Determination of isotopic composition of atmospheric mercury in urban-industrial and coastal regions of Chiba, Japan, using cold vapor multicollector inductively coupled plasma mass spectrometry

Abstract

This study presents a method for the isotope analysis of gaseous elemental mercury (GEM, Hg0(g)) using cold vapor multicollector inductively coupled plasma mass spectrometry. Isotopic compositions of Hg in the atmospheric samples collected from urban-industrial (Ichikawa) and coastal (South Boso Peninsula) regions in Chiba, Japan were investigated. Values of mass-dependent fractionation (MDF) of δ202Hg range from −2.36‰ to −0.11‰ and mass-independent fractionation (MIF) of Δ199Hg range between −0.31‰ and 0.01‰. There was a rough linear correlation between δ202Hg values and Hg concentrations of our GEM samples (r2=0.31, p<0.05). Also, Δ199Hg values were positively correlated with SO2 concentrations; however, air mass source(s) was not identified using NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory model. We suggest that our sampling site, Ichikawa, was largely impacted by nearby anthropogenic sources (high GEM concentration with low δ202Hg value), and a mixing with back ground air (low GEM concentration with high δ202Hg value).