人类活动对南极乔治王岛菲尔德斯半岛环境的影响

HUMAN IMPACTS ON THE ENVIRONMENT OF FILDES PENINSULA OF KING GEORGE ISLAND,ANTARCTICA

人类活动对南极环境的影响主要表现为全球性人类活动的影响和南极局地人类活动的影响两方面。本文在对南极乔治王岛菲尔德斯半岛环境进行调查和采样分析的基础上，明确了南极环境中存在源于北半球中高纬地区人类核活动产生的人工放射性同位素１３７Ｃｓ：土壤表层（０～５ｃｍ）、苔藓活体层、枝状地衣、壳状地衣体中１３７Ｃｓ比活度分别为６．０～１４．８、２５．１、２９．０和５８．１Ｂｑ／ｋｇ；而中国北方地区土壤表层（０～１０ｃｍ）、壳状地衣体中１３７Ｃｓ比活度分别为６．４～３７．３和２９４．０～３１２．０Ｂｑ／ｋｇ，可见这类全球陆地表面广泛分布的壳状地衣是监测人工放射性核素长期扩散影响极为敏感的信息载体。南极科学考察活动对局地生态系统和地表冻融过程有一定程度的干扰，南极生物体（特别是地衣体）和水体是对人类活动影响极为敏感的环境信息载体，考察站区周围的生物体和水体中Ｃｒ、Ｃｕ、Ｎｉ、Ｐｂ、Ｚｎ等污染物含量明显偏高。菲尔德斯半岛作为南极科学考察站最为密集的地区之一，其环境与陆地生态系统受人类活动影响较为明显。

Antarctic environment has some invaluable baseline information for understanding the global changes. The objectives of this study were to investigate the human impacts on the environment of Fildes Peninsula of George Island. Based on the investigation results and the sampling analysis of the environmental elements of Fildes Peninsula, it was shown that there are some artificial radioactive element 137 Cs in the Antarctic environment: the radioactivity of 137 Cs in the surface soil, the surface moss, the fruticose lichen and crustaceous lichen are 6.00 ￣14.80, 25.07, 29.04 and 58.07 Bq/kg separately; the radioactivity of 137 Cs in the surface soil and crustaceous lichen in northern China are 6.4-37.3 and 294-312 Bq/kg separately, i.e. the sequence of 137 Cs activity is as follows: crustaceous lichen>fruticose lichen>surface moss>surface soil.It was shown that the crustaceous lichen is one of the most sensitive monitors for the effect of the long term diffusion of the 137 Cs . The impacts of the activities of Antarctic expedition on the partial environment include: (1)the change of the landscape or the soil material has made the strong freezing thawing processes, which decrease the stability of the ground surface, cause the degradation of the vegetation; (2)the accumulation of solid waste material in the low lying land around lake causes the change of the thermal equilibrium and water equilibrium in the areas, which increases the seasonal fluctuation of the lake level or makes the lake dried up in March or April; (3)during the progresses of building the expedition and the roads, some moss-banks have been damaged. The biomass (esp. lichen ) and the water body in the Antarctic are very susceptible to damage caused by the presence of man. In the surrounding area of the expedition stations, the concentration of Cr, Cu, Ni, Pb and Zn in the lichen and the waters are evidently higher than that of the contrasting area, the organic matter content of the water is also evidently higher than that of the contrasting area. Fildes Peninsula is one of the most crowded areas of expedition stations, at some extent, the environment and terrestrial ecosystem of Fildes Peninsula have been affected by the human activities. The conservation of the environment and ecosystem have been an important aspect of the Antarctic environmental sciences.