Investigation of Harmattan particulates from Kano and Ife,Nigeria

The size distribution, elemental composition, shape and surface texture of harmattan particulates of distinctly located points have been examined. The characterized particle size ranges are 0.7–16.4 μm and 0.6–19.7 μm for Kano and Ife, respectively. A total of 12 elements (Al, Si, P, S, Cl, K, Ca, Mn, Ti, Fe, Cu, and Zn) were detected with varying degrees of concentration. The plotted element concentration curves favored micron and submicron particle diameters. The particle shapes exhibit high/low sphericity. The plotted size distribution curves exhibited a marked downward shift in particle diameter from Kano to Ife.     

Elemental characterization of airborne particulates at two Nigerian locations during the Harmattan season

Airborne particulate matter collected during the Harmattan season at Kano in the northern part, and Ile-Ife in the southern part of Nigeria was analyzed for about 30 elements by a combination of instrumental neutron activation analysis and X-ray fluorescence analysis. Although the total suspended particulate concentration (ng/m³) is much higher in Kano than Ife, the elemental composition at both locations is very similar and cluster analysis shows a strong correlation between the two, indicating a common origin for particulates. Particle-size distribution studies show that Kano dust is mainly coarse while Ife dust is mainly fine. The crustal-type elements are mainly concentrated in the coarse particles (3 m) at both locations while the conventional anthropogenic elements are hosted mainly by the fine particles (0.49 m and below).     

Characterisation of soot particulates from fire retarded and nanocomposite materials, and their toxicological impact

Polyamide 6 (PA 6) and polypropylene (PP) containing fire retardants, nanofillers or a combination of both additives have been investigated using the steady state tube furnace (ISO TS 19700). The samples were tested under three different fire conditions, to determine the effect of additives on the soot production or toxic product yields. The particle size distribution of the soot was investigated with a cascade impactor, and the separated soot fractions examined by SEM. The predicted deposition based on aerodynamic size of particulates in the human respiratory tract shows clear differences between the pure polymer and its additive counterparts. In all ventilation conditions the virgin polymer produces the least amount of soot, both the additives used (fire retardant and nanoclay) increase the amount of soot, mainly within 0.5-1.0 μm range, for each fire condition. A large contribution to the total soot mass originated particles smaller than 0.5 μm.     

Surface analysis of particulates from laboratory hood exhaust manifold

Particulate samples collected from a laboratory ventilation manifold during routine maintenance were analyzed to determine if particulate composition had changed as a result of changes in the laboratory's atmosphere. This ventilation manifold exhausts more than 100 fume hoods. The particulate samples were analyzed using static secondary ion mass spectrometry (SIMS). The negative SIMS spectra showed abundant Cl^?, NO₃^?, and HSO₄^?, consistent with the use of mineral acids in the laboratory. Cluster anions containing primarily Zn (but also other transition metals) were detected, which signaled corrosion of the manifold's galvanized steel by the volatilized acids. The most abundant ions in the cation SIMS spectra were derived from cyclohexylamine (CHA), which had been used as an antiscaling agent in the facility's boiler. Steam from the boiler, which contained CHA, was used to humidify the building air; this practice stopped in 1997. The abundances of the CHA‐derived ions were significantly lower in the samples collected in 2004 and 2006 than in the 1992 samples, indicating that the CHA is being slowly depleted. Changes in the relative abundances suggest exponential depletion from the manifold with rate constants that are on the order of 0.01 to 0.04 month^?1. Published in 2007 John Wiley & Sons, Ltd.     

Ecotoxicological characterisation of exhaust particulates from diesel-powered light-duty vehicles

Diesel exhaust is one of the major sources of fine and ultrafine particulate matter in urban air. Toxicity of diesel-powered engine emissions has been quite widely assessed, however, much less information is available on their ecotoxicity. In our study the kinetic version of the Vibrio fischeri bioluminescence inhibition bioassay, based on the ISO 21338:2010 standard, was used to characterise the ecotoxicity of diesel-powered cars. The method is sensitive enough to test the ecotoxic effect of the emission of individual vehicles. In general, significant positive correlation was found between ecotoxicity (expressed as Toxic Unit /TU/values) and total carbon (TC) as well as between TU and polycyclic aromatic hydrocarbon (PAH) concentrations.      

Bioaccumulation of organic micropollutants from sediments and suspended particulates by aquatic animals

Summary Non-polar organic micropollutants, such as polycyclic aromatic hydrocarbons, polychlorinated biphenyls and some pesticides, which are adsorbed to sediments have a low bioavailability to freshwater and marine animals. Bioaccumulation factors from sediments (concentration in animal/concentration in sediment) of the organic pollutants investigated range from less than 0.1 to about 20, several orders of magnitude lower than bioaccumulation factors from the water for the same compounds. Bioavailability of sediment-adsorbed organic micropollutants is directly related to the solubility of the compound and sediment grain size, and inversely related to sediment organic carbon concentration and animal size. Organic micropollutants adsorbed to sediments are only slightly bioavailable, but sediments in contaminated areas often contain high concentrations of adsorbed pollutants; therefore they represent an important source of contamination of freshwater and marine animals.

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Bioakkumulation organischer Mikro-Verunreinigungen in Seetieren aus Sedimenten und suspendierten Teilchen

Zusammenfassung Nicht-polare organische Verunreinigungen, wie polycyclische aromatische Kohlenwasserstoffe, polychlorierte Biphenyle und einige Pesticide, die an Sedimente adsorbiert sind, besitzen eine niedrige Bioverfügbarkeit für Süßwasser- und Seetiere. Die Bioakkumulationsfaktoren aus den Sedimenten (Konzentration im Tier/Konzentration im Sediment) reichen für die untersuchten Verunreinigungen von weniger als 0,1 bis etwa 20, d.h. mehrere Größenordnungen kleiner als die entsprechenden Faktoren aus Wasser. Die Bioverfügbarkeit der an Sediment adsorbierten Verunreinigungen steht im direkten Verhältnis zu der Löslichkeit der Betreffenden Verbindung und der Korngröße des Sediments, und ist umgekehrt proportional zu der Konzentration an organischem Kohlenstoff im Sediment und der Größe des Tieres. Die an Sediment adsorbierten Verunreinigungen sind nur gering bioverfügbar, die Sedimente in kontaminierten Gebieten enthalten aber oft hohe Konzentrationen an Verunreinigungen. Daher stellen die Sedimente eine bedeutende Verunreinigungsquelle für Süßwasser- und Meerestiere dar.

     

Recovery efficiency of 2,3,7,8-tetrachlorodibenzo-p-dioxin from active carbon and other particulates

The use of Amoco active carbon (grade PX-21) as a cleanup step for the determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in environmental samples was investigated. Benzene/toluene (1:1) removed 95% TCDD from Amoco active carbon dispersed in silica gel. Other solvents, including benzene, carbon disulfide, dichloromethane, acetone, hexane, acetone/hexane (1:1), and diethyl ether, did not remove TCDD from Amoco active carbon. o-Dichlorobenzene is needed to remove TCDD from Pittsburgh active carbon completely. Hot benzene with Soxhlet extraction is adequate for TCDD removal from soil and fly ash particulates. The results derived from this study are consistent with past and present analytical practice for isolating TCDD from different matrices.     

Elemental compositions of atmospheric particulates collected in Japan from 2002 to 2004

Chemical compositions of suspended particulate matter (SPM) in atmosphere collected at Hachioji and Sakata in Japan from 2002 to 2004 were determined by prompt gamma-ray analysis and instrumental neutron activation analysis. About 40 elemental concentrations in SPM could be determined, and enrichment factors and elemental correlations were examined. Several elements such as Cl, Cr, Ag, Sb, and W were largely different between Hachioji and Sakata, although their sources are not clear at present.     

Instrumental neutron activation analysis of limestone and associated calcite samples from Abakaliki,lower Benue Trough,Nigeria

Twenty four elements: Fe, Al, Ca, Mg, K, Na, Sc, Sr, Co, Cr, Zn, V, Hf, Ir, W, REE (La, Ce, Nd, Sm, Eu, Tb, Yb, Lu) and Th were determined in limestone and associated calcite from Abakaliki, South-Eastern Nigeria, by instrumental neutron activation analysis (INAA) technique. The USSG reference materials BCR-1 and AGV-1 were included in the analysis to assure quality control of the accumulated data. Hitherto, there is very little work of this type on the deposits in the region being studied. This study, therefore, provides baseline data for the deposit.     

The microdetection of particulates from organometallic compounds : I. Metal acetylacetonate chelates

The new technique of organic particulate analysis (OPA) has been employed to evaluate the thermal decomposition of metal acetylacetonate chelates. Of the 23 compounds thus evaluated, 13 were found to give organoparticulation signals at temperatures <190 °C as indicated by their effect on the output current of an ion chamber detector. In some instances, very strong particulation was observed, particularly with the transition metal acetylacetonates, such as Co(II), Co(III), Fe(III), Cr(III), and Mn(III).In an attempt to characterize the nature of the particulates derived from these compounds, mass-spectral data were obtained on the effluent species arising from the thermal decompositions of the strongest particulate emitting metal acetylacetonates. The results showed that acetylacetone was the major component identified in both particulate and vapor effluents. With the exception of Cr(III) acetylacetonate, no metal was detected in these effluents.The OPA technique enabled the relative thermal stabilities of the metal acetylacetonates to be ascertained. Zn acetylacetonate was found to have the lowest thermal stability and the alkaline earth compounds the highest; the transition metal acetylacetonates exhibit intermediate thermal stabilities.Since a certain critical minimum particulate size (i.e., 25 Å) seems to be necessary to produce a response on the ion chamber detector instrument, vapor-phase association of acetylacetone molecules may be occurring. This association would most probably occur through H-bonded species involving the enol form of the 1,3-diketone.     

Monitoring and statistical evaluation of heavy metals in airborne particulates in Cairo, Egypt

Airborne particulate material was monitored as total suspended particles and particulate matter less than 10 μm at selected sites in Cairo. The selected sites represent heavily industrial and industrial–residential areas of Cairo, Egypt. The filters were further analyzed for lead, cadmium, zinc and nickel using ion chromatography. The chosen method was modified to improve resolution and decrease the retention time. The data obtained were treated statistically using one-way analysis of variance and correlated with the anthropological and industrial activities of the sites. The concentrations of the heavy metals are studied in terms of particle size, time dependence, and safety.     

Macromolecular conjugate based particulates: Preparation, characterisation and evaluation of controlled release properties

A new particulate delivery matrix based on macromolecular conjugate, chitosan-whey protein isolate ([Ch-WPI]) was found to exhibit controlled release properties. Fourier-Transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) demonstrated the formation of the conjugate. Particle formation of the conjugate was carried out by the ionic crosslinking technique using sodium tripolyphospate (STP). Catechin entrapped particles were prepared by varying the weight ratios of STP to conjugate [Ch-WPI]. Both the placebo and catechin-entrapped particles were found to be positively charged below pH 7.2, indicating their stability to aggregation and their suitability for bioadhesion in the gastrointestinal tract (GIT). The entrapment efficiencies of the particles ranged between 29% and 42% for particles prepared using different weight ratios of the conjugate to STP. There was 34-56% of catechin release in simulated GIT conditions depending on the entrapment efficiencies and the degree of crosslinking of the particles.     

Instrumental neutron activation analysis of some rock samples from Akwana and Arufu areas,Middle Benue Trough,Nigeria

Twenty nine (29) major, minor and trace elements including rare earth elements (REEs) were determined by INAA in rock samples from Akwana and Arufu areas, Middle Benue Trough, Nigeria. The rock units are located within the lead-fluorite and baryte mineralisation there. The concentrations of the major elements in the tertiary basalt (TB) and dolerite are similar while the elemental abundance in the granite gnesses is completely different. The elemental concentrations in the rock samples do not show any known relationship with fluorite abundance. The concentrations of some elements in both tertiary basalt and dolerite show them to be derived from alkali basaltic liquid. The chondritic normalised REE distribution patterns for the TB are similar to those of BCR-1 but the chondritic relative REE abundance is more enriched in TB than in the BCR-1. The chondritic normalised REE distribution patterns for the granite gneisses are also compared to those of the standard granite samples.     

Extractability of dioxins from soil: I. Extractability of dioxins from airborne particulates and humic acid fraction in soil

The extractability of dioxins (polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls) from airborne particulates (APs) and humic acid (HA) in soil was evaluated. APs collected from ambient atmosphere and dioxins-associated precipitated HA fraction (PHA) were extracted by pressurized liquid extraction with either toluene or acetone. Native dioxins were equivalently extracted from APs with both solvents, whereas only acetone could satisfactorily recover the ¹³C-labelled compounds from metal-free PHA. The recovery rates of dioxins by toluene extraction from metal-free PHA varied with the organic carbon content of the PHA. However, even with acetone, the recovery of dioxins from metal-bound HA was poor (11–40%). These results suggest that PHA prevented the solvents from accessing sequestered dioxins. This characteristic of solid HA may influence the extractability of dioxins from humus-rich soil.     

The effect of inorganic particulates on the ASV signals of Cd, Pb and Cu

The potential influence of inorganic particulates on the ASV response of < 100-microg/l. levels of Cd, Pb and Cu, at a thin film mercury electrode, was examined by adding various weights of the solids to the acetate background electrolyte solution. Materials added included the hydrous oxides of Mn(IV), FE(III) or Al(III), clay minerals (kaolinite, illite, montmorillonite) and some contaminated sediments. Abrasion of the mercury film was minimized by deaerating the turbid solutions before their transfer to the measuring cell. The hydrous oxides specifically sorbed all three metal ions, resulting in peak-size changes that varied in magnitude with pH. With the clays, only sorption of Pb by illite or montmorillonite was detected. The presence of the solids had little effect on the peak position or half-peak breadth of the Cd or Pb signals, but the Cu peak parameters changed, indicating some hydroxy-species formation at higher pH. Some contaminated sediment samples released a significant fraction of their total metal content into acetate buffer solutions. Shielding the mercury film with a semipermeable membrane had a similar effect to filtering the suspension before analysis, but diffusion equilibrium was only slowly achieved (> 12 hr).     

Isolation and identification of mutagenic nitro-pah in diesel-exhaust particulates

More than 50 nitro-PAH have been tentatively identified in an extract of diesel-exhaust particulates. Identifications are based on high-resolution mass spectrometry of directly mutagenic fractions derived from sequential fractionation of the extract by both low- and high-resolution liquid chromatography. The diversity of nitro-PAH tentatively identified suggests that large numbers of such compounds are formed during or following the combustion process.     

Multielemental neutron activation analysis of fugitive dust particulates from cement factories in Central India

Knowledge of occurrence and concentration of trace elements in dust particulates from and around industrial establishments is essential to know the source of pollutants and atmosphere quality. Dust particulates from two cement factories in the central part of India were analyzed for 5 minor (Cl, Fe, K, Mg, Na) and 23 trace elements (Ag, As, Ba, Br, Cd, Co, Cr, Cs, Dy, Eu, Ga, Hf, Hg, La, Mn, Sb, Sc, Se, Sm, Sr, Th, W and Zn) by INAA and RNAA techniques. Significant differences have been observed for some toxic trace elements at different locations. Mn content is particularly high in all the dust particulates. Urban particulate (SRM 1648) and Coal fly ash (SRM 1633a) from NIST and Pond sediment (CRM No. 2) from NIES were also analyzed. The data have been analyzed and interpreted in terms of air quality at different locations inside the plant and two factories.