Mercury

Uit Kust Wiki
Ga naar: navigatie, zoeken
Definition of mercury:
Mercury is the heavy metal with the symbol Hg and atomic number 80[1]. It is liquid (at room temperature and atmospheric pressure) and has a silvery-white colour[2].
This is the common definition for mercury, other definitions can be discussed in the article

Notes

Mercury cycle © EPA

Natural mercury derives from the weathering of mercury-bearing rocks, volcano's and hydrothermal vents. It's industrial use includes electronics, light bulbs and thermometers. Within these products, mercury doesn't pose a health problem. However when vaporised into the air by factories producing these products, it can be deposited in soils, and be flushed through rivers towards the ocean. Once deposited in anoxic soils, mercury can be transformed by bacteria to methylmercury.

In the Northern hemisphere anthropogenic sources have largely been eliminated since the 1980's. Mercury is the only contaminant (apart from pathogens) that with certainty has been responsible for human deaths[3]. In humans high levels of mercury can cause:[4]

  • Disruption of the nervous system
  • Damage to brain functions
  • DNA damage and chromosomal damage
  • Allergic reactions, resulting in skin rashes, tiredness and headaches
  • Negative reproductive effects, such as sperm damage, birth defects and miscarriages

Concentrations of mercury on the open ocean range from 0,001 to 0,004 µg/l, in coastal areas concentrations are usually 10 times higher. In heavily polluted systems however (like the Targus estuary in Portugal or Minamata bay in Japan) concentrations have been as high as 80ng/l.

Although inorganic mercury doesn't have biomagnifying characteristics, the organic compound, methylmercury, does.


Case studies

The relation between pollutants and disease in guillemots

Common starfish can act as a bioindicator for heavy metal pollution

Effects of heavy metals on the sperm quality and the larvae survival of sea urchins

Heavy metals in various Belgian benthic invertebrates

PCB and heavy metals in beached sperm whales


Environmental standards and legislation

Included in the OSPAR list of substances of priority action

Included in the water framework list of priority substances


See also

Mercury on the ED North Database

OSPAR background document on mercury

Mercury pollution

Methylmercury

Minamata disease

DPSIR framework applied to global mercury pollution


References

  1. http://en.wikipedia.org/wiki/Mercury_(element)
  2. http://glossary.eea.europa.eu/terminology/concept_html?term=mercury
  3. Kennish, M. J. (1996): Practical Handbook of Estuarine and Marine Pollution, CRC Press 524 pp
  4. http://www.lenntech.com/Periodic-chart-elements/Hg-en.htm
The main author of this article is Daphnis De Pooter
Please note that others may also have edited the contents of this article.