Mass balance and sources of mercury in Tokyo Bay
The mass balance and sources of mercury in Tokyo Bay were investigated on the basis of observations from December 2003 to January 2005. Estimated input terms included river discharge (70 kg yr−1) and atmospheric deposition (37 kg yr−1), and output terms were evasion (49 kg yr−1), export (13 kg yr−1) and sedimentation (495 kg yr−1). Thus, the outputs (557 kg yr−1) considerably exceeded the inputs (107 kg yr−1). In addition, the imbalance between the inputs and outputs of mercury was much larger than that of other trace metals (Cd, Cr, Cu, Pb and Zn), which suggests that there are other major inputs of mercury to Tokyo Bay. The mercury concentrations in rivers correlated significantly with the concentrations of Al and Fe, major components of soil. In Japan, large amounts of organomercurous fungicides (about 2500 tons as Hg) were used extensively in fields in the past, and most of the mercury was retained in the soil. In this study, the mercury concentration in rivers was measured primarily in ordinary runoff. These observations lead to the hypothesis that field soil discharged into stormwater runoff is a major source of mercury in Tokyo Bay. As a preliminary approach to validating this hypothesis, we measured the concentrations of mercury and other trace metals in river water during a typhoon. The mercury concentrations in stormwater runoff increased to 16–50 times the mean value in ordinary runoff, which is much higher than the increases for other metals. This tends to support the hypothesis.
KeywordsMercury mass balance Tokyo Bay stormwater runoff organomercurous fungicides
Unable to display preview. Download preview PDF.
- Asami, T. (2001): Toxic Metal Pollution in Japanese Soils. Agne Gijutsu Center, Tokyo, 402 pp. (in Japanese).Google Scholar
- Balcom, P. H., W. F. Fitzgerald, C. R. Hammerschmidt, C. H. Lamborg and L. J. Graham (2004b): Mercury sources and speciation in the waters of New York/New Jersey Harbor estuary. RMZ-Materials and Geoenvironment, 51, 795–798.Google Scholar
- Geological Survey of Japan (2006): Geochemical Map of Japan. National Institute of Advanced Industrial Science and Technology (AIST), Japan. http://www.aist.go.jp/RIODB/geochemmap/index_e.htm Google Scholar
- Hattori, A. (1983): Oceanographic features of Tokyo Bay water circulation, hydrography, and nutrient chemistry: an overview. Chikyukagaku (Geochemistry), 17, 16–26 (in Japanese).Google Scholar
- Masunaga, S., Y. Yao, H. Takada, T. Sakurai and J. Nakanishi (2001): Sources apportioning of dioxin pollution recorded in Tokyo Bay sediment core based on congener composition. Chikyukagaku (Geochemistry), 35, 159–168 (in Japanese).Google Scholar
- Matsumoto, E. (1983): The sedimentary environment in the Tokyo Bay. Chikyukagaku (Geochemistry), 17, 27–32 (in Japanese).Google Scholar
- Matsumoto, E., K. Kato and K. Matsunaga (1983): Mercury geochemistry in the Tokyo Bay. Chikyukagaku (Geochemistry), 17, 48–52 (in Japanese).Google Scholar
- Matsumura, T. and T. Ishimaru (2004): Freshwater discharge and inflow loads of nitrogen and phosphorus to Tokyo Bay (from April 1997 to March 1999). Oceanogr. Japan, 13, 25–36 (in Japanese).Google Scholar
- Ministry of the Environment, Japan (2004): Manual for Mercury Analysis. http://www.env.go.jp/chemi/report/h15-04/ (in Japanese).
- Ministry of the Environment, Japan (2005): Monitoring results for hazardous air pollutants in the fiscal year of 2004. http://www.env.go.jp/air/osen/monitoring/mon_h16/index.html (in Japanese).
- Shia, R. L., C. Seigneur, P. Pai, M. Ko and N. D. Sze (1999): Global simulation of atmospheric mercury concentrations and deposition fluxes. J. Geophys. Res., 104, 23,747–23,760.Google Scholar
- Sorensen, J. A., G. E. Glass, K. W. Schmidt, J. K. Huber and G. R. Rapp, Jr. (1990): Airborne mercury deposition and watershed characteristics in relation to mercury concentrations in water, sediments, plankton, and fish of eighty northern Minnesota lakes. Environ. Sci. Technol., 24, 1716–1727.CrossRefGoogle Scholar
- The Chemical Society of Japan (1977): Mercury. Maruzen, Tokyo, 213 pp. (in Japanese).Google Scholar