Some persistent organic pollutants (POPs) are chiral in nature (e.g. α-HCH, and some PCBs) and are well recognised in different environmental samples. The effects of this property on their environmental behaviour are not well understood. This research specifically deals with chirality, a characteristic exhibited by asymmetric molecules which can exist as non-superimposable mirror images of one another. Chirality influences chemical behaviour in a number of ways including differences in environmental toxicity and persistence between enantiomers.