Modification of the EPA method 1631E for the quantification of total mercury in natural waters

Abstract

To support the effectiveness of the Minamata Convention, the accurate determinations of mercury (Hg) in natural waters is an important but certainly challenging task due to the low concentrations expected in ambient samples. Mercury contamination may occur from many sources such as the unproperly-cleaning of storage bottles or the use of reagents for sample analysis with Hg traces, thus leading the analyst to easily run into errors. In our work, we propose some key modifications to the United States Environmental Protection Agency(EPA) method 1631E aimed at reducing the Hg contamination of reagents, storage containers, and minimizing the carryover effect in the instrumental line of sampling. The changes introduced have been tailored for the use of the method with cold vapor atomic fluorescence spectroscopy (CV-AFS) instrumentation and tested as part of a United Nations Environment Program (UNEP) ring test. Although the edited method was tested with natural water samples, the proposed method improvements can also apply to the Hg analysis in solid matrices that require the prior acid digestion of the samples. A customized version of the EPA method 1631E is proposed for the analysis of aqueous samples. New protocols for the reduction of contamination in the storage bottles and reagents used for the preparation of BrCl solution are provided. A useful strategy for the control of the memory effect is included.

Seven-Year Monitoring of Mercury in Wet Precipitation and Atmosphere at the Amsterdam Island GMOS Station

“…Wet deposition samples were continuously collected from March 24, 2013, using an automatic wet-only NSA-171 Eigenbrodt collector which comprises a glass funnel connected to a 1-L fluorinated high-density polyethylene (FLPE) bottle. The entire sampling apparatus was thoroughly acid-cleaned, according to the procedures reported by Tassone et al [35], based on the SOPs developed within the GMOS network [36]. Each deployment lasted 6-45 days, depending on the season (wet or dry) and according to exceptional periods of intense rainfall events.…”

“…Each deployment lasted 6-45 days, depending on the season (wet or dry) and according to exceptional periods of intense rainfall events. Analyses of wet deposition samples were performed at the CNR-IIA laboratories following the US-EPA method 1631E guidance reported in the literature [35]. Quality assurance/quality control (QA/QC) procedures were routinely implemented, including the analysis of duplicate samples, accuracy test using certified reference material (NIST1641), matrix spikes, and assessment of Hg contamination through the analysis of the system, transport, reagent and field blanks (more details in Text S2).…”

First atmospheric mercury measurements at a coastal site in the Apulia region: seasonal variability and source analysis

“…In fact, Hg is a global pollutant with a complex biogeochemical cycle that represents a significant public health and environmental issue due to its toxicity, its persistence in the environment, and its ability to undergo long-distance transport before depositing to terrestrial and aquatic surfaces (Pirrone et al 2001 ; Driscoll et al 2013 ; Naccarato et al 2020 ). Among the major sources of Hg pollution for ecosystems, the atmosphere represents the main transport (re-distribution) media of Hg in the environment (Driscoll et al 2013 ) and for this reason, over the years there have been numerous studies of atmospheric Hg, with the aim of both improving knowledge in different areas of the globe (Sprovieri et al 2016 , 2017 ) and improving analytical performance for its monitoring (Tassone et al 2020 ; Naccarato et al 2021 ). In the atmosphere, Gaseous Elemental Mercury (GEM or Hg(0)) is the predominant Hg species and represents 90 to 99% of the Total Gaseous Mercury (TGM) (Sommar et al 2020 ).…”

Improving the Voltammetric Determination of Hg(II): A Comparison Between Ligand-Modified Glassy Carbon and Electrochemically Reduced Graphene Oxide Electrodes

“…Various analytical techniques are currently employed for the detection of Hg(II) in environmental samples: atomic fluorescence spectrometry [7][8][9], UV-VIS spectrophotometry [10], inductively coupled plasma optical emission [11,12] and mass spectrometry [13], and cold vapor generation-quartz crystal microbalance [14]. Hyphenated methods such as gas chromatography-tandem mass spectrometry [15] and high-performance liquid chromatography-inductively coupled plasma mass spectrometry [16] allow both detection and speciation of mercury compounds.…”