Quantitative Evaluation of Real-time Measurements of Atmospheric Mercury in a Mercury- contaminated Area

Abstract

   On-site real-time measurements may be one of the most useful methods to estimate Hg pollution levels at mercury-contaminated sites. However, there are very few reports that estimate the reliability of real-time mercury measurements across a wide concentration range. We performed real-time measurement of atmospheric mercury in a small-scale gold mining (SSGM) area contaminated with mercury and compared results with data obtained by conventional sampling methods.
   On-site real-time atmospheric mercury analysis was conducted at 12 locations in the Cikaniki River Basin, West Java, Indonesia, in July 2011 and February 2012 using an EMP-2 Mercury Analyzer (NIC, Tokyo, Japan). Temporal variations in atmospheric elemental mercury (Hg⁰) concentrations were recorded at each location, and atmospheric Hg⁰ was simultaneously collected by conventional methods using a mercury collector tube (Hg_tube) and KMnO₄ solution (Hg_Mn).
   The concentrations of atmospheric mercury collected by the conventional methods ranged from 0.17 to 36 μg m⁻³ (n=19), while that obtained by the real-time measurement (Hg_real-time) ranged from <0.1 to 38 μg m (n=19). Although the concentration of atmospheric mercury at each location varied widely over time, the median Hg_real-time values for a given sampling time were linearly related to Hg_tube and Hg_Mn (r² =0.95, n=19, p<0.01) with a slope value of 0.99. The analysis showed that atmospheric Hg⁰ concentrations at SSGM sites contaminated with mercury can be quantitatively estimated by real-time measurements.