Difference between revisions of "Pollution and marine mammals"

From Coastal Wiki
Jump to: navigation, search
 
(32 intermediate revisions by 2 users not shown)
Line 1: Line 1:
 +
'''<u>Main substances in marine mammals</u>'''
 +
 
[[Image:feeding-humpback-whales.jpg|thumb|right|400px| <div style="text-align: center;">
 
[[Image:feeding-humpback-whales.jpg|thumb|right|400px| <div style="text-align: center;">
 
Feeding humpback whales © Michael Heithaus  
 
Feeding humpback whales © Michael Heithaus  
 
</div>]]
 
</div>]]
'''<u>Main substances in marine mammals</u>'''
+
Like [[Pollution and sea birds|sea birds]], marine mammals are in all marine ecosystems at the top (or very near the top) of the [[food chain]]. As such, they are particularly sensitive towards [[bioaccumulation|bioaccumulating]] substances. Most studied are [[organochlorine pesticides]] (like [[DDT|DDTs]]), polychlorinated biphenyls ([[PCB|PCBs]]) and [[methylmercury]].
  
Like [[Pollution and sea birds|sea birds]], marine mammals are in all marine ecosystems at the top (or very near the top) of the food chain. As such, they are particulary sensitive towards [[bioaccumulation|bioaccumulating]] substances. Most studied are [[organochlorine pesticides]] (like [[DDT|DDTs]]), polychlorinated biphenyls ([[PCB|PCBs]]) and [[methylmercury]]. Although marine mammals can accumulate large quantities of [[methylmercury]], they rarely display any harmful effects of the contaminant. The reason for this is that marine mammals can transform methylmercuy into less harmful inorganic mercury, which can also efficiently be detoxified by selenium.  
+
The use of DDTs (since the 1970s) and PCBs (since 1991) has been banned in Europe. However because of their stability they are still present in marine ecosystems, even in very remote areas like Antarctica. Of course [[PCBs_and_organochlorine_pesticides_in_Antarctic_algae|concentrations in Antarctica]] will be lower than those in the coastal areas where the discharges occurred.<ref> Kennish, M. J. (1996): Practical Handbook of Estuarine and Marine Pollution, CRC Press 524 pp</ref> Although marine mammals can accumulate large quantities of [[methylmercury]], they rarely display any harmful effects of the contaminant. The reason for this is that marine mammals can transform methylmercuy into less harmful inorganic [[mercury]], which can also efficiently be detoxified by selenium.  
  
The use of DDTs (since the 1970's) and PCBs (since 1991) has been banned in Europe. However because of their stability they are still present in marine ecosystems, even in very remote areas like Antarctica. Of course concentrations in Antarctica will be lower than those in the coastal areas where the discharges occurred.<ref> Kennish, M. J. (1996): Practical Handbook of Estuarine and Marine Pollution, CRC Press 524 pp</ref>
+
<u>'''Toxicant related problems in marine mammals'''</u>
  
<u>'''Toxine related problems in marine mammals'''</u>
+
In the past decades [[organochlorine compounds|organochlorine]]-contaminant-related-mass-deaths have occurred in marine mammals. In Northern Europe, more then 20.000 seals have died in 1988 due to seal plague. It is believed that the seal plague virus caused this extent of damage because the resistance of the seals was lowered due to [[pollutants]]: a process called [[immunodeficiency]]. Later this virus caused mass mortalities of striped dolphins in the 1990-1992 period: More than 1000 dolphins died in the Mediterranean. Again it's believed that casualties were increased due to immunodeficiency caused by contaminants like PCBs. Actually proving the toxicological effects of contaminants in marine mammals is rather difficult due to logistical and ethical reasons. <ref>Sinderman, C.J. 1996. Ocean Pollution: Effects on Living Resources and Humans. CRC Press, Boca Raton, FL. 275 pp</ref> Some marine mammals have reproductive difficulties which might be related to high concentrations of DDTs or PCBs, compounds which might act as [[endocrine disrupting compounds]]. Till today however, no marine mammal has died by the direct toxic effects of any organochlorine compound.
 +
Although marine mammals are usually capable of detoxifying mercury, there have been reports of mercury intoxication and related deaths in marine mammals in 1968. These deaths occurred in an area with heavy industrial mercury dumping. <ref name = pub2>New perspectives: Toxicology and the environment. Toxicology of marine mammals, eds.J. Vos, G. Bossart, M. Fournier, and T. O'Shea, New York: Taylor & Francis. 643p</ref>
  
In the past decades contaminant related mass deaths have occurred in marine mammals. In Northern Europe, more then 20.000 seals have died due to seal plague in 1988. It is believed that the seal plague virus caused this damage because the resistance of the seals was lowered due to toxins: a process called [[immunodeficiency]]. Later this virus caused mass mortalities of striped dolphins in the 1990-1992 period: More than 1000 dolphins died in the Mediterranean. Again it's believed that casualties were increased due to immunodeficiency caused by contaminants like PCBs. <ref>Sinderman, C.J. 1996. Ocean Pollution: Effects on Living Resources and Humans. CRC Press, Boca Raton, FL. 275 pp</ref>
 
  
 
Below you can find some links to Belgian case studies on ecotoxicology in marine mammals.
 
Below you can find some links to Belgian case studies on ecotoxicology in marine mammals.
Line 16: Line 18:
 
== Case studies ==
 
== Case studies ==
  
Case study 1:[[PCB and heavy metals in beached sperm whales | Toxin analysis in beached sperm whales ]]<ref>Holsbeek, L.; Joiris, C.R.; Debacker, V.; Ali, B.I.; Roose, P.; Nellissen, J.P.; Gobert, S.; Bouquegneau, J.-M.; Bossicart, M. (1999). Heavy metals, organochlorines and polycyclic aromatic hydrocarbons in sperm whales stranded in the southern North Sea during the 1994/1995 winter. Mar. Pollut. Bull. 38(4): 304-313</ref>
+
Case study 1:[[PCB and heavy metals in beached sperm whales | Toxic substances in beached sperm whales ]]<ref>Holsbeek, L.; Joiris, C.R.; Debacker, V.; Ali, B.I.; Roose, P.; Nellissen, J.P.; Gobert, S.; Bouquegneau, J.-M.; Bossicart, M. (1999). Heavy metals, organochlorines and polycyclic aromatic hydrocarbons in sperm whales stranded in the southern North Sea during the 1994/1995 winter. Mar. Pollut. Bull. 38(4): 304-313</ref>
  
Case study 2:[[pesticides in harbour porpoises | Organochlorine pesticides in harbour porpoises]]<ref>Covaci, A.; Van de Vijver, K.; De Coen, W.; Das, K.; Bouquegneau, J.-M.; Blust, R.; Schepens, P. (2002). Determination of organohalogenated contaminants in liver of harbour porpoises (Phocoena phocoena) stranded on the Belgian North Sea coast. Mar. Pollut. Bull. 44(10): 1157-1169</ref>
+
Case study 2:[[Organohalogenated contaminants in harbour porpoises|Organochlorine pesticides in Harbour porpoises]] <ref>Covaci, A.; Van de Vijver, K.; De Coen, W.; Das, K.; Bouquegneau, J.-M.; Blust, R.; Schepens, P. (2002). Determination of organohalogenated contaminants in liver of harbour porpoises (Phocoena phocoena) stranded on the Belgian North Sea coast. Mar. Pollut. Bull. 44(10): 1157-1169</ref>
  
 
==References==
 
==References==
 
<references/>
 
<references/>
 +
 +
 +
 +
{{author
 +
|AuthorID=19826
 +
|AuthorFullName=Daphnis De Pooter
 +
|AuthorName=Daphnisd}}
 +
 +
[[Category:Ecotoxicology]]
 +
[[Category:Coastal and marine pollution]]

Latest revision as of 17:43, 5 November 2019

Main substances in marine mammals

Feeding humpback whales © Michael Heithaus

Like sea birds, marine mammals are in all marine ecosystems at the top (or very near the top) of the food chain. As such, they are particularly sensitive towards bioaccumulating substances. Most studied are organochlorine pesticides (like DDTs), polychlorinated biphenyls (PCBs) and methylmercury.

The use of DDTs (since the 1970s) and PCBs (since 1991) has been banned in Europe. However because of their stability they are still present in marine ecosystems, even in very remote areas like Antarctica. Of course concentrations in Antarctica will be lower than those in the coastal areas where the discharges occurred.[1] Although marine mammals can accumulate large quantities of methylmercury, they rarely display any harmful effects of the contaminant. The reason for this is that marine mammals can transform methylmercuy into less harmful inorganic mercury, which can also efficiently be detoxified by selenium.

Toxicant related problems in marine mammals

In the past decades organochlorine-contaminant-related-mass-deaths have occurred in marine mammals. In Northern Europe, more then 20.000 seals have died in 1988 due to seal plague. It is believed that the seal plague virus caused this extent of damage because the resistance of the seals was lowered due to pollutants: a process called immunodeficiency. Later this virus caused mass mortalities of striped dolphins in the 1990-1992 period: More than 1000 dolphins died in the Mediterranean. Again it's believed that casualties were increased due to immunodeficiency caused by contaminants like PCBs. Actually proving the toxicological effects of contaminants in marine mammals is rather difficult due to logistical and ethical reasons. [2] Some marine mammals have reproductive difficulties which might be related to high concentrations of DDTs or PCBs, compounds which might act as endocrine disrupting compounds. Till today however, no marine mammal has died by the direct toxic effects of any organochlorine compound. Although marine mammals are usually capable of detoxifying mercury, there have been reports of mercury intoxication and related deaths in marine mammals in 1968. These deaths occurred in an area with heavy industrial mercury dumping. [3]


Below you can find some links to Belgian case studies on ecotoxicology in marine mammals.

Case studies

Case study 1: Toxic substances in beached sperm whales [4]

Case study 2:Organochlorine pesticides in Harbour porpoises [5]

References

  1. Kennish, M. J. (1996): Practical Handbook of Estuarine and Marine Pollution, CRC Press 524 pp
  2. Sinderman, C.J. 1996. Ocean Pollution: Effects on Living Resources and Humans. CRC Press, Boca Raton, FL. 275 pp
  3. New perspectives: Toxicology and the environment. Toxicology of marine mammals, eds.J. Vos, G. Bossart, M. Fournier, and T. O'Shea, New York: Taylor & Francis. 643p
  4. Holsbeek, L.; Joiris, C.R.; Debacker, V.; Ali, B.I.; Roose, P.; Nellissen, J.P.; Gobert, S.; Bouquegneau, J.-M.; Bossicart, M. (1999). Heavy metals, organochlorines and polycyclic aromatic hydrocarbons in sperm whales stranded in the southern North Sea during the 1994/1995 winter. Mar. Pollut. Bull. 38(4): 304-313
  5. Covaci, A.; Van de Vijver, K.; De Coen, W.; Das, K.; Bouquegneau, J.-M.; Blust, R.; Schepens, P. (2002). Determination of organohalogenated contaminants in liver of harbour porpoises (Phocoena phocoena) stranded on the Belgian North Sea coast. Mar. Pollut. Bull. 44(10): 1157-1169


The main author of this article is Daphnis De Pooter
Please note that others may also have edited the contents of this article.

Citation: Daphnis De Pooter (2019): Pollution and marine mammals. Available from http://www.coastalwiki.org/wiki/Pollution_and_marine_mammals [accessed on 19-03-2024]