Mercury & climate change

Kriya DunlapUniversity of Alaska Fairbanks

what do you know about mercury?

mercury in the environment …

biomagnification and bioaccumulation

the risks of mercury exposure

Mercury has a strong affinity for

sulfhydryl groups (Thiol)

– S-H

H 3C-H

g+

19th Century

Felters

1950’s plastic factory in Minimata Bay

Mercury levels in salmon-fed sled dogs; the potential risks and benefits of subsistence diets

• low incidence of age and nutritional diseases

• 4.8 kg subsistence foods per week

• 60% of subsistence foods is finfish

Village sled dogs

wild Alaskan SALMON

the benefits…

astaxanthin

Eicosapentaenoic acid (20:5ω-3)

Docosahexaenoic acid (22:ω-3)

Phospholipid membrane

Phospholipase A2

Cyclooxygenases (COX)

Prostaglandins (PG)

&

Thromboxanes (TX)

Lipoxygenases (LOX)

Leukotrienes

O

HO

O

HOArachidonic acid Eicosapentaenoic acid

-less biologically active

-poor substrate for cyclooxygenases

-gives rise to series 5 leukotrienes

What is the mercury exposure in salmon-fed sled dogs at different location

along the Yukon River?

What are the health implications?

Why the Yukon River?

Russian Mission

Rampart

Fort Yukon

SalchaGalena

Russian MissionRyan Housler

Rampart

Linda Johnson

Galena Paddy Nolner

Josh Cadzow

Sci Total Environ. 2007 Oct 15;385(1-3):80-5

Why? Life Cycle…

Yukon River Salmon

Health Implications of wild AK salmon?

•WHO Upper Allowable Threshold of 50 ppm (50,000 ng/g)

•EPA suggests a maximum consumption of 226 g of fish per week for a 70 kg person•Reported adverse effects as low as 300 ng/g•Russian Mission sled dogs have some of the highest reported mercury concentrations of any Alaskan mammal

Future direction…

Special Thank you to…

Arleigh ReynoldsJoee Reddington Jr.Paddy NolnerLinda Johnson

Josh CadzowScott CampbellNestlé PurinaINBRE