Analysis of trace transition elements and heavy metals in fish otoliths as tracers of habitat use by American eels in the Hudson River estuary

Transition and heavy metals within the calcified otoliths of estuarine fishes may represent valuable tracers of environmental exposures, allowing inferences on natality, habitat use, and exposure to pollution. Accurate measurement of very low concentrations of these metals in otoliths by inductively coupled plasma mass spectrometry (ICP-MS) is often precluded by the interferences of predominant calcium matrix. We coupled a solid phase extraction procedure to an ICP-MS instrument to overcome the matrix problems and improve the limits of detection. To test this novel application and the utility of otolith transition and heavy metals as tracers of habitat use, otoliths of American eel (Anguilla rostrata) captured from 6 locations (George Washington Bridge, Haverstraw, Newburgh, Kingston, Athens, and Albany) throughout the Hudson River estuary were analyzed for site specific differences expected due to varying environmental exposure. Several trace elements, including Al, Bi, Cd, Co, Cu, Ga, Mn, Ni, Pb, V, and Zn, were selectively extracted from otolith solutions and preconcentrated on a microcolumn of chelating resin. The concentrations of all elements inA. rostrata otoliths were above the limits of detection that ranged from 0.2 ng g^?1 for Co to 7 ng g^?1 for Zn. Differences in the elemental composition of the otoliths among the groups were significant indicating different levels of exposure to environmental conditions. Discriminant analysis yielded an overall location classification rate of 78%. Al, Bi, Cd, Mn, Ni, and V contributed most to the discriminant function. Samples collected at George Washington Bridge showed 100% discrimination from other locations, and higher levels of many transition and heavy metals, consistent with higher exposure to these metals in the most polluted region of the Hudson River estuary.     

Petrological and source region characteristics of ophiolitic hornblende gabbros from the Aksaray and Kayseri regions, central Anatolian crystalline complex, Turkey

Many Neo-Tethyan ophiolitic bodies are well exposed as thrust-slices in Central Anatolia and are predominantly represented by massive hornblende gabbros, most of which are cut by Supra Subduction Zone (SSZ) plagiogranites. The allochthonous gabbros are distinct from their autochthonous counterparts, with their mineralogy including both igneous hornblende, relict diopside rimmed by replacement hornblende and their chemical composition corresponding mostly to gabbro rather than diorite.The results of major and trace element analyses of forty-two samples, and REE analyses of nine samples, indicate that the hornblende gabbros are SSZ-type and formed from a wet magma by high-degree partial melting of peridotite possibly coupled with contamination by predominantly neighbouring-slab derived fluids within an intra-oceanic back-arc basin. The mafic magmas then underwent high-level fractional crystallization involving titaniferous magnetite, diopside, tschermakite and possibly olivine. Emplacement was followed by extensive ocean–floor metamorphism, which has induced crystallization (or recrystallization) of chlorite, biotite, amphiboles and mobilisation of most of the major elements such as alkali and alkali earth elements, and some LREE.     

Ar/Ar age and geochemistry of the post-collisional Miocene Yamadağ volcanics in the Arapkir area (Malatya Province), eastern Anatolia, Turkey

The Neogene Yamadağ volcanics occupy a vast area between Sivas and Malatya in eastern Anatolia, Turkey. These volcanic rocks are characterized by pyroclastics comprising agglomerates, tuffs and some small outcrops of basaltic–andesitic–dacitic rocks, overlain upward by basaltic and dacitic rocks, and finally by basaltic lava flows in the Arapkir area, northern Malatya Province. The basaltic lava flows in the Arapkir area yield a ⁴⁰Ar/³⁹Ar age of 15.8 ± 0.2 Ma, whereas the dacitic lava flows give ⁴⁰Ar/³⁹Ar ages ranging from 17.6 through 14.7 ± 0.1 to 12.2 ± 0.2 Ma, corresponding to the Middle Miocene. These volcanic rocks have subalkaline basaltic, basaltic andesitic; alkaline basaltic trachyandesitic and dacitic chemical compositions. Some special textures, such as spongy-cellular, sieve and embayed textures; oscillatory zoning and glass inclusions in plagioclase phenocrysts; ghost amphiboles and fresh biotite flakes are attributable to disequilibrium crystallization related to magma mixing between coeval magmas. The main solidification processes consist of fractional crystallization and magma mixing which were operative during the soldification of these volcanic rocks. The dacitic rocks are enriched in LILE, LREE and Th, U type HFSE relative to the basaltic rocks. The basaltic rocks also show some marked differences in terms of trace-element and REE geochemistry; namely, the alkaline basaltic trachyandesites have pronounced higher HFSE, MREE and HREE contents relative to the subalkaline basalts. Trace and REE geochemical data reveal the existence of three distinct magma sources – one subalkaline basaltic trachyandesitic, one alkaline basaltic and one dacitic – in the genesis of the Yamadağ volcanics in the Arapkir region. The subalkaline basaltic and alkaline basaltic trachyandesitic magmas were derived from an E-MORB type enriched mantle source with a relatively high- and low-degree partial melting, respectively. The magmatic melt of dacitic rocks seem to be derived from an OIB-type enriched lithospheric mantle with a low proportion of partial melting. The enriched lithospheric mantle source reflect the metasomatism induced by earlier subduction-derived fluids. All these coeval magmas were generated in a post-collisional extensional geodynamic setting in Eastern Anatolia, Turkey.     

The distribution and elevated solubility of lead,arsenic and cesium in contaminated paddy soil enhanced with the electrokinetic field

The objectives of this study were to investigate fractionation, solubility and potential bioavailability of Pb, As and Cs in Mississippi River Delta paddy soil under an electrokinetic field (EKF). Effects of EKF on soil pH changes and solid-phase distributions of metal(loid)s were examined. Results showed that fractionation of Pb, As and Cs was largely determined by the nature of elements, loading levels and EKF treatment. Native Pb in the soil was mostly in the amorphous iron oxide, organic matter and residual fractions, native As in the amorphous iron oxide, easily reducible oxide and residue fractions while native Cs in the residue fraction. Added Pb, As and Cs showed distinguished solid-phase distributions: Pb dominantly in the organic matter fraction; As in the amorphous iron oxide fraction, and Cs in the residue with a significant water-soluble plus exchangeable fraction. EKF treatment is effective on lowering soil pH to 1.5 near the anode due to water electrolysis releasing proton which is beneficial for dissolution of metal(loid)s, increasing their overall solubility. The acidification in the anode soil efficiently increased the water-soluble Pb and the exchangeable Cs, implying enhanced solubility and elevated their overall potential bioavailability in the anode region while lower solubility in the cathode area. The building up of water-soluble As in the anode region may be from electromigration of As anion from the cathode. This study shows significant enhancement of redistribution, elevated solubility and overall bioavailability of Pb, As and Cs in Mississippi Delta paddy soil under the EKF.     

A comparative study on linear and nonlinear site response analysis

Site response analysis is usually the first step of any seismic soil-structure study. Geotechnical earthquake engineers and engineering geologist have been trying to find both practical and most appropriate solution techniques for ground response analysis under earthquake loadings. The paper attempts to give a critical overview of the field of site response analysis. In this paper, the influences of nonlinearity on the site response analysis summarized and were evaluated with a numerical example. Site response of a two layered soil deposit with the assumption of linear and rigid base bedrock (or viscoelastic half-space) was analyzed by using linear and nonlinear approaches. The amplification spectrum of the soil column is computed between the top and the bottom of this soil deposit. Nonlinear analysis was compared with the linear method of analysis. Steps involved in ground response analyses to develop site-specific response spectra at a soil site are briefly summarized. Some of the well-known site response analysis methods are summarized and similarities and differences between linear and nonlinear methods are compared by a numerical example.     

Seismotectonic database of Turkey

Turkey is located in one of the most seismically active regions in the world. Characterizing seismic source zones in this region requires evaluation and integration of geological, geophysical, seismological and geodetical data. This first seismotectonic database for Turkey presented herein was prepared, under the framework of the National Earthquake Strategy and Action Plan—2023. The geographic information system (GIS)-based database includes maps of active faults, catalogues of instrumental and historical earthquakes, moment tensor solutions and data on crustal thickness. On the basis of these data, 18 major seismotectonic zones were delineated for Turkey and the surrounding region. The compilation and storage of the seismotectonic data sets in a digital GIS will allow analyses and systematic updates as new data accrete over time.     

Application of Mineral‐Based Amendments for Enhancing Phytostabilization in Lolium perenne L. Cultivation

An experimental investigation is conducted to explore the suitability of Lolium perenne L., diatomite, chalcedonite, dolomite, and limestone for the phytostabilization of Ni and Cu in contaminated soil. A controlled greenhouse study is conducted. The soil is enriched with rising dose of Cu and Ni, that is, (0, 150, 250, and 350 mg kg^?1) and (0, 150, 300, and 450 mg kg^?1), respectively. The phytostabilization potential of perennial ryegrass is evaluated using a bioaccumulation coefficient and translocation factor. Pseudo‐total and available metal content (0.01 M CaCl₂) in soils and bioaccumulated content in plants are defined in laboratory experiments using spectrophotometry experimental technique. L. perenne is adequate in phytostabilization aided programs, simultaneously, diatomite, chalcedonite, dolomite, and limestone used as modifiers are effective in reducing the accessibility and mobility of metals in Cu‐ and Ni‐polluted soils. The finding of the present study suggests that the studied element in the roots and above‐ground parts of L. perenne differs significantly upon applying mineral‐based modifications to the soil, synchronously the effect of increasing Cu and Ni levels. Application of dolomite and limestone to the soil cause the highest percentage of the above‐ground biomass. Diatomite along with limestone cause a significant boost of Cu and Ni absorption in the roots. Limestone causes an increase in the contents of K, Na, and Ca, as well as a reduction in P in the above‐ground parts of L. perenne. Limestone and chalcedonite leads to the highest decrease in available Cu and Ni.