Mercury pollution causes immune damage to harbor seals

Oct 21, 2008

Methylmercury (MeHg), the predominant form of mercury found in the blood of marine mammals and fish-eating communities, could be more damaging to seals than has previously been thought. Research published in BioMed Central's open access journal Environmental Health shows that MeHg harms T-lymphocytes, key cells in a seal's immune system. Similar results were also found for human lymphocytes.

Mercury exposure is known to occur as a result of man-made pollution and natural events such as volcanic eruptions. According to the lead author of this study, Krishna Das of the Université de Liège, Belgium, "Mercury is known to bioaccumulate and to magnify in marine mammals, which is a cause of great concern in terms of their general health. In particular, the immune system is known to be susceptible to long-term mercury exposure". In order to determine the scale of this problem, the authors carried out analysis of the blood mercury levels of harbour seals caught in the North Sea and tested the effects of MeHg in lab experiments.

By applying increasing doses of MeHg to lymphocytes, a type of white blood cell, the authors determined that the amount of mercury found in the blood of the seals studied was enough to cause damage to the important immune system cells. They said, "Although the in vitro approach utilised in this investigation represents an extreme reductionism relative to the complex situation in the intact organism, it provides an insight into the specific effects of mercury pollution."

Immune system damage may already have taken a toll on the population of harbour seals. The 1998 and 2002 outbreaks of phocine distemper virus, known to have killed thousands of seals, were linked to the deleterious effects of pollution on the seals' ability to fight the infection.

Citation: Mercury immune toxicity in harbour seals: links to in vitro toxicity, Krishna Das, Ursula Siebert, Audrey Gillet, Aurélie Dupont, Carole Di-Poi, Sonja Fonfara, Gabriel Mazzucchelli, Edwin De Pauw and Marie-Claire De Pauw-Gillet, Environmental Health (in press)
www.ehjournal.net/

Source: BioMed Central

Explore further: More management needed for Rottnest marine debris

add to favorites email to friend print save as pdf

Related Stories

Australia PM rebuffs Booker Prize winner criticism

21 minutes ago

Prime Minister Tony Abbott on Thursday brushed off criticism about Australia's environmental policies by newly crowned Booker Prize winner Richard Flanagan, saying the country had "a very, very strong" record.

Netflix hammered by weak subscriber growth

23 minutes ago

Netflix shares plunged Wednesday after its quarterly report showing disappointing subscriber growth for the streaming video group which has been expanding globally.

Recommended for you

New Marine Protected Area proposed for Myanmar

1 hour ago

The proposed establishment of a new Marine Protected Area (MPA) in the Myeik archipelago has received enthusiastic support by participants in a workshop held recently in Myanmar's Tanintharyi region.

Beijing's focus on coal lost in haze of smog

6 hours ago

The soaring, grimy chimneys of the coal-fired power station have belched the last of their choking fumes into Beijing's air, authorities say—but experts doubt the plan will ease the capital's smog.

User comments : 0