Tracers of Atmospheric Mercury Pollution in Sedimentary Organic Matter

Background:

Atmospheric pollution, the release of harmful substances into the atmosphere by human activity is one of the major challenges of our industrial civilization (1). In particular, Mercury (Hg) has attracted attention as a highly toxic contaminant on human health and ecosystems. Successful efforts have reduced the Hg emissions from anthropogenic activities during the last decennia (2).

However, in recent years atmospheric levels have been increasing again. This has been attributed to the increased energy demand in developing countries, which is strongly based on coal-fired power plants (3).

Volcanism and the release of volcanic volatiles can be a major natural source of atmospheric pollution in the geological past. Sedimentary Hg spikes have been used as a proxy for periods of massive volcanism, which released toxic levels of Hg and eventually causing mass extinctions, such as the End-Triassic and End-Permian (4, 5, 6). However, the relationship between sedimentological processes, the composition of the organic matter and the preservation of the sedimentary mercury signal remains poorly constrained.

               

Aim:

The aim of the present MSc thesis is to study the distribution of Hg in modern terrestrial and aquatic sediments and its relationship with the composition of the sedimentary organic matter.

Also, rock samples from relevant geological intervals will be analyzed.

               

Learning goals:

The thesis will introduce the student in methods commonly used in environmental geology and sedimentary geochemistry.

In particular, the study will cover methods of laboratory work to analyze heavy metal (Hg) and to extract and characterize the composition sedimentary organic matter based on microscopy and organic geochemistry.

               

References:

  1. Pirrone N., et al., 2010. Global mercury emissions to the atmosphere from anthropogenic and natural sources. Atmos. Chem. Phys., 10, 5951–5964.
  2. Streets D.G., et al., 2017, Total mercury released to the environment by human activities. Environ. Sci. Technol., 51, 5969−5977.
  3. Wilcox J., et al., 2012 Mercury adsorption and oxidation in coal combustion and gasification processes, Int. J. Coal Geology, 90–91,4-20.
  4. Sanei et al., 2012. Latest Permian mercury anomalies. Geology, 40, 63-66.
  5. Percival, L. et al., 2018. Mercury evidence for pulsed volcanism during the end-Triassic mass extinctions. PNAS, 114, 7929-7934
  6. Percival, L. et al., 2018. Does large igneous province volcanism always perturb the mercury cycle? Comparing the records of oceanic event 2 and the end-Cretaceous to other Mesozoic events. Am. J. Sci., 318, 799-860.
Published Sep. 17, 2020 9:50 AM - Last modified Sep. 17, 2020 10:44 AM

Scope (credits)

60