Application of lead isotopic methods to the study of the anthropogenic lead provenance in Spanish overbank floodplain deposits.

Changes in the principal sources of Pb in overbank sediment profiles have been documented for two Spanish areas by using Pb isotopes and Pb concentrations. These locations (Madrid and Tinto-Odiel basin) represent two of the most contaminated regions in Spain. The Community of Madrid is characterized by heavy industrial and urban activity, focused mainly in Madrid City. The Tinto-Odiel basin drains the Iberian Pyrite Belt, which hosts many polymetallic massive sulphides and is heavily affected by mining activities in their headwaters. It has been proven that the influence of anthropogenic activity is reflected in these overbank deposits by variations in Pb concentrations that, in general, correlate with shifts in the (206)Pb/(207)Pb ratio. Rivas profile (downstream of Madrid) was found to be the most anthropogenically influenced site. The sediments within this profile which were recently deposited (170 ± 40 years BP) have the least radiogenic signatures. (206)Pb/(207)Pb ratios ranged between 1.1763 and 1.1876 indicating significant contributions of anthropogenic Pb. In contrast, profiles upstream of Madrid possess an average (206)Pb/(207)Pb ratio of 1.2272. It is difficult to clearly identify the most prominent source as the sediments appear to be characterized by an input from several sources. The floodplain profiles in the Tinto-Odiel basin exhibit uniform (206)Pb/(207)Pb ratios ranging from 1.1627 (Odiel river) to 1.1665 (Tinto river). These ratios are similar to the ones possessed by sulphide ores in the area and differ from the ratios of other nonmineralized formations in the basin, indicating that mining activities are the primary, if not sole, source of Pb to the sediments.

Factors controlling Mn and Zn contents in leaves of silver and downy birch in acidified soils of Central Europe and Norway.

In Central European mountain forests, foliar element concentrations (FECs) of manganese (Mn) in silver birch (Betula pendula Roth) are occasionally approximately 5000 mg kg-1 and can represent stress for these plants. Factors controlling the Mn FECs in silver birch in Central Europe and downy birch (Betula pubescens Ehrh.) in Norway have not yet been fully deciphered. In this study, the Central European silver birch specimens were sampled in 2022. The samples were analysed by X-ray fluorescence spectroscopy. Norwegian data were obtained from the literature. Mn FECs are commonly negatively correlated with magnesium and, in certain areas, with potassium. Mn FECs are simultaneously elevated with zinc (Zn), likely because of soil acidification and anthropogenic emissions. Mn FECs in birch were previously thought to be related to altitude, which was assigned to (i) downslope washes of Mn or (ii) the historical load of acid emissions. The highest Mn FECs in silver birch were found in the Harz Mountains, Germany, and have been attributed to historical atmospheric contamination and the abundance of soils on felsic silicic rocks poorly buffering acid rains. The historical emission load from iron and steel production was hypothesised to be the cause of elevated Mn and Zn FECs in the Beskid Mountains, Czech Republic. Mn FECs in birch can be used to map historical soil acidification caused by industrial emissions. Zn FECs in birches can reflect soil contamination by this element.

Excess Cr and Ni in top soil: Comparing the effect of geology, diffuse contamination, and biogenic influence.

Chromium (Cr) and nickel (Ni) are among the elements that are most mined, processed and used in modern industry and society. A realistic estimate of the diffuse contamination that has left a footprint on soil during the last 200 years by worldwide industrialization requires recognition and assessment of the dominant natural and anthropogenic sources. The relations between geogenic, anthropogenic, and biogenic Cr and Ni sources are estimated from eight large-scale geochemical surveys, by comparing the cumulative distribution functions (CDF) of the elements in top- and sub soil using cumulative probability (CP) diagrams. This method makes it possible to estimate the effect of long-term diffuse contamination on soil without monitoring. The method offers a cheaper and more reliable method for estimating diffuse contamination at the continental to regional scale than classical monitoring methods. The impact of diffuse contamination can be recognized at the low-concentration end while strong local contamination is shown as a distort at the high-concentration end of the distribution. Chromium, due to its structural similarities with essential nutrients, shows a clear biological signal in the CP-diagram. The bio-adjustment of Cr and Ni limits the accuracy of the diffuse contamination estimates. Combining CDF analysis with spatial mapping provides insight into the dominant contamination processes that distort the top soil CDF relative to the sub soil CDF. For both elements, a diffuse contamination signal of <1 mg/kg is obtained for soils at the European scale. Agricultural soil is affected by contamination from farming practices and shows higher excess Cr and Ni in top soil than forest soil. Although the world has faced several centuries of industrial development and Cr and Ni are used "everywhere", this is not reflected in surface soil at the continental to regional scale. The regional distribution of both elements is dominated by natural sources and processes.

Cadmium enrichment in topsoil: Separating diffuse contamination from biosphere-circulation signals.

Eight regional to continental scale datasets providing Cd concentrations in subsoil (C horizon or mineral soil collected at depth) and topsoil are used to compare the statistical distribution of Cd in the two soil layers. Topsoil is invariably enriched in Cd when compared to subsoil. When both horizons are mineral soil the concentration ratio CdTOP/CdSUB is 1.3-2.2. This ratio is substantially larger (6.6-16.5) when mineral subsoil is compared to an organic topsoil O horizon. Data from regional multi-media transects underline that Cd, despite of toxicity, plays an important role in the biosphere, and several plants and a mushroom not only accumulate but also adjust their Cd content. Because organic topsoil is derived from local vegetation residues, its Cd cumulative distribution function (CDF) reflects also Cd accumulation related to local plant diversity. This is a major difference to Pb which is not usually actively taken up by plants, whereby a linear concentration shift between mineral soil and organic soil dominates the CDFs. To estimate the amount of excess Cd due to diffuse contamination, the low-concentration ends of the CDFs from the regional datasets are studied. For two datasets a diffuse Cd contamination below 0.03 mg/kg emerges, a reasonable value when compared to either the median concentration of 0.15 mg/kg Cd in topsoil, or to published Cd fluxes. For the other datasets the apparent diffuse Cd input is between 0.05 and 0.28 mg/kg. In one data set this seems to indicate a true contamination blanket due to several large-scale regional anthropogenic sources at the single country scale. In many surveys, the low end of the subsoil Cd concentration is difficult to assess due to analytical limitations. The results suggest that hitherto neglected natural processes selectively accumulate Cd and substantially change its distribution characteristics in the biosphere and the organic topsoil.

Reliability of geochemical analyses: Deja vu all over again.

Today the vast majority of commercial laboratories are accredited. Quality control (QC) results are documented and, upon request, available to the customer. That has led many customers of analytical services to neglect the need for their own, laboratory independent, external QC for large geochemical mapping or monitoring projects. Here, based on recent examples from projects of the Geological Survey of Norway, it is demonstrated how such an external QC procedure should look. Simple graphics are used to visualize QC results. R scripts for producing these graphics are provided. Despite of the laboratories' own internal QC procedures, a number of quality issues like time trends, sample mix-ups, concentration breaks between different batches due to the use of several instruments and excessive rounding of analytical results were detected. Thus, even in these times of accreditation, it is still a necessity to install project-level, laboratory independent, QC procedures in order to produce reliable and comparable datasets.

The large-scale distribution of Cu and Zn in sub- and topsoil: Separating topsoil bioaccumulation and natural matrix effects from diffuse and regional contamination.

A realistic estimate of diffuse contamination requires to recognize and assess the dominant natural and anthropogenic element sources. For eight large-scale geochemical surveys, the relations between geogenic, anthropogenic and biogenic Cu and Zn sources are estimated by comparing the cumulative distribution functions (CDF) of the elements in top- and subsoil using cumulative probability (CP) diagrams. Strong local contamination distorts the high-concentration end of the distribution function considerably in topsoil. In contrast the impact of diffuse contamination can best be recognized at the lower end of the data distribution. Copper and Zn are important plant micronutrients, studying their concentrations in a variety of plant materials and soils along a number of transects demonstrates that both are adjusted to narrow concentration levels in many plant materials. Plants regulating the element concentrations to certain fixed levels will distort the low-concentration end of a topsoil CDF, the bio-adjustment thus limits the accuracy of diffuse contamination estimates. Combining CDF analysis with spatial mapping provides insight into the dominant contamination processes that distort the topsoil CDF relative to the subsoil CDF. For Cu a most likely diffuse contamination signal of 1-2 mg/kg with a maximum of 5 mg/kg is obtained for soils at the European scale. The higher estimate is clearly influenced by bio-adjustment. For Zn diffuse contamination appears to be higher on first glance, about 5-10 mg/kg, but again the lower end of the investigated CDFs is strongly shifted by biosphere adjustment, plants striving to avoid Zn deficiency. The true input through diffuse contamination will thus be considerably lower. Data from projects that sampled minerogenic instead of organogenic topsoil lead to lower estimates for diffuse Zn contamination in the range of <1-5 mg/kg at the continental scale.

Geosphere-biosphere circulation of chemical elements in soil and plant systems from a 100 km transect from southern central Norway.

Geochemical element separation is studied in 14 different sample media collected at 41 sites along an approximately 100-km long transect north of Oslo. At each site, soil C and O horizons and 12 plant materials (birch/spruce/cowberry/blueberry leaves/needles and twigs, horsetail, braken fern, pine bark and terrestrial moss) were sampled. The observed concentrations of 29 elements (K, Ca, P, Mg, Mn, S, Fe, Zn, Na, B, Cu, Mo, Co, Al, Ba, Rb, Sr, Ti, Ni, Pb, Cs, Cd, Ce, Sn, La, Tl, Y, Hg, Ag) were used to investigate soil-plant relations, and to evaluate the element differentiation between different plants, or between foliage and twigs of the same plant. In relation to the soil C horizon, the O horizon is strongly enriched (O/C ratio > 5) in Ag, Hg, Cd, Sn, S and Pb. Other elements (B, K, Ca, P, S, Mn) show higher concentrations in the plants than in the substrate represented by the C horizon, and often even higher concentrations than in the soil O horizon. Elements like B, K, Ca, S, Mg, P, Ba, and Cu are well tuned to certain concentration levels in most of the plants. This is demonstrated by their lower interquartile variability in the plants than in the soil. Cross-plots of element concentration, variance, and ratios, supported by linear discrimination analysis, establish that different plants are marked by their individual element composition, which is separable from, and largely independent of the natural substrate variability across the Gjøvik transect. Element allocation to foliage or twigs of the same plants can also be separated and thus dominantly depend on metabolism, physiology, and structure linked to biological functions, and only to a lesser degree on the substrate and environmental background. The results underline the importance of understanding the biological mechanisms of plant-soil interaction in order to correctly quantify anthropogenic impact on soil and plant geochemistry.

Trace element analysis of scales from four populations of Norwegian Atlantic salmon (Salmo salar L.) for stock identification using laser ablation inductively coupled plasma mass spectrometry.

The pre-smolt stage of the scale of adult Norwegian Atlantic salmon from four populations, encompassing both farmed and wild hatchery stocks, has been analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-HR-ICP-MS). The purpose of this study was to test for differences in elemental composition between stocks of Atlantic salmon that have lived in separate fresh water locations until the smoltification and natural run out or transportation to the sea-cages. The populations studied were from fish farms located at Bremanger and Sorfold, a cultivated stock from Mossa, and one wild local stock from the river Gaula. The following elements were included in the analytical protocol: Li, Mg, Ca, Cr, Mn, Fe, Zn, Sr, Ba, Pb, and U. Calcium was used as a natural internal standard. Classification of the analytical data is studied by multivariate statistical techniques such as principal component analysis (PCA). We have been able to delineate the population of Atlantic salmon (Salmo salar L.) from Gaula and Mossa from the Bremanger and the Sorfold stock based on the ten elements analyzed. The Bremanger and Sorfold stocks were partially delineated. The differences in elemental composition in the scales, which makes the delineating of the four stocks possible, probably reflects geological differences in the bedrock at the four fresh water locations experienced by the salmon during the pre-smolt stage.

Submarine and deep-sea mine tailing placements: A review of current practices, environmental issues, natural analogs and knowledge gaps in Norway and internationally.

The mining sector is growing in parallel with societal demands for minerals. One of the most important environmental issues and economic burdens of industrial mining on land is the safe storage of the vast amounts of waste produced. Traditionally, tailings have been stored in land dams, but the lack of land availability, potential risk of dam failure and topography in coastal areas in certain countries results in increasing disposal of tailings into marine systems. This review describes the different submarine tailing disposal methods used in the world in general and in Norway in particular, their impact on the environment (e.g. hyper-sedimentation, toxicity, processes related to changes in grain shape and size, turbidity), current legislation and need for future research. Understanding these impacts on the habitat and biota is essential to assess potential ecosystem changes and to develop best available techniques and robust management plans.