Critical Review Of The Article “Spatial Variation Of Mercury Bioaccumulation In Bats Of Canada Linked To Atmospheric Mercury Deposition”
In the article, Spatial variation of mercury bioaccumulation in bats of Canada linked to atmospheric mercury deposition (2018), Chételat, Hickey, Poulain, Dastoor, Ryjov, McAlpine, Vanderwolf, Jung, Cooke, Hobson, Jonasson, Kaupas, McCarthy, McCelland, Morningstar, Norquay, Novy, Player, Redford, Simard, Stamler, Webber, Yumvihoze and Zanuttig examine the levels of mercury and the bioaccumulation of mercury in the fur of little brown bats. The purpose of this study is to further look in the various ways in which the total and methylmercury levels of mercury can be found in the fur of bats, understanding if there are other external factors like sex or age that may cause levels to be higher, if certain regions in Canada have higher chances for bat to bioaccumulate mercury and to look into how mercury travels through the atmosphere into bats.
This study was conducted from the dorsal fur of bats by clipping hair from the scapulae from 1178 bats, a majority of the bats being little brown bats and big brown bats with a smaller amount northern long-eared bats, silver-haired bats and hoary bats from all over Canada. When looking at the data analysis and the connection between mercury concentrations in the fur and internal tissue it was hard to see if there was any direct correlation since the factors used like sex, age and species were unbalanced until they broke up their analysis using these factors in smaller geographical regions. The results of this study demonstrate how there is a correlation between the mercury found within the bat fur and the bioaccumulation of mercury within the bats. The total mercury and methylmercury were found to be positively correlated in the brain, kidney and liver, in comparison to the correlation between the fur and liver or fur and kidney which did not prove to have any significant correlation. They have also demonstrated that species variation had a certain effect on the amount of mercury found within the bats as northern-long eared and big brown bats showed to have higher concentrations of mercury in comparison to little brown bats with about 1. 7 +- 0. 2 more mercury. When looking into sex and age its seen that juvenile bats had about 0. 4 +- 0. 04 times less total mercury compared to adult bats and sex didn’t prove to have any significance with the levels found.
Geographic patterns did have an effect of the bioaccumulative levels of mercury found as there is a guideline of 10 μg/g and in and places like New Brunswick (7. 97 μg/g) and Nova Scotia (12. 78 μg/g) overall showing that these places are close or exceeding the guideline proving that the east coast of Canada has a greater area of bioaccumulation for mercury. Some of the limitations of this study include not knowing if methylmercury has any direct effect on the brains of bats, knowing if the diet of different bats can effect the amounts of mercury found in their fur and how various geographic regions have an impact on the mercury levels.
When you look at that article all together and fully understand the way that mercury can effect the interior organs of bats and it can be ingested through sources of water, the food they eat and where they live helps to put things into perspective of how similar effects can be taking place in humans and other species.
I believe that this article entails all the important elements that are needed to understand the ways that mercury bioaccumulates in bats and how even through the limitations it is still clear that mercury is being spread through spatial variation, aquatic factors and other things that would impact the life of bats and the environment.
