Nikunja Bihari Sahu
Holi, the festival of colours, is also a playground of chemistry. The colours people playing Holi use are industrial dyes mixed with different inorganic bases that can have detrimental effects on our body and the environment. Four types of Holi colours are available in the market today. These are abira, or gulal, dry powder, pastes and water colour.
Abira has two components: The first is a colourant, which is usually an oxidised heavy metal such as cadmium, chromium, iron, lead, mercury, nickel and zinc, or toxic coal tar dyes or ‘azo’ group dyes such as Auramine (for producing yellow), Malachite (for producing green), Rhodamine (for producing orange) and Methylene (for producing blue); the second part of abira is a base that could either be asbestos or silica, in which colourants are blended. Besides, abira also contains sand, starch, salt, mica or powdered glass to provide lustre. The dry powder contains various inorganic compounds such as copper sulphate (for producing blue), lead oxide (for producing black), mercury sulphite (for producing red), chromium iodide (for producing purple), and aluminium bromide (for producing silver). Sometimes, inorganic dry colours are mixed in a base of engine oil or other inferior quality oils to make a paste that is easy to be applied on the body. Adding oils to the colour increases its toxicity and the permeability of the colours to human skin, which aggravates symptoms. Liquid colours commonly used during Holi include solutions of gentian violet, methylene blue, mercurochrome and potassium permanganate. In all these colours, the colourant either contains a heavy metal or some inorganic dye.
All these substances are highly toxic to the body in the short or the long term. Lead, the most harmful heavy metal, mainly affects the nervous system, kidneys and the reproductive system. Exposure to lead causes complications such as anaemia, headache, abdominal pain, joint discomfort and osteoporosis in old age. Lead poisoning also retards physical and mental growth of children.
Mercury is another toxic metal, which causes conditions such as cough, breathlessness or even pneumonia. Mercury poisoning has symptoms such as headache, increased heart rate, itching and tremors, fall in blood pressure and forgetfulness. Mothers exposed to mercury may give birth to underweight babies with mental retardation.
Certain dyes used during Holi, such as auramine, malachite and rhodamine also have toxic effects on our body. Auramine causes irritation of the mouth, throat, stomach, liver, eyes and skin. Malachite damages bones, eyes and lungs. It can cause malignant tumours in the testes, ovary, urinary bladder, kidney, liver, spleen and breast. Rhodamine causes cancer and genetic disorders, besides degenerative changes in the liver, spleen, kidney and urinary bladder.
Asbestos, silica and powdered glass, widely used as bases in dry colours, harm the body. Asbestos is a known carcinogen and silica and powdered glass can damage skin and eyes. Oils of inferior quality used in pastes can cause skin allergy, itching or even temporary blindness. Several water colours contain alkalis as the base. When such colours enter the eyes, they cause serious eye problems. Gentian violet, the most widely used colour concentrate used during Holi, can cause discolouration of the skin, dermatitis, skin allergy or irritation of the mucous membrane.
The way people apply colours on Holi also poses certain risks. Some make a thick paste of a dry colour using a little water and rub it on faces of others. If fine particles such as powdered glass in the colour enters the eyes, it can cause irritation, swelling or pain in the eyes. Rubbing cheap and inferior quality abira on the face can lead to scratches and rashes on delicate skin.
Apart from these serious health problems, the use of inorganic toxic colours also has various environmental impacts. All colouring ingredients of Holi are non-biodegradable. When washed away, their residues enter water sources and affects the entire food chain.
Given the potential health risks the synthetic dyes hold, the only way to play Holi safely is to go for natural and eco-friendly colours.
The writer is education officer, Regional Science Centre, Bhopal.