The GEMAS (geochemical mapping of agricultural soil) project collected 2108 Ap horizon soil samples from regularly ploughed fields in 33 European countries, covering 5.6 million km2. The <2 mm fraction of these samples was analysed for 53 elements by ICP-MS and ICP-AES, following a HNO3/HCl/H2O (modified aqua regia) digestion. Results are used here to establish the geochemical background variation and threshold values, derived statistically from the data set, in order to identify unusually high element concentrations for these elements in the Ap samples. Potentially toxic elements (PTEs),

A reliable overview of measured concentrations of TC, TN and TS, TOC/TN ratios, and their regional distribution patterns in agricultural soil at the continental scale and based on measured data has been missing - despite much previous work on local and the European scales. Detection and mapping of natural (ambient) background element concentrations and variability in Europe was the focus of this work. While total C and S data had been presented in the GEMAS atlas already, this work delivers more precise (lower limit of determination) and fully quantitative data, and for the first time high-quality TN data. Samples were collected from the uppermost 20cm of ploughed soil (A horizon) at 2108 sites with an even sampling density of one site per 2500km for one individual land-use class (agricultural) across Europe (33 countries). Laboratory-independent quality control from sampling to analysis guaranteed very good data reliability and accuracy. Total carbon concentrations ranged from 0.37 to 46.3wt% (median: 2.20wt%) and TOC from 0.40 to 46.0wt% (median: 1.80wt%). Total nitrogen ranged from 0.018 to 2.64wt% (median: 0.169wt%) and TS from 0.008 to 9.74wt% (median: 0.034wt%), all with large variations in most countries. The TOC/TN ratios ranged from 1.8 to 252 (median: 10.1), with the largest variation in Spain and the smallest in some eastern European countries. Distinct and repetitive patterns emerge at the European scale, reflecting mostly geogenic and longer-term climatic influence responsible for the spatial distribution of TC, TN and TS. Different processes become visible at the continental scale when examining TC, TN and TS concentrations in agricultural soil Europe-wide. This facilitates large-scale land-use management and allows specific areas (subregional to local) to be identified that may require more detailed research.

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Kwecko, P., 2016. Rare earth el e ments (REE) and tho rium in the youn gest Pleis to cene gla cial tills in Po land. Geo log i cal Quar terly, 60 (2): 451-460, doi: 10.7306/gq.1295The study en com passed out crops of gla cial tills (top soil, sub soil-1, sub soil-2) of the max i mum stadial of the Vistulian Glaci ation and of the Wartanian Stadial of the Odranian Gla ci ation, oc cur ring along the max i mum ex tent of the Vistulian ice sheet. The youn gest Pol ish gla cial tills show very sim i lar con cen tra tions of REE and Th. The con cen tra tions of these el ements vary across a wide range from 0.08 mg/kg (Tm and Lu) to 70.3 mg/kg (Ce), with slightly higher val ues for the older tills (Wartanian). Both these tills show clear frac tion ation of LREE and HREE, with a higher and more var ied LREE con centra tion. The most prom i nent fea ture dis tin guish ing one till from the other is the dis tri bu tion of REE frac tions along their verti cal sec tions. In the youn ger (Vistulian) tills the max i mum con cen tra tion of in di vid ual LREE is found at a depth of 1.0 m, and of HREE, Sc and Th, at 2.0 m; while in the older (Wartanian) tills the high est con cen tra tions of all el e ments in ves tigated are ob served at a depth of 1.0 m. Also, the min eral com po si tions of the tills are very alike. The dom i nant min er als are quartz (av er age 56%) and feld spars (ap prox i mately 9%), with a trend of de creas ing con cen tra tions with depth. There are no car bon ates in the top soil (0.3 m level), and the clay min er als are dom i nated by illite (ap prox i mately 16%) and kaolinite (av er age 5%). Sta tis ti cal anal y sis in di cates over a dozen fac tors de ter min ing the con cen tra tion of REE and Th in both tills. Three of them have a cru cial (96% of to tal vari a tion) ef fect on the con cen tra tions of these el e ments. These fac tors are prob a bly of geogenic na ture, in ti mately as so ci ated with sim i lar source ar eas, and with sim i lar pro cesses of de po si tion, diagenesis and weath er ing of the tills.