formula: Cr; CAS Registry Number: 7440-47-3

Naturally occurring transition metal

Chromium is a ubiquitous chemical element, which mostly occurs as chromite ore (FeCr2O4) in nature. In metal working industries chromium is used in alloys and as surface coatings against corrosion. Other applications include catalysts, pigments, oxidants, tanning, and wood preservation. It enters the environment mainly through anthropogenic activities. Natural emission sources include volcanic action, weathering and biological processes. Chromium is found in the atmosphere, in soils, waters, plants and animals. It is essential for humans. Some chromium compounds, however, are

  • highly toxic to humans
  • carcinogenic
  • mutagenic
  • toxic to aquatic and terrestrial organisms in acute tests
  • highly toxic to aquatic organisms in chronic and prolonged tests
  • bioaccumulative, i.e. some organisms are capable to accumulate chromium


  • Fine insoluble mineral or organic particles in the water phase
  • Common brown alga of the coastal areas of the North and Baltic Sea
  • A major primary producer in semi-natural and anthropogenic affected ecosystems.
  • A major primary producer in semi-natural and anthropogenic affected ecosystems.
  • A deciduous tree typical of ecosystems close to dense conurbations and an indicator for the characterisation of the immission situation during the vegetation period.
  • As the most dominant deciduous tree species in Central Europe, it plays a significant role in most nearly natural and also anthropogenically influenced forest ecosystems up to an altitude of 1100 m.
  • Soil is livelihood and biosphere for humans, animals, plants and soil organisms. All the substances brought in are transported, transformed and/or accumulated in the soil.
  • Student groups with an even number of female and male students at the age of 20 to 29.

Sampling area

Sampling period

1985 - 2022