Mercury is the single most toxic element for seabirds. Mercury, along with Cadmium and lead, is one of the heavy metals that are of environmental concern as it can be toxic at levels only moderately elevated above natural ambient levels.

Selenium is an essential micronutrient for animals. Concentrations of approximately 30 mg/kg dry weight are considered as background levels.

Chlordane was used as a pesticide in the United States from 1948 to 1988. Chlordane is considered to have high acute toxicity based on short-term animal tests in rats.

Arsenic is a highly poisonous metalloid with many allotropic forms, including a yellow (molecular non-metallic) and several black and grey forms (metalloids).

Zinc is an essential trace element. It is an especially important element in enzymes and plays a critical role in normal functioning of the brain and central nervous system.

 Overall there has been a significant reduction of hexachlorobenzene concentrations in seabird eggs during the time period from 1983 to 2003.

Black-legged kittiwak (Photo: Norwegian Polar Institute)

Environmental pollutants from industrialised parts of the world reach the Arctic via air, ocean currents, rivers and sea ice. A wide range of persistent organic pollutants (POPs) and heavy metals have been detected in Arctic wildlife. The levels of the most toxic trace elements (mercury and cadmium) measured in muscle and liver tissue of seabirds from the Barents Sea exceed background levels, but are low compared to those in similar seabird species from

Lindane and the other HCH isomers are members of the organochlorine family of chemicals. For decades, lindane, the gamma isomer, has been widely used as an insecticide.

DDT was developed as the first of the modern synthetic insecticides in the 1940s. It was initially used with great effect to combat malaria, typhus, and other insect-borne human diseases among military and civilian populations.

It was also used for insect control in crop and livestock production, institutions, homes, and gardens. Today, DDT is classified as a probable human carcinogen. There have been restrictions on the use of DDT since 1972. However, DDT has a limited use in mosquitoes control and prevention of malaria.

Cadmium has a high toxicity and is carcinogenic. Cadmium, along with mercury and lead, is one of the heavy metals that are of environmental concern as it can be toxic at levels only moderately elevated above natural ambient levels.

The PCB makes up the majority of persistent organic pollutants in seabird eggs.

There has been a significant reduction of HCH concentrations in seabird eggs in the period from 1983 to 2003.

Chromium is an important metal in industry, for example as additive in iron for stainless steel production.

Animal studies show that long time exposure to hexachlorobenzene can harm the liver, immune system, kidneys, and blood and it can produce eruptions and pigmentations of the skin.

PBDEs are accumulating in the environment, including humans, and have shown an exponential increase over the past few decades.

The persistence and bioaccumulative characteristics of PBDEs and their similarities to known toxic PCBs, raises concern over potential human health effects, especially during early development.
PBDEs increased in the period from 1983 to 1993 and then leveled out from 1993 to 2003.

Copper is an essential element that is metabolically regulated in the tissue of seabirds.

Polychlorinated biphenyls (PCBs) are a class of organic compounds with 1 to 10 chlorine atoms attached to biphenyl. Theoretically there are 209 different congeners of PCB, of which 130 different are found in environmentally samples.

Perfluorinated compounds (PFCs) refer to a class of organofluorine compounds that have all hydrogens replaced with fluorine on a carbon chain—but also contain at least one different atom or functional group.

The kidneys of adult animals excrete excess Manganese efficiently. Therefore Manganese is not seen as a problem in Arctic marine ecosystems.

Hexabromocyclododecane (HBCDD) is a brominated flame retardant.