Contamination of tsunami sediments in a coastal zone inundated by the 26 December 2004 tsunami in Thailand

Tsunami sediments deposited in a coastal zone of Thailand by the 26 December 2004 tsunami wave were sampled within 50 days after the event. All surface and ground waters in tsunami- inundated zone revealed significant salinity at that time. The tsunami sediments, composed mainly of fine to medium sand, contain significantly elevated contents of salts (Na⁺, K⁺, Ca⁺², Mg⁺², Cl and SO ₄ ⁻² ) in water-soluble fraction, and of Cd, Cu, Zn, Pb in the bioavailable fraction and As in the exchangeable fraction in relation to the reference sample. The origin of contaminants is marine, as well as litho- and anthropogenic. The salts and Pb, Zn and Cu reveal high correlation to each other and to the mean grain size (pore size and porosity). Serious environmental hazard exists in that region because, due to gentle morphology, there is a risk of migration of the contaminants into ground waters and food chain.     

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Application of the Mussel Watch concept in studies of the distribution of hydrocarbons in the coastal zone of the Ebro Delta

The Mussel Watch concept was applied in a study of man-induced chemical changes in the Ebro Delta on the Catalonian coast to obtain a preliminary assessment of the distribution of synthetic organic compounds, petroleum and biogenic hydrocarbons in the local coastal zone. Mussels, oysters and clams were selected as the indicator organisms. Levels of petroleum accumulated by mussels were generally high, in the order of 100–800 μg^?1 dry weight, equivalent to those in mussels in the most polluted harbours and bays of California. The relative distributions of the steranes and pentacyclic triterpanes in the mussels were significantly different from those found in petroleum from a local field, indicating that local petroleum was not contributing to the present contamination. The composition of biogenic compounds was variable, probably reflecting differences in the composition of local plankton communities, PCB levels were high in relation to current levels in mussels from US sites, reflecting continuing PCB use in Spain. The Delta appears to be a point source of a number of organochlorine compounds, including HCB, the DDT compounds, endrin and γ-chlordane. Levels of the DDT compound o,p′-DDD, a pharmacologically active substance, were unexpectedly high; identification was confirmed by GS/MS. Many unidentified peaks were present on EC chromatograms, indicating a more complex pattern of contamination than might be suggested by printed summaries of data.     

Chemistry of Neutral and Alkaline Waters with Low Al<Superscript>3+</Superscript> Activity Against Hydroxyaluminosilicate HAS<Subscript>B</Subscript> Solubility. The Evidence from Ground and Surface Waters of the Sudetes Mts. (SW Poland)

A wide set of aqueous chemistry data (574 water analyses) from natural environments has been used to testify and validate of the solubility of synthetic hydroxyaluminosilicate (HAS_B)_, Al₂Si₂O₅(OH)₄. The ground and surface waters represent regolith and/or fissure aquifers in various (magmatic, sedimentary and metamorphic) bedrocks in the Sudetes Mts. (SW Poland). The solubility of HAS_B in natural waters was calculated using the method proposed by Schneider et al. (Polyhedron 23:3185–3191, 2004). Results confirm usefulness and validity of this method. The HAS_B solubility obtained from the field data (logK_sp = −44.7 ± 0.58) is lower than it was estimated (logK_sp = −40.6 ± 0.15) experimentally (Schneider et al. Polyhedron 23:3185–3191, 2004). In the waters studied the equilibrium with HAS_B is maintained at pH above 6.7 and at [Al³⁺] ≤ 10⁻¹⁰. Silicon activity (log[H₄SiO₄]) ranges between −4.2 and −3.4. Due to the calculation method used, the K_sp mentioned above cannot be considered as a classical solubility constant. However, it can be used in the interpretation of aluminium solubility in natural waters. The HAS_B has solubility lower than amorphous Al(OH)₃, and higher than proto-imogolite. From water samples that are in equilibrium with respect to HAS_B, the solubility product described by the reaction, is calculated to be logK_sp = 14.0 (±0.7) at 7°C.     

A parallel GPU-based approach for reporting flock patterns

Data analysis and knowledge discovery in trajectory databases is an emerging field with a growing number of applications such as managing traffic, planning tourism infrastructures or better understanding wildlife. In this paper, we study the problem of finding flock patterns in trajectory databases. A flock refers to a large enough subset of entities that move close to each other for, at least, a given time interval. We present parallel algorithms, to be run on a Graphics Processing Unit, for reporting three different variants of the flock pattern: (1) all maximal flocks, (2) the largest flock and (3) the longest flock. We also provide their complexity analysis together with experimental results showing the efficiency and scalability of our approach.     

Housing inequalities in Bucharest: shallow changes in hesitant transition

Much has been said, yet little remains known, about the impacts of the changes associated with post-socialist transition on housing inequalities in metropolitan Central and Eastern Europe. To some extent, this depends on the scarcity of ‘hard evidence’ about the socialist epoch against which the subsequent developments may be gauged. Based on a case study of Bucharest, the Romanian capital and one of the region’s major cities, this study investigates various lines of housing inequality using data from a 20 % sample of the national censuses of 1992 and 2002. With only minor changes having taken place since the revolutionary events of late 1989, the year 1992 provides an accurate picture of the housing inequalities inherited from the socialist epoch, whereas the new societal order had largely been established by 2002. We use linear regression and binary logistic regression modeling to identify the factors that predict living space and level of facilities. The results suggest that the first decade of transition did not exert any major influences on the housing inequalities inherited from socialism, with the exception of notable improvements at the very top of the social pyramid. This finding is at odds with the literature that highlights the (suggested) effects of socio-economic polarization on the residential structure of cities after socialism. However, the results from 1992 indicate that housing was segmented along socio-economic lines already under socialism, and perhaps more so than one would have expected in the light of the literature on housing inequalities during this period.     

Mineralizing fluids of the shallow epithermal Au–Ag deposits of the El Barqueño district, Jalisco, Mexico

La composición de elementos trazas y de isótopos de las secuencias magmáticas del terciario inferior en dos localidades de la Sierra Madre Occidental al norte de México, muestran una variación que manifiesta la composición y la edad del basamento por el cual fueron eyectadas. La corteza subyaciente en San Buenaventura corresponde a la parte asociada al basamento Norte Americano, en cambio en El Divisadero, la corteza subyaciente correspondería a los terranos alocthonos acrecionados durante el Mesozoico.En estas localidades las rocas volcánicas aparecen fuertemente diferenciadas, variando en su composición de basáltica a riolítica (SiO₂=50–76%). Las secuencias erupcionadas en los terranos de acreción presentan la más baja dispersión en su cociente isotópico, con un cociente mínimo inicial de Sr (>0.7044, corregido por la edad), y máximo de Nd (<0.5126) y de Pb (²⁰⁶Pb/²⁰⁴Pb 18.9).Los cocientes isotópicos correspondientes a la serie continental presentan una dispersión variable y una distribución fuera de la serie de los terranos hacia la composición más típica de la corteza antigua (⁸⁷Sr/⁸⁶Sr 0.710 y ¹⁴³Nd/¹⁴⁴Nd 0.5123). Las rocas volcánicas de la zona continental, muestran valores relativamente altos en elementos incompatibles en comparación con las rocas de los terranos acrecionados (Ce/Yb=25–45 vs. 13–33, respectivamente), y al mismo tiempo están empobrecidos en algunos elementos incompatibles como U y Rb (p.e. Th/U=3.8–7.5 vs. 2.5–4.0, respectivamente), lo cual indica una posición estratigráfica superior, con cocientes de ⁸⁷Sr/⁸⁶Sr, ²⁰⁸Pb/²⁰⁴Pb, y Th/U más altos, y ¹⁴³Nd/¹⁴⁴Nd más bajos.Los resultados tienen implicaciones sobre la composición original y la petrogénesis de las rocas volcánicas. Los cocientes isotópicos de los dos lugares revelan una composición que se sitúa entre las rocas de composición máfica de la Sierra Madre Occidental y los xenolithos intermediarios y félsicos característicos del norte de México o del sud-oeste de los Estados Unidos de América. La relación entre los cocientes isotópicos de las secuencias y la edad del basamento, así como el hecho de que la totalidad de los resultados obtenidos presenten una disposición bien definida, demuestran la fuerte contribución de la corteza en la química de los magmas silicatados. En la serie continental los cocientes de isótopos covarían con los cocientes de Th/Pb y U/Pb, aproximándose a la composición observada en los xenolithos intermediarios y en las rocas de composicion félsica. Esto indica claramente que no se trata de una fusión anatéxica de la corteza inferior, sino más bien de una interacción del magma basáltico del manto y la corteza. La contribución de la corteza es del orden de 20–70%. La estrecha variación del cociente isotópico en la zona de la secuencia de terranos acrecionados refleja la interacción del magma basáltico con una corteza relativamente joven, cuya composición isotópica es similar a los magmas derivados del manto. Los altos cocientes de Th/U y de Th/Rb indican que la contaminación de la corteza tiene lugar en su parte inferior. Además, los cocientes menos radiogénicos de ²⁰⁶Pb/²⁰⁴Pb y ²⁰⁷Pb/²⁰⁴Pb en la serie continental indican que el empobrecimiento de elementos fuertemente incompatibles en la corteza inferior corresponde a un rasgo antiguo. Los cambios seculares de los cocientes isotópicos de la sección estratigráfica indica que la contribución de la corteza superior aumenta con el tiempo, predominando al principio una corteza inferior máfica y, más tarde, una corteza intermediaria de rocas félsicas. Analizando rocas volcánicas externas a las dos secciones fuertemente muestreadas, las diferencias obtenidas en su composición isotópica de las rocas volcánicas, los terranos acrecionados y el basamento antiguo permiten deducir la localización del límite corteza continental-corteza oceánica.