In order to evaluate the state of the environmental pollution in Chiba City, the correlation between air pollutants and metal concentrations in leaves of woody plants has been investigated. The elements of Zn, Pb, Cd, and Fe as pollutant indicators were extracted from the leaves (Viburnum awabuki, Euonymus japonica, Juniperus chiennsis, and Nerium indicum) by conventional method and their concentrations were determined. On the other hand, the dust in the atmosphere was collected by the high volume airsampler to measure the concentrations of metals. NO_x and SO₂ concentrations were automatically analyzed.
The following results were obtained:
1) Metal concentrations in the leaves of woody plants were widely changed in each plant, for example, at H sampling site where was near factory area, the average concentrations of Zn, Pb, Cd, and Fe in the leaves of Viburum awabuki were 41-56 μg/dry-g, 8.5-12.1 μg/dry-g, 0.79-0.92 μg/dry-g, 407-507 μg/dry-g and the concentrations of Zn, Pb, Cd, and Fe in the leaves of Euonymus japonica were 18-26 μg/dry-g, 9.8-17.5 μg/dry-g, 0.90-4.03 μg/dry-g, 490-583 μg/dry-g, respectively.
2) The leaves of woody plants had much Pb concentrations, when the Pb concentration in the leaves of woody plants was high at the site where concentrations of the air pollutants such as NO_x, SO₂ and dust were high.
3) The highest correlation coefficients of Pb-NO_x, Pb-SO₂, and Pb-dust were 0.87, 0.80, and 0.88, respectively.