Do We Understand What the Mercury Speciation Instruments Are Actually Measuring? Results of RAMIX

Abstract

From August 22 to September 16, 2012, atmospheric mercury (Hg) was measured from a common manifold in the field during the Reno Atmospheric Mercury Intercomparison eXperiment. Data were collected using Tekran systems, laser induced fluorescence, and evolving new methods. The latter included the University of Washington-Detector for Oxidized Mercury, the University of Houston Mercury instrument, and a filter-based system under development by the University of Nevada-Reno. Good transmission of total Hg was found for the manifold. However, despite application of standard protocols and rigorous quality control, systematic differences in operationally defined forms of Hg were measured by the sampling systems. Concentrations of reactive Hg (RM) measured with new methods were at times 2-to-3-fold higher than that measured by Tekran system. The low RM recovery by the latter can be attributed to lack of collection as the system is currently configured. Concentrations measured by all instruments were influenced by their sampling location in-the-manifold and the instrument analytical configuration. On the basis of collective assessment of the data, we hypothesize that reactions forming RM were occurring in the manifold. Results provide a new framework for improved understanding of the atmospheric chemistry of Hg.

Observations of atmospheric mercury in China: a critical review

“…Recent field and laboratory intercomparisons suggested that the GOM measured by the Tekran system may be biased low by a factor of 1.6-10.6 times compared to recently developed methods using the Detector for Oxidized Hg Species (DOHGS), nylon membranes and cation exchange membranes, and the magnitude of bias can be influenced by the forms of GOM, ozone and relative humidity (Lyman et al, 2010;Huang et al, 2013;Gustin et al, 2013;Ambrose et al, 2013;McClure et al, 2014). A manual method similar to the Tekran 2537/1130/1135 system has also been deployed (Fu et al, 2012a;Zhang et al, 2015a).…”

Deciphering potential chemical compounds of gaseous oxidized mercury in Florida, USA

“…Ambrose et al, 2013;Gustin et al, 2013;Huang et al, 2013;Lyman et al, 2010Lyman et al, , 2016McClure et al, 2014). Since GOM is considered an important form that can be rapidly removed from the atmosphere due to high water solubility (Lindberg et al, 2007), it is important to understand both atmospheric concentrations and chemistry (i.e., specific chemical compounds).…”

A smart nanofibrous material for adsorbing and detecting elemental mercury in air

“…Fortunately, many advances in analytical methodologies have made it possible to study atmospheric Hg in different environmental locations. However, several limitations and difficulties are still experienced in Hg analysis, as most methods cannot yet directly or accurately determine minor Hg species (Gustin et al, 2013). Hence, efforts should be continued to further secure the reliability, traceability, and accuracy of Hg levels measured in air.…”

“…In addition, the limitations and potential interferences with our current measurement methods have not been adequately investigated; thus alternate methods to measure atmospheric Hg are needed. Given the uncertainty and restrictions associated with automated and/or semi-automated Hg measurements (Gustin et al, 2013;Pirrone et al, 2013), particularly in responding to the technical needs of an expanding Hg global observation network, we developed a reliable, sensitive, and inexpensive surface for atmospheric Hg detection. In particular, we investigated and demonstrated the utility of composite nanofibrous electrospun layers of titania decorated with gold nanoparticles (AuNPs) to obtain nanostructured materials capable of adsorbing GEM as a useful alternative system for making regional and global estimates of air Hg concentrations.…”