IN recent months, the harmful impact of plastic has earned quite a bit of attention in national media. For instance, the article `Age of plastic` (Jan 11) mentioned a study that found 240,000 plastic particles in a litre of bottled water. The bottle itself is made of plastic polymer, or polyethylene terephthalate (PET).

More recently, a wire report from Paris, `Chewing gum releases microplastics into mouth: researchers` (March 26), quoted a PhD student at the University of California in the United States as claiming chemical analysis had found that one gram of chewing gum, which has a petroleum base, released 100 microgram of plastic in the consumers` mouth.

Plastic, indeed, has established its importance in all walks of lives, including food-containers. Most of the kitchen utensils are also made of plastic. Its usage had increased because many people could not afford buying metallic utensils.

Besides, even fabrics are weaved witha mixture of cotton and plastic fibres or threads. Plastic is now an indispensable material in our lives.

The two pieces referred to above came as a surprise. PET dissolves in a variety of solvents, like dimethyl sulfonamides (DMSO), toluene, phenol, acetone, among others, but not in water.

That being so, the detection of plastic particles in PET bottles is surprising, and the same applies to chewing gum.

Plastic, if ingested, can cause one of the most serious cancers. The matter should draw the attention of scientists associated with the Pakistan Council of Scientific and Industrial Research (PCSIR) to investigate when and how plastic loses its innate properties.

Isit during storage, or does environmental temperature have a role? Plastics are made by combining two or more molecules of specific chemicals. I think weak polymerisation may result in the disintegration of the binding molecules.

Dr M. Qudrat-e-Khuda Karachi