Anion Deficit Research Articles

A potential prognostic indicator in methanol intoxication: Body temperature

Objective: Methanol intoxication is a type of poisoning with high mortality and morbidity. The current study aims to examine patients diagnosed with methanol intoxication and treated with standardized treatment to collect data that may be used to predict patient outcomes and mortality. Materials and Methods: The current study was a retrospective study and included patients over 18 years of age diagnosed with methanol intoxication between 1st March, 2011 and 1st March, 2021. All patients were treated with the treatment protocol determined by the clinic in accordance with the guidelines. Sociocultural characteristics, vital and laboratory findings, and clinical outcomes of the patients were analyzed. Results: Of the 28 patients included in the study, 80% were male, and the median age was 49. Patients were divided into two groups: survived and deceased. The median time since last alcohol intake was higher in surviving group (7 hours (Q1-Q3:6-12) vs 4 hours (Q1-Q3:2-17), p=0.005) and the amount of alcohol per kilogram of weight was lower in surviving group (3.13 ml/kg (Q1-Q3: 1.34-4.46) vs 8.81 ml/kg (Q1-Q3:5.22-9.49), p=0.002). The body temperature was lower in deceased group (35.40 °C (Q1-Q3:34.95-35.50) vs 36.40 °C (Q1-Q3:36.10-36.55), p=0.001). The current study showed that the other diagnostic factors of mortality in methanol intoxication are serum pH, lactate levels, bicarbonate levels, base deficit, anion deficit, the level of consciousness of the patient at admission, the time since the last alcohol consumption, and the amount of methanol ingested. Conclusion: In this study, it was concluded that moderate hypothermia may be an indicator of mortality in addition to classical findings. Thus, it has been shown that hypothermia will be effective in methanol intoxication in addition to other early markers for early diagnosis and rapid initiation of treatment.

Ecohydrology of two northern Wisconsin bogs

AbstractThe dynamics of water and solutes were investigated in two northern bog ponds using sensor networks and discrete water samples. Embedded sensors monitored water level (S), precipitation (P), evaporation (E), water temperature (T) and specific conductivity (SC) in the peatlands and encircled ponds at 30 min time intervals from 2009 to 2015. Pond water chemistry was monitored seasonally from 2000 to 2020. Daily hydrographs and water budgets indicated that both bogs are ombrotrophic systems, perched above the local water table. Although the predominant flowpath for liquid water was precipitation → pond → peatland → underlying glacial deposits, evaporation accounted for 70% to 90% of water losses. High dissolved organic matter (DOM) in the ponds resulted from transient reversals of flowpath and from molecular diffusion across the peatland/pond interface (a tea bag effect). DOM of peatland origin dominated pond water chemistry, regulating the concentration of important metals, major nutrients and the acid–base status of both bog ponds. Elevated concentrations of Fe, Hg and MeHg in the ponds reflected ligand binding by DOM. The formation of DOM‐Fe‐PO4 complexes likely accounted for >3‐fold higher P concentration relative to nearby clearwater lakes. Linear regression of dissolved organic carbon (DOC) against the anion deficit indicated that DOM contributed up to 6.6 mEq of strong acid per gramme carbon in pond waters. Winter maxima in the seasonal cycles of DOC, Ca, Mg, N, P, Hg and MeHg in both bog ponds were attributable, in large part, to salting out during ice formation. We conclude that multiple methods are needed to understand the dynamics of water and solutes in bog ecosystems.

Hydrogeochemistry and Mercury Contamination of Surface Water in the Lom Gold Basin (East Cameroon): Water Quality Index, Multivariate Statistical Analysis and Spatial Interpolation

Artisanal and small-scale gold mining activities have an impact on natural resources and human health. This study addresses the assessment of surface water quality in the Lom gold basin. A combined approach of water quality index calculation, multivariate statistical analysis and spatial interpolation was used. Sampling was performed at 15 stations during low- and high-water periods in 2021 for classical physicochemical parameters and total mercury measurements. The results show that the physicochemical parameters were below drinking water standards for both periods, except for pH, total suspended solids and total mercury. These waters show a large cation deficit as well as an anion deficit. The water chemistry is controlled by precipitations and silicate dissolutions in rock that convert the water into the Ca-HCO3 and Ca-Mg-HCO3 types. The level of mercury contamination varied from acceptable to high due to high flow rates during high water that cause a dilution effect for the mercury concentration upstream and its accumulation downstream. The water quality varied from excellent to very poor with better quality during the high-water period. The Lom watershed is locally affected by physical and chemical pollution due to the abundance of suspended solids and mercury resulting from the different gold mining activities.

Detection of H2S gas sensing performance of sol gel prepared metal oxide (In2O3, SnO2, Sn doped In2O3) thin films

Gas monitoring and control of hazardous and polluting gases (CO, H2S, CH4, H2, NH3, and alcohol) are required in industrial and laboratory applications where air quality must be regulated to protect public health, the environment, and security. Transparent conducting metal oxide semiconductors (TCO) have been shown to be extremely sensitive to both reducing and oxidising gases. They are caused by a lack of oxygen, also known as anion deficit. The present emphasis of scientific and technical endeavours is to improve the selectivity, stability, and practicability of response. Wide bandgap semiconducting oxides such as SnO2, In2O3 and Sn doped In2O3 have long been employed in gas sensing. The sensitivity of the gas sensor has increased as the thickness of the metal oxide semiconductor film or particle used to produce it has decreased. In the presence of reducible gases and adsorbed oxygen on the crystal surface, the conductivity is lowered by surface potential, when SnO2 is heated to high temperature, however, conductivity increases noticeably for In2O3 and indium tin oxide films. Indium oxide and tin oxide gas sensors detected H2S gas at working temperatures of 115 °C and 120 °C, respectively. Response and recovery times for indium oxide ranged from 10 s to 26 s and 34 s to 91 s, respectively, and for tin oxide from 3 s to 37 s and 82 s to 40 s. At 100 °C working temperature, ITO sensors with 10% tin concentration had the highest H2S sensitivity.

Photo-induced macro/mesoscopic scale ion displacement in mixed-halide perovskites: ring structures and ionic plasma oscillations

Contrary to the common belief that the light-induced halide ion segregation in a mixed halide alloy occurs within the illuminated area, we find that the Br ions released by light are expelled from the illuminated area, which generates a macro/mesoscopic size anion ring surrounding the illuminated area, exhibiting a photoluminescence ring. This intriguing phenomenon can be explained as resulting from two counter-balancing effects: the outward diffusion of the light-induced free Br ions and the Coulombic force between the anion deficit and surplus region. Right after removing the illumination, the macro/mesoscopic scale ion displacement results in a built-in voltage of about 0.4 V between the ring and the center. Then, the displaced anions return to the illuminated area, and the restoring force leads to a damped ultra-low-frequency oscillatory ion motion, with a period of about 20–30 h and lasting over 100 h. This finding may be the first observation of an ionic plasma oscillation in solids. Our understanding and controlling the “ion segregation” demonstrate that it is possible to turn this commonly viewed “adverse phenomenon” into novel electronic applications, such as ionic patterning, self-destructive memory, and energy storage.

Nanostructured Crystals of Fluorite Phases Sr1 – xRxF2 + x (R Are Rare-Earth Elements) and Their Ordering. 13: Crystal Structure of SrF2 and Concentration Dependence of the Defect Structure of Nonstoichiometric Phase Sr1 – xLaxF2 + x As Grown (x = 0.11, 0.20, 0.32, 0.37, 0.47)

The defect structure of as-grown SrF2 and nonstoichiometric phases Sr1 – xLaxF2 + x (x = 0.11, 0.20, 0.32, 0.37, 0.47) single crystals, grown from a melt under identical conditions, has been studied by X-ray diffraction analysis. All crystals belong to the CaF2-type structure, sp. gr. $$Fm\bar {3}m$$ . Deficit of fluorine anions is found in the 8c site in SrF2. Interstitial anions are not visualized in SrF2 in difference electron-density maps. The Sr1 – xLaxF2 + x phases exhibit the presence of vacancies in the main anion motif and interstitial fluorine ions of three types: in two sites 32f (w, w, w) with different coordinates w and in one site 4b. A model of the defect structure of Sr1 – xLaxF2 + x phase is proposed, according to which interstitial fluorine ions and impurity cations La3+ are grouped into clusters of the [Sr1 – nLanF26] tetrahedral configuration. Calculations based on structural data revealed that the average number of La3+ ions per cluster linearly increases from 2.6 to 3.13 with an increase in the LaF3 concentration. The average crystal volume corresponding to one cluster decreases from 1170.6(3) to 336.1(5) A3. The volume of the anion cluster core decreases from 2.52(7) to 2.42(7) A3, passing through a minimum in the composition with x = 0.32, which is similar to that of congruently melting phase, and then increases to 2.44(9) A3 at х = 0.47. Dynamic thermal displacement of matrix anions in Sr1 – xLaxF2 + x is observed in the [111] direction towards the cubic void center in the anion sublattice. Therefore, according to the mechanism of electrical conductivity, anion jumps are most likely in this direction.

Cationic ordering in tysonite type structures: III: Crystal structure of Ba5U4F26, the first fully ordered superstructure of anion-deficient tysonite

Ba5U4F26, the first fully ordered superstructure deriving from tysonite type with anionic deficit is prepared by annealing, below 983 K, the high temperature Ba1+xU1-xF6-2x tysonite solid solution for x = 0.11. It is structurally characterized in the monoclinic C2/c space group [a = 22.420(10) Å; b = 12.898(6) Å; c = 16.871(7) Å; β = 117.36(5)°].This new phase presents a full cationic and anionic ordering with 5 Ba and 4 U cationic sites. The BaF10 and BaF11 polyhedra are close to Edshammar polyhedra whereas U4+cations are 8-fold and 9-fold coordinated. Ba5U4F26 has structural features analogous to the BaUF6 ordered varieties and particularly to β-BaUF6. This description extends to the anion-deficient Ba1+xU1-xF6-2x and more generally to the M(II)1+x M’(IV)1-xF6-2x solid solutions the short range order features proposed for all the disordered tysonite M(II)M’(IV)F6 phases: decrease of the coordination number of M’(IV) cations and of the connectivity of M(II) and M’(IV) polyhedra from face-sharing to edge-sharing and from edge-sharing to corner-sharing, with anionic vacancies located in the neighbourhood of U cations.

Water-soluble Ions in PM2.5 on the Qianhu Campus of Nanchang University, Nanchang City: Indoor-Outdoor Distribution and Source Implications

Ambient PM2.5 was sampled in three indoor environments (a common office, a photocopy room and a student dormitory) and one outdoor environment (a rooftop) on a campus of Nanchang University in Nanchang city, China, on June 5–20, 2009. Analysis by ion chromatograph showed the indoor-outdoor differences and relationships of water-soluble ions. The indooroutdoor distributions indicated that chemicals and household garbage contributed most to the generation of water-soluble ions indoors. The indoor-outdoor relationships of water-soluble ions in PM2.5 in the common office and student dormitory were unrelated or weak, which indicated that the ions were produced indoors rather than carried in from outdoors. Correlations between various water-soluble ions in indoor and outdoor PM2.5 are discussed here, and it is suggested that the photocopier machine contributed little to the water-soluble ions indoors. Ion balance calculations indicated that the anions and cations in the photocopy room and outdoor environment shared an origin, but part of the anions and cations in the common office room and student dormitory originated indoors. The linear regression slopes (anion/cation) are all lower than 1, with the anion deficits probably affected by the absence of data on F − , PO4 3− , NO2 − , CO3 2− and organic acid salt.

Inorganic ion composition in Tardigrada: cryptobionts contain large fraction of unidentified organic solutes

Many species of tardigrades are known to tolerate extreme environmental stress, yet detailed knowledge of the mechanisms underlying the remarkable adaptations of tardigrades is still lacking, as are answers to many questions regarding their basic biology. Here, we present data on the inorganic ion composition and total osmotic concentration of five different species of tardigrades (Echiniscus testudo, Milnesium tardigradum, Richtersius coronifer, Macrobiotus cf. hufelandi and Halobiotus crispae) using high-performance liquid chromatography and nanoliter osmometry. Quantification of the ionic content indicates that Na(+) and Cl(-) are the principal inorganic ions in tardigrade fluids, albeit other ions, i.e. K(+), NH4(+), Ca(2+), Mg(2+), F(-), SO4(2-) and PO4(3-) were also detected. In limno-terrestrial tardigrades, the respective ions are concentrated by a large factor compared with that of the external medium (Na(+), ×70-800; K(+), ×20-90; Ca(2+) and Mg(2+), ×30-200; F(-), ×160-1040, Cl(-), ×20-50; PO4(3-), ×700-2800; SO4(2-), ×30-150). In contrast, in the marine species H. crispae, Na(+), Cl(-) and SO4(2-) are almost in ionic equilibrium with (brackish) salt water, while K(+), Ca(2+), Mg(2+) and F(-) are only slightly concentrated (×2-10). An anion deficit of ~120 mEq l(-1) in M. tardigradum and H. crispae indicates the presence of unidentified ionic components in these species. Body fluid osmolality ranges from 361±49 mOsm kg(-1) in R. coronifer to 961±43 mOsm kg(-1) in H. crispae. Concentrations of most inorganic ions are largely identical between active and dehydrated groups of R. coronifer, suggesting that this tardigrade does not lose large quantities of inorganic ions during dehydration. The large osmotic and ionic gradients maintained by both limno-terrestrial and marine species are indicative of a powerful ion-retentive mechanism in Tardigrada. Moreover, our data indicate that cryptobiotic tardigrades contain a large fraction of unidentified organic osmolytes, the identification of which is expected to provide increased insight into the phenomenon of cryptobiosis.

Diffusion and sorption of Cs +, I − and HTO in samples of the argillaceous Wakkanai Formation from the Horonobe URL, Japan: Clay-based modeling approach

Diffusion and sorption behaviors of cationic Cs +, anionic I − and neutral HTO in samples of the Wakkanai Formation from the Horonobe underground research laboratory (URL), Japan, were investigated as a function of ionic strength ( I) of synthetic groundwater by through-diffusion and batch sorption experiments and mechanistic modeling. The effective diffusivities ( D e) measured by through-diffusion experiments showed cation excess and anion exclusion effects, which were strongly dependent on I; D e for Cs + decreased as I increased, D e for I − showed the opposite dependency and D e for HTO showed no dependence. The sorption of Cs + measured by through-diffusion and batch sorption experiments were described by Freundlich isotherms with consistent parameters and decreased with I as a result of competitive ion exchange. Diffusion and sorption behaviors were interpreted by assuming the clay components of illite and smectite control diffusion and sorption mechanisms. The component additive (CA) sorption model, which includes illite and smectite contents and their ion exchange constants, provided a reasonable account of the Cs + sorption trends measured as functions of I and Cs concentration. The diffusion model was developed by coupling the electrical double layer (EDL) model, describing the change of ionic concentrations (cation excess and anion deficit) and viscoelectric effects caused by electrostatic interaction at negatively charged clay surfaces, and a simplified pore model assuming one type of pore shape and includes their size distribution. When averaging the electrostatic effects by using the pore surface area distribution, the model could predict the cation excess and anion exclusion effects, and its dependence on I reasonably well. This result implies the nanoscale pores dominating the pore surface area can strongly impact on ionic diffusion in argillaceous rocks. The clay-based modeling approach described here provides a useful tool to predict ionic diffusion and sorption in argillaceous rocks.

Composition of fine and coarse particles in a coastal site of the central Mediterranean: Carbonaceous species contributions

Total Suspended Particulate (TSP) and PM2.5 samples simultaneously collected at a coastal site (40.4°N; 18.1°E) in the central Mediterranean are analyzed to investigate the relative role of ions (Cl−, NO3−, SO42−, Na+, NH4+, K+, Mg2+, Ca2+) and carbonaceous species in the fine (PM2.5) and coarse (TSP–PM2.5) sampled mass. A methodology is described to determine carbonate carbon (CC), organic carbon (OC), and elemental carbon (EC) levels from Thermal Optical Transmittance (TOT) measurements since carbonate particles may significantly contribute to the Mediterranean particulate. We have found that CC levels vary up to 1.7 μg m−3 and 0.8 μg m−3 in the coarse and fine fraction, respectively. OC and EC levels vary up to 3.0 μg m−3 and 1.5 μg m−3, respectively in the coarse fraction, and vary within the 2.2–10 μg m−3 and 0.5–5 μg m−3 range, respectively in the fine fraction. Hence, OC levels may be overestimated mainly in the coarse fraction, if the CC contribution is not accounted for. CO32− levels (calculated from CC concentrations) account on average for 6% and 10% of the fine and coarse mass, respectively and allow balancing the anion deficit resulting from the ionic balance of ions detected by ion chromatography (IC). Total carbon TC = (OC + EC) accounts on average for 29% and 6% of the fine and coarse mass, respectively. IC ions account for 38% and 17% of the fine and coarse mass, respectively. OC, EC, SO42−, NH4+, and K+ are the major components in the fine fraction, accounting on average for 84% of the analyzed PM2.5 mass. Marine- and crust-originated ions (Cl−, Mg2+, Na+, Ca2+, CO32−) and NO3− are mainly in the coarse fraction and represent on average 83% of the analyzed coarse mass.

WATER ANALYSES FROM SOME IRISH BOGS AND FENS, WITH THOUGHTS ON 'THE <i>SCHOENUS</i> PROBLEM'

WATER ANALYSES FROM SOME IRISH BOGS AND FENS, WITH THOUGHTS ON 'THE <i>SCHOENUS</i> PROBLEM'

Influence of Agricultural Biomass Burning on Aerosol Size Distribution and Dry Deposition in Southeastern Brazil

The size distributed composition of ambient aerosols is used to explore seasonal differences in particle chemistry and to show that dry deposition fluxes of soluble species, including important plant nutrients, increase during periods of biomass (sugar cane trash) burning in São Paulo State, Brazil. Measurements were made at a single site centrally located in the State's sugar cane growing region but away from the immediate vicinity of burns, so that the airsampled was representative of the regional background. Calculation of ion equivalent balances showed that during burning periods smaller particles (Aitken and accumulation modes) were more acidic, containing higher concentrations of SO4(2-), oxalate, NO3-, HCOO-, CH3COO-, and CI-, but insufficient NH4+ and K+ to achieve neutrality. Larger particles showed an anion deficit due to the presence of unmeasured ions and comprised resuspended dusts modified by accumulation of nitrate, chloride, and organic anions. Increases of resuspended particles during the burning season were attributed to release of earlier deposits from the surfaces of burning vegetation as well as increased vehicle movement on unsurfaced roads. During winter months the relative contribution of combined emissions from road transport and industry diminished due to increased emissions from biomass combustion and other activities specifically associated with the harvest period. Positive increments in annual particulate dry deposition fluxes due to higher fluxes during the sugar cane harvest were 44.3% (NH4+), 42.1% (K+), 31.8% (Mg2+), 30.4% (HCOO-), 12.8% (CI-), 6.6% (CH3COO-), 5.2% (Ca2+), 3.8% (SO4(2-)), and 2.3% (NO3-). Na+ and oxalate fluxes were seasonally invariant. Annual aerosol dry deposition fluxes (kg ha(-1)) were 0.5 (Na+), 0.25 (NH4+), 0.39 (K+), 0.51 (Mg2+), 3.19 (Ca2+), 1.34 (Cl-), 4.47 (NO3-), 3.59 (SO4(2-)), 0.58 (oxalate), 0.71 (HCOO-), and 1.38 (CH3COO-). Contributions of this mechanism to combined aerosol dry deposition and precipitation scavenging (inorganic species, excluding gaseous dry deposition) were 31% (Na+), 8% (NH4+), 26% (K+), 63% (Mg2+), 66% (Ca2+), 32% (Cl-), 33% (NO3-), and 36% (SO4(2-)).

Temporal variation in the surface‐water chemistry of a blanket bog on Dartmoor, southwest England: analysis of 5 years' data

SummaryBlanket‐bog peats, mapped as the Winter Hill and Crowdy associations by the Soil Survey of England and Wales, are an oceanic manifestation of the ombrotrophic ‘raised‐bog’ (Hochmoor) peats that cover large tracts in the boreal zone of the northern hemisphere. This paper examines monthly analyses from 1992 to 1997 of major ions and other variables from an upland blanket bog in southwest England in relation to seasonality, rainfall, and the chemical composition of rainwater. Average ionic composition of surface water (and peat) integrates variable atmospheric solute inputs over the years. The dominant ions in the surface water, Na+ and Cl–, showed only weak seasonality, but divalent cations a stronger seasonal pattern with a summer maximum. Mean pH ranged from c. 4.4 in February to c. 4.2 in August. Changes in concentration of different cations were closely interlinked by cation exchange. The anion deficit, accounted for by anionic groups on the dissolved organic matter, was strongly seasonal with a summer maximum, as was optical absorbance at 320 nm. Nitrate and NH4+ were both at much smaller concentrations than in rain. Nitrate exceeded 1 μmol l−1 only during cold periods in winter, mainly following drought in the summer of 1995; NH4+ reached a few μmol l−1 only in summer. There was evidence of net retention of S by the peat in wet sites and during wet periods, and of net release of SO42– (and acidity) under dry conditions. The 1995 summer drought and ensuing dry year in 1996 had marked and persistent effects on pH, apparent ion deficit (DEF), SO42–, the divalent cations and Fe.

Throughfall chemistry and canopy interactions in a Sitka spruce plantation sprayed with six different simulated polluted mist treatments

Throughfall chemistry was studied in a mature Sitka spruce plantation in order to investigate canopy interactions, such as nitrogen absorption, cation leaching, and neutralization of rainfall passing through the canopy. The plantation had been exposed to six different simulated mist treatments including N (NH 4NO 3) and S (H 2SO 4 at pH 2.5) in four replicated blocks since 1996. Throughfall and rainfall were collected from May to September 2000. The results showed that 30–35% of the applied N was retained by the canopy. There were linear relationships between the loss of H + and increased K +, Mg 2+ and Ca 2+ deposition through the canopy. However these increases in K +, Mg 2+ and Ca 2+ deposition accounted for only about 50% of total neutralization of the acidity. The relationship between the anion deficits in throughfall and the loss of H + implied that weak organic acid anions were involved in the neutralization of the acidity in throughfall.

Trace elements and major species in precipitation at African stations: concentrations and sources

Abstract The chemical composition of rainwaters is important in obtaining information on the aerosols and gaseous species present in the atmosphere. Original data on the concentrations of trace elements and major species in the dissolved and particulate fractions of rainwater samples collected in intertropical Africa were used to determine the potential sources of chemical species. The photographic and mineralogical characterization of rainwater particles using scanning electron microscopy allow to identify the various origins of aerosols and the associated chemical elements: (i) the crustal source characterized by clay minerals, kaolinite (Al, Si), illite (Al, Si and K) and Fe, Ti, and Mn oxides, (ii) vegetation relicts: Mg, Si, Cl, Mn and Zn have been identified in these biogenic particles and (iii) carbonaceous particles (mainly Si) emitted during vegetation fires. Ionic charge balance calculation for the stations located in the rain forest and wet savanna zones (Cameroon, Centrafrican Republic and Ivory Coast) exhibit an anion deficit from 20 to 50 % (between 7 and 9 μeq.l−1). Measured total organic carbon concentrations (between 0.5 and 3.3 mg.l−1), are much higher than acetic and formic acid. The presence of mimic and/or fulvic substances emitted from the vegetation can explain this anion deficit. The results obtained in this study confirm the existence of three important sources of atmospheric compounds in intertropical Africa: (i) the silicate upper crust source: Sc, Ti, Fe, Y, Zr, Nb, Cs, La, Ce, Nd, Yb, Th and U exhibit enrichment factors very close to 1, (ii) the biogenic and biomass burning source characterized by the following elements: Mg, Cl, K, Ca, Mn, Zn, Rb, Sr, and (iii) two minor sources; marine (Mg, Na, Cl) and anthropogenic (Cr, Co, Zn, Ba and Pb). For the stations located in the rain forest zone, all these sources appear strongly linked. High correlations are observed between elements of various origins. This suggest a strong interaction between terrigenous, biogenic, marine and anthropogenic aerosols. The deposition of aerosols onto vegetation and the re-mobilization of the chemical species through natural emissions or biomass burning could explain these correlations and the observed chemical fractionation of marine origin elements such as Cl and Na.

Altered Podzolization Resulting from Replacing Heather with Sitka Spruce

Podzolization processes were studied under heather (Calluna vulgaris L. Hull) and Crowberry (Empetrum nigrum L.) and sitka spruce [Picea sitchensis (Bong.) Carr] planted on former heathland at Hjelm Hede, Jutland, Denmark. The aim was to compare changes in soil‐water chemistry with changes in the solid‐state chemistry after vegetation change. Fourteen profiles under heather and five profiles under spruce were examined and soil water was collected in lysimeter wells from the bottom of individual soil horizons A, E, Bh, and Bs from four representative profiles. The investigated area has been heathland for more than 2000 yr and part of it was planted with sitka spruce in 1933. The sitka spruce litter provided a more acidic soil environment, and the taller canopy increased the deposition of seasalts. The acidifying effects were increased by increased evapotranspiration from the plantation compared with the heathland. The investigation indicates disturbance of the podzolization process under spruce. Soil‐water chemistry showed a lack of Al immobilization in the B horizon under spruce, contrary to the heather system. Analyses of the spruce soil reveal a depletion of pyrophosphate (PYR) extractable Al and Fe. The charge balance in soil water showed a high deficit of anions under spruce compared with the dissolved organic C (DOC) concentration. Therefore, the deficit cannot be exclusively ascribed to negative charge on DOC. Sources of anion deficit might include (i) dissociated organic acids (R‐COO−), (ii) reduction in positive charge because of the existence of organo‐metal complexes [R‐(COO)2Al+], and (iii) reduction in positive charge because of an inorganic pH‐dependent species distribution of Al [Al(OH)2+, Al(OH)+2

Chemical Characteristics in Stemflow of Japanese Cedar in Japan

To clarify the characteristics in stemflow of Japanese cedar (Cryptomeria japonica), we conducted the annual and extensive observation. We examined the chemistry of bulk and wet deposition, throughfall and stemflow at 26 forested sites in June and September 1998. The each sampling site was broadly distributed in all over the Japanese archipelago. The stemflow pH of Japanese cedar was significantly lower (p<0.01) than precipitation and stemflow of broad-leaved species in both months. There were significant anion deficits in stemflow of Japanese cedar, suggesting that organic anions derived from plant sources play an important role in the stemflow acidity. Our results suggested that the strong stemflow acidity in Japanese cedar was derived from an internal biological characteristic rather than influences of external acidic deposition.

Estimating organic acid dissociation in natural surface waters using total alkalinity and TOC

Organic acid dissociation has usually been estimated from the difference between measured cations and anions (the anion deficit approach). An alternative is to use alkalinity titrations and an estimate of strong organic acids from TOC as an independent measure of organic acid dissociation (the CBALK approach). This approach may reduce the potential for errors relative to the anion deficit approach, which relies on summing up all measured constituents. Organic acid dissociation in a set of Swedish surface water samples from 700 different lakes, as well as 200 samples from 11 streams was predicted using a triprotic analogue model with buffering characteristics similar to those of the widely used “Oliver” model (OTM), but with a lower site density of organic acids. The average equilibrium pH of the samples in the weakly buffered pH range of 4.7–6.7 could be predicted more precisely (±0.16 pH units) using the CBALK approach, than when using the usual anion deficit approach (±0.41 pH units). The study supports the general applicability of models similar to the empirical OTM for predicting the dissociation of natural organic acids on a regional scale.

Acidic properties of dissolved organic matter leached from organic layers in temperate forests

The production of organic acids in forest organic layers is one of the major acid producing processes. In the organic layer leachates collected in Central Japan, the negative charge deficit between cations and inorganic anions ranged from 10 to 92% of the total positive charge of cations. The anion deficit was well correlated with the concentration of dissolved organic carbon (DOC). Carboxyl group contents in DOC and their pK a values were statistically optimized so that the anion deficit could be evaluated by the measurement of the DOC concentration and pH value. Optimized values for carboxylic group contents were in the range of 4.9 to 5.9 μmolc mg-1 C, which were lower than the amounts determined by titration, with the average values ranging from 5.7 to 7.8 μmolc mg-1 C. The optimized values were rather close to those with pK aless than 3.2 determined by the titration. The dissolved organic matter was fractionated into four groups according to hydrophobicity and acid-base properties. Hydrophobic acid fraction was the largest and accounted for 52 to 71% of the whole DOM. It contained about 10 μmolc mg-1 C of carboxylic groups, and 68±9% of them showed a pK a value of less than 3.2. Such a low pK a value of carboxylic groups is considered to have been caused by paired carboxylic groups with much higher pK a values, and hydroxyl groups. Hence the carboxylic groups were considered to exhibit a large range of pK a values. The carboxylic groups which were actually dissociated in the analyzed leachates were considered to be those with low pK a values. The estimation assuming a single pK a value did not give reliable results, and was biased in that it reflected the properties of the low pKa carboxylic groups. The proportion of the hydrophilic acid fraction was lower than that reported by other authors in cooler regions. The amounts of the carboxylic groups in the hydrophilic acids ranged from 16 to 22 μmolc mg-1 C, values about two times as high as those of hydrophobic acids.