| Summary: | Global industrialization has led to emissions of heavy metal pollutants that are transported to the most remote areas of the planet. Elevated concentrations of heavy metals are ecological toxins in soils, water, and air. Monitoring has only been implemented during the last few decades with anthropogenic emissions superimposed over natural sources. Furthermore, most monitoring programs generally target local sources of emissions near cities rather than large-scale impacts. Thus quantifying safe limits and controlling industrial emissions is complicated by a lack of knowledge about natural sources and variability on regional, hemispheric, and global scales. New baseline studies are needed to determine i) natural background concentrations of heavy metals, ii) contributions of anthropogenic emissions, and iii) the degree to which atmospheric transport affects background heavy metal concentrations. Due to the remoteness of Antarctica, ice cores can be used as sensitive recorders of background heavy metal atmospheric concentrations over thousands of years. This provides the opportunity to determine natural variability and contributions to the atmosphere on a hemispheric scale, as well as dating the onset of anthropogenic emissions. This thesis presents a 2,300-year time-series record of six heavy metals from a new high-resolution coastal ice core from the Ross Sea region of Antarctica. Roosevelt Island is an ice dome located in the north-eastern Ross Ice Shelf, and a 763m deep ice core was collected over two field seasons as part of the Roosevelt Island Climate Evolution (RICE) project. In addition to 31 other trace elements, concentrations of iron, aluminium, manganese, lead, arsenic, and thallium were measured using inductively coupled plasma mass spectrometry (ICPMS) in the RICE ice core, snow pit, and snow precipitation samples. Sample resolution over the 20th century is extremely high (~1.6 months per sample), with ~four-year resolution extending the record back to 2,300 years ago. We use this record to first ...
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