BQE

Biological Quality Elements (BQE)

For the implementation of the Water Framework Directive, the assessment of ecological status of water bodies is based on biological indicators from several groups of organisms known as Biological Quality Elements (BQE). These indicators may be related to the composition, abundance and diversity of species, as well as the presence or absence of some disturbance-sensitive species.

For inland surface waters the BQE's are:

Phytoplankton	Macrophytes and phytobenthos	Benthic invertebrates	Fish