Temporal Variation of Wet Deposition of Atmospheric Mercury in Metropolitan Taipei
Date Issued
2006
Date
2006
Author(s)
Chen, An-Peng
DOI
zh-TW
Abstract
Abstract
Temporal variation of wet deposition flux of mercury (Hg) in metropolitan Taipei, Taiwan was investigated from October 2004 to December 2005. A total of 65 individual events, including typhoon, Asian dust and plum rain events, was collected by automatic Teflon-coated rain collector. Total Hg concentration was measured by Cold Vapor Atomic Fluorescence Spectrophotometry (CVAFS) for all rain samples and dissolve-, particle- and operation-defined reactive-phases Hg were measured in some selected events as well. Total Hg concentration ranged from 1~65 ng/L with a volume-weighted mean of 7±11 ng/L (n = 65). Dissolve-phase Hg averaged 4±8 ng/L (n = 23) about 63% of total Hg while particle-phase and reactive Hg were 3±2 ng/L (n = 30) and 0.4±1.4 ng/L (n = 9), respectively. A negative relationship between total Hg concentration and precipitation amount was observed in all precipitation events, signifying the scavenging of atmospheric particulates and colloids bearing Hg. A significant seasonal variation in total Hg showed the highest concentration in the winter (12±18 ng/L，n =18 ) as result of terrestrial and anthropogenic matters from mainland China during northeast monsoon and lowest in summer (4±2 ng/L，n =22) due to a dilution effect caused by a huge of precipitation. There was additionally a maximum of wet Hg deposition flux the in summer and fall mainly associated with typhoon-induced rainfalls of marine materials. The annual total Hg deposition flux was about 21.7μg/m2 positively correlation with the precipitation amount which was much higher in Japan. The highest concentration was observed in Asian dust event about 65 ng/L (n = 1) relative to those in plum rain (2±3 ng/L, n = 20) and typhoon events (8±3 ng/L , n = 6). Further, typhoon events accounted for 40% of total Hg deposition flux, plum rain for 10% and Asian dust only for 0.1%.
Subjects
汞
降雨
大氣汞
沉降通量
颱風
梅雨
沙塵暴
mercury
wet deposition flux
typhoon
plum rain
Asian Dust
SDGs
Type
thesis
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