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The chronological accumulation, enrichment influencefactorsand ecological risk assessment of heavy metals are examined on two sediment cores retrieved from Xuwen National Coral Reef Nature Reserve, China.210Pbex and 137Cs dating reveal the mean sedimentation rate is about 1.5 cm·a-1 in the reserve.Evident increasing trends of Pb, Cd, As and Hg concentrations begin to appearat 1980s in sediments.This is most likely to be caused by anthropogenic excessive inputs induced by the large scale development of agriculture chemical usage, coal combustion in canesugarindustry and marine transportation after the implement of China open policy in 1979.The annual load of heavy metals received by the reserved in recent years is estimated about 594 tons, in which Cr and Zn are dominated and account for a proportion of 64%.The assessments based on sediment quality guidelines (China marine sediment quality and US NOAA screening quick reference) and acid volatile sulfides-simultaneously extracted metals (AVS-SEM)medel indicate low ecological risk of heavy metals in the sediments of study area.Appropriate pollution control measures should be undertaken to prevent the occurrences of significant adverse biological effects induced bythe continuous accumulations of Pb, Cd, As and Hg in sediments of study area.