the sample and absorbance refers to the amount of light absorbed by the sample. This information is then collated into a digital report (Gaston College, 2017).
The OligoScan is specifically measuring heavy metals found intracellularly. It does not measure heavy metal levels in deeper tissues, such as adipose and bone. Circulating heavy metals are highly toxic to the body, so the body tends to sequester and store heavy metals, such as cadmium, mercury, and lead, in adipose tissue, bone, coordination bonds (i.e. heavy metals are bound to albumin, enzymes, small peptides, cysteine, or methionine) or cloistered with gut microflora (Sears, 2013). Different inorganic compounds or molecules absorb energy at different wavelengths. The OligoScan compares this measurement to current references ranges, as identified in their report (OligoScan, 2017).
As research progresses, it has been discovered that acute poisoning from heavy metals can be seen at lower body burdens than previously thought. For example, early lead exposure is now found to cause IQ decrements at a blood level below 2 micrograms per deciliter. The blood reference level for which the US Centre for Disease Control recommends action and remediation of a child’s exposure is 5 micrograms per deciliter, while chelation is recommended at levels at or above 45 micrograms per deciliter (Sears, 2013). The OligoScan can be used in acute situations when the body is dumping heavy metals from the bloodstream, into tissues, at the early stages, before being sequestered into deeper body tissues (OligoScan, 2017). In comparison, a urinalysis measures the extent to which the body can excrete heavy metals, and a hair analysis shows heavy metals that have been acquired in the past few months; both are measuring past exposure rather than the current body state.
Heavy metal and nutrient interactions
Heavy metals displace vital nutrients necessary for proper physiological body function. According to Singh et al. (2011) heavy metals disrupt body function in two ways:
- Accumulation in the body and disruption of vital organs, such as the heart, brain, kidney, liver and bone;
- displacement of vital nutrients, such as minerals, from their original place, thereby inhibiting their biological function.
It is impossible to live in an environment free of heavy metals. As previously discussed, heavy metals can be introduced into the body via food, air, water, skin exposure and agricultural pollution. Indiscriminate human activities have altered their geochemical cycles and biochemical balance within the Earth’s crust, making them more available to humans (Singh et al., 2011).
The most common nutrient displacements are zinc and iodine disruption. Zinc is commonly displaced by copper, and iodine is commonly displaced by mercury. Zinc and copper are antagonistic to each other, meaning they compete for the same absorption sites within the body. The balance between zinc and copper is an example of biological dualism; our bodies need both minerals however, they are needed in very different quantities. Too much of one and too little of the other can lead to a disruption of the body’s physiological and metabolic processes. Both minerals play an important role in the body.
Copper is needed for blood vessel formation, collagen synthetization, proper brain development, and for appropriate communication between neural cells. Zinc is needed for hormonal function, immune support, a catalyst in enzyme reactions, and is needed for synthetization of hydrochloric acid in the stomach. A similar scenario is evident on the relationship between mercury and iodine, however, mercury is not needed by the body. Iodine plays a critical role in thyroid health and nearly all cells in the body have receptor sites for thyroid hormones. The thyroid is involved in metabolic regulation, but also plays a role in hormone, adrenal, and gut health stability.
Achieving balance via measuring heavy metal levels
Based on the findings from the OligoScan and the collated report, recommendations may include specific nutrient/mineral supplementation for mild chelation therapy. For example, supplementation with zinc, iodine, selenium, or the application of herbal medicines or supplements to draw out heavy metals, may be administered based on individual findings. Several professionals may come into the treatment picture, including general practitioners, nutritionists, herbalists, dietitians and naturopaths. Each treatment protocol is designed to meet the needs of individuals, and the health plan is tailored as such.
Gaston College Learning Solutions. Dallas, North Carolina. (2017). Retrieved from http://www.lsteam.org/projects/videos/how-does-spectrophotometer-work.
Health Blog. (2013). Role of the spectrophotometer in medicine. Retrieved from http://healthyone.org/role-of-the-spectrophotometer-in-medicine/.
Jarup L. Hazards of heavy metal contamination. Br Med Bull. 2003;68:167-182. Retrieved from http://http://www.ncbi.nlm.nih.gov/pubmed/14757716.
OligoScan WordPress. (2017). Retrieved from http://www.oligoscan.net.
Sears, M. Scientific World Journal. 2013;2013:219840. Doi: 10.1155/2013/219840. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3654245/.
Yantasee W, Lin Y, Hongsirikarn K, Fryxell G, Addleman R, Timchalk C. Electrochemical sensors for the detection of lead and other toxic heavy metals: the next generation of personal exposure biomonitors. Environ Health Perspect. 2007;Dec:115(12):1683-1690. Retrieved from http://http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2137133/