关键词: 有机碳, 轻组有机碳, 重组有机碳, 黄土高原, 土壤侵蚀

Abstract: In order to understand the distribution characteristics and potential ecological risk of manganese (Mn) in the main river watershed areas of Shenyang, the samples of surface water, groundwater, sediments, soils, crops, and human hairs were collected, and their Mn concentration was determined. In surface soil samples, the mean Mn concentration was within the range of geochemical background value of soil Mn in the Liaohe  River Plain, and lower than the Earth crust abundance. The mean Mn concentration in surface water samples was within the normal range. The Mn concentration (0.01 mg·L^-1) in the drinking water at its source site met the requirement of national standard, while that in the groundwater at several villages in the Xihe River watershed was averaged 4.17 and 2.75 mg·L^-1 in autumn and summer, respectively, both exceeding the national standard for levels III and IV of waters. The Mn concentration in the crops and vegetables in Zhangyi region was 3-266 μg·g^-1dry mass, possibly caused by shallow groundwater irrigation. The daily Mn intake of local inhabitants via drinking water, crops, and vegetables was less than the minimum toxic dose 0.06 mg·kg^-1 body weight·d^-1. The Mn concentration in the human hairs from the inhabitants in the villages near Xihe River watershed was averaged 24.6 μg·g^-1, being three times higher than the normal Chinese hair Mn concentration (1.3-9.8 μg·g^-1). The women’s mean hair Mn concentration was onefold greater than the men’s, and the 20-30 years old group’s mean hair Mn concentration was higher than the other age groups’.

Key words: Soil organic carbon, Light fraction, Heavy fraction orgnic carbon, Soil erosionorgnic carbon, Loess Plateau of China, Canadian Prairie