PM07 Pollutant Chemistry Transport, Cycling and Fate
Exhibit Hall
8:00 AM - Monday
(PM066) Characteristics of elemental concentrations and extractabilities of the street dust in Tokyo.
INADA, M1, WATANABE, I1, KUNO, K1, 1 Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan
ABSTRACT- Tokyo is one of the largest cities in the world. Motor vehicle is taken advantage of for industrial and private use, whereas it causes air and soil pollution which become critical. This study aimed to understand metallic pollution caused by traffic. So, trace element concentrations in the street dust collected at 18 sites, from urban to rural, in Tokyo MP were measured. These samples were collected from 2000 to 2003. Dried dust samples were riddled two size mesh (2.0 and 0.2 mm). Concentrations of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Hg, Tl and Pb extracted with mixed acid and artificial fluid, 0.2 mm and less in diameter, were determined. Concentrations of these elements but Tl in the extracted fraction with mixed acid roughly increased at the more urbanized site that traffic is larger than rural area, vice versa, concentration of Tl decreased. It was suggested that particulate matter derived from traffic affected the concentrations in the street dust. At some unspecified sites, the concentrations were higher than those in adjoining sites. This hot spot phenomenon in the site of Sasaduka might be caused by street canyon structure with elevated road along the canyon. In another sites, The concentrations showed similar variation to seven-day precipitation before sampling. In short, wet deposition might affect concentrations of these elements in the street dust. In extracted fraction with artificial gastric fluid, extractability of Zn was higher than that of other elements. In the following fraction used intestinal fluid, extractability of As was higher than those of other elements. These might be caused by different chemical state of each element.
Key words: trace element, street dust, artificial fluid, extractability