Distribution of ~(137)Cs and Relative Influencing Factors on Typical Karst Sloping Land
Based on the field survey and the analysis of a large number of soil samples, the distribution of ~(137)Cs and its influencing factors were studied using ~(137)Cs tracer technology on typical karst sloping land. The results indicate that the distribution of ~(137)Cs in soil profile in karst areas show the similar characteristics as that in non-karst areas, fitted an exponential pattern in forest soils and a uniform pattern in cultivated soils. In the sinkhole points in karst areas, ~(137)Cs exists in deep soil layers and its specific activity vary from 1.7 to 3.3 Bq/kg in soil layers above 45cm, suggesting the existing soil around karst sinkhole is mainly formed by the accumulation of erosion materials. The ~(137)Cs specific activity in the soil from two rock cracks are 16.8 Bq/kg and 37.6 Bq/kg respectively, which are much higher than that in the soil around the rock, this phenomenon indicates that bare rock is an important influencing factor for ~(137)Cs spatial movement. With the increment of altitude, the ~(137)Cs area activity exhibits an irregular fluctuation and evident spatial heterogeneity. On the forest land, the ~(137)Cs area activities which range from 299.4 to 1592.6 Bq/m~2 are highly positively correlated with the slope gradient and positively correlated with the altitude; while on the cultivated land, the ~(137)Cs area activities which range from 115.8 to 1478.6 Bq/m~2 are negatively correlated with the slope gradient but negatively correlated with the altitude. Topography, geomorphology and human disturbance intensity are the key factors influencing ~(137)Cs spatial distribution.
NETL
NSTL
万方数据
