Thallium

formula: Tl; CAS Registry Number: 7440-28-0

Rare element which occurs naturally as trace element in many minerals

It is of limited commercial importance. Thallium is used e.g. in metal working industry, in the production of special-purpose glass and in measuring technology. Thallium sulfate is highly toxic and used as rodenticide and insecticide. It is banned, however, in many countries, e.g. Germany, Switzerland and the USA.

Thallium is released into the environment during weathering of rocks and anthropogenic activities. Water contaminations are mostly caused by industrial waste waters and atmospheric deposition. In aquatic ecosystems, thallium is bioavailable and quickly accumulated by organisms.
Through plants and animals thallium may enter the human food chain.

Environmentally relevant characteristics of thallium and its compounds include:

 

Specimen

Bream Bioindicator in rivers and lakes
Suspended particulate matter Fine insoluble mineral or organic particles in the water phase
Common bladder wrack Common brown alga of the coastal areas of the North and Baltic Sea
Common spruce A major primary producer in semi-natural and anthropogenic affected ecosystems.
Pine A major primary producer in semi-natural and anthropogenic affected ecosystems.
Lombardy poplar A deciduous tree typical of ecosystems close to dense conurbations and an indicator for the characterisation of the immission situation during the vegetation period.
Beech 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.
Students Student groups with an even number of female and male students at the age of 20 to 29.

Sampling area

BR/NP Berchtesgaden The only high mountains national park in Germany and an area of the Limestone Alps with international relevance
Saarländischer Verdichtungsraum Important, old-industrialised conurbation in Germany.
Bornhöveder Seengebiet Main water divide between the North- and Baltic Sea
Rhein Longest river in Germany
NP Bayerischer Wald Germany's first national park
NP Vorpommersche Boddenlandschaft National Park in the largest brackish water (Bodden) habitat of the world.
BR/NP Wattenmeere National park in the world largest connected sand and mud flats.
Elbe Fourth largest river basin in Central Europe
Verdichtungsraum Halle-Leipzig Region in the chemical triangle of Central Germany
NP Harz Germany's largest forest national park
Solling Second highest and largest low mountain range in Northern Germany
BR Pfälzerwald Germany's largest connected forest area in a range of low mountains
Oberbayerisches Tertiärhügelland The Upper Bavarian Tertiary Uplands are a part of the Southern German Molasse Basin
Donau Second largest river in Europe
Sampling sites (humans) 4 university cities as sampling areas.

Sampling period

1985 - 2019