Influence of forest canopies on the deposition of methylmercury to boreal ecosystem watersheds

• Author / Creator

  Mowat, Linnea

• Methylmercury (MeHg) is a potent vertebrate neurotoxin and a contaminant of global concern. Increased anthropogenic emissions of mercury (Hg) to the atmosphere have led to increased bioaccumulation of MeHg in top predatory organisms such as fish, the consumption of which is the main exposure pathway of this toxin to humans and other animals. Forest canopies significantly increase the deposition of Hg in general to watersheds, but sources and fates of MeHg deposition in particular remain poorly understood. In this study, wet and dry loadings of MeHg to a watershed were quantified, and the retention and (photo)reduction of MeHg on foliage were measured using unique stable isotope experiments. We found that traditional methods of quantifying net deposition underestimate incoming sources of MeHg, and that retention of MeHg on forest canopies results in delayed transport of a significant portion of newly deposited MeHg from terrestrial catchments into adjacent lakes.

• Subjects / Keywords

  • Methyl mercury
  • Dry-deposition
  • Mercury
  • Boreal
  • Wet-deposition
  • Photoreduction
  • Canopy

• Graduation date

  Fall 2010

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R36S6X

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.