Journal of JSCE, Vol. 2, 249-268, 2014 FLUCTUATION OF ION COMPONENTS, TRACE METALS, AND Pb/Zn RATIO IN PRECIPITATION AT TSU CITY Makiko SENDA1, 2, 3, Tadashi NISHI4, Naoko TAKAGI5, Fuki SUGIYAMA6 and Yasuhisa KUZUHA7 1Member of JSCE, Lecturer, Faculty of Health Science, Kyoto Koka Women's University and Kyoto Koka Women's College (38, Nishikyougokukadono-cho, Ukyo-ku, Kyoto City, Kyoto 615-0882, Japan) E-mail: [email protected] 2Lecturer, Faculty of Management, Osaka Seikei University and Osaka Seikei College (3-10-62, Aikawa, Higashiyodogawa-ku, Osaka City, Osaka 533-0007, Japan) E-mail: [email protected] 3Lecturer, Faculty of Human Development and Education, Kobe Shinwa Women's University (7-13-1, Suzurandaikitamachi, Kita-ku, Kobe City, Hyogo 651-1111, Japan) 4Nonmember of JSCE, Graduate student, Graduate School of Bioresources, Mie University (1577 Kurimamachiya-cho, Tsu City, Mie 514-8507, Japan) E-mail: [email protected] 5Nonmember of JSCE, Faculty of Bioresources, Mie University (1577 Kurimamachiya-cho, Tsu City, Mie 514-8507, Japan) 6Nonmember of JSCE, Faculty of Bioresources, Mie University (1577 Kurimamachiya-cho, Tsu City, Mie 514-8507, Japan) 7Fellow of JSCE, Professor, Graduate School of Bioresources, Mie University (1577 Kurimamachiya-cho, Tsu City, Mie 514-8507, Japan) E-mail: [email protected] To elucidate the air pollution, its features, its sources, and the influence of yellow sand (kosa) in Tsu City, the ion components and trace metals in precipitation at Mie University were measured along with their temporal changes. From the obtained correlation coefficients and the results of the principal component analysis, the ions and the trace metals in the precipitation were classified into three groups: the SSI group - + + 2+ 2- 2+ (the ions of Cl , Na , K , Mg , ss-SO4 and ss-Ca , of which the main sources were sea salt); the ASI - - + 2- 2+ group (the ions of F , NO3 , NH4 , nss-SO4 and nss-Ca , of which the main sources were anthropogenic pollution and soil); and the ASM group (trace metals of Al, Fe, Mn, Pb, and Zn, of which the main sources were anthropogenic pollution and soil). The concentrations of the SSI group tended to be higher with in- creased wind velocity. Results suggest that seawater was raised into the atmosphere in proportion to the wind velocity, and that the sea salt ions were transported and increased in the precipitation. The effects of long-range transport and local pollution on the pollutants and the soil elements in the precipitation were discussed from measurements of the concentration ratios of Pb and Zn (Pb/Zn) and backward trajectory analysis. The concentrations of ion components and trace metals during the rain events in Tsu City, Mie generally decreased over time. The condensed pollutants in the air are regarded as removed in the initial period of the rain events. We can confirm that the concentration ratios (Pb/Zn ratios) are almost identical to reported values for rain clouds through Japan. Only one day showed high rates of pollutants, but it is pre- sumed to be not the effect of kosa but of the industrial zone to the north east of Tsu City. Key Words : precipitation, trace metals, ion components, Pb/Zn Ratio, wash-out, rain-out 1. INTRODUCTION pollution in China has raised concerns related to the increase of transboundary air pollution and acid rain Recently, various environmental problems have in Japan. The combination of yellow sand (kosa) and become important global social issues. Severe air air pollutants, their transformation, and photochem- 249 Table 1 Pollution process of precipitation7), 8), 9), 10). Transport of pollutants Local emission Main process z Rain-out : Rain clouds catch atmos- z Accumulation pheric pollutants during their move- z Wash-out : Raindrops catch atmospheric ment. pollutants. Pollutants Trace metals insoluble in water. Nitrogen oxides and sulfur oxides which are Exhaust gas of cars, boilers, steel industries, soluble in water. waste combustion facilities, etc. Exhaust gas of cars, smoke of factories, vol- canic ashes, etc. ical pollution have been observed. Therefore, it is considered effective, particularly because they have important to clarify the pollutants’ influence on the not been strongly influenced by meteorological environment1). Acid rain, which results from artifi- conditions11). Hioki et al.8) showed that the ratio of cial pollutants released into the atmosphere, has in- Pb/Zn tended to shift upward under the influence of fluenced precipitation water quality in recent years. It the long-range transport from the Asian Continent, has been regarded as a global environmental de- and reported that this ratio was an effective index for struction problem2). The acidification substances of pollution by both the long-range transport (rain-out) - 2- NO3 and SO4 are known to be generated from ni- and local emissions (wash-out). To examine whether trogen oxide and sulfur oxide emitted by the com- the trace metal concentrations are an effective index bustion of fossil fuels. for air pollution by long-range transport, Okuda et Studies of acid rain in Europe and the United al.12) measured the concentrations at Rishiri Island, States show that the acidification of precipitation in located in northernmost Japan and easternmost from the United States spread from the northeast region to the Asian continent. The measured concentration the west region and the south region from 1956 ratios of Pb and Zn and the backward trajectory through 1976. Moreover, acidity in the northeast analysis with the four divided areas of the sea, Japan, region had increased3). China, and Siberia showed that the ratios varied ac- Ezcurra et al.4) reported the precipitation water cording to their source areas. The effect of the quality of 52 rain events in 1986 in Basque Provinces long-range transport is regarded as indicated by the in Spain. The study showed that the pressure pattern ratio of highly correlated trace metals with the same and the atmospheric air inflow at the precipitation sources. Salient results of some studies of the Pb and influenced the precipitation water quality. The con- Zn ratio are presented in Table 28), 11)–22). - 2- + centrations of NO3 , SO4 and NH4 were high with In this study, to assess air pollution, its features, its highly acid precipitation, which pointed out that sources, and its influence of kosa on Tsu City, the ion acidification was highly influenced by industrial components and the trace metals in the precipitation areas in the south of France and the north of Spain. and their temporal changes were measured at Mie Regarding acid rain in Japan, harm to the human University. Then the effects of long-range transport body such as eye irritation from rain drizzle, was and local pollutants and the soil elements are ex- reported in Shizuoka and Yamanashi prefectures in plained based on the Pb and Zn (Pb/Zn) concentra- 19735). That study triggered acid rain studies in Ja- tion ratio and backward trajectory analysis. pan. The causes of the precipitation pollution are re- garded as divisible into natural and artificial factors 2. MATERIALS AND METHODS according to their generation processes and forms. Coarse particles with diameter greater than about 2.5 (1) Study area μm originate mainly from soil, sea salt, and so forth. Tsu City (Fig.1) in Mie prefecture is surrounded Smaller microparticles are produced by waste incin- by Ise Bay on the east, by mountains on the west, and eration facilities, automobile exhaust gas, and so on6). by urban areas to the north and south. Fig.1 shows The pollution process of the precipitation water is that the industrial zones of the cities of Yokkaich and classified into the transport of pollutants (rain-out) Suzuka are located on the north of Tsu City. From the and the local emissions (accumulation, wash-out), as north to the east across Ise Bay, there are the Indus shown in Table 17)–10). trial zones of the cities of Nagoya, Toyota, Toyo- As indicators of the long-range transport of the air hashi, and Okazaki. Iron and steel factories 23), au- pollutants, the concentration ratios of metal elements tomotive factories24), thermal power plants25), pet- are adopted and the ratio of Pb and Zn (Pb/Zn) is rochemical complexes26), refuse incineration facile- 250 Table 2 Pb/Zn ratio in precipitation and aerosols. Through Sampling area Through North Aerosols Aerosols Through Central Year Sample China, Sources in China in Japan Japan China, Japan China Far east Korea Russia 1974 Atmospheric Sakai City, Mizohata & - - 0.62 - - - -1977 aerosols Osaka Mamuro, 198015) Total 1985 Suspended Oki island, Mukai et al., - - - 0.5 1 0.6 -1991 Particles Shimane 199016),199417) (TSP) 1990 National parks Snow - - - 0.36 0.7~1.32 - Mukai et al., 199918) -1992 (24 points) National Total atmosphere The Environmental 1995 Suspended measurement - - 0.34 - - - Administration -1996 Particles station Bureau, 199622) (TSP) (16 points) 1995 Atmospheric Furuta et al., Tokyo - - 0.28 - - - -2004 aerosols 200513) Total 1998 Suspended Matsue City, Marumoto et al., - - - 0.21 0.55 - -2000 Particles Shimane 200114) (TSP) 2000 Komae City, Sakata & Rainwater - - - 0.2~0.3 - - -2001 Tokyo Marumoto, 200420) 2001 PM2.5 Tango peninsula, Hioki et al., - - - 0.26 0.65 - -2002 +PM10-2.5 Kyoto 20088) 2001 Rishiri island, Okuda et al., Aerosol - - - 0.7 2.8 2.6 12) -2003 Hokkaido 2006 2001 Beijing Okuda et al, Aerosol - 0.56 - - - - -2003 City 200419) 2007 Fukuoka City, Shimada et al, Rainwater - - - 0.26 0.50 0.23 -2008 Fukuoka 200821) Total Matsuyama City 0.28 0.62 Suspended Hioki et al., 2007 Osaka City - - 0.18 - 0.31 - Particles 200911) Tsukuba City 0.16 - (TSP) Precipitation is indicated in bold italic type. Lake Express highway and Toll road Biwa National road Nagoya Airport 23) Toyota Iron and steel factory Yokkaichi 24) Suzuka Automotive factory Thermal power plant25) Okazaki Petrochemical complex26) Ise Bay Toyohashi Refuse incineration facility27) -31) Sampling point (Tsu City) Fig.1 Sampling sites for rain water.