Alum Shale Research Articles

Regional burial heating vs. local magmatic heat influence of the Röstånga area, Scania, southern Sweden

Illite crystallinity and vitrinite-like reflectance were studied within the Röstånga area to evaluate the degree of burial-related heat versus magmatic influence from the Permo-Carboniferous dolerite intrusions. At Röstånga three non-contact metamorphosed samples gave low diagenetic illite crystallinities with Kübler index values of 0.64–0.78 Δ°2θ. These results are in contrast to statements in the literature of high organic maturity (mean random reflectance, Ro 2–2.7%) within the area, and suggest that the short-lived magmatic heating, also at localities outside immediate dolerite contact zones, improved the organic maturity more than it did the illite crystallinity. The Kübler index and the reflectance values from the contact-metamorphosed Alum Shale at Åkarpsmölla are clearly affected by the magmatic heating caused by the dolerite intrusion. The crystallinity as well as the vitrinite-like Ro values show significantly higher maturity than indicated by the regional reference samples. All the Åkarpsmölla Ro values indicate that the rocks are overmature (3.9–5.8%) with respect to any petroleum generation, and fall within the anchimetamorphic to epimetamorphic zone, whereas the Kübler index values (0.42–0.73 Δ°2θ), due to the sluggish reaction rate of the clay mineral reactions, lag behind throughout the whole section and range within the diagenetic zone.

The Caledonian foreland basin in Scandinavia: Constrained by the thermal maturation of the Alum Shale. A reply

The Caledonian foreland basin in Scandinavia: Constrained by the thermal maturation of the Alum Shale. A reply

The Caledonian foreland basin in Scandinavia: Constrained by the thermal maturation of the Alum Shale. A discussion

The Caledonian foreland basin in Scandinavia: Constrained by the thermal maturation of the Alum Shale. A discussion

Association of cadmium, zinc, copper, and nickel with components in naturally heavy metal‐rich soils studied by parallel and sequential extractions

In this study, a new parallel and sequential extraction procedure was proposed to investigate the solubility of metals [cadmium (Cd), zinc (Zn), copper (Cu), and nickel (Ni)] and their association with soil components in naturally metal‐rich soils of Norway. Two different soils, alum shale (clay loam) and moraine (loam), developed on alum shale minerals were used. Each soil had two pH levels. For parallel and successive extractions, H2O, 0.1M NH4OAc (soil pH), 0.3M NH4OAc (soil pH), 1M NH4OAc (soil pH), and 1M NH4OAc (pH 5.0) were used. A significant amount of Cd was extracted by NH4O Ac related to concentration of NH4OAc in the extracting solution. The amounts of Zn, Cu, and Ni extracted by these reagents were almost negligible except with 1M NH4OAc (pH 5.0). Thus these metals were strongly bound to soil components. A seven step sequential extraction procedure was applied to evaluate the association of metals with soil constituents. The extractions were performed sequentially by extracting the soil with reagents having an increasing dissolution strength: 1M NH4OAc (soil pH), 1M NH4OAc (pH 5.0), 1M NH2OH.HCl (in 25% HOAc), 1M NH2OH.HCl (in 0.1M HNO3), 30% H2O2 (in 0.1M HNO3), 30% H2O2 (1M HNO3), and aqua regia. In both soils at both pH levels investigated, appreciable percentages of total Cd (20–50%) were found associated with the NH4OAc extractable fraction (mobile fraction). For Zn, Cu, and Ni, the percentage of total metal extracted with NH4OAc was low (<4%), but it increased significantly by introducing a reducing agent (NH2OH.HCl). The NH2OH.HCl‐extractable fraction was the greatest fraction (>60%) for all four metals examined. These results suggest that among the metals studied, only Cd was easily desorbed from soil and should be considered mobile and potentially bioavailable. Other metals (Zn, Cu, and Ni) were strongly associated with the soil components and should be considered less available to plants. Using the sequential fractionation technique as a measure of availability, mobility and potential bioavailability of these four metals in the alum shale soils were: Cd>Zn>Ni>Cu.

Petrographic evidence for hydrocarbon migration in Lower Cambrian sandstones, Bornholm, Denmark

The Lower Cambrian sandstones from Bornholm, and in particular the Hardeberga Sandstone, contain a substance that has been interpreted to be pyrobitumen which causes the dark colour seen at many outcrop localities. The presence of pyrobitumen indicates the former presence of hydrocarbons that migrated through the sandstones during the Mid Palaeozoic subsidence. In contrast to previous assumptions it is shown that even though the sandstones were extensively com-pacted, it had only very little cement, and consequently excellent reservoir quali-ties at the time of hydrocarbon generation and migration. The only known source rock is the Middle Cambrian Alum Shale that must have been down-faulted rela-tive to the lower Cambrian sandstones at the time of hydrocarbon generation. Quartz cement did not form until deep burial, and similar sandstones at locations outside the onshore Bornholm area that have not been so deeply buried may not have quartz cement and therefore still posses good reservoir properties.

Vendian-Cambrian subsidence of the passive margin of western Baltica - application of new stratigraphic data from the Scandinavian Caledonian margin

Stratigraphic information from the Neoproterozoic to Cambrian cover sequences at the Caledonian margin in central Scandinavia has been compiled from the literature and our own data. Four flooding events can be recognized in the autochthonous cover rocks and parts of the eastern Caledonian Lower Allochthon: one, at the base of the Vendian at 590 Ma, two Early Cambrian events (540 and 530 Ma), and the fourth at the base of the Mid Cambrian and the alum shales (518 Ma). Stratigraphic successions of the western Baltica margin from northern Sweden to southern Norway are correlated using these flooding events. Based on these correlations, depth and time sections are constructed and subsidence curves calculated. Although Early Cambrian flooding events lead to temporarily higher sedimentation rates, the subsidence appears to have decreased through time. Such a decrease is consistent with models of lithospheric stretching and subsequent thermal subsidence. A review of available age data on tectonic events suggests a transition from continental rifting to ocean-floor formation off western Baltica at ca. 600 Ma ago. Accordingly, the Vendian to Cambrian evolution of the western Baltica continental margin is interpreted as a stage of post-rift subsidence showing the 'steer's head' geometry characteristic of sequences onlapping from an older zone of active rifting and of ocean-floor formation farther west. The gradual decrease in thermal subsidence through Cambrian time also shows that the Baltica lithosphere was essentially thermally re-equilibrated prior to earliest Caledonian tectonic activity in Early Ordovician time.

Geochemistry and the early alum industry

Abstract One of the earliest chemical industries in Britain was the alum production industry. The early alum industry relied on a complex series of extractions from suitable shale deposits, until the rise of alternative methods in the 19th century, based on industrially produced sulphuric acid. Relatively little is known about the actual processes involved. This paper discusses the evidence that can be gleaned for the chemical processes involved and reports investigations on residues recovered from waste tips at the 17th–18th century alum works at Carlton Bank, North Yorkshire. For the first time it can be said that the sulphur content of the alum shale would have limited yields from the alum production process. Wide variability in the sulphur content of unworked shale implies variable yields in the alum production process, which may have contributed to the historically recorded boom and bust of individual alum works. Analyses of waste calcined shale were shown to be of limited value without experimental reconstruction of shale processing. Future investigations need to concentrate on waste residues recovered from alum works during excavations, and on reconstructions of the process.

Hydrothermal activity in the Upper Permian Ravnefjeld Formation of central East Greenland – a study of sulphide morphotypes

Bituminous shales of the Ravnefjeld Formation were deposited in the subsiding East Greenland basin during the Upper Permian. The shales are exposed from Jameson Land in the south (71°N; Fig. 1) to Clavering Ø in the north (74°20′N) and have attracted considerable attention due to their high potential as hydrocarbon source rocks (Piasecki &amp; Stemmerik 1991; Scholle et al. 1991; Christiansen et al. 1992, 1993a, b). Furthermore, enrichment of lead, zinc and copper has been known in the Ravnefjeld Formation on Wegener Halvø since 1968 (Lehnert-Thiel 1968; Fig. 1). This mineralisation was assumed to be of primary or early diagenetic origin due to similarities with the central European Kupferschiefer (Harpøth et al. 1986). Later studies, however, suggested base metal mineralisation in the immediately underlying carbonate reefs to be Tertiary in age (Stemmerik 1991). Due to geographical coincidence between the two types of mineralisation, a common history is a likely assumption, but a timing paradox exists. A part of the TUPOLAR project on the ‘Resources of the sedimentary basins of North and East Greenland’ has been dedicated to re-investigation of the mineralisation in the Ravnefjeld Formation in order to determine the genesis of the mineralisation and whether or not primary or early diagenetic base metal enrichment has taken place on Wegener Halvø, possibly in relation to an early period of hydrothermal activity. One approach to this is to study the various sulphides in the Ravnefjeld Formation; this is carried out in close co-operation with a current Ph.D. project at the University of Copenhagen, Denmark. Diagenetically formed pyrite is a common constituent of marine shales and the study of pyrite morphotypes has previously been successful from thermalli immature parts of elucidating depositional environment and thermal effects in the Alum Shale Formation of Scandinavia (Nielsen 1996; Nielsen et al. 1998). The present paper describes the preliminary results of a similar study on pyrite from thermally immature parts of the Ravnefjeld Formation which, combined with the study of textures of base metal sulphides in the Wegener Halvø area (Fig. 1), may provide an important step in the evaluation of the presence or absence of early thermal activity on (or below) the Upper Permian sea floor.

The Caledonian foreland basin in Scandinavia: Constrained by the thermal maturation of the Alum Shale

Various palaeotemperature estimates from preserved Palaeozoic sedimentary rocks in Sweden indicate the existence of a considerably higher temperature in the past. Earlier workers have suggested that the reason for this higher palaeotemperature was due to the development of a foreland basin which buried the sediments, during the Caledonian orogeny. Palaeotemperature estimations from vitrinite reflectance are indicating a maximum palaeotemperature of approximately 165 °C for the autochthonous Alum Shale in Jämtland and 100 °C for the Alum Shale in Västergötland. These palaeotemperature estimations converted to burial depths are used as boundary conditions in the modelling of the Caledonian mountain range and the connected foreland basin. This study suggests, that to accommodate a basin fitting palaeotemperature constraints, a mountain chain similar to the Himalayas must have occurred, which implies a flexural rigidity of the lithosphere in the order of 4×1024 Nm. The heat flow is assumed to have been approximately 60 mW/m2. The model is used to estimate the overthrusted load of the Caledonian mountain range from calculated burial effects of an elastic lithosphere and does not include any other heat producing sources, i.e. fluid flow or igneous intrusions on a regional scale.

Plant uptake and DTPA-extractability of Cd, Cu, Ni and Zn in a Norwegian alum shale soil as affected by previous addition of dairy and pig manures and peat

Residual effects of cow manure, pig manure and peat soil on the DTPA-extractability and plant uptake of cadmium, copper, nickel and zinc were investigated in the second and third years after application to an alum shale soil. Wheat and barley were grown in alternate years. The effects of the organic matter applied differed among metals, sources of organic matter and time after application. The Cd concentrations in grain was reduced by the rates of peat soil, whereas the manures had no significant effect. Copper concentrations in grain and Zn concentrations in both grain and straw generally increased with rates of organic matter. Nickel concentration in grain tended to decrease with increasing rates of cow and pig manure applied, whereas it tended to increase with the addition of peat soil.The concentrations of DTPA-extractable metals in the soil were generally higher in the second and third years than in the first year after application of organic matter. Some of the metals bound by organic matter in the first year were probably released as the organic matter was decomposed. Decreases in DTPA-extractable Cd and Ni were found by the addition of pig and cow manure, whereas these manures resulted in increased DTPA-extractable Zn. The application of peat soil, on the other hand, resulted in increased amounts of DTPA-extractable Cu, Zn and Ni, probably due to decreased soil pH. Key words: Heavy metals, solubility, plant uptake, organic matter

Extractability and plant uptake of heavy metals in alum shale soils

Fifty soil samples (0–20 cm) with corresponding numbers of grain, potatoes, cabbage, and cauliflower crops were collected from soils developed on alum shale materials in Southeastern Norway to investigate the availability of [cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), and manganese (Mn)] in the soil and the uptake of the metals by these crops. Both total (aqua regia soluble) and extractable [ammonium nitrate (NH4NO3) and DTPA] concentrations of metals in the soils were studied. The total concentration of all the heavy metals in the soils were higher compared to other soils found in this region. Forty‐four percent of the soil samples had higher Cd concentration than the limit for application of sewage sludge, whereas the corresponding values for Ni, Cu, and Zn were 60%, 38%, and 16%, respectively. About 70% the soil samples had a too high concentration of one or more of the heavy metals in relation to the limit for application of sewage sludge. Cadmium was the most soluble of the heavy metals, implying that it is more bioavailable than the other non‐essential metals, Pb and Ni. The total (aqua regia soluble) concentrations of Cd, Cu, Zn, and Ni and the concentrations of DTPA‐extractable Cd and Ni were significantly higher in the loam soils than in the sandy loam soils. The amount of NH4NCyextractable metals did not differ between the texture classes. The concentrations of DTPA‐extractable metals were positively and significantly correlated with the total concentrations of the same metals. Ammonium nitrate‐extractable metals, on the other hand, were not related to their total concentrations, but they were negatively and significantly correlated to soil pH. The average concentration of Cd (0.1 mg kg‐1 d.w.) in the plants was relatively high compared to the concentration previously found in plants grown on the other soils. The concentrations of the other heavy metals Cu, Zn, Mn, Ni, and Pb in the plants were considered to be within the normal range, except for some samples with relatively high concentrations of Ni and Mn (0–11.1 and 3.5 to 167 mg kg‘1 d.w., respectively). The concentrations of Cd, Cu, Zn, Ni, and Mn in grain were positively correlated to the concentrations of these respective metals in the soil extracted by NH4NO3. The plant concentrations were negatively correlated to pH. The DTPA‐extractable levels were not correlated with plant concentration and hence DTPA would not be a good extractant for determining plant availability in these soils.

Effect of Organic Materials on Partitioning, Extractability and Plant Uptake of Metals in an Alum Shale Soil

Soils developed on sulphide-bearing shale (alum shale) in Norway contain naturally high amount of heavy metals. We conducted a greenhouse pot experiment to study the effect of four rates (0, 2, 4, and 8%) and three sources (cow manure, pig manure and peat soil) of organic matter in partitioning and distribution, extractability and plant uptake of Cd, Cu, Ni and Zn in an alum shale soil. Sequential extraction scheme was used to determine the distribution patterns of metals in the soil. DTPA was used for extracting the metals from the soil. Wheat (Triticum aestivum) was used as a test crop to study the plant uptake of metals. The highest amount of Cd was present in the exchangeable fraction, irrespective of the rate and source of organic matter applied. Copper, Ni, and Zn, on the other hand, were present only in small quantities in this fraction. The largest fraction of Cu was associated with organic matter and the amounts present in the oxide, carbonate and exchangeable fractions were very small. Nickel and Zn were found mainly in the residual fraction. Increasing rates of cow and pig manure decreased the amounts of Cd and Ni associated with the exchangeable fraction whereas, the addition of peat soil at the same rate increased the amounts of these metals associated with this fraction. This effect of organic matter was primarily associated with the change in soil pH caused by different organic matter sources. The DTPA-extractable metals were decreased with increasing rates of organic matter application, irrespective of its source. Grain and straw yields of wheat were decreased with increasing rates of organic matter. The application of organic matter increased the Cu and Zn concentrations in both grain and straw. The concentration of all metals was lower in plants grown in the cow manure amended soil as compared to those grown in the soil amended with either pig manure or peat soil. These results sugggest that the source of organic matter was a determining factor for metal distribution in the soil and for metal uptake by plants. In this study cow manure slightly increased the soil pH and thus was more effective than either pig manure or peat soil in reducing the plant uptake of metals but in general the efficiency of the organic material in reducing heavy metal uptake was small.

The Mid-Tournaisian event in the Northern Urals and conodont dynamics

The distribution of conodonts across several sections in the Northern Urals is documented for the interval spanning the Carboniferous Mid-Tournaisian (‘Lower Alum Shale’) global event. In the Northern Urals the event interval is represented by cherty sediments with layers of clastic limestone. The event interval comprises the uppermost part of the duplicata-sandbergi Conodont Zone and the lower part of the quadruplicata Conodont Zone, and is marked by an extensive radiation of conodonts. At this interval a number of siphonodellids, pseudopolygnathids. and a new species of primitive Eotaphrus appear. This new species ( Eotaphrus simplex sp. nov.) is described herein. Although some conodont taxa became extinct at the event level, the predominant conodont radiation is in contrast to the worldwide extinction of goniatite faunas previously described. The abundant and characteristic post-event conodont fauna has good potential for correlation of the Mid-Tournaisian boundary in deep-water facies both in the Northern Urals and worldwide.

High-temperature programmed pyrolysis of Paleozoic source rocks from Northern Germany and adjacent areas and its thermodynamic constraints

In order to determine the hydrocarbon generating potential of high-maturity source rocks (>2% R max VR), it is necessary to conduct pyrolysis experiments at high temperatures. However, kinetic and thermodynamic considerations suggest that, with increasing temperatures, the gas forming reactions become more and more unrealistic. Since there are no reliable alternative physical and chemical methods for the evaluation of late hydrocarbon potential, pyrolysis conditions have to be optimized so as to minimize the secondary degradation of methane. This necessitates the use of high-temperature programmed micropyrolysis, which permits the quick removal of pyrolysis products from the hot reaction zone. This paper discusses how a pyrolysis procedure that is similar to Rock-Eval pyrolysis was used to investigate the hydrocarbon potential of highly mature Paleozoic rocks from Northern Germany and adjacent areas. The objective of the experiments was to determine whether small amounts of dry gas, formed at maturities beyond 2% R max, can fill commercially interesting gas reservoirs. The finding was that coals, coaly shales, and also Cambro-Ordovician Alum Shales retain a sufficiently large methane generating potential at high maturities. In many of the rocks pyrolyzed, the kerogen clearly contained organic material of different structures and different thermal stability. These kerogen fractions decomposed one after another at different maturity stages. An isotopic inversion of the carbon in the methane released could be observed as soon as a new and more stable structure was degraded.

Reference concentrations for heavy metals in mineral soils, oat, and orchard grass (D�ctylis glomer�ta) from three agricultural regions in Norway

Background values for heavy metals are necessary for the assessment of metal pollution of soils and plants. Samples of cultivated and uncultivated soils, oat grain, and seed heads of orchard grass (Dactylis glomerata) were collected from central, southeastern, and southwestern Norway. Total and easily extractable concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were determined in soil samples and total concentrations in plant samples. Element distributions have been correlated with petrology of soil parent material, type of mineral deposit, soil depth, geographic area, and land use. Concentrations of heavy metals are generally within the lower part of the normal global range. The petrology of the soil parent material has the greatest influence on aqua regia extracted metal concentrations among the factors studied. DTPA extracted metals show less dependence on rock types. Presence of alum shale results in particularly high values for Cd in both soil extracts and in oat grain. Soil cultivation seems to influence the relative concentration of metals in the topsoil. The ratios of easily extractable to total concentrations of metals are primarily related to the organic matter content. Metal concentrations in oat grain can best be predicted by concentrations in DTPA extracts and soil pH among the factors studied. Seed heads of orchard grass are less affected by concentrations in the soil and appear therefore to be a poor indicator of heavy metals in soils.

Neoformation of Inert Carbon during the Natural Maturation of a Marine Source Rock: Bakken Shale, Williston Basin

The Bakken Shale (Mississippian/Devonian) of the Williston Basin was used as a natural laboratory for comparing the disproportionation reactions occurring in nature with those occurring in pyrolysis experiments. A uniform kerogen type and a broad maturity range made this possible. Mass balance calculations, analytical pyrolysis, and MSSV simulation experiments together provided strong evidence that generative yields from open system pyrolysis are not equal to potential petroleum yields in nature for this particular source rock. This is because inert kerogen formation is enhanced under both natural and closed system simulation conditions, ostensibly because of aromatization and condensation reactions involving primary aromatic structures and possibly cross-linked moieties. The outcome is that mass balance models normalized to inert carbon give overestimates of petroleum generated in nature. This is the second case where we have been able to substantiate that the phenomenon occurs in nature. The presence of high concentrations of aromatic moieties in the most immature equivalents is common to both the Alum Shale and Bakken Shale. A maturity zonation based on the residues of simulated and natural maturation allowed the quantitative and qualitative evolution of liquid natural petroleums to be predicted. The occurrence of enhanced concentrations of low molecular weight hydrocarbons in the immature zone nevertheless remains enigmatic.

Radium and uranium concentrations in two eskers with enhanced radon emission

Concentrations of 226Ra and 238U in soil samples from two Swedish eskers were determined. One of the eskers, containing rock material from a radioactive granite, revealed a high degree of radioactive disequilibrium between 226Ra and 238U. The disequilibrium ratio was positively correlated with particle size and soil permeability, indicating that a major part of the 226Ra is adsorbed on the surface of the mineral particles. The other esker, with uraniferous alum shale material and carboniferous slates, revealed a much lower degree of disequilibrium, indicating that a major part of the 226Ra is bound to primary uranium minerals. A less intense weathering of the uranium minerals due to the protective effect from the kerogen compounds in the alum shale is thought to be the main reason for this. The results indicate that 226Ra may be present in a weathered soil in two ways: in primary uranium minerals or precipitated on the surface of the mineral particles. The proportions may vary depending on the type of rock material, weathering conditions, and permeability of the soil. This is of great importance to the process of radon emanation, since it is much higher from radium that is adsorbed on the surface of soil particles compared to radium bound in primary uranium minerals.

Siliceous rocks of the Culm Basin, Germany

Abstract The classic Dinantian cherts of the Rhenish Massif and Harz Mountains, Germany, were analysed for their petrography and sedimentology. They occur in five lithostratigraphic units: the Lower Alum Shale Formation, the Black Chert Formation, the Pale Chert Formation, the Siliceous Limestone Formation, and the Siliceous Transitional Formation (upper Hastarian to Asbian, CuII to CuIIIα of the German cephalopod zonation). Mafic volcanic rocks are locally associated with these strata. Four regional facies zones have been defined. Radiolarian chert, spiculitic chert, homogeneous chert, and silicified quartz-trachytic tephra and tuffite are the main chert types. These mostly form current-laminated grey, black, greenish or reddish beds rhythmically alternating with layers of siliceous mudstone and, in places, variably intercalated with grey and black mudstones and siltstones, phosphorites, metabentonites, limestone turbidites, greywackes and quartz arenites. The siliceous rocks were deposited in a moderately deep (upper bathyal) strait of an equatorial sea that was part of palaeo-Tethys. Westward-driven nutrient-rich currents from the palaeo-Pacific Ocean favoured high radiolarian fertility. Relatively pure biosiliceous ooze was deposited under temporarily anoxic conditions when, due to dry climate and high sea-level, detrital input decreased. Deposition of the siliceous facies ended with increased detrital input and breakdown of the ocean-current system due to the collision of Laurasia and Gondwana during the Variscan Orogeny.

Elucidation of the Alum Shale kerogen structure using a multi-disciplinary approach

The significance and validity of integrating data obtained from a variety of analytical techniques to understand, elucidate and model kerogen's complex chemical structure is reported here using degradative (open and closed system pyrolysis, chemical oxidation), non-degradative ( 13C CP/MAS NMR) and optical (incident white light and blue light) methods. Seven Cambrian Alum Shale samples, ranging in maturity from immature to post-mature with respect to petroleum generation, were studied and were chosen for their simple geological history, uniform organic matter type and high organic carbon content. The Alum Shale kerogens, which primarily consist of algal organic matter, liberate low molecular weight gaseous and aromatic compounds on pyrolysis and give mostly branched dicarboxylic acids on chemical oxidation. 13C NMR spectroscopy shows that the Alum Shale kerogens are anomalously rich in oxygen-bearing functional groups (such as C = O, ArCO, CHO, CH xO), most of which apparently remain intact within the kerogen macro-molecule (KMM) through the diagenetic and catagenetic stages. Fragments released by different degradative techniques are quantified and the aromaticity (f a), O/C and relative proportions of various carbon types estimated by 13C NMR. A synthesis of these data has allowed us to better understand the chemistry of the Alum Shale kerogen.

Crop uptake and extractability of cadmium in soils naturally high in metals at different pH levels

Abstract A greenhouse experiment was conducted for three years to study the effect of different pH levels on metal concentrations in plants and the cadmium (Cd) extractability by DTPA and NH4NO3. The soils used were an alum shale (clay loam) and a moraine (loam), which were adjusted to pH levels of 5.5, 6.5, 7.0, and 7.5. Wheat (Triticum aestivum), carrot (Daucus carota L.), and lettuce (Lactuca sativa) were grown as test crops. Crop yields were not consistently affected at increasing soil pH levels. The concentration of Cd in plant species decreased with increasing soil pH in both soils and in all three years. Significant concentration differences between soil pH levels were only seen in wheat and carrot crops. Increasing soil pH also decreased the nickel (Ni) and zinc (Zn) concentrations in plants in the first year crop but the copper (Cu) concentration was not consistently affected by soil pH. The effect of pH was more pronounced in the moraine then the alum shale soil. The DTPA‐and NH4NO3‐extractable ...