The research topic for this study looked at concentrations of different types of mercury in streams after forest clear-cutting. And the researchers asked the question, what is the comparison between the concentration of Mercury in streams draining from young forests that are clear-cut and streams draining from old forests that are clear-cut?

This study measured concentrations of mercury (inorganic and methyl, chemically shown as Hg” and MeHg) from a stream that drained 0-4 year old clear-cuts of former Norway Spruce forest stands (trees) and then compared those measurements to concentrations in streams that drained over 70 year old Norwegian Spruce reference stands (trees). The study essentially found that concentrations of mercury (all kinds tested) were significantly higher in the 0-4 year clear-cuts compared to the older trees. They assumed that the mercury was mobilized from the soil to the stream as a consequence of clear-cutting and they calculated that about 1/6 of the higher mercury concentration in the 0-4 year clear-cuts could be attributed to enhanced mobilization from soil. They calculated that 5/6 of the concentration was due to a new kind of mercury (Hg”). Logging residue as well as soil organic matter contributed to an environment for electron donors for mercury-creating bacteria, which in turn became more common. Therefore this new kind of mercury became stimulated and created through this bacteria and clear cutting. The researchers found this information through survey, ratio data.

The researchers sampled all of the streams once within a two-week period in August 2007. They collected 150 mL of stream water in acid washed Teflon Nalgene bottles and transported by cooler. To determine the concentrations of the different types of Mercury they used isotope dilution analysis. Essentially the analysis consists of multiple chemical experiments and tests. The final test determined the total mercury concentration by cold vapor atomic fluorescence spectroscopy.

This research was very hard to understand, especially if little to nothing is known about chemistry. Many chemical terms and elements were used without a lot of explanation of what the authors were discussing making it difficult for the reader to completely appreciate the research study.

Skyllberg, Ulf; Bjorkman, Mattias Westin; Meili, Markus; Bjorn, Erik. Elevated Concentrations of Methyl Mercury in Streams after Forest Clear-Cut: A consequence of Mobilization from soil or New Methylation? Enviornmental Science & Technology. 2009, 43, 8535-8541.