Studies on the levels in atmospheric concentrations of mercury in Japan

The influence of long-range transport on atmospheric mercury on Jeju Island, Korea

The concentrations of total gaseous mercury (TGM) and relevant environmental parameters were measured at a remote area on Jeju Island, Korea from May 2006 to May 2007. The hourly mean concentration of Hg for the entire study period was 3.85+/-1.68ng m(-3) (range of 0.10-17.9: n=7450). The temporal patterns of Hg at the island site were characterized by the relative dominance in spring/fall over summer/winter and in daytime over nighttime. The possible impact of Asian dust (AD) on Hg distribution was examined by assessing its relationship with PM(10) data. Because of a strong inverse log-log correlation between Hg and PM(10) levels (above 200microg m(-3)), a direct relationship between the two parameters is difficult to account for. However, the analysis of air mass movement patterns confirmed that the Hg levels on Jeju Island were affected most by the combined effects of major source processes in the surrounding areas: industrial and AD (China), industrial (Korea), and volcanic activity (Japan).

Atmospheric gaseous mercury in Northern Taiwan

The first attempt to systematically investigate the atmospheric mercury over the territory of Taiwan has been undertaken. Four sampling sites were selected in localities qualified as urban, suburban, industrial-rural and rural ones, within the northern part of Taiwan. The sites were monitored for atmospheric gaseous mercury alternately from September to December 2003 and from April to June 2004, by using a portable automated mercury analyzer Model Gardis-3. The results have shown rather high atmospheric gaseous mercury levels (up to 30 ng/m3 at the urban site, up to 22 ng/m3 at the rural site, up to 24 ng/m3 at the industrial-rural site, and up to 90 ng/m3 at the suburban site) which may indicate the presence of considerably strong point and area mercury sources whose origin still has to be detected more precisely.

Atmospheric mercury monitoring survey in Beijing, China

With the aid of one industrial, two urban, two suburban, and two rural sampling locations, diurnal patterns of total gaseous mercury (TGM) were monitored in January, February and September of 1998 in Beijing, China. Monitoring was conducted in six (two urban, two suburban, one rural and the industrial sites) of the seven sampling sites during January and February (winter) and in four (two urban, one rural, and the industrial sites) of the sampling locations during September (summer) of 1998. In the three suburban sampling stations, mean TGM concentrations during the winter sampling period were 8.6, 10.7, and 6.2 ng/m3, respectively. In the two urban sampling locations mean TGM concentrations during winter and summer sampling periods were 24.7, 8.3, 10, and 12.7 ng/m3, respectively. In the suburban-industrial and the two rural sampling locations, mean mercury concentrations ranged from 3.1-5.3 ng/m3 in winter to 4.1-7.7 ng/m3 in summer sampling periods. In the Tiananmen Square (urban), and Shijingshan (suburban) sampling locations the mean TGM concentrations during the summer sampling period were higher than winter concentrations, which may have been caused by evaporation of soil-bound mercury in warm periods. Continuous meteorological data were available at one of the suburban sites, which allowed the observation of mercury concentration variations associated with some weather parameters. It was found that there was a moderate negative correlation between the wind speed and the TGM concentration at this suburban sampling location. It was also found that during the sampling period at the same site, the quantity of TGM transported to or from the sampling site was mainly influenced by the duration and frequency of wind occurrence from certain directions.

Atmospheric mercury levels in the Slovak Republic

Total mercury concentrations (as a sum of vapor and particulate mercury) were measured in 24-h samples of ambient air in 20 different localities of the Slovak Republic eight times during the period 1996-1997. Vapor mercury was analyzed on site by atomic fluorescence with amalgamation technique. Particulate mercury was determined by vapor hydride atomic absorption spectrometry after wet digestion of filters with particulate air samples. The results showed that 34% of the 160 individual total mercury concentrations exceeded 5 ng/m3--the ambient air quality guideline value recommended by the WHO. The range of total mercury concentrations in the ambient air of Slovakia was: 1.13-3.98 ng/m3 (geom. mean 2.63) in the background area; 2.25-5.27 ng/m3 (geom. mean 3.64) in the agricultural areas; 1.73-20.53 ng/m3 (geom. mean 4.57) in the urban areas; and 1.53-39.85 ng/m3 (geom. mean 5.28) in the industrial areas. The highest mercury levels occurred in areas with metallurgical industry and coal combustion. The predominant form of mercury present in air was vapor mercury. The particulate fraction of mercury in ambient air (as a percentage of total mercury) varied widely from 0.4% to 42.1% (geom. mean = 4.4%). This fraction was lower in agricultural areas (2.3%) than in urban areas (5.3%). Although the atmospheric vapor mercury concentrations were slightly higher in summer than in winter, a direct correlation of vapor mercury concentrations and ambient air temperature was not found. Furthermore, the particulate mercury concentrations did not correlate with total particulate levels.

Geographical distribution and background levels of total mercury in air in Japan and neighbouring countries

Concentrations of total atmospheric mercury were determined in air collected from several locations in Japan and neighbouring countries to elucidate the geographical distribution and the background levels of total mercury in environmental air. The concentrations of mercury in urban air in Japan were 2.3-67 ng/m3, mean value 11.2 ng/m3. Those values were higher relative to those in urban air of other countries around Japan. In the past, a large quantity of mercury was used as an agricultural fungicide and a chloralkali catalyst in Japan. Therefore, the concentrations of mercury in rural air were higher rather than those in urban air. This phenomenon supports the hypothesis that the residual mercury used in the paddy field in the 1970s still remains in soils of Japan.