Mercury wet depositions study during plum rain, regular precipitations and near typhoon periods

Abstract

This study analyzed the rainwater collected in Central Taiwan during the near typhoon period. Mercury (Hg) was analyzed and the Hg volume weighted mean concentrations (VWM) and wet depositions were calculated during the near typhoon period. In addition, the Hg wet depositions, VWM and precipitation values obtained were compared with Plum rain and regular precipitation periods. The relationship between wet Hg depositions, VWM and precipitations were also discussed. Wet Hg depositions, VWM and precipitations were also compared with the precipitation collected from other parts of the world during 2009 to 2021. The results indicated that the precipitations, VWM and wet Hg depositions in the near typhoon period were 152.5 mm, 0.82 ng/L, and 0.29 μg/m2, respectively. The Hg precipitation ratio values of this study to the plum rain and regular precipitation periods were 3.70 and 6.63, respectively. The Hg VWM ratios values of this study to the plum rain and regular precipitation periods were 12,852.56 and 1.56, respectively. Moreover, the wet Hg deposition ratios values of this study to the plum rain and regular precipitation periods (near typhoon period) were 105.97 and 9.90, respectively. The results further indicated that the Hg VWM and wet depositions obtained in the near typhoon period showed the lowest values when compared with plum rain and regular precipitations periods. Compared with Hg(p) VWM and Fw values obtained from plum season, regular precipitation, this study (typhoon period) demonstrated it has the average lowest VWM and Fw values among these three sampling periods. The correlation coefficient of precipitation and the mercury wet deposition was 0.72051 which was significant in this study. The correlation coefficient for the VWM of mercury was 0.0826 which displayed insignificant relationship in this study. Finally, when comparing the Hg VWM, wet deposition and precipitation values from various studies, the results further indicated that the near typhoon period has the lowest average Hg VWM, wet deposition and precipitation values.

Keyword:

• near typhoon period
• VWM
• wet depositions
• precipitations

Additional information

Funding

The authors gratefully acknowledge the National Science Council of the ROC (Taiwan) for financially supporting this work under project no. MOST 110-2221-E-241-006.