Determination of polynuclear aromatic hydrocarbons (PAHs) in selected water bodies in the Niger Delta

Several water bodies in the Niger Delta region of Nigeria where extensive crude oil production activities take place were analyzed for the presence of 16 US EPA priority polynuclear aromatic hydrocarbons(PAHs) namely: naphthalene, acenaphthylene, acenaphthene, fluorine, phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene,benzo(a)pyrene, benzo(ghi)perylene dibenz(a,h)anthracene and indeno(1,2,3-cd)pyrene. The concentrations ranged from as low as 1.95 ug/L for relatively clean stream with practically no crude oil activity to10.9 ug/L for the most polluted. The analysis was carried out using GC/MS. The quantitation was done by means of internal standardization using four isotopically labeled internal standards namelyacenaphthene-d10, chrysene-d12, phenanthrene-d10 and perylene-d12. High molecular mass PAHs such asbenzo(ghi)perylene, dibenz(a,h)anthracene and indeno(1,2,3-cd)pyrene were mostly absent confirming low water solubility of these compounds and carcinogenic PAHs were general lower in concentrationthan the non carcinogenic ones

Assessment of polynuclear aromatic hydrocarbon content in four species of fish in the Niger Delta by gas chromatography/mass spectrometry

Analysis for the presence of sixteen priority polynuclear aromatic hydrocarbons (PAHs) (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene,  benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene,dibenz[a, h]anthracene and indeno[1,2,3-cd]pyrene) was carried out on four different species of fish found in the Niger Delta region of Nigeria. The fish species included Parachanna obscura, Pseudolithuselongatus, Liza dumerillii and Clarais gariepinnus. Individual PAHs were identified through both retention time match with authentic standards and simultaneous maximization of several major ionsfrom gas chromatography/mass spectrometry (GC/MS) data. Four isotopically-labeled internal standards namely D10-acenaphtalene, D12-chrysene, D10-phenanthrene and D12-perylene, were usedfor quantitation. All four species of fish were found to contain high levels of PAHs ranging from 0.41 to 39.64 ug/kg. The high molecular weight PAHs such as benzo[ghi]perylene, dibenzo[a,h]anthracene andindeno[1,2,3-cd]pyrene were consistently present in much higher amount than other PAHs in all four species of fish studied, suggesting higher resistance of these compounds to degradation

Novel high-temperature, high-vacuum, all-metal sample cells for microcalorimetric measurements of solids

The design of a novel microcalorimetric sample cell which allows rapid transfer of heat from the sample to the cell wall is described. The solid sample is dispersed around the internal walls of the cell. Since the thermopiles of the microcalorimeter are in contact with the outer surface of the cell, the new design of the cell allows rapid recording of the heat generated by the sample. The robust all-metal cell allows in situ sample activation under conditions of high vacuum and at temperatures up to 500 °C. The dispersion of the sample avoids any “deep bed” effects where gas may not be able to diffuse freely to the surface of all of the sample, which may be the case when a thick layer or plug of the sample is used. The cell enables faster acquisition of heat data and minimizes effects of self-heating of the sample. A simple tool, which assists the introduction of the solid sample into the cell and a compact resistor-element, which fits inside the cell for calibration, are described

Water-management models in Florida from ERTS-1 data

The author has identified the following significant results. The usefullness of ERTS 1 to improving the overall effectiveness of collecting and disseminating data was evaluated. ERTS MSS imagery and in situ monitoring by DCS were used to evaluate their separate and combined capabilities. Twenty data collection platforms were established in southern Florida. Water level and rainfall measurements were collected and disseminated to users in less than 2 hours, a significant improvement over conventional techniques requiring 2 months. ERTS imagery was found to significantly enhance the utility of ground measurements. Water stage was correlated with water surface areas from imagery in order to obtain water stage-volume relations. Imagery provided an economical basis for extrapolating water parameters from the point samples to unsampled data and provided a synoptic view of water mass boundaries that no amount of ground sampling or monitoring could provide

Advantages of ERTS data collection system in south Florida

There are no author-identified significant results in this report

Calculation of accurate permanent dipole moments of the lowest 1,3Σ+^{1,3} \Sigma^+ states of heteronuclear alkali dimers using extended basis sets

The obtention of ultracold samples of dipolar molecules is a current challenge which requires an accurate knowledge of their electronic properties to guide the ongoing experiments. In this paper, we systematically investigate the ground state and the lowest triplet state of mixed alkali dimers (involving Li, Na, K, Rb, Cs) using a standard quantum chemistry approach based on pseudopotentials for atomic core representation, gaussian basis sets, and effective terms for core polarization effects. We emphasize on the convergence of the results for permanent dipole moments regarding the size of the gaussian basis set, and we discuss their predicted accuracy by comparing to other theoretical calculations or available experimental values. We also revisit the difficulty to compare computed potential curves among published papers, due to the differences in the modelization of core-core interaction.Comment: accepted to J. Chem. Phy

Acquisition and processing problem of ERTS data in south Florida

There are no author-identified significant results in this report

Surface water modeling Everglades Water Basin, Florida

There are no author-identified significant results in this report