TY - JOUR AU - Trüe, A. AU - Panichev, N. AU - Okonkwo, J. AU - Forbes, P.B.C. PY - 2012/06/03 Y2 - 2024/03/29 TI - Determination Of The Mercury Content Of Lichens and Comparison To Atmospheric Mercury Levels In The South African Highveld Region JF - Clean Air Journal JA - Clean Air J. VL - 21 IS - 1 SE - Research Article DO - 10.17159/caj/2012/21/1.7075 UR - https://cleanairjournal.org.za/article/view/7075 SP - 19-25 AB - <p><em>The concentration of mercury vapour in ambient air is routinely determined using specialised instruments.</em><br><em>As an economical alternative, actively pumped Hopcalite sorbent tubes can be used to trap atmospheric</em><br><em>mercury, which is subsequently analysed by cold vapour atomic absorption spectroscopy. Plant materials</em><br><em>are also readily available in most regions and can be analysed to obtain information on time averaged</em><br><em>atmospheric mercury levels.</em><br><em>Lichen and tree bark samples were collected in the cities of Pretoria and Witbank, dried and acid digested</em><br><em>with subsequent cold vapour atomic absorption spectroscopy. Average mercury concentrations ranging</em><br><em>from 74 to 193 μg.kg<sup>-1</sup> were found in lichens from three Pretoria suburbs, whilst average Hg levels of 228</em><br><em>μg.kg<sup>-1</sup> were determined in lichens collected in Witbank. The average mercury concentration in tree bark</em><br><em>was consistently lower than in lichens, with concentrations between 28 and 72 μg.kg<sup>-1</sup> determined in</em><br><em>samples from three Pretoria suburbs and 75 μg.kg<sup>-1</sup> determined in samples taken in Witbank. This study is</em><br><em>the first in South Africa to determine mercury levels in lichens and tree bark.</em><br><em>Average total gaseous mercury concentrations in ambient air at the three Pretoria suburban sites, as</em><br><em>determined by a semi-continuous spectroscopic method using Hopcalite sampling, ranged between 1.6</em><br><em>and 2.5 ng.m<sup>-3</sup>, while an average of 1.7 ng.m<sup>-3</sup> was measured in Witbank over the sampling interval.</em></p> ER -