Fig. 2. Mean pattern of polycyclic aromatic hydrocarbons (PAHs) (a) in recent Russian topsoils (collected 1996–2003) and North American Prairie topsoils (Wilcke and Amelung, 2000) and (b) in Russian topsoils archived between 1910 and 1922. In (b) additionally the pattern of PAHs in the Bronnitsi topsoil sample of 1922, an outlier, and in the Schapovo topsoil sample of 1954 is shown. ACEN, acenaphthene; ACENY, acenaphthylene; ANTH, anthracene; B(A)A, benz(a) anthracene; B(A)P, benzo(a)pyrene; B(BJK), benzo(b+j+k)-fluoranthenes; B(E)P, benzo(e)pyrene; B(GHI), benzo(ghi)perylene; CHRY, chrysene + triphenylene; COR, coronene; DIBE, dibenz-(a,h)anthracene; FLUA, fluoranthene; FLUO, fluorene; IND, indeno-(1,2,3-cd)pyrene; NAPH, naphthalene; PERY, perylene; PHEN, phenanthrene; PYR, pyrene.