关键词: 天目山, 亚热带老龄森林, 涡度相关, CO₂通量, 碳汇

Abstract: Dust and soil samples were taken from 41 parks in inner-city of Tianjin and 10 parks in Tianjin Binhai New Area to study the physicochemical properties and contents of heavy metals in the samples, with the special distribution patterns and possible sources of the heavy metals analyzed. In the parks, the particle sizes of dusts and soils presented bi or multimodal distribution, the organic matter content in the dusts and soils was averagely 49.10 and 27.15 g·kg^-1, and the Cu, Pb, Cr, Cd, and Ni contents in the dusts and soils were averagely 113.88, 76.81, 141.53, 1.30, and 114.70 mg·kg^-1, and 41.68, 30.76, 96.43, 1.01, and 34.03 mg·kg^-1, respectively, being much higher than the background values in Tianjin. The Heping District, northeastern part of Nankai District, and Hexi District were less polluted by the heavy metals. Pearson correlation analysis and principal component analysis indicated that organic matter was the main carrier of Cd, while traffic flux and industrial activities were the main pollution sources of Cr, Ni, Cu, and Pb.

Key words: Tianmu Mountain, old-growth subtropical forest, eddy covariance, CO₂ flux, carbon sink.