| Antarctica,an internationally managed natural reserve devoted to peace and science,is under serious pressure of climate change and human activities.The Fildes Peninsula,located in the southwest of Antarctica,is a large ice-free area in the Antarctica with significant climate change and frequent human activities.Therefore,it is suitable that the Fildes Peninsula is chosen as a research area to analyze environmental threats and status,which is of great significance to the assessment of potential risks,early warning of future changes and police development of Antarctic ecological environment.DASAR（Drivers,Activities,State change,Assessment,Responses）assessment framework is formed creatively based on marine ecosystem assessment approaches for comprehensive and quantitative assessment the status of the peninsula’s ecological environment under the multiple threats.According to this assessment framework,human activities,climate change and environmental contaminants are used as the significant threats for cumulative impact assessment and ecological health assessment to quantitatively analyze the pressure and status of the Fildes Peninsula ecological environment.In order to clarify the pressure of various threats on the terrestrial ecosystem,cumulative impact assessment of the 103×0.25 km2 is carried out.The results show that cumulative impact score Ic range from 0 to 39.4 and the overall cumulative impact is low.The area ratio of high（Ic>13.46）,medium（9.76<Ic≤13.46）,and low（Ic≤9.76）cumulative impact is about 1:1:3,.The area with high cumulative impact（21.3%）mainly located in the central,and eastern of the peninsula,Ardley island.Climate change（Ic=5.1）,organic contaminants（Ic=2.6）and tourism（Ic=0.7）have the greatest impact in all threats.Based on the results of the cumulative impact assessment,the Fildes Peninsula is divided into 9 units for ecological health assessment to understand the status of the terrestrial ecosystem in the Fildes Peninsula.The results show that the overall ecological health of the peninsula is in good condition.Two regions have“Bad”status with huge cumulative impacts.However,1 region has“Poor”status with low cumulative impact with the reason of the changes in the number of Southern giant petrel which are sensitive to human activities.Biology indicators have a greater impact on the finial assessment results.As a major pressure threatens ecological environment in the Fildes Peninsula,organic contaminant is the second only to climate change.This study conducted research on three semi-volatile organic compounds（SVOCs）:polycyclic aromatic hydrocarbons（PAHs）,polychlorinated biphenyls（PCBs）,and hexabromocyclododecanes（HBCDs）in the peninsula’s atmosphere,soil,and lakes from 2013 to 2019.This is the first reports of continuing 7 years monitoring research on SVOCs in three mediums for concentration analysis,source analysis and health risk assessment.Compared to other middle-low latitude regions,concentrations of these contaminants are lower.But it is should be noted that there are concentrations higher than middle-low latitudes.PAHs and PCBs in atmosphere show decreasing temporal trend,however,there are no remarkable interannual variation trends are found in lake and soil.Low detected rate is found of HBCDs in lake and atmosphere.The results of sources apportionment show that the role of local sources such as fossil fuel combustion for traffic and power generation,oil siplling,release from building materials and hazardous waste is siginificant.In addition,incremental life cancer risk（ILCR）recommend by U.S.EPA of SVOCs through drinking and breathing for researchers exposured one year is much lower than 10-6,which confirmed no cancer risk.Based on comprehensive analysis and assessment,it is necessary to strictly control tourism and station-based waste gas and garbage discharge,strength the ability of emergency incident treatment,improve daily facility maintenance so as to effectively improve the peninsula’s ecological environmental protection. |
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