Heavy Metals in Ayurveda - Toxicity, Sources, Analysis & Testing

Heavy metals are defined as those metals that have relatively high density and atomic weight. They are termed “Heavy” as they have a high atomic number. These metals tend to be dense and solid at room temperature.

Heavy metals are found naturally in the earth’s crust. They are released into the atmosphere either through natural processes like volcanic eruptions or through various human activities like mining, burning fossil fuels, metal refining, incinerating waste, exhaust fumes from vehicles, and the use of fertilizers and pesticides.

Once in the atmosphere, Heavy metals can travel long distances and get deposited onto soil or water bodies. They can also enter the food chain through water, soil or air and pose a threat to living beings and the environment due to their toxic nature. Also, being non-biodegradable they tend to accumulate in living beings.

Heavy metals are toxic to humans and other living organisms at certain levels of exposure. The toxicity of Heavy metals depends on the specific metal, the dose and the route of exposure (viz. inhalation or skin contact). Heavy metals such as Lead (Pb), Mercury (Hg), Cadmium (Cd) and Arsenic (As) are particularly toxic and cause a no. of health problems,

Neurological disorders: Heavy metals can cause damage to the nervous system, leading to disorders such as tremors, seizures, and memory loss.
Kidney damage: Heavy metals can accumulate in the kidneys and cause damage, leading to renal failure.
Hepatotoxicity: Exposure to high levels of Heavy metals can overwhelm the liver’s detoxification capacity and cause damage to liver cells.
Respiratory problems: Heavy metals can irritate the respiratory system and cause coughing, wheezing or shortness of breath.
Skin and Hair related problems: Exposure to Heavy metals can lead to skin rashes and irritation, hair loss hair thinning, discolouration of the skin as well as nails and premature ageing.
Blood disorders: Heavy metals can inhibit the synthesis of haemoglobin, inhibit red blood cells and disrupt clotting mechanisms..

Ayurveda often uses Heavy metals in form of “Bhasmas” for their therapeutic properties. However, these metals can be toxic in their raw forms, and specific purification methods are stated in the classics of Ayurveda to remove the toxicity as well as enhance their therapeutic properties.

The purification process is known as “Shodhana”, which includes a no. of steps such as calcination, boiling, trituration etc. The purified metal/ mineral is then incinerated into a bhasma, which is used to prepare Herbo-mineral preparations under strict dosage and safety guidelines. If not purified as per the principles of Ayurveda, these metals can be toxic to the body.

Besides, the plant and animal-origin raw materials used may at times contain Heavy metals. This is because Heavy metals are naturally present in the environment and can accumulate in plants and animals through various sources such as soil, water and air.

Therefore, it is crucial to ensure that the raw materials are sourced from reliable sources and tested for the absence of Heavy metals before being used in formulations. Also, the metals/ minerals must be purified as well as processed and then taken into use. The manufacturing must also be done by qualified and trained personnel under strict quality control guidelines.

The probable sources of Heavy metal contamination are as mentioned below:

• Polluted Air, Water and Soil
  
• Contaminated Food and Herbal raw materials
  
• Metals/Minerals not purified as per the principles of Ayurveda
  
• Excessive use of Insecticides, Herbicides and Pesticides

The permissible limit of Heavy metals as per the Ministry of AYUSH is as follows:

• Lead: 10 ppm
  
• Mercury: 1.0 ppm
  
• Cadmium: 0.3 ppm
  
• Arsenic: 3.0 ppm
  

Heavy metal analysis is the process of identifying and quantifying the presence of Heavy metals in various matrices, such as water, soil, air, medicines, food, biological samples etc. Different methods are available for heavy metal analysis, depending on the type of sample, target heavy metal and the required level of sensitivity and accuracy.

Some commonly used analytical instruments include:

• Atomic Absorption Spectroscopy (AAS)
  
• Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES)
  
• Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
  

Samples to be analysed

• • Plant, animal, metal/ mineral raw materials
    
  • Herbal and Ayurvedic medicines
    
  • Herbal extracts
    
  • Herbo-mineral preparations
    
  • Cosmetics
    
  • Food and Nutraceuticals
    
  • Pharma products and Excipients
    
  • Water
    
  • Soil