Determination of thorium concentrations in soil and sand samples using instrumental neutron activation analysis

Thorium along with its daughter products present in the soil is one of the major contributors to the external gamma dose in the environment. To establish the dose levels, quantification of thorium contents in soil samples is very important. As a part of pre-operational environmental radiological surveillance, a total of 23 soil and six sand samples were collected from different locations around the proposed nuclear power plant site of Jaitapur, Maharashtra. Thorium concentrations in these samples were determined by instrumental neutron activation analysis (INAA). Samples were irradiated with neutrons in Apsara reactor at a neutron flux of?~5?×?10¹¹ cm^?2 s^?1 and radioactive assay was carried out using high resolution gamma ray spectrometry. Relative method of INAA was used for quantification of thorium utilizing 311.9?keV gamma ray of ²³³Pa, the daughter product of ²³³Th. The concentrations of thorium in the soil and sand samples were in the ranges of 4.0?C18.8 and 1.2?C6.2?mg?kg^?1 respectively.     

Experimental assessment of a large sample cell for laser ablation-ICP-MS, and its application to sediment core micro-analysis

The coupling of laser ablation (LA) to inductively coupled plasma-mass spectrometry (ICP-MS) enables the direct analysis of solid samples with micrometric resolution. Analysis is often restricted to relatively small samples owing to the dimensions of conventional ablation cells. Here, we assess the performance of a large rectangular, commercially-available sample cell which enables analysis over a 10.2?×?5.2 cm² area. Comparison with the conventional cell shows a small to moderate performance decrease for the large cell resulting from the dilution of ablated particles in a larger volume with a 4–31% lower signal output and longer signal tailings. The performance of this cell is however sufficient for the determination of both major and trace elements in many kinds of samples. The applicability of the large cell LA-ICP-MS setup was demonstrated by the determination of Al, Si, Mn, Fe, Cu, Zn Pb and U in sediment core sections at a resolution of 0.6 mm. Detection limits for sediment analysis were 7 mg Al kg^?1, 68 mg Si kg^?1, 0.5 mg Mn kg^?1, 20 mg Fe kg^?1, 0.2 mg Cu kg^?1, 0.3 mg Zn kg^?1, 0.08 mg Pb kg^?1 and 0.003 mg U kg^?1. Cyclic patterns, which would have been overlooked by conventional analysis at cm resolution, were observed in analysed sediments. This study demonstrates the potential of LA-ICP-MS in environmental analysis, with the large sample cell setup offering the possibility to analyse a wider range of samples without sectioning.     

Quantitative Speciation of Arsenic in Water and Sediment Samples from the Mokolo River in Limpopo Province,South Africa

The Mokolo River is disposed to environmental contaminants such as arsenic (As) due to its proximity to several anthropogenic activities. Speciation of As in water and sediment samples from Mokolo River is crucial to evaluate the level and distribution of As in the river and underlying sediment since toxicity depends on its chemical forms. In this study, As species in water and sediment were determined by developing a new method for sediment extraction. Effective microwave-assisted extraction of As species in sediment samples was achieved using 0.3?M (NH₄)₂HPO₄ and 50?mM EDTA, which showed no species interconversion during extraction. The chromatographic separation and detection of As(III), dimethylarsinic acid (DMA), monomethylarsonic acid, and As(V) in water and sediment samples were achieved by coupling to high-performance liquid chromatography to inductively coupled plasma mass spectrometry. Baseline separation of four As species was achieved in 12?min using gradient elution with 10 and 60?mM NH₄NO₃ at pH 8.7 as the mobile phase. The analytical figures of merit and validation of analytical procedures were assessed and adequate performance and percentage recoveries ranging from 81.1 to 102% for water samples and 73.0–92.0% for sediments were achieved. The As species concentration in water and sediment samples was found to be in the range of 0.304–4.99?µg?L^?1 and 74.0–92.0?ng?g^?1, respectively. DMA was not detected in both water and sediment samples.     

Analysis of tributyltin in estuarine sediments and oyster tissue,Crassostrea virginica

An analytical method to determine tributyltin (TBT) in oyster tissue, Crassostrea virginica, and estuarine sediments is described. Recoveries of TBT from oysters range from 86 to 102% when samples are fortified at concentrations ranging from 22 to 890 μg kg^?1 (wet weight); recoveries from sediment range from 92 to 105% for samples fortified from 20 to 500 μg kg^?1 (dry weight). Feral oysters and natural sediments were analysed and shown to be contaminated with TBT. Oysters collected near a marina contained concentrations as high as 1.5 mg kg^?1 (wet weight).     

Rare earth element (REE) in surface mangrove sediment by instrumental neutron activation analysis

A study is carried out on the concentrations of rare earth element (REE) elements present in surface mangrove sediments from 10 locations throughout west coast Malaysia. In carrying out the analysis, the best and most convenient method being the instrumental neutron activation analysis (INAA). Samples were obtained, dried, crushed to powdery form and samples prepared for INAA. All the samples for analysis were weighted approximately 150 mg for short irradiation and 200 mg for long irradiation time. As calibration and quality control procedures, blank samples, standard reference material SL-1 were then irradiated with thermal neutron flux of 4 × 10¹² cm^?2 s^?1 at the MINT TRIGA Mark II research reactor which operated at 750 kW by using a pneumatic transport facility. The REE elements of surface sediment samples in this study are Dy, Sm, Eu,Yb, Lu, Tb, La and Ce. It was found that the level of concentrations of all the REE elements varies in the range (0.35–117.4 mg/kg). The geochemical behavior of REEs in surface sediments and normalized pattern (chondrite and shale) has been studied. The degree of sediments contaminations were computed using an enrichment factor. The results showed that the enrichment factor varied in the range (0.75–6.75).     

Element geochemistry of Holocene sediment and paleoenvironmental change in the Changjiang Estuary

Analyses of 41 elements reveal that Holocene sediments in the Changjiang Estuary bear regular elemental compositions in different sedimentary environments, and Holocene sediments came mainly from the Changjiang River based on compositions of REEs and most trace elements. Some heavy metals are more enriched in the surface sediment than in the deltaic sediments, reflecting human impact. Elemental compositions of the river channel sediment are related to the influence of proximal sediments. Sedimentary environments exert some influences on elemental compositions. Some chemical indices can be used to record chemical weathering undergone by the Changjiang sediment and environmental change.     

Element geochemistry of Holocene sediment and paleoenvironmental change in the Changjiang Estuary

Analyses of 41 elements reveal that Holocene sediments In the Changjiang Estuary bear regular elemental compositions in different sedimentary environments, and Holocene sediments came mainly from the Changjiang River based on compositions of REEs and most trace elements. Some heavy metals are more enriched in the surface sediment than in the deltaic sediments, reflecting human impact. Elemental compositions of the river channel sediment are related to the influence of proximal sediments. Sedimentary environments exert some influences on elemental compositions. Some chemical indices can be used to record chemical weathering undergone by the Changjiang sediment and environmental change.     

Multielement Analysis of South Serbian Strawberry Cultivars by Inductively Coupled Plasma—Optical Emission Spectrometry

The contents of 17 elements in thirteen strawberry cultivars grown in the five districts of Southern Serbia were determined using inductively coupled plasma optical emission spectrometry (ICP-OES). The most abundant elements are K (875–1148 mg?·?kg^?1 fresh weight), P (307–664 mg?·?kg^?1 fresh weight), Ca (192–256 mg?·?kg^?1 fresh weight), and Mg (111–189 mg?·?kg^?1 fresh weight) in all samples. Strawberries were also found to be a good source of Sr (8.05–18.6 mg?·?kg^?1 fresh weight) and Fe (3.09–10.4 mg?·?kg^?1 fresh weight). The contents of As and Cd were below the detection limit (0.0828 mg?·?kg^?1 and 0.0205 mg?·?kg^?1, respectively) in all strawberry samples, while the contents of Ni, Cr, and Cu were below the recommended tolerable levels proposed by Joint Food and Agriculture Organization of the United Nations and World Health Organization Expert Committee on Food Additives, and did not a pose a health risk for the consumer. The application of Duncan’s test showed significant differences between contents of analyzed elements in all strawberry cultivars. The highest mean levels of analyzed elements were detected in strawberries grown in the Topli?ki, Jablani?ki, and P?injski districts. The spike recovery test was used to verify the accuracy of the method, and the spike recovery was in the range 93.8–107.8%. The contents of the metals in strawberry samples were also comparable with values previously reported in the literature.     

Determination of zinc in marine/lacustrine sediments by graphite furnace atomic absorption spectrometry using Pd/Mg chemical modifier and slurry sampling

Effectiveness of Pd/Mg chemical modifier for the accurate direct determination of zinc in marine/lacustrine sediments by graphite furnace atomic absorption spectrometry (GF-AAS) using slurry samples was evaluated. A calibration curve prepared by aqueous zinc standard solution with addition of Pd/Mg chemical modifier is used to determine the zinc concentration in the sediment. The accuracy of the proposed method was confirmed using Certified Reference Materials, NMIJ CRM 7303-a (lacustrine sediment) from National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Japan, and MESS-3 (marine sediment) and PACS-2 (marine sediment) from National Research Council, Canada. The analytical results obtained by employing Pd/Mg modifier are in good agreement with the certified values of all the reference sediment materials. Although for NRC MESS-3 an accurate determination of zinc is achieved even without the chemical modifier, the use of Pd/Mg chemical modifier is recommended as it leads to establishment of a reliable and accurate direct analytical method. One quantitative analysis takes less than 15 minutes after we obtain dried sediment samples, which is several tens of times faster than conventional analytical methods using acid digested sample solutions. The detection limits are 0.13?µg?g^?1 (213.9?nm) and 16?µg?g^?1 (307.6?nm), respectively, in sediment samples, when 40?mg of dried powdered samples are suspended in 20?mL of 0.1?mol?L^?1 nitric acid and a 10?µl portion of the slurry sample is measured. The precision of the proposed method is 8–15% (RSD).     

Application of nuclear analytical techniques for assessment of coastal impact

Marine sediments contain a record of past events and proved to be an interesting indicator matrix for this study. Instrumental neutron activation analysis and energy dispersive X-ray fluorescence techniques offer adequate sensitivity for analysis of trace elements. Grain size analysis of sediment samples before and after tsunami showed a shift in textural characteristics of the sediment which is not observed during regular monsoon and seasonal changes. Some general characteristics of sediments revealed sand content ranges between 39 and 65% and silt from 33 to 53%. Clay content was found low averaging 5.4% and varied from 2 to 13% (by weight). The concentration of Cu, Ni, Fe, Pb, Zn, Mn, Rb, Sr, Ti, K, and Ca varies from 12 to 53, 19?C46, 21,952?C36,785, 21?C39, 39?C67, 335?C856, 47?C61, 223?C400, 4,991?C8,054, 11,000?C15,791, and 5,878?C11,214?mg?kg^?1, respectively. The positive correlation was observed for Cu, Ni, Ti, K, and Rb with respect to Fe. The negative correlation was observed for Ca, Sr, Zn, and Pb with respect to Fe, indicating the different source for these metals in the marine sediment. Decrease of the particle-reactive element in the tsunami impacted sediment indicates removal of clay component in the sediment, which is supported by the presence of low Th/U ratio.     

Adsorption and desorption of tributyltin in sediments of San Diego Bay and Pearl Harbor

Adsorption and desorption of butyltin compounds from sediment under simulated estuarine conditions depends upon the characteristics of the sediment including grain size distribution, percentage of organic carbon, clay mineralogy and aqueous butyltin concentration in the overlying water column. Sediments from Pearl Harbor, Hawaii, USA, primarily consisting of calcium carbonate mud and 18–28% organic carbon by weight, have generally abundant adsorption sites and display tributyltin partition coefficients (K_p) ranging from 1000 to 5000 μg kg^?1 per μdm^?3. Adsorption and desorption of butyltin from San Diego Bay, California, USA, sediments is linearly dependent upon the characteristics of each sediment and the range in K_p values is from approximately 20 to 2500 μg kg^?1 per μg dm^?3. Sandy, low-organic carbon sediments have low K_p while fine-grained, relatively organic-rich sediments have high K_p values. Similarly, samples containing significant amounts of high cation exchange capacity (CEC) clay minerals have relatively higher adsorption potentials than those consisting of low CEC minerals.     

Tracking Hg historical inputs by Pb-210 geochronology for the Itapessoca Estuarine Complex,Pernambuco, Brazil

The application of geochronology for tracking mercury contamination was remarkably demonstrated in the Itamaracá Estuarine Ecosystem, Pernambuco State, Brazil. Here, two sediment cores were sampled, layered and analyzed by the Gas Flow Proportional Counter technique for determining ²¹⁰Pb, radionuclide applied to geochronology. Mercury was quantified in sediment samples by Cold Vapor Atomic Absorption Spectrometry, varying from 0.17 to 1.29 mg kg^?1 in deep sediments. From ²¹⁰Pb results, the sedimentation rates of 0.84 (0.07) cm year^?1 and 1.03 (0.22) cm year^?1 confirmed Hg contamination in Itamaracá since mid-1965. Events of extreme precipitation and drought have been also related to the distribution pattern for Hg concentrations in deep sediments.

     

Behaviour of polycyclic aromatic hydrocarbons in dissolved,colloidal, and particulate phases in sedimentary cores

Solid-phase microextraction (SPME) has been successfully used for extracting polycyclic aromatic hydrocarbons (PAHs) from porewater samples from the Mersey Estuary, UK. The majority of the PAHs in porewater samples are associated with colloids due to the high DOC concentrations. The truly dissolved PAH concentrations varied from 66 to 1050?ng?L^?1 in core 2 and from 95 to 740?ng?L^?1 in core 3, and were dominated by naphthalene, fluoranthene, and pyrene. Although absent in the dissolved phase, the high-molecular-mass compounds were found in the colloid-associated fraction of porewater. PAHs in sediments arose from a range of compounds with 4- and 5-ring PAHs dominating. The partitioning of PAHs between sediment and porewater shows that PAHs are enriched in the sediment phase. When the soot carbon content was considered, predictions of the partition behaviour were found to agree more closely with the observed distribution. The results reiterate the importance of evaluating the speciation of organic pollutants in both porewater and sediments in order to accurately predict their environmental fate and potential toxicity.     

Copper content of vineyard soils at Sremski Karlovci (Vojvodina Province,Serbia) as affected by the use of copper-based fungicides

The present study investigated the copper content of nine vineyard plots soils and four control plots as affected by the application of copper-based fungicides. The study was carried out at the site of Sremski Karlovci in the Serbian province of Vojvodina. The results showed that Cu soil concentrations are increased at the site and that there is a tendency towards soil contamination by this element. Of the 27 total samples studied, only one had Cu concentration above the maximum allowable concentration of 100?mg?kg^?1. That sample's concentration was 111.7?mg?kg^?1. All the samples from the 0–15?cm layer had copper levels that were above the critical value of 60?mg?kg^?1. The mean value of the samples was 79.4?mg?kg^?1, contrasting with the background concentration of 19.8?mg?kg^?1. The results obtained for the studied vineyard soils indicate that these soils are potentially at risk and call for reduced application of Cu-based fungicides along with soil monitoring.     

Occurrence of organochlorine pesticides and polychlorinated biphenyls in soils and sediments from Eastern Romania

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), such as DDT and analogues, hexachlorocyclohexane (HCH) isomers and hexachlorobenzene (HCB), were measured in surface soils and sediments from Eastern Romania. Thirty-nine soil samples from the forested zone, eight soil samples from a municipal waste-disposal site, and 10 sediment samples from the Bahlui River along the Iassy city were analysed using accelerated solvent extraction (ASE) and gas chromatography coupled to electron capture detection or mass spectrometry. The low mean concentrations of OCPs (11–31 and 22–84?ng?g^?1 for HCHs and DDTs, respectively) and PCBs (8–43?ng?g^?1) in soil samples from the forested zone suggest that contamination at most of these sites occurred predominantly through atmospheric transport from zones where these compounds were used and subsequently through atmospheric deposition. Contrarily, soil samples collected in the vicinity of a waste-disposal site near Iassy contained higher mean levels of PCBs (278?ng?g^?1, range 34–1132?ng?g^?1) than OCPs (6 and 101?ng?g^?1 of soil for HCHs and DDTs, respectively). The sediment samples collected along the Bahlui river throughout the Iassy city revealed higher mean levels of PCBs (59?ng?g^?1, range 24–158?ng?g^?1) compared with OCP levels (2 and 37?ng?g^?1 of soil for HCHs and DDTs, respectively). Furthermore, PCB profiles and concentrations in the sediment samples varied considerably along the river due to a wide variety of sources, such as different industries and waste sites. Although their sources are difficult to evaluate, the presence of POPs at most sites (especially at the waste-disposal site) may constitute a potential health hazard.     

Distribution of rare earth elements in the estuarine and coastal sediments of the Daliao River System, China

The Daliao River System (DRS) estuary in Liaodong Bay features a highly industrial, urbanized, and agricultural catchment. The objective of this study was to determine the content, behavior, and distribution of the rare earth elements (REEs) in the estuarine and coastal sediments. To this end, 35 sediment samples were collected from the estuarine and coastal area and analyzed for REEs, Fe, Al, and Mn. The mean concentrations in mg kg^?1 of the sediments were 33.4 (La), 64.1 (Ce), 7.9 (Pr), 29.0 (Nd), 5.4 (Sm), 1.2 (Eu), 4.2 (Gd), 0.78 (Tb), 4.0 (Dy), 0.84 (Ho), 2.3 (Er), 0.40 (Tm), 2.3 (Yb), and 0.37 (Lu). The REE concentrations in the sediments were significantly correlated with one another (r ²  = 0.959–0.988) and the concentrations of Fe, Al, and Mn (r ²  = 0.768–0.870). The total concentration ∑REE ranged from 73.5 to 203.5 mg kg^?1, with an average of 156.0 mg kg^?1 being observed, and generally higher in the estuarine sediments than in the coastal sediments, most likely due to the salt-induced coagulation of river colloids and subsequently their accumulation at the estuarine bottom. The ratio of light REEs (∑LREE) to heavy REEs (∑HREE) was 9.4. Chondrite-normalized REE distributions were observed to be similar for the estuarine and coastal sediments, riverine suspended particles, and watershed soils of the DRS with higher LRRE enrichment than HREE and greater Eu depletion than Ce depletion. These results demonstrate that neither geochemical processes that carry soils to estuarine sediments nor long-term industrial and agricultural activities alter the distribution or fractionation of the REEs in the study area.     

The analyses of alkyllead compounds in fish and environmental samples in Ontario,Canada (1981–1987)

Analyses of fish and other environmental samples (clams, macrophytes, sediments and waters) from areas upstream and downstream from two alkyllead manufactures beside the St Lawrence and St Clair Rivers, Ontario, show a clear indication of elevated alkyllead levels in samples near the industries. Most species of fish contained alkyllead compounds with tetraethyllead and triethyllead as the predominant forms. Most fish from the contaminated areas contained 50–75% of total lead as alkylleads. Carp, yellow perch and white sucker were generally the most contaminated species while pike, alewife and rock bass were the least contaminated. Average alkyllead levels varied from year to year but declined steadily after 1981. For example, the geometric mean of alkyllead compounds in carp from the St Lawrence River decreased from 4207 μg kg^?1 in 1981 to 2000 μg kg^?1 in 1982 and to 49 μg kg^?1 in 1987, reflecting the reduction of alkylleads in the effluents and the closure of one of the manufactures in 1985. Alkyllead levels were consistently lower in muscle and carcass samples in comparison with whole fish containing fatty intestines. However, muscle levels were generally equal to carcass levels. The concentrations of alkyllead compounds were generally low in clams, macrophytes, sediments and waters except from the immediate vicinity of the manufactures' final effluent discharges.     

Extraction efficiencies for hydrocarbons from sediments polluted by oily drill cuttings

Alkaline digestion with sodium hydroxide/methanol/pentane, Soxhlet extraction with methanol/dichloromethane, and ultrasonication with methanol/dichloromethane were applied to subsamples of three surface sediments polluted by oily drill cuttings to different levels (about 50, 1000 and 25 000 mg kg^?1 hydrocarbon pollution). For the two most polluted sediments the three methods were not significantly different in their ability to extract petroleum hydrocarbons from the sediments, at a 90% confidence level. The amounts extracted from the least polluted sediments using ultrasonication was, however, significantly above the amounts obtained by the other two methods. The average relative standard deviations increased in the order Soxhlet method (4.5%), alkaline digestion (12.4%) and ultrasonication (16.1%). Small differences in the relative amounts of some individual components were observed in the moderately polluted sediment.     

The determination of chlorinated long-chain paraffins in water,sediment and biological samples

Methods are described for the routine determination of traces of industrial chloro-n-paraffins having 13–30 carbon atoms and chlorine contents of 42–45% (frw/w), in environmental samples of water, sediments and biota. The procedures are based on thin-layer chromatography detection and measurement. All samples are cleaned up by liquid—solid adsorption chromatography and thin-layer chromatography but those rich in lipids require preliminary solvent extraction. The methods distinguish between chloro-n-paraffins based on long carbon chains (C₂₀–C₃₀) and those based on shorter chains (C₁₃–C₁₇). The methods cover the ranges 500 ng l^?1 to 8 μg l^?1 for water (i.e. from about the solubility limit upwards) and 50 μg kg^?1 to 16 mg kg^?1 for sediments and biota. The precision of the methods ranges from ± 50% relative at the lowest concentrations to ± 12% relative at the highest. Recoveries are about 90% for water, 80% for sediments and between 80 and 90% for biota according to sample type.     

A study of environmental analysis of urban river sediments using activation analysis

Sediments of the Kitajukkengawa River (Sumida-ku, Tokyo, Japan) were analyzed by activation analyses. Concentrations of 36 elements for each sample were determined by instrumental neutron activation analysis (INAA) and neutron induced prompt gamma-ray analysis (PGA). Based on the correlation matrix between the elements in vertical distribution, principal component analysis (PCA) was performed. The degree of chemical weathering of silicate minerals was highest in the middle layer of the Kitajukkengawa River sediment and that adsorbed amount of trace metals such as Cd and Cr was increased along with chemical weathering.