Environmental Geology

Speciation of Arsenic, Chromium, and Vanadium in Red Mud Samples from the Ajka Spill Site, Hungary

by William Mayes

Burke, I.T., Mayes, W.M., Peacock, C.L., Brown, A.P., Jarvis, A.P., Gruiz, K. (2012) Speciation of arsenic, chromium and vanadium in red mud samples from the Ajka spill site, Hungary. Environmental Science and Technology. doi: 10.1021/es3003475.

Results are presented from X-ray absorption spectroscopy based analysis of As, Cr and V speciation within samples of... more Results are presented from X-ray absorption spectroscopy based analysis of As, Cr and V speciation within samples of bauxite ore processing residue (red mud) collected from the spill site at Ajka, Western Hungary. Cr K-edge XANES analysis found that Cr is present as Cr3+ substituted into hematite, consistent with TEM analysis. V K-edge XANES spectra have E½ position and pre-edge features consistent with the presence of V5+ species, possibly associated with Ca-aluminosilicate phases. As K-edge XANES spectra identified As present as As5+. EXAFS analysis reveals arsenate phases in red mud samples. When alkaline leachate from the spill site is neutralised with HCl, 94 % As and 71 % V is removed from solution during the formation of amorphous Al-oxyhydroxide. EXAFS analysis of As in this precipitate reveals the presence of arsenate Al-oxyhydroxide surface complexes. These results suggest that in the circumneutral pH, oxic conditions found in the Torna and Upper Marcal catchments, incorporation and sorption respectively will restrict the environmental mobility of Cr and As. V is inefficiently removed from solution by neutralisation, therefore, the red mud may act as a source of mobile V5+ where the red mud deposits are not removed from affected land.

Pleistocene palaeoecology and environmental change on the Darling Downs, southeastern Queensland, Australia

by Gilbert Price

Price, G.J., Sobbe, I.H., 2005. Pleistocene palaeoecology and environmental change on the Darling Downs, southeastern Queensland, Australia. Memoirs of the Queensland Museum 51, 171-201.

A diverse Pleistocene fossil assemblage was recovered from a site (QML1396) exposed in the southern banks of Kings... more A diverse Pleistocene fossil assemblage was recovered from a site (QML1396) exposed in the southern banks of Kings Creek, Darling Downs, southeastern Queensland. The site includes both high-energy lateral channel deposits and low-energy vertical accretion deposits. The basal fossil-bearing unit is laterally extensive, fines upward and its geometry and sedimentary structures suggest deposition within a main channel. The coarse channel fill passes upward into overbank levee deposits made up of lenticular sandy-shelly strata alternating with muds. Several taphonomic biases relating to preservation of different faunal groups and skeletal elements was discerned. Biases may be related to fluvial sorting of the assemblage, but causes for differences between the preservation and accumulation of mammal versus non-mammal terrestrial vertebrates remain unclear. In general, the vertebrate material was accumulated and transported into the deposit from the surrounding proximal floodplain. The assemblage is composed of 44 species including molluscs, teleosts, anurans, chelids, squamates, and small and large-sized mammals. Palaeoenvironmental analysis suggests that a mosaic of habitats, including vine thickets, scrublands, open sclerophyllous woodlands interspersed with sparse grassy understories, and open grasslands, were present on the floodplain during the late Pleistocene. From sedimentological and ecological data, it is evident that increasing aridity during the late Pleistocene led to woodland and vine thicket habitat contraction, and grassland expansion on the floodplain. At present, there is no evidence to support the suggestion that the retraction of late Pleistocene Darling Downs habitats was due to anthropogenic factors.

Evidence for bias in C/N, δ13C and δ15N values of bulk organic matter, and on environmental interpretation, from a lake sedimentary sequence by pre-analysis acid treatment methods.

by Chris Brodie

In Press - Quaternary Science Reviews

Lead Author: Dr. Chris Brodie (Hong Kong University, Hong Kong)

Co-Authors: Dr. James Casford (Durham University); Dr. Jeremy Lloyd (Durham University, UK); Prof. Melanie Leng (NIGL, UK); Dr. Timothy Heaton (NIGL, UK); Christopher Kendrick (NIGL, UK); Dr. Zong Yongqiang (Hong Kong University, Hong Kong).

ABSTRACT:
There is a known bias in C/N, d13C and d15N values of organic matter (OM) due to pre-analysis acid... more ABSTRACT:
There is a known bias in C/N, d13C and d15N values of organic matter (OM) due to pre-analysis acid treatment methods. We report here, for the first time, the results of a pre-analysis acid treatment method comparison of measured C/N, d13C and d15N values in bulk OM from a sedimentary sequence of samples to illustrate this bias. Here we show that acid treatment significantly reduces the accuracy (between method biases) and precision (within method bias) of C/N, d13C and d15N values of OM, suggesting a differential response of sample OM between methods and sample horizons, and in some cases inefficient removal of inorganic carbon. We show that different methods can significantly influence environmental interpretation in some of our sample horizons (i.e. interpretation of aquatic vs. terrestrial OM source; C3 vs. C4 vegetation). Specifically, there are unpredictable and non-linear differences between methods for C/N values in the range of ~ 1 – 100; d13C values in the range of 0.2 – 6.8 ‰ and; d15Nvalues in the range of 0.3 – 0.7 ‰. Importantly, these ranges are mostly much greater than the instrument precision (defined as the standard deviation of replicate analysis of standard reference materials; for this study, ± 0.5 for C/N values, ± 0.1 ‰ for d13C values and; ± 0.1 ‰ for d15N). The accuracy and precision of measured C/N, d13C and d15N values of bulk OM is not just dependent upon environmental variability, but on acid pre-treatment, residual inorganic carbon and organic matter state and composition. Collectively, this makes the correlation between samples prepared in different ways, including those from down core reconstructions, highly questionable.

Keywords: C/N ratios, δ13C, δ15N, organic matter; pre-analysis acid treatment methods, environmental interpretation, palaeoclimate.

Assessment of NO 3− Contamination In a Karstic Aquifer, With the Use of Geochemical Data and Spatial Analysis

by Evangelos Tziritis

Kopaida plain is a cultivated region of Eastern Greece, with specific characteristic related with the paleogeographic... more Kopaida plain is a cultivated region of Eastern Greece, with specific characteristic related with the paleogeographic evolution and the changes in land use. The present article examines the contamination that derives from nitrates, in terms of contaminant levels, definition of sources and spatial distribution of contaminant plume. For this purpose, 50 water samples were collected from the karstic aquifer and analyzed for 15 parameters including major ions, trace elements, physicochemical parameters, and stable isotopes. The assessment of the above parameter values along with the notes derived by the statistical process revealed the existence of nitrate contamination which has been spatial defined with the aid of spatial interpolation techniques. The correlation of NO3 − concentrations with the stable isotope values, defined the infiltration conditions and showed contaminant transport. Nitrate values revealed the potential environmental threat for local people, as 10% of the samples exceeded the parametric value of 50 ppm and 54% of them are above 25 ppm, indicating no optimal quality conditions. The origin of nitrate contamination seems to derive exclusively from the application of N-fertilizers, since the rest of potential sources were not verified by analytical data and field works.

Hydrogeochemical conditions and groundwater quality in the SE part of Samos Island, Greece

by Evangelos Tziritis

Pb, Cr, Ni and Cd contamination in Hand pump and Tap water of Mardan District

by Wajid Ali

principal author, published in The Environ Monitor, 2009 vol. IX (11-12)

This study was conducted in order to ascertain the present status of heavy metals in Hand pumps and tap water of more This study was conducted in order to ascertain the present status of heavy metals in Hand pumps and tap water of
Mardan District. A total of eight heavy metals (Fe, Zn, Cu, Mn, Pb, Cr, Cd, and Ni) were investigated in hand pump
and tap water samples collected in the study area. Atomic Absorption Spectrometry was used to determine the heavy
metals. Fe, Zn and Cu levels were within the permissible limits, while Pb, Cr, Cd and Ni levels in the study area
exceeded the WHO permissible limits. The high concentration of heavy metals in the drinking water can be
attributed to the corrosiveness and aggressiveness of the water in the study area.Keywords: Mardan City, Drinking Water, Contamination, Stability Index, Plumbosolvency.

Application of the chlorine-36 Method for the characterization of the groundwater circulation in tectonically active areas: Examples from northwestern Anatolia/Turkey

by Werner Balderer

Co-author: H. A. Synal

Publications

by Werner Balderer