London, Oct 24 (IANS): The clothes that we wear, even those made from organic cotton, may retain chemicals that could potentially harm our health and environment, suggests new research.

As thousands of chemicals are used in clothes manufacturing, the researchers examined if there are chemicals in the clothes we buy as well.

In the study, 60 garments from Swedish and international clothing chains were tested.

An initial analysis found thousands of chemicals in the clothes and around a hundred chemicals were preliminary identified. Several of the substances were not on the producers' lists and were suspected to be by-products, residues or chemicals added during transport.

"Exposure to these chemicals increases the risk of allergic dermatitis, but more severe health effect for humans as well as the environment could possibly be related to these chemicals. Some of them are suspected or proved carcinogens and some have aquatic toxicity," said study author Giovanna Luongo from Stockholm University in Sweden.

Depending on occurrence, quantity, toxicity and how easily they may penetrate the skin, four groups of substances were chosen for further analysis.

The highest concentrations of two of these, quinolines and aromatic amines, were found in polyester.

Cotton contained high concentrations of benzothiazoles, even clothes made from organic cotton.

When the researchers washed the clothes and then measured the levels of chemicals, some of the substances were washed off, with a risk of ending up in aquatic environments.

Others remained to a high degree in the clothes, becoming a potential source of long-term dermal exposure, said the study conducted as part of Luongo's doctoral thesis.

"It is difficult to know if the levels of these harmful substances are hazardous, and what effects chemicals in our clothes can have in the long run,” a statement released by Stockholm University said on Friday.