Mineralogy and heavy metal contents of soils and stream sediments in a rural region of Western Germany

This paper presents the results of a study of clay mineralogy and Pb, Zn, Cu, Rb, Sr, Y and Zr analyses of soils and stream sediments of the Schwarzach watershed, a drainage system located in a secluded rural region of eastern Bavaria, far removed from major industrial installations.Clay fractions of soils and stream sediments differ significantly in their mineralogy. The soils average 50% secondary chlorite and 40% illite, whereas recent stream sediments average 20% chlorite and 70% illite. These assemblages are possibly interconvertible under the influence, or on withdrawal, of Schwarzach water. Proportions of clay minerals in fossil stream sediments average approximately 30% chlorite, 50% illite, and 20% kaolinite with up to 10% of 10–14 Å interstratified minerals.Surface soil layers have been enriched in Pb, as have recent stream sediments. The latter have also been enriched in Zn and Cu. The increased amounts of Pb plus its close association with organic C indicate atmospheric deposition of Pb and incipient eutrophication of the Schwarzach River.     

Predictive relationships between pH and sodicity in soils of tropical Queensland

Abstract

Interrelations between soil pH and exchangeable sodium percentage (ESP) were examined using soils from the Burdekin River area in tropical Queensland. Highly significant correlations were found but the goodness of fit differed between groups of soil profile classes. In general, Typic Natrustalfs of the flood plains had better relationships (r² = 0.85) between these soil properties than did the Chromusterts (r² = 0.50). The regression ESP = 1.935 × 10^‐5 _pH6.205 (_r2 = 0.61; n= 288) for all soils and depths underestimated ESP in Typic Natrustalfs groupings and overestimated this soil property in the Chromusterts.

By using the appropriate regression, pH levels associated with non‐sodic, sodic and strongly sodic horizons have been defined. Either laboratory or field determined estimates of pH may be used but the laboratory determined value is preferred. It is expected the predictive models will remain valid until soil ESP or pH levels are significantly modified as a consequence of agricultural development.     

Fractionation of copper and uranium in organic and conventional vineyard soils and adjacent stream sediments studied by sequential extraction

Purpose

Particularly in organic viticulture, copper compounds are intentionally released into the environment as fungicide, whereas uranium originates from conventional phosphate fertilization. Both activities contribute to the metal contamination in wine-growing areas. This pilot study aimed to better understand how soil properties influence the presence and environmental fate of copper and uranium with respect to viticultural management.

Materials and methods

We characterized metal binding forms, i.e., their association with different soil constituents, in organically and conventionally cultivated vineyard soils and adjacent upstream and downstream sediments. The available metal fraction and the fractions associated with manganese oxides, organic matter, iron oxides, and total contents were extracted sequentially.

Results and discussion

Total soil copper ranged from 200 to 1600 mg kg^?1 with higher contents in topsoil than subsoil. The majority of copper (42–82%) was bound to soil organic matter. In all fractions, copper contents were up to 2-fold higher in organic than in conventional vineyards, whereas the sediment concentrations were independent of the adjacent viticultural management. A net increase of copper in downstream sediments was found only when water-extractable organic carbon (WEOC) in an adjacent vineyard was elevated. With 11 ± 1 mg kg^?1, total uranium was 25% higher in conventional than in organic vineyard soils. Its affinity to iron or WEOC potentially rendered uranium mobile leading to a substantial discharge to downstream sediments.

Conclusions

Translocation of copper and uranium from vineyards into adjacent stream sediments may rather be attributed to WEOC and iron contents than the viticultural management. Follow-up studies should scrutinize the processes driving metal availability and transport as well as their interaction at the aquatic–terrestrial interface.

     

Hydrogeochemistry of a stream draining sulfide-bearing postglacial sediments in Finland

The influence of hydrological conditions and overburden type on the stream-water quality in a catchment effected by fine-grained sulfide-bearing sediments was studied. Water samples for measurement of pH and electric conductivity were collected at 16 sites along the main course of the stream during autumn and spring high water flow and during low and intermediate water flow. On one occasion (spring high-water flow) samples for analysis of total organic carbon were collected at these sites. Seventeen water samples for analyses of chemical elements (ICP-MS and ICP-AES) were taken within the catchment basin during autumn high water flow. The pH and conductivity of snow, and the geochemistry of the sulfide sediments were also studied. The occurrence of fine-grained sediments within the catchment was estimated from topographic and geologic maps and by visit to areas were the overburden type could not be determined from the maps. The hydrological conditions had a strong influence on the water quality. During high water flow in spring and autumn the concentrations of ionic components (conductivity) and hydrogen ions in the stream water were high, while the concentrations were much lower during low and intermediate water flow and when the ground was frozen. Extensive leaching of the sulfide-bearing sediments, which had higher contents of S and metals than the fine fraction of till in the study area, resulted in elevated contents of Li, Ni, Zn, Co, B, Al, Mg, U, Sr, Ca, K and Na in the stream water during autumn high water flow. The contents of Cr, Ba, Pb, Si and Fe in stream water were not much influenced by the type of overburden, while V was depleted in drainage waters from the sulfide sediments. Humic substances flocculated in the water in the middle section of the stream, which may have been caused by di- and trivalent metal cations leached in large quantities from the oxidizing sulfide sediments.     

Deposition of trace metals in stream sediments

Sediment samples have been collected downstream from a Pb smelter and analyzed for Cd, Cu, Fe, Pb, and Zn. The concentrations of these trace metals decrease with increased distance from the smelter. The decrease in trace metal contant has been utilized to provide an indication of how rapidly artificially high levels of trace metals are reduced to the carrying capacity of a natural water. Equilibrium calculations are utilized to predict the water's intrinsic trace metal carrying capacity.     

Functional relationships between Collembola and plant pathogenic fungi of agricultural soils

The interactions between the collembolan Mesaphorura krausbaueri and four soilborne plant pathogenic fungi all living in the same layer of agricultural soil were studied under laboratory conditions. Mycelia of Gaeumannomyces graminis var. tritici, Fusarium culmorum and Rhizoctonia cerealis were palatable to Collembola and were a food source adequate for reproduction. Hyphae of Bipolaris sorokiniana were toxic and repellent for M. krausbaueri, but its conidia were eaten and proved to be a sufficient diet for reproduction. The four fungi fed had a different impact on the life processes of M. krausbaueri. Depending on the species of fungus, the animals produced significantly different numbers of eggs and had different life spans. In particular, animals fed with G. graminis var. tritici showed early maturation, early burst in egg production, early loss of fertility and early death. The different nutritional values of the four fungi pathogen for cereals might have a different influence on the life strategy of Collembola in the field. Thus, since these fungi usually coexist in agricultural soils, though in different percentages, this influence might also affect the capacity of different fungi to attack the plant and thus modulate the appearance of disease.     

Transformation and sorption of fipronil in urban stream sediments

Fipronil is an urban-use insecticide, and the increased use has led to its frequent detections in urban streams. Most studies on the environmental fate of fipronil so far have focused on soils, and little is known about its behavior in sediment-water systems. In this study, we investigated the transformation and sorption of fipronil in urban stream sediments from California, incubated under facultative and anaerobic conditions. Degradation of fipronil in sediments generally followed exponential decay kinetics, and the first-order half-lives of fipronil were only 4.6-18.5 days in anaerobic sediments. The persistence of fipronil under facultative conditions was considerably longer, with half-lives from 25 to 91 days. Sterilization generally decreased the dissipation of fipronil, indicating that microbial activity was an important factor in fipronil transformations in sediments. Under facultative conditions, fipronil sulfide and sulfone were observed, while only fipronil sulfide was detected in anaerobic samples. The sorption coefficient K d consistently increased with organic carbon contents of sediments. In the same sediment, K d usually also increased with contact time, suggesting decreased availability for aged residues. Results from this study showed that the stability of fipronil in sediments depends closely on the oxygen status and that due to the readily conversion of fipronil to the sulfone and sulfide metabolites, the overall risk assessment of fipronil in surface aquatic systems should take into consideration fipronil as well as its metabolites.     

Liquid chromatographic method for quantitation of glyphosate and metabolite residues in organic and mineral soils, stream sediments, and hardwood foliage

A liquid chromatographic method for determining glyphosate (GLYPH) and its major metabolite aminomethylphosphonic acid (AMPA) in various environmental substrates is described. Ion-exchange column chromatography is coupled with post-column ninhydrin derivatization and absorbance detection at 570 nm. Use of a valve-switching technique allowed quantitation of both analytes in a single chromatographic run and eliminated slow-eluting, coextracted interferences. The method was successfully used to quantitate GLYPH and AMPA in organic and mineral soils, stream sediments, and foliage of 2 hardwood brush species. Mean recovery efficiencies for GLYPH as determined from fortified blank field samples were as follows: bottom sediment 84%, suspended sediment 66%, organic soils 79%, mineral soils 73%, alder leaf litter 81%, salmonberry leaf litter 84%, and artificial deposit collectors 87%. Precision for GLYPH determination was good with less than 14% coefficient of variation on mean recovery for all substrates. Limits of detection were lowest for sediments (0.01 microgram/g dry mass) and highest for foliage substrates (0.10 microgram/g dry mass). Using this system, 6 samples/person/day were routinely analyzed.     

Solubility relationships of silica in soils

Abstract

Twenty‐one mineral soils of different physicochemical properties were used in this study. Soil suspensions, 30 grams of soil in 150 ml of distilled water, were shaken for 96 hours at 200 rpm and 25±1°C.

The activity of H₄SiO₄°, maintained in soil suspensions after shaking for 96 hours, was higher than quartz, cristobalite, and tridymite suggesting that comparatively more soluble forms of silica may be present in soils. All the soils, except Soil P and Soil Q, used in this study supported lower activity of Si than amorphous SiO₂. The average activity of H₄SiO₄° was 10^?3.08 M. It may be reasonable, for general purposes, to assume soil Si level as 10^?3.1 M. The activity of H₄SiO₄° found in soil suspensions was independent of soil pH. None of the selected physicochemical properties of soils was significantly correlated (at 5% significance level) to the activity of H₄SiO₄° in soil suspensions.     

The influence of particle size and mineralogy on both phosphorus retention and release by streambed sediments

Journal of Soils and Sediments - In many streams worldwide including those on the south coast of Western Australia (WA), sediments of the >?2-mm fraction often contribute up to 50% of...     

Extracellular enzyme activity within hyporheic sediments of a small lowland stream

The activity of extracellular α-glucosidase, β-glucosidase and β-xylosidase were measured in stream water, interstitial water and hyporheic sediments of a small lowland stream. Percent contribution of all the activity in the solution phase (<0.2 μm) to the total enzyme activity was low (15-40%), indicating that the enzyme activities are predominantly associated with bacterial cells. Generally, hyporheic sediments dominated the enzyme activity. Stream water, interstitial water and sediments showed activites that decreased in the order β-glucosidase>α-glucosidase>β-xylosidase. The fine fraction of the sediment (<0.063 mm) had much higher enzymatic activities than the coarser fraction (0.063-1 mm). All the extracellular enzymes, had higher activities during summer, period was attributed to the maximum input of allochthonous organic carbon into the sediments being at this time. A low ratio of α-glucosidase to β-glucosidase activity in the sediments, and no obvious spatial and seasonal changes in the ratio of β-xylosidase to β-glucosidase activity, suggested that cellulose is a predominant carbon source for hyporheic heterotrophic bacteria.     

Mercury in soils,sediments, and clams from a North Carolina peatland

Mercury concentrations were measured in samples of peat soils, sediments and clams (Rangia cuneata) from a peatland region of the Albemarle-Panlico Peninsula of North Carolina. Total Hg concentrations in peat cores ranged from 40 to 193 ng g^?1 (dw); no depth-related trends were noted. Mercury concentrations in surface sediments from canals draining the peatlands and from the Pungo River that receives this drainage ranged from 8 to 20 ng g^?1 (dw). Selective extractions of these peat and sediment samples revealed that the bulk of the Hg was associated with organic matter-associated fractions (particularly humic/fulvic acid bound and organic-sulfide bound fractions). No Hg was detected in the relatively mobile and bioavailable water-soluble or ion-exchangeable fractions. Total Hg concentrations in the soft tissues of clams from the Pungo River ranged from 25 to 32 ng g^?1 (ww). No concentrations of methyl Hg above the detection limit of a 25 ng g^?1 were measured in soils, sediments, or clams. These data indicate that Hg concentrations in this region are at the low end of the distribution of levels reported for uncontaminated systems and that mining of these peatlands is unlikely to significantly elevate Hg concentrations in the receiving estuarine system.     

Spatial distribution of sediments and transfer properties in soils in a stormwater infiltration basin

Purpose  

The aim of our study was to characterise the heterogeneity of sediment distribution in a stormwater retention/infiltration basin (Pont de Cheviré, Nantes, France) and to determine the impact of this distribution on water transfer properties in the soil.     

Distribution of mercury species in soil from a mercury-contaminated site

The distribution of mercury species was determined in soil from a site with Hg contamination. Mercury contamination was primarily confined to the top 40 cm of soil, and the concentration of total Hg ranged from 0.5 to 3000 µg Hg g^?1. Of total Hg present, we determined that 91% was inorganic, 0.01% organic (as methyl Hg), and 6% elemental Hg. Furthermore, of total inorganic Hg present, 85% was in the insoluble mercuric sulfide form. Thus, of total Hg present in soil at this contaminated site, 91% was in the relatively insoluble HgS and Hg⁰ forms.