A compilation of field surveys on gaseous elemental mercury (GEM) from contrasting environmental settings in Europe, South America, South Africa and China: separating fads from facts

Abstract

Mercury is transported globally in the atmosphere mostly in gaseous elemental form (GEM, [Formula: see text]), but still few worldwide studies taking into account different and contrasted environmental settings are available in a single publication. This work presents and discusses data from Argentina, Bolivia, Bosnia and Herzegovina, Brazil, Chile, China, Croatia, Finland, Italy, Russia, South Africa, Spain, Slovenia and Venezuela. We classified the information in four groups: (1) mining districts where this contaminant poses or has posed a risk for human populations and/or ecosystems; (2) cities, where the concentration of atmospheric mercury could be higher than normal due to the burning of fossil fuels and industrial activities; (3) areas with natural emissions from volcanoes; and (4) pristine areas where no anthropogenic influence was apparent. All the surveys were performed using portable LUMEX RA-915 series atomic absorption spectrometers. The results for cities fall within a low GEM concentration range that rarely exceeds 30 ng m(-3), that is, 6.6 times lower than the restrictive ATSDR threshold (200 ng m(-3)) for chronic exposure to this pollutant. We also observed this behavior in the former mercury mining districts, where few data were above 200 ng m(-3). We noted that high concentrations of GEM are localized phenomena that fade away in short distances. However, this does not imply that they do not pose a risk for those working in close proximity to the source. This is the case of the artisanal gold miners that heat the Au-Hg amalgam to vaporize mercury. In this respect, while GEM can be truly regarded as a hazard, because of possible physical-chemical transformations into other species, it is only under these localized conditions, implying exposure to high GEM concentrations, which it becomes a direct risk for humans.

Gaseous Elemental Mercury and Total and Leached Mercury in Building Materials from the Former Hg-Mining Area of Abbadia San Salvatore (Central Italy)

“…We evidenced the persistence of gaseous mercury despite the fact that the mining activity at Abbadia San Salvatore terminated in 1976, although high GEM concentrations were also measured in other decommissioned mining districts (e.g., Almaden, Spain, and Idrija, Slovenia; [18]) or even in apartments and studios built in Hoboken (NJ, USA), where a tool-and-dye company and, successively, a factory of manufacturing mercury valor lamps operated in the past [62,63]. GEM concentrations >1000 ng·m −3 were recorded [64].…”

“…Mercury affects cellular, cardiovascular, hematological, pulmonary, renal, immunological, neurological, endocrine, reproductive and embryonic systems of humans, e.g., [17]. According to [18], atmospheric mercury poses two specific risks: (i) a direct one, which involves the inhalation of gaseous mercury, causing different problems to human physiology, e.g., [18,19], and (ii) a collateral one, which refers to the transformation of the Hg-species, i.e., from either GEM into GOM or GOM into methyl-Hg, the latter being the most toxic form of mercury, e.g., [20,21,22,23,24]. Many international projects have provided detailed information on the distribution of GEM on a global scale, e.g., [25,26].…”

Soil pollution related to mercury-mining activities in the proximity of Usagre (Badajoz, SW Spain)

“…It can be seen that the values are markedly different; at the surface, the concentrations are relatively low, i.e. comparable with background values from polluted sites [28] Orange and red areas surpass the tolerable level for agronomic crops [36]. All values in mg kg −1 .…”

“…The survey included both surface data and underground data since the Mariquita mine was accessible during the survey. Technical information about the analytical device used and the type of survey undertaken can be found in a number of previous papers published by this and other teams [24][25][26][27][28][29][30][31][32]. The measurement range was between 2 and 25,000 ng m −3 , and the precision and accuracy were appropriate for this type of survey.…”

In-depth review of atmospheric mercury: sources, transformations, and potential sinks

“…Recently compiled survey data comparing measured gas phase elemental mercury in different geographic regions across the globe can currently be used for model validation. 75 However, without detailed measurements of atmospheric mercury species beyond operationally defined gas phase elemental mercury designation, any disagreement between models and field measurements cannot be adequately assessed. These intercomparisons using novel instrumentation developed to examine specific mercury forms including more detailed information on complexes and their recycling times in the atmosphere and various deposition environments will be needed if we are to develop a better fundamental understanding of how increased levels of mercury will impact the environment and human health now and in the future.…”