Determination of iodine value by bromine/instrumental neutron activation analysis

A new microanalytical method has been developed to measure iodine value (IV) of oils and fats. Bromine vapor was used to saturate the ethylenic double bonds, and reacted bromine was determined by instrumental neutron activation analysis. The method was applied to measure the iodine values of 7 commercially available vegetable oils: almond oil, sunflower oil, peanut oil, soy oil, sesame oil, corn oil, and olive oil. No significant difference was observed between the iodine value determined by the proposed method and that determined by an officially approved (Hübl) method. Bromine measurements can be performed up to 150 days after bromination with no significant variation in iodine value; thus, availability of an irradiation facility on the premises is not a limitation. No corrosive and toxic reagents are required, and the method is faster than the official methods. The method is also applicable to measuring iodine values of free or esterified fatty acids.     

Non-destructive neutron activation analysis of particle size fractions and soil extracts

Non-destructive instrumental neutron activation analysis was examined. Using long-lived isotopes, La, Sm, Ce, Sc, Fe, Co, Cs, Th, Cr, Hf, and Tb, and using short-lived isotopes, Al, V, Na, and Mn in various particle size Tractions of clay, silt, fine sand, and coarse sind, and the oxalic acid extracts of the soil were determined. Relative standard deviations (CV) were in the range of 1.7 to 12%. The reliability of the analysis was also examined. Recovery percentages ere in the range of 87 to 120%. The analytical results of geochemical reference samples of JG-1 and JB-1 showed general agreement with the other worker's results.

Distribution patterns of those elements among the six fractions of highly weathered and ively unweathered soils were briefly discussed in relation to weathering processes.     

Determination of heavy metals in municipal sewage plant sludges by neutron activation analysis

Research is presented which deals with the use of Neutron Activation Analysis (NAA) to scan sewage sludges for their trace metal content. Of special interest are the metals Hg, Se, Cr, Sb, Co and Fe which are highlighted in sludges from six North Carolina cities that represent the spectrum of rural to heavily industrialized pollution sources. Trace metal content variations and possible meanings for these variations are presented along with the precision and potential of NAA for trace metal scanning.     

Determination of aluminium,manganese and sodium in soil solutions by neutron activation analysis

Neutron activation analysis has been applied to the determination of aluminium, manganese and sodium in ammonium acetate soil extract. The method is simple, rapid and sensitive, and the precision in routine application is of the order 2–4%.     

Using in situ solid phase microextraction (SPME) for depth profiling in sediments treated with activated carbon

Purpose

Sediment contamination in US waterways is an expensive and complicated issue, and as acceptance of nontraditional sediment remediation strategies broadens, novel and efficient methods to assess and monitor the bioavailability of hydrophobic organic contaminants (HOCs) in contaminated sediments will play an important role.

Materials and methods

In this project, solid phase microextraction (SPME) fibers inside perforated steel tubes were used as in situ passive samplers to measure polycyclic aromatic hydrocarbon (PAH) concentrations in sediment before and after treatment with activated carbon (AC). Two modes of waterjet amendment injection were used to apply the AC. In the first treatment, a single 2-min injection was shot into the center of a test vessel, and in the second treatment, multiple 7-s injections in a grid were placed in sediment.

Results and discussion

In the single injection, no treatment was observed 5 cm away from the injection, while at 2.5 cm, >90 % decrease of PAH pore water concentration was observed, indicating a similar bioavailability decrease. In the multiple injection experiment, >90 % PAH pore water level reductions were observed throughout the test vessel. Highly contaminated and less contaminated sediments were mixed with 0–5 % AC by weight to develop AC treatment curves. Over 99 % reduction in PAH pore water concentrations and bioavailability was observed in the less contaminated sediment at 3 % AC, while 99 % reduction was never reached even at 5 % AC addition in the highly contaminated sediment. Different treatment curves were observed for the different contaminated sediments. In situ equilibration times were 120, 215, and 250 h for phenanthrene, pyrene, and benzo(a)anthracene, respectively.

Conclusions

The results show that in situ SPME is a viable method to observe AC treatment and evaluate reductions in pore water concentrations and bioavailability.     

Assessment of diffuse pollution associated with metals in urban sediments using the geoaccumulation index (Igeo)

Purpose

This study investigated the behavior of cadmium (Cd), lead (Pb), nickel (Ni), and zinc (Zn) in urban sediments collected in commercial, residential, and industrial areas of the city of Porto Alegre, Brazil, and evaluated different degrees of pollution in this urban subdrainage basin through the use of the geoaccumulation index (I_geo).

Materials and methods

Concentrations of Cd, Ni, Pb, and Zn were analyzed using acid digestion (EPA method 3050) in fractions <63 μm in 20 composite samples of urban sediment collected using a portable vacuum in 20 different sampling points on roads from three areas with diverse use: commercial, industrial, and residential.

Results and discussion

The values of I_geo were commercial area (3.35, Zn; 3.76, Cd; 3.60, Ni; 2.63, Pb) > residential area (3.34, Zn; 3.36, Cd; 2.94, Ni; 1.46, Pb) > industrial area (2.74, Zn; 1.78, Cd; 3.01, Ni; 1.45, Pb), indicating that the sediment was “highly contaminated” in the case of Zn and Ni, while for Cd, it was “moderately to highly contaminated,” and for Pb, it was “moderately contaminated.” The pollution is associated with traffic flow in all areas.

Conclusions

Research should be increased to make urban systems more sustainable, reducing their pollution potential and minimizing the delivery of potentially polluting particles into freshwater bodies. The I_geo allows for the determination of a simple index of diffuse pollution state associated with urban sediments.     

Determination of 129i in water and air samples near a reprocessing plant by neutron activation analysis

The neutron activation analysis was used to determine ¹²⁹I in water and air samples collected in the neighbourhood of a reprocessing plant. The method involved preconcentration of ¹²⁹I on AgI from water samples, separation of Ag⁺, followed by distillation, loading on Dowex-1, irradiation and post irradiation purification steps. Filter air samples were wet oxidised follwed by distillation and other chemical procedure steps as described for water samples. The concentration of ¹²⁹I in rain water and air samples ranged from 0.155×10^?3 to 0.327×10^?3 Bq L^?1 and 0.054×10^?6 to 0.295×10^?6 Bq m^?3 respectively. The average concentration of ¹²⁹I in seawater samples was 0.157×10^?3 Bq L^?1. The concentration of ¹²⁹I obtained in these samples have been translated to dose rates to an individual and have been found to be insignificant.     

Trace metals in Valencia lake (Venezuela) sediments

An exploratory study of the trace metals Cd, Cu, Mn, Ni, Pb, and Zn in sediments of lake Valencia (Venezuela), South America, 10° 10′N, 68°68′W, gave the following results: (A) Total amounts of Cu, Ni, Pb, and Zn were within the normal range reported by the literature. (B) No consistent pattern of variation with depth was found. A and B could be taken as lack of evidence for contamination by Cu, Ni, Pb, and Zn of the studied sediments. Absence of Cu, Ni, Pb, and Zn pollution after more than 40 yr of anthropogenic discharges on this lake, was attributed mainly to the exploratory nature (limited sampling) of this work, together with some possible dilution effects due to the high CaCO₃ content of these lake sediments. (C) Manganese was above normal values in most samples, but in absence of known anthropogenic sources of this metal, the results found could not be clearly ascribed to metal pollution. (D) Cadmium showed enrichment factors of 10 to 30 indicating pollution of the lake sediments by this metal (probably by urban effluents, runoff, and electroplating industries). (E) The proportion of exchangeable metals was nil in most cases. Exceptions (Ni and Mn) had very low exchangeable fractions (<1.22%). (F) The most abundant fraction (except for Mn) was the residual one (59.7–97.8% of total metal). Other fractions (carbonates, oxides, and organic) showed intermediate values. The general pattern was that the bulk of trace metals studied were present in non-mobile, slightly or non-reactive, poorly or non-available forms.     

NaCI contamination in pine trees determined by neutron activation techniques

The NaCl content in samples of pine needles was measured to establish the extent of contamination from rock salt which is used for deicing roadways. Neutron activation analysis techniques were used to determine the NaCl content in the samples, and the irradiation neutrons were obtained from a portable²⁵²Cf neutron source. The average Na content in samples from the diseased trees was 50 times greater than in the control samples.     

Chemical patterns in sediments of ancient Theodosius Harbour (Istanbul)

Purpose

The use of fossil fuels, cement production and the reduction of forest areas cause a high amount of CO₂ emissions to the atmosphere which in turn causes the ocean to be acidified. Acidity of seawater can directly change sediment properties. It is expected that the average pH value of the ocean surface water will decrease between 0.3 and 0.5 pH units according to the projection to year 2100. This study aimed to make a contribution to the understanding of long-term pollution trends. In the study, sediment samples from Neolithic Era, Early Byzantine Era and Byzantine Era from archaeological excavations jointly conducted by Istanbul Archaeological Museums and the Istanbul University Department of Conservation of Underwater Cultural Heritages were investigated.

Materials and methods

The sediment samples were taken from ancient Theodosius Harbour (5000 BC). Major elements (Si, Al, Fe, Mg, Ca, K, Na, Mn, Ti), rare earth elements (Tb, Yb, Eu, Dy, Tm) and toxic elements (As, Cr, Co, Cu, Ni, Pb and Zn) in sediment samples were determined by X-ray fluorescence spectrometer. The chemical abundance of the ancient sediments was evaluated with the ecological risk factor and geo-accumulation index.

Results and discussion

The sediment samples from the Neolithic Era reflect the contribution of both parent rock and also anthropogenic pollution. In the Early Byzantine and Byzantine Era, the development of the industry has increased the basic element concentrations in the environment and potential ecological risk and geo-accumulation indices. As, Cu, Cr, Zn, Ni and Co contents of Neolithic Era samples were found to be lower than Early Byzantine and Byzantine Era.

Conclusions

The obtained the results showed that the toxic elements in the Neolithic Era, which the industry never developed, started to rise and increased concentrations of Ni by about two and a half times, Zn four times, Pb two times, Cr two times, Co six times and As three times in the Early Byzantine and Byzantine Eras. The concentrations of major elements (Al, Ba, Ca, Fe, K, Mg, Mn, Na, Si) did not show any significant difference during these three eras.

     

Multielement analysis of natural waters by neutron activation,group chemical separations,and gamma-ray spectrometric techniques

A multielement analytical technique of thermal neutron activation of frozen water samples has been developed and applied to the studies of natural waters. A rapid group chemical separation utilizing ion exchange resins and a precipitation step to reduce ²⁴Na and 42K interferences, followed by γ-ray analysis of the fractions with Ge (Li) and multiparameter NaI (TI) systems, permits the simultaneous measurement of a large number of trace constituents. Samples of river water, rain water, processed sewage water and Greenland ice were analyzed for 19 trace elements — Ag, As, Br, Cl, Co, Cs, Cr, Cu, Fe, Hg, K, Mn, Na, Rb, Sb, Se, Se, U, and Zn. These data have been used in studies of trace element concentration factors in aquatic biota, precipitation scavenging processes, and environmental pollution.     

Horizontal and vertical distribution of selected metals in the kubanni river,nigeria as determined by neutron activation analysis

Abstract

Neutron Activation Analysis (NAA) was used for the determination of metal concentrations of sediments sampled at specific locations of the Kubanni River in Nigeria. The sedimentation process was assessed by examining the variation of the concentrations of the metals in different cores with sediment depths. Fifteen metals: arsenic (As), cerium (Ce), europium (Eu), iron (Fe), gadolinium (Gd), hafnium (Hf), holmium (Ho), potassium (K), lanthanum (La), lutetium (Lu), samarium (Sm), scandium (Sc), thorium (Th), uranium (U), and ytterbium (Yb) were detected from the sediments in substantial concentrations; higher than the parts per million (μg g^‐1) value in some cases. Our results showed contamination of the surface sediments by U and Th, suggesting contributions from phosphate fertilizers used in farmlands around the basin as potential sources of these pollutants. Aeolian depositions emanating from the uranium‐rich region of Air (Niger) in the Saharan desert were considered to be other possibilities.     

Monitoring of sewage pollution in the surface sediments of coastal ecosystems using linear alkylbenzenes (LABs) as molecular markers

Journal of Soils and Sediments - Molecular organic markers are an effective tool to detect the adverse effects of anthropogenic inputs in the aquatic environment. Linear alkylbenzenes (LABs) are...     

The role of reactive iron in long-term carbon sequestration in mangrove sediments

Journal of Soils and Sediments - Despite occupying only 0.5% of the global coastal ocean, mangroves play a disproportionately large role in the capture and retention of atmospheric carbon dioxide...     

Detection of adulteration in Australian orange juices by stable carbon isotope ratio analysis (SCIRA)

Stable carbon isotope ratio analysis (SCIRA) was used to determine the authenticity of commercial Australian orange juices. Thirty-five samples of Valencia (delta(13)C values from -23.8 to -24.7 ppt) and eight samples of Navel juices (delta(13)C values from -24.1 to -24.5 ppt) of known origin were used to establish a decision level before analysis. No significant seasonal variations in (13)C/(12)C ratio were observed. Variations in combustion temperature in the method were also found to be insignificant.     

Magnetic spherules in sediments of the karstic Dobra River (Croatia)

Purpose

The paper describes an unusual finding of magnetic particles in stream sediments of the karstic Dobra River (Croatia). It aims to investigate the magnetic susceptibility properties of river sediments and to find links with their mineralogical and chemical composition. The goal of our research was to suggest the possible origin of magnetic particles in the river sediments within the Dinaric karst region, which to our knowledge was not exposed to metal manufacturing processes.

Materials and methods

A preliminary, exploratory sediment sampling programme was undertaken. Sediments were collected near the channel bank (from the top layer) at 16 representative stations distributed along the length of the Dobra River (110 km). Sediments were air-dried and passed through 2-mm and 63-μm sieves, and analysed for magnetic susceptibility (and Curie temperature), isothermal remanent magnetism (IRM), stereo-microscopy of separated magnetic grains, mineralogical analysis (using X-ray diffraction), and chemical analysis (using inductively coupled plasma–mass spectrometry).

Results and discussion

Increased magnetic susceptibility and IRM values were observed mostly in the sediments of the Upper Dobra. Thermomagnetic curves show a distinctive Curie-point of magnetite at 580 °C. Additional transformation observed at 520–560 °C derives from titanomagnetite. There was no significant correlation between magnetic susceptibility and Fe. Magnetic particles from the Dobra River sediments contain pyroxene, plagioclase, hematite and quartz, in addition to magnetite. White spherules within magnetic grains are also present. The major constituent of five separated magnetic spherules is Fe; the minor constituents are Al, Ca, Mg and Si, and there are numerous trace elements (Ba, Cr, K, Mn, Na, Ni, Ti and V). The ratio Ni/ Fe versus Cr/Fe suggests that the magnetic spherules are impactites.

Conclusions

Magnetic spherules were discovered for the first time in stream sediments of the sinking karstic Dobra River, a region where anthropogenic sources for that contribution are absent. Preliminary results point to a possible impactite, formed either by a shock event caused by a meteorite impact or by volcanic processes. The presence of magnetic spherules in the fluvial sediments of the Upper Dobra River represents a new and exciting finding and deserves further field work and laboratory research.     

Analysis of the distribution of some polycyclic aromatic hydrocarbons in sediments and suspended matter in the River Seine (France)

Sixteen EPA chosen polycyclic aromatic hydrocarbons (PAH) were studied in the sediments and the suspended matter of the River Seine to determine existing pollution. Analyses were carried out by HPLC with coupled fluorimetric and UV detectors. PAH contents were found to be highly variable depending on many factors such as anthropogenic activities, weather and flow rate of the river, and occasionally they rose to alarming levels. Contents of 16 PAH ranged from 1.5 to 7.4 μg g^?1 in the sediments, but a peak at 60.7 μg g^?1. In the suspended matter the contents were usually below 10 μg g^?1. From these results and taking into account the mean content of suspended matter in the river downstream from Paris, the total adsorbed PAH concentration in the river Seine should be about 60 ng l^?1. Evidence has been established that storm drain discharges are a major source of pollution.     

Bathymetric modeling of sediments and organic carbon of polluted rivers in southeastern China

Purpose

Rivers in low plains in the subtropical regions of China, where the population is dense and economies are active and well-developed, might be a large terrestrial carbon pool. This present study of the Sanyang wetlands in Wenzhou, southeastern China, aims to quantitatively estimate the volume of sediments in this region’s polluted river systems and their carbon storage.

Materials and methods

The bathymetry of river sections were surveyed using an echo sounder equipped with a differential GPS. An underwater digital elevation model (DEM) was then developed using the anisotropic ordinary Kriging method. Sediment samples were collected and analyzed for carbon content and sediment properties. Carbon storage in sediments was calculated using bathymetric and sediment analysis data.

Results and discussion

The studied rivers have been receiving organic pollutants from local residences and industries for decades. Results from a river network of 1.2 km² revealed a total carbon storage of 46.7 million kg in the sediments which had a volume of 1.4 million m³, with the upper 20 cm depth of sediments contributing about one third of this carbon storage.

Conclusions

The present work demonstrated that GIS technologies can be used to create digital river sediment surfaces and assess sediment amounts as well as determine the spatial distribution of sediments and their components. This could provide further insight into river restoration planning and other options from a carbon-balance perspective.

     

Chronic toxicity of unresolved complex mixtures (UCM) of hydrocarbons in marine sediments

Background, Aim and Scope  Unresolved complex mixtures (UCM) of hydrocarbons, containing many thousands of compounds which cannot be resolved by conventional gas chromatography (GC), are common contaminants of sediments but little is known of their potential to affect sediment-dwelling organisms. Evidence exists for reduced health status in mussels, arising from aqueous exposure to aromatic UCM components acting through a narcotic mode of action. However, UCM contaminants in sediments may not be sufficiently bioavailable to elicit toxic effects. The aim of our study was therefore to measure the sublethal effects of chronic exposure to model UCM-dominated oils at environmentally realistic concentrations and compare this to effects produced by a UCM containing weathered crude oil. A further aim was to determine which, if any, fractions of the oils were responsible for any observed toxicity. Materials and Methods  Whole oils were spiked into estuarine sediment to give nominal concentrations of 500 μg g⁻¹ dry weight. Juveniles of the estuarine amphipod Corophium volutator were exposed to the contaminated sediment for 35 days and their survival, growth rate and reproductive success quantified. Using an effect-directed fractionation approach, the oils were fractionated into aliphatic and two aromatic fractions by open column chromatography and their toxicity assessed by further chronic exposures using juvenile C. volutator. Results  The growth rates of amphipods were reduced following exposure to the oils although this was only statistically significant for the weathered oil; reproductive success was reduced by all oil exposures. Sediment spiked with UCM fractions also caused reduced growth and reproduction but no particular fraction was found to be responsible for the observed toxicity. Survivorship was not affected by any oil or fraction. Discussion  The study showed that chronic exposure to sediments contaminated by UCM-dominated oils could have population level effects on amphipods. The observed effects could not be explained by hydrocarbons resolved by conventional GC and effects were similar for both UCM-dominated and weathered oils. All of the fractions appeared to contribute to the observed effects; this is in contrast to previous research which had shown that an aliphatic UCM did not cause adverse effects in mussels. Conclusions  To our knowledge, this is the first study to demonstrate population-level effects arising from exposure to sediments contaminated by realistic environmental concentrations of UCM hydrocarbons. The results are consistent with many compounds, at very low individual concentrations, contributing towards the overall observed toxicity. Recommendations  Risk assessments of contaminated sediments should take into account the contribution towards the potential for toxic effects from UCM hydrocarbons. Studies into sediment contamination should report both aliphatic and aromatic UCM concentrations to aid risk assessments. ESS-Submission Editor: Henner Hollert (hollert@uni-heidelberg.de) This paper has been developed from a presentation at SETAC Europe 16^th Annual Meeting 2006 held at the The Hague, The Netherlands.