The toxic alkaloid nicotine, a natural component of tobacco, has been detected in many food crops, medicinal plants and plant food such as spices and teas, thus threatening food security. So far the origin of such nicotine contamination was unknown. Plant scientists Selmar et al. studied the possible contamination of peppermint by soils enriched in nicotine from cigarette residues. They also checked whether peppermint could take up nicotine from cigarette smoke. They found that peppermint take up nicotine from soil and from smoke. The tobacco industry and users are therefore responsible, at least partly, by the wide contamination of many crops and food by nicotine. Selmar et al. also explain that the passive incorporation and metabolisation of nicotine by peppermint is surprising and unprecedented with respect to current knowledge in allelopathy.
