Mercury Threat to Oceans Escalating due to Climate Change

More mercury than ever before threaten aquatic ecosystems –Study

Mercury levels in fish could increase by up to seven times the current levels as temperatures continue rising, say researchers.

Marine ecosystems, and mainly their coastal zones, have been estimated to contribute more than 60% of the total economic value of the biosphere . These ecosystem services are currently threatened by anthropogenic pollution and a changing climate. Increased terrestrial water runoff and accompanied input of terrestrial NOM and nutrients to lakes and coastal sea areas have been observed in several regions during the late 20th century. These increases are predicted to escalate for large regions worldwide following increased air temperatures and precipitation events.

The study Terrestrial discharges mediate trophic shifts and enhance methylmercury accumulation in estuarine biota has been published in Science Advances. 

Abstract

The input of mercury (Hg) to ecosystems is estimated to have increased two- to fivefold during the industrial era, and Hg accumulates in aquatic biota as neurotoxic methylmercury (MeHg). Escalating anthropogenic land use and climate change are expected to alter the input rates of terrestrial natural organic matter (NOM) and nutrients to aquatic ecosystems. For example, climate change has been projected to induce 10 to 50% runoff increases for large coastal regions globally. A major knowledge gap is the potential effects on MeHg exposure to biota following these ecosystem changes. We monitored the fate of five enriched Hg isotope tracers added to mesocosm scale estuarine model ecosystems subjected to varying loading rates of nutrients and terrestrial NOM. We demonstrate that increased terrestrial NOM input to the pelagic zone can enhance the MeHg bioaccumulation factor in zooplankton by a factor of 2 to 7 by inducing a shift in the pelagic food web from autotrophic to heterotrophic. The terrestrial NOM input also enhanced the retention of MeHg in the water column by up to a factor of 2, resulting in further increased MeHg exposure to pelagic biota. Using mercury mass balance calculations, we predict that MeHg concentration in zooplankton can increase by a factor of 3 to 6 in coastal areas following scenarios with 15 to 30% increased terrestrial runoff. The results demonstrate the importance of incorporating the impact of climate-induced changes in food web structure on MeHg bioaccumulation in future biogeochemical cycling models and risk assessments of Hg.

Terrestrial discharges mediate trophic shifts and enhance methylmercury accumulation in estuarine biota

Sofi Jonsson et al. http://advances.sciencemag.org/content/3/1/e1601239.full

Open Sewer: The Primal Function of a River

“12,000 years of [alleged] human civilization and all we have to show for is Google, Facelift [Facebook] … and cluster bombs.” —JPB

Perhaps, the title of this post could also be incorporated in the above quote, which comes from an email written by one of the blog’s contributors.

12,000 years of civilization and the Neanderthals are still using rivers as an open sewer; however, the waste is getting deadlier each year.

High levels of mercury found in Cataraqui River: Queen’s study

Public release: Queen’s University, CanadaThe Inner Harbour on the Cataraqui River in Kingston, Ont., has mercury levels in sediment more than two times the Canadian government’s most severe effect limits, according to a Queen’s University study.

“Mercury levels in this part of the river have never been studied before,” says biology professor Linda Campbell. “Now we know the sources of the problem and just how widespread it is.”

Most of the western shore of the Cataraqui River south of Belle Park and above the LaSalle Causeway Bridge had levels of contamination, with the worst area around the Cataraqui Canoe Club, just south of the former Davis Tannery.

Over the past century, the area has been home to many industries, such as a coal gasification plant, tannery and lead smelter, municipal dump, textile mill and fuel depot. The report found rain is washing contaminated shoreline soil near the canoe club into the river, adding to the sediment already contaminated by decades of industry.

The mercury comes in two forms, mercury and its organic and more toxic form, methylmercury. Right now, most of the mercury around the rowing club seems to be associated with the sediment in its inorganic form, with very little if any actually being mobile in the river water.

Rower and canoeists don’t have to be too concerned about the high mercury levels because they don’t drink the water or spend a long periods of time swimming there. But more studies will be needed to determine the impact on marine life.

“People have always been worried about lead, chromium and PCBs in the Cataraqui River,” says Professor Rutter, Director of Analytical Services Unit in the Environmental Studies department who worked on the study. “This study looked at mercury. We need to know what and where the major sources of contamination are before we can make a decision on how to solve the problem.”

The findings are were just published in Science of the Total Environment. The City of Kingston and Ontario Ministry of Environment have also received the study results for consideration when making future decisions about contaminants in the river.

Related Links:

• Another Dark Day for Global Climate, Environment
• Eat S***, So Many Canadians Can’t Be Wrong!
• AVATAR !!!
• Winter Olympics: With Glowing Hearts Burning to CO2 and Soot
• Suncor lives to pollute another day!

• Large spill at Canada’s oil sands terminal
• Canada Makes Pollution Progress
• Canada: A Cesspool of Industrial Pollution
• Canada, Racism, Genocide, and the Bomb