Characterization of Chromium- Contaminated Soils Using Field-Portable X-Ray Fluorescence

A detailed characterization of the underlying and adjacent soils near a chrome plating shop utilized field-portable X- ray fluorescence (XRF) as a screening tool. XRF permitted real-time acquisition of estimates for total metal content of soils. A trailer-mounted soil coring unit was used to recover soil samples for XRF analyses. This approach minimized the number of samples required for adequate characterization of the chromium distribution in the soils at the site and permitted immediate delineation of source'hot spots.'The nondestructive nature of the XRF analyses permitted correlation analysis using inductively coupled plasma (ICP) techniques. Correlation between XRF and ICP was very good (r²= 0.95) but the XRF analyses underestimated the total chromium concentrations, probably because of inappropriate calibration samples.     

Penetration of bomb radiocarbon in the tropical Indian Ocean measured by means of accelerator mass spectrometry

Radiocarbon measurements performed on seawater samples by means of accelerator mass spectrometry (AMS) enable to reduce by a factor of 2000 the water sample size needed for the¹⁴C measurements. Therefore no chemical treatment on board the oceanographic vessel is required. Seventy-four AMS¹⁴C determinations on samples collected in the tropical-equatorial Indian Ocean during the second leg of the INDIGO program (1986) are presented and compared with the β-counting results obtained during the same campaign and the GEOSECS program (1978). A pronounced reduction of the equatorial¹⁴C deficit suggests that substantial amounts of bomb-¹⁴C are associated with the westward flowing Pacific water which enters the Indian Ocean via passages through the Indonesia archipelago and/or to meridional mixing with¹⁴C-rich water of the southern subtropical gyre.     

Magnetic parameters and variations in the composition of igneous rocks of the Franz Josef Land archipelago

A combined study of magnetic parameters of basalt and andesite samples is performed in the framework of geological investigations of the Franz Josef Land at the paleomagnetic laboratory of Munich University. The study included the determination of the coercivity, saturation magnetization, Curie points, natural remanent magnetization (NRM), and magnetic susceptibility and the examination of ferromagnetic minerals with a microscope. Data on the chemical composition of rocks are obtained for all samples, and radiological ages are determined for the majority of rocks.Thermomagnetic curves of samples are subdivided into four types depending on the composition of ferromagnetic NRM carriers.The data obtained point to multiple changes in the predominant composition of igneous rocks. Each stage of magmatism is characterized by a specific type of the ferromagnetic component in the rocks and, therefore, magnetomineralogical investigations can be used for differentiation and correlation of the igneous rocks.     

Understanding the Seismic Velocity Structure of Campi Flegrei Caldera (Italy): From the Laboratory to the Field Scale

We report laboratory measurements of P- and S-wave velocities on samples of tuff from Campi Flegrei (Italy), and a new tomographic velocity map of the Campi Flegrei caldera. Laboratory measurements were made in a hydrostatic pressure vessel during both increasing and decreasing effective pressure cycles. Selected samples were also thermally stressed at temperatures up to 600°C to induce thermal crack damage. Acoustic emission output was recorded throughout each thermal stressing experiment, and velocities were measured after thermal stressing. Laboratory P- and S-wave velocities are initially low for the tuff, which has an initial porosity of ~45%, but both increase by between 25 and 50% over the effective pressure range of 5 to 80 MPa, corresponding to a decrease of porosity of ~70%. Marked velocity hysteresis, due to inelastic damage processes, is also observed in samples subjected to a pressurization-depressurization cycle. Tomographic seismic velocity distributions obtained from field recordings are in general agreement with the laboratory measurements. Integration of the laboratory ultrasonic and seismic tomography data indicates that the tuffs of the Campi Flegrei caldera can be water or gas saturated, and shows that inelastic pore collapse and cracking produced by mechanical and thermal stress can significantly change the velocity properties of Campi Flegrei tuffs at depth. These changes need to be taken into account in accurately interpreting the crustal structure from tomographic data.     

Soil Gas Sampling for 1,4‐Dioxane during Heated Soil Vapor Extraction

Soil gas sampling for 1,4‐dioxane at elevated soil temperatures, such as those experienced during in‐situ thermal treatment, has the potential to yield low results due to condensation of water vapor in the ambient temperature sampling vessel and the partitioning of 1,4‐dioxane into that condensate. A simple vapor/condensate sampling apparatus was developed to collect both condensate and vapor samples to allow for determination of a reconstituted effective soil gas concentration for 1,4‐dioxane. Results using the vapor/condensate sampling apparatus during a heated air injection SVE field demonstration are presented, along with those of a comparable laboratory system. Substantial 1,4‐dioxane mass was found in the condensate in both the lab and field (as high as ~50% in field). As soil temperatures increased, less 1,4‐dioxane mass was detected in field condensate samples than expected based on laboratory experiments. Extraction well effluent sampling at the wellhead by direct vapor canister sampling provided erratic results (several biased low by a factor of 5 or more) compared to those of the vapor/condensate apparatus. Direct vapor canister sampling of extraction well effluent after the air‐water separator, however, provided results reasonably comparable (within 35%) to those using the vapor/condensate apparatus at the wellhead. Soil gas sampling at elevated temperatures using the vapor/condensate apparatus alleviates potential low sampling bias due to condensation.     

Impact of Turbidity on TCE and Degradation Products in Ground Water

Elevated particulate concentrations in ground water samples can bias contaminant concentration data. This has been particularly problematic for metal analyses where artificially increased turbidity levels can affect metals concentrations and confound interpretation of the data. However, few studies have been conducted to determine the impact of particulates on trichloroethylene (TCE), cis-dichloroethylene (c-DCE), and vinyl chloride concentrations.
Laboratory batch studies and field investigations were conducted to evaluate the effects of suspended solids on VOC concentrations in ground water samples analyzed by purge-and-trap gas chromatography. Three different solids were used to assess the effects of suspended particulates. The solids were aquifer material from a field site in North Carolina and two reference clay minerals (kaolinite and Namontimorillonite). During the laboratory portion of this study, the solids were used to determine effects on TCE concentrations under controlled laboratory conditions.
The same solids were used in a field study to compare the laboratory results with field results. Solids were added to the sample vials prior it) sample collection to intentionally increase turbidity levels in the water samples. Results of the study indicate essentially no decrease in TCE, c-DCH, or vinyl chloride concentrations due to increased turbidity levels.     

湖泊沉积物XRF元素连续扫描与常规ICP-OES分析结果的对比及校正--以兹格塘错为例

岩芯X荧光光谱扫描仪(XRF)可以无需破坏样品,直接通过对剖开岩芯表面扫描获知沉积物的元素化学组成,但目前少有关于XRF连续扫描方法测试结果精度和准确性的研究.本文以高原封闭咸水湖泊兹格塘错湖相沉积岩芯为研究对象,利用XRF方法进行了高分辨率连续扫描,同时在岩芯不同层位选取了60个样品利用ICP-OES方法进行元素测定...     

Atomabsorptionsspektrometrische Metallbestimmung in natürlichen Gewässern und Abwässern

With the aid of the Soviet atomic-absorption two-channel spectrometer “Saturn” successful attempts were made to improve the sensitivity of the heavy-metal determination after the previous two-step separation and concentration technique. Compared with other combustible gases, the propane/nitrogen-oxide flame is preferred. Because of the possibility of the direct determination of the heavy metals in the water samples the duration of analyses could be reduced by fifty per cent. Besides the heavy-metal analytics, a rapid-determination technique for calcium and magnesium was developed. The results of the different determination techniques and the ranges of measurement are given in several tables.     

Characterization of Chlorination By-products in Cooling Effluents of Coastal Nuclear Power Stations

In power stations, the cooling effluents are chlorinated to avoid excessive biofouling. Yet, this disinfecting treatment leads to the formation of halogenated by-products. In spite of possible toxicity of such compounds towards aquatic organisms, there is an evident lack of information on the formation of halogenated compounds in chlorinated seawater samples. So, this study was undertaken to identify and quantify halogenated compounds (i.e. trihalomethanes, haloacetonitriles, halophenols and haloacetic acids) in effluents from three French nuclear power stations. In addition, experiments conducted in the laboratory allowed the determination of the kinetics of formation of the main compounds detected: bromoform, dihaloacetonitrile, 2,4,6-tribromophenol and dibromoacetic acid. Good agreement was obtained between the experiments conducted either on site or in the laboratory. In particular, evidence was given on the formation of brominated compounds (due to the high concentrations of bromide ions in seawater).     

Natural and anthropogenic heavy metals in estuarine cohesive sediments: geochemistry and bioavailability

The geochemistry, mineralogy, and grain size distribution of several estuarine cohesive sediment samples from potentially human-influenced areas without such an influence were analyzed to determine the natural heavy metal content and evaluate its impact on the Bahía Blanca estuarine environment. The data were compared with different ranges of concentrations for heavy metals in marine sediments established by the NOAA Screening Quick Reference Tables in which values range from background levels to those considered toxic to the marine environment. Our total heavy metal contents were below the established hazardous levels in all the analyzed samples, even though the potentially human-influenced areas (harbors, industry, urban spread) showed the highest total concentration values as well as greater percentages of bioavailable compounds. This would imply a low and not extensive anthropogenic input into the environment. The relatively high proportions in which Cd, Pb, and Cr appear as bioavailable compounds at some sites not influenced by human activity suggest the presence of a natural source for these elements. This could be attributed to the weathering of naturally occurring volcanic minerals, indicating that special care must be taken when monitoring of sediment for anthropogenic activity is carried out within this environment. According to the results obtained, and in order to minimize the environmental impact caused by periodic water injection dredging, relocation of sewage outfalls from vessel mooring areas into open waters is strongly recommended.     

Evidence for polychlorinated biphenyls dechlorination in the sediments of Sado Estuary, Portugal

Sediment gravity cores and grab samples were collected in the Sado Estuary and in its coastal area. The cores were sliced on board and the percentage of weight loss on ignition was determined in the laboratory, and analysed for polychlorinated biphenyl (PCB) congeners. PCB contents were higher in samples from the North Channel of the estuary, nearby the industrial zone (max. 114 ng g-1 dry weight), while levels in the coastal area were lower than 4.9 ng g-1. The concentrations of the quantified congeners varied irregularly with sediment depth in the estuary, but showed two opposite distribution patterns in cores from the coastal area: the proportions of lower chlorinated congeners increased with depth, while congeners with higher number of chlorines decreased. This suggests a dechlorination of the most chlorinated congeners into less toxic compounds, under reductive conditions of the sediment. Though measurements were done in natural environment it appears that dechlorination was not entirely dependent on chlorine position in the phenyl rings.     

Assessment of heavy metal contamination in the sur?cial sediments from the lower Meghna River estuary,Noakhali coast,Bangladesh

Sediment samples were collected from ten selected sites of the lower Meghna River estuary, and six heavy metals were analyzed with Atomic Absorption Spectrophotometry(AAS) to assess the contamination level and the metals' association with sediment grain size. The current results revealed that the mean concentrations of the studied metals were ranked in descending order of iron(Fe)(1.29 ? 103 mg/kg) zinc(Zn)(42.41 mg/kg) lead(Pb)(12.48 mg/kg) chromium(Cr)(10.59 mg/kg) copper(Cu)(6.22 mg/kg) cadmium(Cd)(0.28 mg/kg). The geo-accumulation, contamination, and pollution load indexes suggested that the lower Meghna river estuary was not contaminated by Fe, Zn, Pb, Cr, and Cu.The mean size of the sediment ranged from 28.92 to 126.2 mm, and the Pearson correlation coefficient showed a significant association between Fe and Pb(coefficient of determination, r2? 0.836; p 0.05),and no significant correlation was found between individual metals and grain size, indicating no or low influence on the metals distribution.     

Biologisch-chemisches Verfahren zur Prüfung des Abbau- und Eliminierungsverhaltens organischer Abwasserinhaltsstoffe

After the checking for the toxic inhibition of degradation, the testing of the degradation behaviour at concentrations below the toxicological threshold value should be performed. For this, activated sludge with 1.5 … 2 g/l organic dry weight in special reaction vessels with a stirring and aeration equipment as well as electrochemical oxygen measurement is used. The possibly necessary adaptation is effected by a repeated change of the aqueous phase with the test substance as the single carbon source. Measurements are carried out in three vessels: control, experimental vessel and another experimental vessel for the makeup of volume at sampling. The increase of biomass and the consumption of substrate are determined from samples. Determinations of totals as COD and/or C_organic are recommended, since the determination of the pure substrate allows only statements on the persistence, but not on the full degradation. The technique, represented with the schematic diagram and examples of application, can be automated easily.     

Evaluation of Bioavailability and Partitioning of Aluminum in Sediment Samples of Different Ecosystems by Modified Sequential Extraction Methods

Sequential extraction procedures are widely used to characterize the different operational fractions with different potential toxicity of metals in environmental solid samples. The present work describes the application of different analytical approaches for sequential extraction of aluminum to evaluate its mobility, availability, and persistent chemical forms in sediment samples of different fresh water ecosystems (lake, canal, and river). The conventional BCR three‐stage sequential extraction procedure (C‐BCR) was modified at each stage, by applying ultrasonic device (U‐BCR), in order to shorten the required shaking time of 16 h for each three steps (excluding the hydrogen peroxide digestion in step 3, which was not performed with ultrasonic bath), could be completed in 40, 50, and 45 min, respectively. The aluminum in all extracts were determination by atomic absorption spectrometry using nitrous oxide – acetylene flame. The accuracy of results obtained from C‐BCR and proposed U‐BCR was verified with literature reported values of certified sediment sample (BCR 701). The overall recoveries of aluminum obtained by proposed U‐BCR were found in the range of 96.7–113% of those values obtained with C‐BCR for all fractions. Use of ultrasonic device, provided a large saving in extraction time relative to conventional shaking. It was observed that major part of Al in real sediment samples (80–83% of total Al) were bound to residual fraction. The acid soluble fraction of aluminum extracted by 0.11 mol/L CH₃COOH has good correlation with aluminum content in corresponding water samples of each ecosystem.     

饱和砂土最大动剪切模量的不同试验对比研究

对233个饱和砂土土样室内试验确定的最大动剪切模量和同一位置现场原位试验确定的最大动剪切模量进行了对比研究。结果表明：两者相差很大,室内试验结果基本上小于现场试验结果,埋藏深的土样相差更大;室内试验的最大动剪切模量与深度符合幂函数规律,且与砂土的密实度有关,与砂土的颗粒成分关系不大。通过工程实例,比较了2种试验最大动剪切模量对地震反应分析的影响,得到了室内试验最大动剪切模量与现场剪切波速的统计经验关系式。该经验关系式对工程场地地震反应分析具有一定的参考应用价值。     

A Screening Procedure for Heavy Metals in Soil Extracts by Alcohol Dehydrogenase and Urease Inhibition Eine Screening-Methode für Schwermetalle in Extrakten aus Bodenproben,basierend auf der Inhibierung der Enzyme Alkoholdehydrogenase und Urease

A screening method for heavy metals in aqueous extracts of soil is presented which is based on inhibition of the enzymes urease and alcohol dehydrogenase. The method is suitable to detect cupric and mercury ions in concentrations below 0.01 mg/L and several other heavy metal ions in 1000 fold higher concentration. It is shown that the test may be used for screening of mercury ion concentrations exceeding 0.03 mg/L in aqueous solution when copper chelators are added to the test system. The usefulness of the presented tests to detect heavy metals eluted from soil was verified with samples from ore mining waste. The concentration of copper, lead, and zinc eluted from these samples to different amount was determined by atomic absorption spectrometry and was in good agreement with the enzyme inhibition data obtained with these samples.     

Cooling rate effect as a cause of systematic overestimating of the absolute Thellier paleointensities: A cautionary note

Cooling rate (CR) effects on the intensity of thermoremanent magnetization has been documented for archaeomagnetic materials, where cooling in laboratory conditions is generally much faster compared to natural cooling rates. Since the latter condition also applies to many volcanic rocks, we have investigated in this study the influences of the CR on the determination of absolute paleointensity using recent basaltic rocks. We used magnetically and thermally stable samples mainly containing Ti-poor pseudo-singledomain titanomagnetites (the most widely used material for Thellier paleointensity experiments). These samples previously succeed in retrieving the strength of laboratory field intensities with the Coe’s version of the Thellier method in a simulated paleointensity experiment using similar cooling rates. Our experimental results indicate that the cooling rate effects produce systematic and significant overestimates of the absolute intensity up to 70%. The effect can be much larger than predicted by Neél theory for non-interacting single-domain grains.     

Dating the recent past (<500 years) by post-IR IRSL feldspar – Examples from the North Sea and Baltic Sea coast

The applicability of the post-IR IRSL single-aliquot regenerative-dose protocol (termed pIRIR protocol) has been tested on K-rich feldspar from recent coastal sediment samples (<500 a) from the southern North Sea coast and southern Baltic Sea coast. The most suitable post-IR IRSL (pIRIR) stimulation temperature is found to be 150 °C by using a preheat temperature of 180 °C. For this pIRIR stimulation temperature, a detectable pIRIR signal is obtained and the residual dose is minimized. Furthermore, anomalous fading is found to be negligible in the pIRIR₁₅₀ signal for our young samples whereas the fading rates for the conventional IRSL signal measured at 50 °C (IRSL₅₀) is between 5 and 7%/decade. However, the pIRIR₁₅₀ signal bleaches significantly slower compared to the IRSL_50, according to bleaching experiments using daylight, solar simulator and IR diodes, although the residual doses of both signals are similar. The laboratory residual doses in perfectly bleached aliquots are variable from sample to sample and vary between 300 ± 170 and 800 ± 460 mGy for the pIRIR₁₅₀. The precision of the residual dose determination is generally poor and causes large uncertainties on the residual subtracted ages. The laboratory residual doses alone cannot account for the observed overestimation in our two youngest samples (<70 a), indicating that the feldspar signals in these samples were presumably not fully bleached prior to aeolian or beach deposition. However, even if the age uncertainties are large we obtained pIRIR₁₅₀ ages in agreement with independent age estimates for the two older samples, which are 70 and 390 years old.     

Assessment of soils pollution extent in surroundings of ironworks based on magnetic analysis

This paper reports on magnetic and magnetomineralogical studies of soils influenced by ironworks activity. Researches were conducted in five areas, of which Ostrowiec Świętokrzyski ironworks area is described in detail. A map of magnetic susceptibility was created based on field measurements and samples taken from soil profile were analyzed in laboratory. Measurements of magnetic susceptibility in two frequency ranges, anhysteretic remanent magnetization, isothermal remanent magnetization thermomagnetic and geochemical analysis were carried out. SEM was used to identify ferromagnetic fractions. As a result the horizontal and vertical extent of heavy metals pollution was established.     

Experimental modeling of the chemical remanent magnetization and Thellier procedure on titanomagnetite-bearing basalts

The results of the experimental studies on creating chemical and partial thermal remanent magnetizations (or their combination), which are imparted at the initial stage of the laboratory process of the oxidation of primary magmatic titanomagnetites (Tmts) contained in the rock, are presented. For creating chemical remanent magnetization, the samples of recently erupted Kamchatka basalts were subjected to 200-h annealing in air in the temperature interval from 400 to 500°С under the action of the magnetic field on the order of the Earth’s magnetic field. After creation of this magnetization, the laboratory modeling of the Thellier–Coe and Wilson–Burakov paleointensity determination procedures was conducted on these samples. It is shown that when the primary magnetization is chemical, created at the initial stage of oxidation, and the paleointensity determined by these techniques is underestimated by 15–20% relative to its true values.