Environmental samples are analysed for a range of purposes such as meeting statutory requirements of the Environment Protection Act 1970 and the Pollution of Waters by Oils and Noxious Substances Act 1986. It is important to obtain samples that faithfully represent a waste or element of the environment from which they are taken. Care must be taken in the field to ensure samples are not contaminated during collection, and analyte concentrations do not change between the time of collection and analysis.It is not possible to address all the issues that could arise in the field and advice may be needed from specialists including statisticians, chemists, microbiologists or hydrogeologists on the behaviour of a pollutant in different elements of the environment.