Featured Research

from universities, journals, and other organizations

Mercury Contamination Found In Stranded Victorian Dolphins

Date:
June 11, 2008
Source:
Monash University
Summary:
Research by an honors student has revealed high mercury levels may be a contributing factor to dolphin deaths in Australia.

Monash University research into heavy metal contaminant levels in dolphins from Port Phillip Bay and the Gippsland Lakes has revealed high mercury levels may be a contributing factor to dolphin deaths.

Researchers from the School of Biological Sciences have confirmed levels of mercury found in the dolphins were within a range considered to cause negative health and mental effects and were higher than mercury levels found in populations around the world.

Supervisory researcher Dr Ross Thompson said the mercury concentrations in 20 live and eight dolphins which died after becoming stranded, collected over the last two years, were measured by Honours student Alissa Monk. Levels in the dead dolphins averaged 3.45 milligrams of mercury per kilogram of tissue compared to 1.32 mg/kg in living dolphins.

"Mercury levels detected are sufficient to cause significant health impacts and were comparable to those found in areas of the world that are considered highly polluted, including the Mediterranean Sea," Dr Thompson said.

Mercury has been shown in previous national studies to bioaccumulate in dolphins, but this is the first study to find particularly high levels in stranded animals in coastal Victoria. Bioaccumulation is the food chain process whereby smaller fish containing mercury are eaten by larger mercury contaminated fish, which are then consumed by dolphins, who can consume up to ten kilograms of fish a day. Mercury levels found in fish were considered low (<0.5 mg/kg) and were fine for human consumption.

"Dolphins may be becoming stranded as a direct consequence of mercury contamination which damages their neurological system. They become potentially confused and disorientated, and strand themselves. Even the apparently healthy dolphins had high levels of mercury which put them at risk of future health complications," Dr Thompson said.

Dr Thompson said mercury is likely to have come from the sediments of the Bay and researchers are concerned that dredging activities may increase the dolphins' exposure.

"Sediment contains mercury, which is likely to have originated from historical gold mining sites where mercury was used in gold processing, as well as from other industrial sources. Over time, the mercury has been washed down through waterways, including the Yarra River, and come to rest on the bottom of the Bay," Dr Thompson said.

Dr Thompson said it was critical that further studies were done throughout the bay dredging process to ensure any further decline in dolphin health could be identified and managed.

The School of Biological Sciences research was supported by Coastcare, West Gippsland CMA, the Gippsland Lakes Board and the Dolphin Research Institute.


Story Source:

The above story is based on materials provided by Monash University. Note: Materials may be edited for content and length.


Cite This Page:

Monash University. "Mercury Contamination Found In Stranded Victorian Dolphins." ScienceDaily. ScienceDaily, 11 June 2008. <www.sciencedaily.com/releases/2008/06/080610092720.htm>.
Monash University. (2008, June 11). Mercury Contamination Found In Stranded Victorian Dolphins. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2008/06/080610092720.htm
Monash University. "Mercury Contamination Found In Stranded Victorian Dolphins." ScienceDaily. www.sciencedaily.com/releases/2008/06/080610092720.htm (accessed July 22, 2014).

Share This




More Plants & Animals News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
Powered by NewsLook.com
San Diego Zoo Welcomes New, Rare Rhino Calf

San Diego Zoo Welcomes New, Rare Rhino Calf

Reuters - US Online Video (July 21, 2014) An endangered black rhino baby is the newest resident at the San Diego Zoo. Sasha Salama reports. Video provided by Reuters
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins