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Coastal erosion is a natural phenomenon,however,due to ongoing climate changes,the abrasion rate increased in the last decades in many regions.As a result of this process,in a short time,substantial quantities of sediments and soils are introduced to the marine coastal zone.Along with them various types of pollutants gets into the sea.One of the most dangerous of them is mercury,which is highly neurotoxic,and produces also mutagenic,embryotoxic and allergic effects in organisms.The purpose of this study was to estimate the mercury levels in the cliffs and eroded parts of coast of the Southern Baltic Sea.Research also aimed to the identification of the impact of coastal erosion on mercury input and its budget in the marine environment.The study was conducted in the region of the Polish coast(Southern Baltic Sea)in 2011-2013.Sampling stations were located along the coast(including open waters and bays),in areas undergoing intense erosion.Samples of colluvial sedimentary material from the cliffs were collected manually,and then were lyophilized and homogenized.Total mercury concentrations in sediments were analyzed by AAS method using the AMA-254 analyzer.Mercury load,calculated on the basis of the erosion rates of cliffs,for a Gulf of Gdansk(length of the erosive shore 36 km),was 12,5 kg per year.This value accounted for 46%of total atmospheric deposition of mercury,and 7%of the load introduced with rivers(including the Vistula River,the second largest river in the Baltic Sea catchment area).In case of the entire length of the Polish coast(length of the erosive shore 147 km)sedimentary material derived from cliffs abrasion supplied to the Southern Baltic Sea over 50 kg of mercury per year.This represented 28%of the load imparted with the Vistula River to this region.Considering the Hg budget in the Gulf of Gdansk created in previous years,mercury introduced to the sea by coastal erosion increases the amount of metal on at least 13%.This leads to the conclusion that coastal erosion,can be an important source of mercury into the marine environment.