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PubMedDate not supplied

Phenanthrene adsorption by soils treated with humic substances under different pH and temperature conditions.

The mobility of phenanthrene (PHE) in soils depends on its sorption and is influenced by either the existing soil humus or exogenous humic substances. Exogenous humic acids (HAs) were added to soil to enhance the amount of soil organic carbon (SOC) by 2.5, 5.0, and 10.0 g kg(-1). PHE desorption of the treated soils was determined at two pH levels (3.0 and 6.0) and temperatures (15 and 25 degrees C). Soil PHE adsorption was related to pH and the type and quantity of added HAs. Humic acid (HA) and fulvic acid (FA) derived from peat had different effects on adsorption of PHE. Adsorption increased at first and then decreased with increasing quantity of exogenous FA. When the soil solution pH (in 0.005 M CaCl(2)) was 4.5 or 3.0, the turning points were 2.5 g FA kg(-1) at pH 3.0 and 5 g FA kg(-1) at pH 4.5. When soil solution pH was 6, the amount of adsorbed PHE was enhanced with increasing exogenous HAs (HA or FA) and amount of adsorption by soil treated with FA was higher than with HA. Adsorption of PHE in the FA treatment at 10.0 g kg(-1) was lower than the controls (untreated soil or treatment with HAs at 0 g kg(-1)) when the soil solution pH was 3.0. This suggests that FA adsorbed by soil was desorbed at low pH and would then increase PHE solubility, and PHE then combined with FA. PHE adsorption was usually higher under lower pH and/or lower temperature conditions. PHE sorption fitted the Freundlich isotherm, indicating that exogenous humic substances influenced adsorption of phenanthrene, which in turn was affected by environmental conditions such as pH and temperature. Thus, exogenous humic substances can be used to control the mobility of soil PAHs under appropriate conditions to decrease PAH contamination.

Adsorption↗
PubMed2007

Geochemistry of the barkinite liptobiolith (Late Permian) from the Jinshan Mine, Anhui Province, China.

This paper discusses the geochemistry and mineralogy of the barkinite liptobiolith of the Late Permian age from the Jinshan Mine, Guangde County, Anhui Province, China. Samples were examined using inductively coupled plasma-mass spectroscopy, X-ray fluorescence, cold-vapor atomic absorption spectrometry, ion-selective electrode, sequential chemical extraction, scanning electron microscopy equipped with energy-dispersive X-ray, and optical microscopy. The coal is a medium-ash and high-sulfur resource. Minerals in the coal are composed of kaolinite, pyrite, calcite, and quartz. Pyrite and calcite are derived from seawater during peat accumulation. Quartz in the coal is of authigenic origin. Part of the kaolinite is from a land-source region, and part occurs as cell-fillings and is of authigenic origin. The results also indicate that the barkinite liptobiolith contains some toxic elements in high concentrations. Elements including Li, Be, Si, Sc, Ti, V, Cr, Fe, Ga, Se, Y, Zr, Mo, the rare earth elements (REEs), W, Hg, Tl, Pb, Th, and U in the coals are enriched in the barkinite liptobiolith. Results of sequential chemical extraction showed that Li, Sc, Ti, Cr, Y, Zr, REEs, and Th in the coal mainly occur as silicates, while Be and W are related to organic matter. Pyrite is the dominant source of S, Mo, Hg, Tl, and Pb. Gallium only occurs in silicate, and U and V occur both in organic and silicate associations.

China↗
PubMed2006

Drought-induced sulphate release from a wetland in south-central Ontario.

Increased sulphate (SO(4)) export from wetlands following summer droughts in central Ontario, Canada has been associated with the delayed chemical recovery of downstream surface waters following decreased sulphur (S) emissions. Prolonged summer droughts result in a decrease or cessation of stream flow, declines in wetland water table level and oxidation of reduced S compounds to SO(4), which is subsequently flushed into drainage streams when stream flow resumes. Sulphate input-output budget calculations (1983-1995 and 1999-2001) at a conifer Sphagnum swamp in the Plastic Lake catchment, indicate that SO(4) is retained in most years but is exported on a net basis following particularly severe summer droughts that result in the cessation of stream flow for more than 54 days (95% CI: 41-72 days). Hindcast calculations using long-term (1916-2000) stream discharge records from a nearby station indicate that while droughts occurred frequently in south-central Ontario over the past 85 years, sufficiently dry conditions to cause net SO(4) export occurred in only 18 of the past 85 years, and indicate a cumulative positive SO(4) balance for the swamp (i.e. net SO(4) retention). Furthermore, the S pool at the Plastic Lake swamp has been estimated to be approximately 1500 kg S/ha in the upper 40 cm peat layer, which is large compared to the amount of net SO(4) export that occurs even in years with particularly dry summers (e.g. -43 kg S/ha in 1987/88). Together, these data suggest that the wetland S pool at Plastic Lake has not been depleted by previous droughts and will continue to sustain episodic drought-related SO(4) export for the foreseeable future.

Disasters↗
PubMed1990

Biphasic voltage relaxation pattern observed in cells of Eremosphaera viridis after injection of charge-pulses of short duration: detection of tip clogging of intracellular microelectrodes by charge-pulse technique.

Charge pulse experiments performed on the peat-bog alga Eremosphaera viridis revealed an unusual voltage relaxation behaviour. Injection of charge pulses of 1 microseconds duration resulted in an immediate charging of the membranes (time constant of the order of 40 ns). Nevertheless, the potential-measuring microelectrode recorded an exponential increase in membrane voltage with a time constant of about 1.3 ms. The maximum voltage value was recorded after about 3 ms, followed by an exponential decay with a time constant of about 9.6 ms. This biphasic time course was independent of the amplitude of the injected charge and of the location of the impaled microelectrodes in the vacuole. Centrifuged cells in which the chloroplasts and the other organelles were pelleted in one part of the cells showed the same electrical response. Electrical breakdown of the cell membranes resulted in the disappearance of the biphasic voltage response. In this case only the decaying relaxation process could be recorded with a time constant of 3 ms. After resealing of the membranes the original biphasic relaxation response was restored. Increasing concentrations of KCl in the bathing medium reduced both time constants almost correspondingly. The experimental findings were evaluated with an electrical equivalent circuit. Theoretical analysis with reference to the experimental data suggested that the delayed voltage response of the potential-recording electrode resulted from a membrane seal across the tip of this electrode. The resistance of this seal was calculated to be about 400 M omega. The specific resistances and capacitances of tonoplast and plasmalemma membranes were calculated from the decaying part of the biphasic relaxation curves. The average values were found to be 2.58 omega.m2 and 5 mF.m-2. The investigations reported here suggest that charge pulse experiments can be generally used for the detection of membrane and cytoplasmic material clogging of the tip of intracellular microelectrodes, a problem with which most electrophysiologists are faced when interpreting data obtained from impaled microelectrodes.

Cell Membrane↗
PubMed1983

Effect of coal rank on the interferon system.

Studies on the induction of interferon by influenza virus in monkey kidney (LLC-MK2) cell monolayers pretreated with coal dust revealed that the inhibitory activity of the mineral on this process was related to coal rank. Maximal inhibition of viral interferon induction was noted with high rank coal and the degression of this activity was related to coal's position in the carboniferous series; anthracite, bituminous, subbituminous, lignite, and peat. The cytocidal activity of each rank of coal, however, was comparable in relation to the corresponding quantities of coal dust that were tested indicating that findings related to interferon production are not explicable on the basis of remaining viable cells. Coal dust, irrespective of rank, also did not affect the ability of exogenous interferon to confer antiviral cellular protection. An inverse relationship mediated by coal of different rank occurred between influenza virus growth and interferon levels which suggested that increased virus growth reflected the ability of higher rank coal to affect adversely interferon production.

Animals↗
PubMed1992

Supercritical fluid extraction of polychlorinated biphenyls and pesticides from soil. Comparison with other extraction methods.

A comparison is made of supercritical fluid extraction (SFE) with two other techniques widely used for the extraction of polychlorinated biphenyls (PCBs) and organochlorine pesticides in soil. Extraction conditions for the SFE of PCBs and pesticides were first determined. An experimental approach was set up to determine the influence of different extraction parameters such as pressure, extraction time, static and dynamic extraction, restrictor type and collection solvent for off-line SFE. The use of carbon dioxide at 50 degrees C and 20 MPa, 10 min static followed by 20 min dynamic extraction with collection in iso-octane were been found to be the optimum conditions. Two types of soil, with a low and high content of organic carbon, respectively, spiked with 16 PCBs and organochlorine pesticides with a wide range of volatility and polarity at a level of 5 ng/g dry matter, were used as test materials. Conventional solvent extraction gives a good extraction yield for soil with a low content of organic carbon, but for peat soil the recoveries decrease dramatically to 30% for DDE, DDT and PCB 138 and 153. The recoveries with Soxhlet extraction are good, but an extra clean-up step before analysis is necessary. SFE gives good extraction yields for PCBs and organochlorine pesticides, varying between 85 and 105% with a reproducibility of 5% for each component for both types of soil. SFE is a fast, clean and reproducible method for the extraction of PCBs and organochlorine pesticides from these two soil matrices.

Carbon↗
PubMed1995

Chemical forms of gamma-emitting radionuclides in soils adjacent to the Chernobyl NPP.

Samples of sandy forest soils, meadow sandy-peat soil and meadow sandy-loam soil were taken at different sites within a 30-km zone around the Chernobyl NPP (ChNPP). The samples were extracted with water and a 0.1-N solution of ammonium acetate. The extracts were measured for gamma-radionuclides and stable cation content. The content of all mobile forms of the radionuclides present in the 0-10-cm soil layer accounts for 0.5-5% of the total radionuclide content in this layer, depending on the type of radionuclide and soil. Water soluble forms of the radionuclides were found in the 0-5-cm layer only. Exchangeable radionuclide forms were represented, as a rule, by radiocaesium in both the 0-5- and 5-10-cm layers. Content of Cs-137 exchangeable forms in the organic-mineral horizon were roughly inversely proportional to the sum of stable exchangeable cations and organic matter content. Forest vegetation takes up a significant share of the mobile forms of radiocaesium from the soils.

Cesium Radioisotopes↗
PubMed1996

Burning radionuclide question: what happens to iodine, cesium and chlorine in biomass fires?

Fires can mobilize radionuclides from contaminated biomass through suspension of gases and particles in the atmosphere or solubilization and enrichment of the ash. Field and laboratory burns were conducted to determine the fate of I, Cs and Cl in biomass fires. Straw, wood, peat, dulse (seaweed) and radish plants were combusted with temperatures varying from 160 to 1000 degrees C, representing the normal range of field fire temperatures. Loss to the atmosphere increased with fire temperature and during a typical field fire, 80-90% of the I and Cl, and 40-70% of the Cs was lost to the atmosphere. The remainder was left behind in the ash and was soluble. Typically, the ash was enriched in I by a factor of two to three, with higher enrichments of Cs and lower enrichments of Cl, when compared to the initial fuel concentration during field burns. Most of the I was lost to the atmosphere as a gas. If the elements were radioactive isotopes, such as 129I, 137Cs and 36Cl, fires could cause an increased radiological dose to people through inhalation, exposure to ash, or ingestion of plants because of increased uptake of ash leachate.

Air Pollutants, Radioactive↗
PubMed1996

Mobility of Chernobyl-derived 137Cs in a peatbog system within the catchment of the Pripyat River, Belarus.

The behaviour of Chernobyl-derived 137Cs in a hydrologically isolated bog system in the catchment of the Pripyat River, Belarus was investigated. Measurements were made of 137Cs activities in the solids and pore waters of the bog soils, as well as the variability in activity in water draining from the bog. It was found that the radiocaesium activity of the pore water, and hence the measured distribution coefficient, Kd, was dependent upon the pressure at which the water was removed from the soil. Measured values of Kd were of the order 10(2) l/kg at an extraction pressure of 0.8 MPa, approximately one order of magnitude lower than those measured in a similar system, Devoke Water, in the UK [1]. Results of comparative measurements suggested that this was a result of the different pore water extraction techniques used. The vertical migration of radiocaesium was modelled using a solution of the advection-diffusion equation. Using a mass balance approach, it was estimated that 137Cs was removed from the system at a rate of 0.3% of the catchment inventory per year, approximately 8 years after the Chernobyl accident. It was shown that both vertical migration and removal of 137Cs is best modelled using a Kd based on a measurement of pore water held at low pressure in the soil, approximately 10(3) l/kg. 137Cs activities in soil pore waters and in drainage waters were very strongly related to the aqueous potassium concentration, and both showed concentration minima in drainage water during the spring. It was shown that runoff coefficients of radiocaesium from peat bogs 8 years after the Chernobyl accident were approximately one order of magnitude greater than those from unsaturated soils of higher mineral content.

Cesium Radioisotopes↗
PubMed1996

Absorption of radiocaesium by sheep after ingestion of contaminated soils.

The absorption of 137Cs by sheep following ingestion of contaminated soil was studied using an established dual isotope method. Two agricultural soils were studied: an alluvial gley contaminated by discharges to the sea from the Sellafield Reprocessing Plant, and a lowland organic soil that had been artificially contaminated. Values of the true absorption coefficient of radiocaesium of 0.19 +/- 0.03 and 0.03 +/- 0.01, respectively, were obtained for these soils. This implies that availability of soil-associated radiocaesium for uptake following ingestion is up to about 20% of that when the activity is incorporated in vegetation. These results have been compared to estimates of availability made using an in-vitro approach described previously and found to be in good agreement. However, comparison with in-vitro data obtained for an upland peat indicated that absorption from some upland organic soils could be greater than from the lowland organic soil.

Absorption↗
PubMed1996

Factors affecting the transfer of radiocaesium from soil to roe deer in forest ecosystems of southern Germany.

Since 1987, in Southern Germany, as a consequence of the Chernobyl accident, the 137Cs activity concentration in roe deer (Capreolus capreolus) has been intensively monitored. A large data set is now available with approximately 5000 samples, with information about the location of the animal, the time of slaughtering, soil characteristics and distance to intensively managed agricultural land. Both the roe deer 137Cs activity concentrations and aggregated transfer coefficients soil-roe deer (T(ag,r)) show a considerable variability with geometric mean and geometric standard deviation in meat of 270.3.5 +/- 1 Bq.kg-1 and 0.01.3.5 +/- 1 m2.kg-1, respectively. From 1987 to 1991, T(ag,r) values exhibited a decline with an ecological half-life of about 3 years. Since 1991, no further decrease of the roe deer contamination level was observed. This general trend is superimposed by an increase in T(ag,r) in autumn that has occurred in almost every year, which is probably due to consumption of mushrooms. This hypothesis is supported by a significant positive correlation between the precipitation during July and August, stimulating the fungi's growth and the height of the maximum in T(ag,r) in autumn. Animals are less contaminated when living in parts of the forest from where they have access to intensively managed agricultural land. A small, but significant correlation is observed between the T(ag,r) and soil parameters; the total potassium content of the soil and the pH of the organic soil layer. The highest transfer coefficients soil-roe deer were found on a peat bog, where most values ranged from 0.01-0.1 m2.kg-1, and neither a pronounced seasonal variation, nor a long-term decrease was observed. On sites with coniferous forests, most T(ag,r) values range from 0.005 to 0.05 m2.kg-1, on sites with a mixture of coniferous and deciduous trees, the transfer coefficients range mostly from 0.002 to 0.02 m2.kg-1. This is a further indication of the importance of the uppermost soil layers and the biological processes therein with respect to the bioavailability of caesium. On the two sites, the values at the lower boundary are more typical for animals that have access to agricultural areas, whereas the higher values were observed in autumn and for animals grazing distant from agricultural areas.

Animals↗
PubMed1989

Objective and subjective attractiveness and early adolescent adjustment.

Using data from the Pennsylvania Early Adolescent Transitions Study (PEATS), this study assessed how objective physical attractiveness (PA), indexed by appraisals from others, and subjective PA, indexed by self-appraisals, relate to each other and, in turn, to early adolescent adjustment (indexed by self-esteem and anxiety). Findings indicated a low relationship between objective and subjective PA. Only subjective PA was associated with adjustment.

Adaptation, Psychological↗
PubMed1987

The fate of some components of acidic deposition in ombrotrophic mires.

The ability of ombrotrophic Sphagnum species to immobilise inorganic nitrogen deposited from the atmosphere was investigated in a series of simple lysimeter experiments. In an unpolluted mire, Sphagnum fuscum mats retained all the nitrogen deposited to them in natural precipitation events. Sphagnum capillifolium mats, transplanted from an unpolluted site to the polluted southern Pennines in England, also initially retained a large proportion of deposited nitrate and ammonium. However, a laboratory experiment demonstrated that high rates of nitrogen supply cause a loss of the ability of the moss to retain nitrate, which suggests that this may occur as a result of increased nitrogen deposition in polluted regions, resulting in increased nitrate availability in the peat. Investigation of the volume of precipitation and amounts of sulphate and chloride passing through the Sphagnum mats in the southern Pennines, as compared to that collected in adjacent bulk deposition gauges, showed that conventional deposition monitoring grossly underestimates rates of deposition to vegetation. Efficient trapping of occult and dry deposition by the moss led to much greater volumes of precipitation and amounts of sulphate and chloride being measured in throughflow than in bulk precipitation samples. Physiological response of S. fuscum to occult precipitation and heavy rainfall was investigated by measuring nitrate reductase activity induced in the moss by nitrate supplied in 'fine mist' and 'large droplet' applications of solutions to moss in the field. Greater response was shown to occult deposition, suggesting that this form of precipitation may be important in vegetation damage in polluted regions.

Journal Article↗
PubMed1989

Statistical modelling of water colour in the uplands: The Upper Midd catchment 1979-1987.

The increasing colour of raw water from the uplands is a matter of concern to water managers. The colour record for the period 1979-1987 is examined for the catchment of Upper Nidderdale, North Yorkshire. The variation in colour shows a marked seasonality with peaks occurring during the autumn months. No long-term sustained increase in colour is found, although colour levels were high in 1980, 1985 and 1987. Colour is found to be highly correlated with iron and, more particularly, aluminium. There is no relationship between colour and turbidity which suggests that there is no direct link between colour levels and erosion on the catchments. Colour increases appear to relate to large soil moisture deficits in months immediately prior to the colour flush and to high soil moisture deficits in the previous year. Complementary relationships are found between monthly rainfall totals and colour. In the light of these findings, it is suggested that high colour is associated with water table lowering and aerobic decomposition of the upper organic peat layers.

Journal Article↗
PubMed1991

Effects of Sphagnum moss and urban runoff on bioavailability of lead and zinc from acidic wetlands of the New Jersey pinelands.

The effects of Sphagnum and urban runoff on the bioavailability of metals were tested by adding PbCl2 and ZnCl2 to laboratory microcosms constructed of peat substrate with or without live Sphagnum spp. and planted with Acer rubrum L. seedlings or Vaccinium macrocarpon Ait. shoots. We hypothesized that Sphagnum would increase bioavailability through its acidifying action, while urban runoff would decrease availability through increases in alkalinity. Metals were more available to the test plants treated with acidic swampwater than with alkaline runoff. Sphagnum moss caused increases in tissue concentrations in V. macrocarpon, but not in A. rubrum. The latter species took up more metals when grown on substrate from sites receiving runoff, whereas the former took up more metals from substrate from undisturbed sites, despite the lower substrate metal concentrations. Differences in uptake by the two species may reflect differences in their ability to root in the Sphagnum mat. The results demonstrate that Sphagnum spp. exerts strong species-specific effects on the uptake of metals by vascular plants, and that plant species native to acidic wetlands vary widely in their response to metals in the substrate.

Journal Article↗
PubMed1991

Caesium concentration factors in wild herbivores and the fox (Vulpes vulpes L).

A selection of wild animals was sampled in the winter of 1986/87. The sites chosen for sampling were based on information obtained from survey carried out by The Institute of Terrestrial Ecology in the spring and autumn of 1986. Animals included deer, grouse, hares and rabbits, and foxes which were collected as a top carnivore in the food chain. Variation in concentration of caesium between species from the same area was unpredictable; rabbits, for instance, never exceeded 200 Bq kg(-1) (fresh wt) of (137)Cs in their flesh, even when adjacent to deer forests with over 1000 Bq kg(-1) in the venison. The greatest complication grose from areas of peaty uplands where the pre-Chernobyl (137)Cs from weapons-testing was much higher than expected. This pre-Chernobyl contribution amounted to 630 Bq kg(-1) in a red grouse from the Pennines, and 650 Bq kg(-1) in a roe deer from near the Borders, being c. 60% of the total. Concentration factors were calculated using values from freshly ingested vegetation and tissues from individual animals. Significant differences in concentration factors were found depending on species, food, sex, breeding condition and age. Contrasting the decrease of the two caesium isotopes in roe deer from forestry on peat with those from woodlands on mineral soils, it appeared that after an initial fall in concentration, the only decrease thereafter occurred on the mineral soils. Nowhere were radiocaesium concentrations high enough to cause concern amongst consumers of game and other wild animals, even when levels exceed 3000 Bq kg(-1) (fresh wt) as they did in red deer, red grouse and the blue hare.

Journal Article↗
PubMed1992

Active biomonitoring of polycyclic aromatic hydrocarbons by means of mosses.

Spherical bags, packed with 20 g of peat moss (Sphagnum spp.), were exposed to ambient air at a distance of 1 km from a plant manufacturing electrodes for the production of aluminium, near Rotterdam, The Netherlands. In these bags, the concentrations of six polycyclic aromatic hydrocarbons were determined, and compared with the concentrations in moss bags that had been exposed in relatively clean areas. From the results it can be concluded that, in addition to their useful application for biomonitoring of heavy metals, mosses can be applied in active biomonitoring of polycyclic aromatic hydrocarbons in ambient air.

Journal Article↗