mountainous ecosystems are highly sensitive to any disturbances in natural balance , what makes them especially interesting for observations of chemical and radiochemical contamination .
the area of the babia gra national park ( bpn ) , being located along the main ridge of the flysch carpathian mountains , is just the proper place in this respect .
the terrain belongs to the young folded mountains , built mainly of flysch and some other lithology .
the highest summit of the babia gra mountain s massif ( west part of the beskid ywiecki chain of mountains ) is diablak reaching 1,725  m  asl . to protect this unique area
the area of the bpn , like other regions of poland , was exposed to substantial contamination with radionuclides due to the chernobyl accident in 1986 and nuclear weapon tests since the fifties of the twentieth century [ 16 ] .
researches on radionuclides distribution in the environment are important not only because these are perfect markers of the environment pollution but also because radioactive isotopes are not immobilized in soil but are constantly interchanged between inorganic matter and living organisms .
the aim of the work was to establish the spatial distribution of -radionuclides i.e. anthropogenic cs ( t1/2  =  30.07  years ) and natural k ( t1/2    10  years ) in the soil samples collected in the described above area .
10  cm thick soil core samples were collected with the use of a cylindrical corer ( 10  cm in diameter ) .
13 sampling points were selected in the studied area , most of them localized along the mountains main ridge .
each of the sampling points was described by its geographical coordinates and height above the sea level . in case of few points
it was impossible to determine their precise coordinates ( the lack of gps signal ) , so the closest available coordinates were interpolated . in the laboratory , the cores were divided into three sub - samples each to enable radioisotopes determination in various depths .
the samples were then dried at 105  c and the total weight was determined .
after removal of organic macro - particles and small stones , the samples were sieved mechanically ( 2  mm mesh ) .
after preparation , the samples were analysed by means of gamma ray spectrometry with the use of hpge ( high purity germanium ) coaxial detectors of relative efficiency 7 and 21  % . prior to the measurements ,
each measurement lasted 72  h. the reference materials iaea-154 , iaea-375 , and iaea-447 of the international atomic energy agency ( vienna , austria ) were used in the measurements . in the present work cs radioactivity in the 
for the whole core samples , cs and k activities were expressed in bq  m units .
after gamma spectrometric measurements organic matter content in the soil samples was determined by means of incineration at 600  c . to extract relevant information out of the obtained data ,
chemometric tools i.e. cluster analysis ( ca ) and principal components analysis were used ( using statistica 10 software ) .
the most important values are written in bold.table  1the babia gra national park sampling points descriptionpoint no.geographical coordinatesheight ( m  asl)place description1n 49st 34,7971,515red hiking trail , after sokolica , right from this red routee 19st 33,4142n 49st 34,6161,577near zimny staw lake , at the top of babia grae 19st 32,7723n 49st 34,3411,707by green hiking trail from babia gra to lipnicae 19st 31,8244n 49st 34,4261,701the yellow hiking trail from babia gra , on the right sight of this routee 19st 31,7695n 49st 34,3861,695the route from diablak ( red hiking trail)e
19st 31,6896no data1,600the route from diablak below cross ( red hiking trail)7no data1,530krzywka szlakw na markowe szczawiny i ma babi.8no data950mokry stawek lake , from the site of krowiarki pass9no data951brona pass10n 49st 34,5281,463by yellow hiking trail , dwarf pine zonee 19st 31,45311n 49st 34,6671,350yellow hiking trail , at the end of higher montane zonee 19st 31,30112n 49st 34,9531,257at the intersection of szumica woda valley with the route to markowe szczawinye 19st 31,46713n 49st 34,293836hala mietanowa , above little bridge on syhlec streame 19st 35,609table 
2 
 cs and k radioactivities , density and organic matter content in the soil samples collected in the babia gra national park areapoint no.height ( m  asl)soil density ( g  cm)organic matter content ( % ) activity cs ( bq  kg ) ( layer  a)activity cs ( bq  m ) ( whole core)activity k ( bq  m ) ( whole core)11,5150.7017416    118,837    2416,900    61921,5770.1790405    163,757    2114,127    37431,7070.5520304.1    9.26,591    2247,914    71541,7010.6515 
 831    21 
 28,551    72016,477    1,49751,6950.7014246.2    8.48,166    27510,848    97761,6000.2473697    217,231    2192,134   
19471,5300.2281214    103,276    1777,869    71389500.99936.8    2.11,783    119 
 25,654    2,28899510.,703765.8    6.42,119    15212,907    1,164101,4630.5021137.3    6.11,916    838,368    775111,3500.5719309    105,472 
  230 
 25,200    2,255121,2570.1782326    152,030    951,642   
151138360.4023408    1316,152    48417,480    1,573 the babia gra national park sampling points description 
 cs and k radioactivities , density and organic matter content in the soil samples collected in the babia gra national park area soil in the bpn originates from the carpathian flysch waste . as in the area vegetation levels
the resulting soil type classification is given in table  3 .table  3prevailing soil types of the considered sampling pointsvegetation levelheight ( m  asl)prevailing soil typesampling pointsalpine zone1,6501,725lithic leptosol,3 , 4 , 5regosol skeletic , podzolic ranker ( leptosol)dwarf pine zone1,3901,650haplic podzol,1 , 2 , 6 , 7 , 10tangel 
ranker(umbric leptosol)higher montane zone1,1501,390dystric cambisol12 , 11partially haplic podzollower montane zone7001,150eutric and dystrict cambisol13 , 8 , 9 prevailing soil types of the considered sampling points chemometric tools are widely used in the environmental data analysis especially when high variability and uncertainty of the data may be expected . for the obtained set of data the ca according to ward and principal components analysis ( pca ) after initial normalization / auto - scaling ,
the outcome of the analyse is presented in figs .  1 and 2.fig . 
activity of cs [ bqm ] represents activity in the whole profile ; activity of cs [ bqkg ] represents activity in  a  layerfig . 
activity of cs [ bqm ] represents activity in the whole profile ; activity of cs [ bqkg ] represents activity in  a  layer cluster analysis ( samples ) in fig . 
the first one represents soil density and k radionuclide activity ( k activity is in constant relation to the total potassium , about 31  bq k per 1  g of potassium ) .
these two variables belong to the same cluster what suggests that potassium is incorporated mainly in mineral components of the soil .
the higher is mineral content of soil , the higher is soil density ( table  2 ) . in the second cluster , radioactivities of artificial cs in the  a  soil layer and in the whole core as well as the sampling point height asl and organic matter content ,
similar course of changes of cs activity and soil organic matter content can be attributed to the sorptive properties of this soil fraction . as cs presence in
the soil results only from the distant transport of the contaminant , its retention in soil is a direct result of its sorption .
the other important factor is the amount of precipitation in the area ( rain , snow ) .
the higher is the location of the sampling point in the mountains , the higher is the amount of precipitation .
thus , the variable  altitude  belongs to the same cluster . in fig . 
but the chosen criteria i.e. analysed variables , enabled proper and logical division of the sampling points into groups ( clusters ) for which the soil type is a common feature ( table  3 ) .
however , it should be noted that in mountains , soil types are not sharply defined . as a result
the revealed clusters do not classify soil types directly , but the obtained classification is relevant for a given soil complex structure ( fig .  2 ;
principal components are the linear combination of the previous variables . taking into consideration the kaiser criterion in further analysis only the first and the second principal component should be used ( table 4 ) .
the scree diagram suggests however , that it would be reasonable to consider three components as they describe 92.36  % of global variation of the data ( fig . 
3scree diagram in table 5 factor loadings ( after varimax rotation ) for the three principal components are given.table  4eigenvaluesprincipal components analysiseigenvalues% total variancecumul .- eigenvaluecumul.-%12.7946.482.7946.4821.9732.784.7679.2630.7913.105.5592.3640.254.235.8096.5950.132.125.9398.7160.071.296.00100.00table  5factor loadings ( varimax)vf-1vf-2vf-3altitude0.0900.232 
 0.942 
 density 
 0.950 
 0.1070.096radioactivity of cs (  a 
layer)0.235 
 0.906 
 0.271radioactivity k 
 0.721 
 0.0940.556radioactivity cs ( whole core)0.247 
 0.945 
 0.025organic matter 
 0.956 
 0.1080.050significant values are given in bold factor loadings ( varimax ) significant values are given in bold the first component ( explaining 46  % of variability ) covers mainly the following variables : density , organic matter content and potassium concentration .
all these parameters are connected with the physical properties and chemical composition of the soil . the second principal component , explaining 33  % of variability , considers only anthropogenic variable i.e. radioactivity of cs .
third principal component explaining 13  % of variability refers to the height asl of the sampling point .
it should be stressed , that this component supplies additional information related to some aspects explained by the first two principal components .
the height above sea level has the influence on such soil properties like density and organic matter content .
with increasing altitude the pace of organic matter decomposition decreases ( the same tendency is noted for temperature ) .
simultaneously , anthropogenic cs was introduced to the soil mainly with rainfall  in the mountains , the higher located is the place the more rain is precipitated . in fig .  4
it may be noted that the variables ( soil density and potassium content ) are positively correlated witch each other and negatively correlated with organic matter content . on the other hand
it is clear that cs radioactivity is orthogonal to those variables ( soil density and potassium content)no correlation was found.fig . 
4projection of the variables onto the plane of the first two principal components projection of the variables onto the plane of the first two principal components
it was established that : caesium radioactivity in the soils of the bpn is changeable . in the top (  a  layer ) 3  cm thick soil layer it is in the range from 36 to 831  bq  kg , while in the whole core ( 10  cm ) it spans from 1,916 to 28,551  bq  m. ca enabled grouping of the sampling points according to the soil type .
it may be assumed that the sampling points are better characterized by the cs radioactivity expressed in surface units rather than radioactivity of the first layer only.the pca reduced the number of analysed variables to three principal components , explaining 92  % of the total variance of the variables .
first three principal components differentiate the variables into : natural ( connected with physical and chemical soil properties ) like soil density , organic matter and potassium contents , anthropogenic  cs radioactivity , and sampling points characteristic  altitude above sea level .
(  a  layer ) 3  cm thick soil layer it is in the range from 36 to 831  bq  kg , while in the whole core ( 10  cm ) it spans from 1,916 to 28,551  bq  m. ca enabled grouping of the sampling points according to the soil type .
it may be assumed that the sampling points are better characterized by the cs radioactivity expressed in surface units rather than radioactivity of the first layer only .
the pca reduced the number of analysed variables to three principal components , explaining 92  % of the total variance of the variables .
first three principal components differentiate the variables into : natural ( connected with physical and chemical soil properties ) like soil density , organic matter and potassium contents , anthropogenic 
cs radioactivity , and sampling points characteristic  altitude above sea level . presented above conclusions
it is true especially for the neighbouring tatra mountains national park [ 3 , 5 , 12 ] .
the similar positive correlation of cs activity with the sampling point altitude and organic matter content in the soil were found in the tatras .
soils of the mountains neighbouring to the bpn constitute currently the subject of complementary research projects .
 the aim of this work was to determine 137cs and 40k radioactivities in soil samples taken from the babia gra national park ( bpn ) in south poland . 
 the cluster analysis ( ca ) and principal component analysis ( pca ) were used to discuss the obtained data . 
 10  cm thick soil cores were collected from the bpn area . 
 each sample was divided into three sub - samples . 
 the samples were dried , homogenized and packed in polyethylene containers . 
 the radioactivities of 137cs and 40k were measured by means of gamma spectrometry . 
 it was found that 137cs radioactivity in the whole 10  cm soil cores was in the range from 1,916 to 28,551  bq  m2 . 
 the radioactivity of 40k varied from 1,642 to 25,654  bq  m2 . using ca it was possible to diverse the soils taking into account soil types . by use of the pca method , 
 it was chosen three factors which are appropriate to characterize researched parameters . 
Introduction
Materials and methods
Results and discussion
Conclusions