Electrolytic Conductivity Values Research Articles

Multivariate statistics as means of tracking atmospheric pollution trends in Western Poland

This study was carried out over a period of 4 years (2002–2005) at 2 sites located in western Poland differing as regards to human impact by analysis of chemical composition of bulk precipitation. The aim of the study was to determine the sources of pollutions and assess their quantitative contribution to the bulk precipitation composition and to analyse long term-changes in the chemical quality of precipitation. Based on this information the possible transboundary impacts of pollution were also determined. The samples were characterized by determining the values of pH, electrolytic conductivity and concentration levels of Cl−, F−, SO4 2−, NO3 −, Na+, K+, Mg2+, Ca2+ and NH4 +. Analytical measurements were connected with application of principal component regression (PCR) and time series analysis (TS). Based on PCR results three major sources of pollutants in central part of Poland have been identified and quantitatively assessed as follows: “combined” (Poznań – 31%, WNP – 32%), “soil-particulates” (Poznań – 2%, WNP – 26%), “anthropogenic-fossil fuels” (Poznań – 43%, WNP – 23%). Time series analysis enabled discovering 12-month time cycle for NO3 −, NH4 +, Cl−, F− and SO4 2− in average monthly concentration values in bulk precipitation collected in Wielkopolski National Park. Seasonal variation in the emission of precursors of NO3 − and NH4 + was caused by changes in intensity of fertilizer application in agriculture and automobile exhaust emissions. Decreasing trend was visible for sulphates, nitrates, chlorides and fluorides which is an important indication of the acid rain reduction in the ecologically protected area and in Poznań.

Effect of Irrigation Water Salinity and Sodicity and Water Table Position on Water Table Chemistry Beneath Atriplex lentiformis and Hordeum marinum

Coal bed methane (CBM) extraction in Montana and Wyoming's Powder River Basin (PRB) produces large quantities of modestly saline-sodic water. Such water can cause dispersion of clays, degradation of soil structure, and osmotic stress in plants. This study assessed effects of irrigation water quality and water table position on water chemistry of closed columns, simulating a perched or a relatively shallow water table. The experiment presents an assessment of potential salt loading in areas where shallow or perched water tables prevent leaching or where artificial drainage is not possible. Water tables were established in sand filled PVC columns (0.20 m diameter × .005 m wall thickness × 1.22 m tall) at 0.38, 0.76, and 1.14 m below the surface, after which columns were planted to one of three species, two halophytic Atriplex spp. and Hordeum marinum Huds. (maritime barley), a glycophyte. Results for the two Atriplex ssp. did not differ significantly, and therefore, only results from Atriplex lentiformis (Torr.) S. Wats. (big saltbush) and H. marinum are presented in this article. Columns were irrigated for 224 d; irrigation water supplied every 7 d was equal to evapotranspiration (ET) + 100 mL. This amount replaced the water lost to ET between sampling, plus the volume of the water sample. Irrigation water representing one of two irrigation sources was used: Powder River (PR) [electrolytic conductivity (EC) = 0.19 Sm−1, sodium adsorption ratio (SAR) = 3.5] or CBM water (EC = 0.35 Sm−1, SAR = 10.5). Irrespective of species, continuous irrigation with CBM and PR water led to salt loading over time, the extent of which was proportional to the salinity and sodicity of applied water. Water in columns planted to A. lentiformis with water tables maintained at 0.38 m depth consistently had significantly greater EC and SAR values than those with 0.76 and 1.14 m water table positions. Elevated EC and SAR values most likely reflect the shallow rooted nature of A. lentiformis, which resulted in enhanced ET with the water table close to the soil surface. H. marinum's deep rooted nature and subsequent ability to utilize water from a variety of depths did not produce any significant differences in EC and SAR as a result of varying water table positions.

Chemometric analysis of rainwater and throughfall at several sites in Poland

Precipitation and throughfall samples were collected over a period of 4 years (1 January 1996–31 December 1999) at three different sites in Poland: one on moraine hills, one in the lowlands and one in a mountainous region. The aim of this project was to study the chemical composition of the samples, ionic correlations and fluctuations of selected variables with time in relation to geographical location, type of tree cover and climatic conditions. The samples were characterized by determining the values of pH, electrolytic conductivity and concentrations levels of SO 4 2− , NO 3 − , Cl − , Ca 2+ , K + , Na + and Mg 2+ . Statistical analysis revealed significant differences between the results obtained for different sampling site locations and characteristics (region of Poland, open area vs. throughfall) in four cases. The results obtained for precipitation samples were similar to those for throughfall samples only for acidic anions (SO 4 2− and Cl − ). For open areas, pH fluctuations were observed in 12-month cycles. Differences between the concentration levels of ions in the samples from the three sites could be explained by different amounts of precipitation at these sites. Concentrations of ions in precipitation and throughfall samples followed similar trends, the concentration levels being dependent on the kind of trees in the area, their age, and acidity of the precipitation. Significant differences were found for the concentration factors of the individual ions in throughfall between the sampling sites. Ionic correlations were examined to determine which salts contributed to the observed ion levels.

Electrolytic Conductivity of Semiarid Soils (Southeastern Spain) in Relation to Ion Composition

Salt-affected soils are frequent in arid and semiarid regions, where the resulting ill-effects on plant growth and the difficulties for proper soil management make knowledge of the total soil salt content essential. In this study, the relation between the electrolytic conductivity (EC) soil saturation and the 1:1 soil:solution extracts, the salt content, and various saline parameters were analyzed. Ionic characterization data referring to agricultural soils from a semiarid zone (Murcia, southeastern Spain) were used to study the relationship between EC and ion composition. Sixty samples per depth (0–30 cm, 30–60 cm and 60–90 cm) were taken in two years. EC, and Na+, K+, Ca2+, Mg2+, Cl−, NO3 − and SO4 2−concentrations were measured in both extracts. Total dissolved salts (TDS), sodium adsorption ratio (SAR), and total anions and cations were calculated from the relevant data to determine any correspondences among them using Spearman rank correlations. The mean EC values ranged from 0.56 to 0.93 S m−1 and the TDS values from 173 mmolc L−1 to 288 mmolc L−1 in the soil saturation extract and from 0.49 to 0.75 S m−1 and 153 to 233 mmolc L−1, respectively, in the 1:1 soil extract. The correlation coefficient between EC and NO3 −, K+ and Ca2+ (r < 0.70) was lower than between EC and Na+, Mg2+, Cl−, and SO4 2− (r > 0.85) in the saturation extract, in which a strong influence of the ionic ratios (SO4 2−/Cl−, Ca2+/Na+ and Mg2+/Na+) were evident. Increased concentrations of Mg2+, Ca2+ and SO4 2− were not always matched by increases in EC values, suggesting that the measurement of EC in the saturation extract was a good saline content indicator only when the salt content was low, but was less suitable in the presence of high Cl− or Na+ concentrations. The behavior of the ions in the 1:1 soil:solution extract was the same. The best correlation model between the EC values measured in the saturation and 1:1 extracts was a third order polynomial, although good results were obtained with linear and quadratic models.

Molality-based primary standards of electrolytic conductivity (IUPAC Technical Report)

Abstract New values of electrolytic conductivity were determined for aqueous KCl solutions with molalities of 0.01, 0.1, and 1.0 mol/kg in the temperature range 0 to 50 °C, at 5 K intervals. Expanded uncertainties, 2u c, were also calculated in accordance with the presently accepted protocol for the treatment of uncertainty. The new conductivity values are recommended as primary standards of electrolytic conductivity based on molality. They replace the previous values, based on the nonstandard demal scale, which were determined only at 0, 18, and 25 °C. The accuracy of the technique used was evaluated by repeating the determination of the previously recommended demal-based IUPAC standards of electrolytic conductivity and through comparison with other absolute measurements.

Straw Management Effects on Organic Matter Mineralization and Salinity in Semiarid Agricultural Soils

The impact of straw incorporation (6 Mg ha -1 year -1 ) into agricultural soils compared with straw removal on organic matter mineralization and salinity was studied. The mineralization coefficient (CO 2 -C evolved/organic C ratio) was obtained to evaluate organic matter mineralization. Soil salinity was measured as means of electrolytic conductivity of saturation paste extract. Both parameters were measured seasonally during two years in two salt-affected soils of the semiarid Central Ebro Valley (northeast Spain), a saline soil and a saline-sodic soil. The electrolytic conductivity (ranging from 2.5 dS m -1 to 24.3 dS m -1 ) and the mineralization coefficient (ranging from 5.9 10 -4 day -1 to 37.9 10 -4 day -1 ) varied widely during seasonal samplings of both soils. The lowest electrolytic conductivity values, coincided with the highest mineralization coefficient values. Straw mulching and burying decreased significantly the average seasonal electrolytic conductivity of both soils: 2.5 times in the saline soil, and 1.9 times in the saline-sodic soil. The EC reduction only increased significantly (P < 0.05) the mineralization coefficient on saline soil (1.6 times). Straw amendment, followed by rainy periods, allowed the soluble salts leaching but did not modify significantly sodium content. A logarithmic regression was found between mineralization coefficient and electrolytic conductivity (r 2 = 0.41), considering both soils. Infiltration, water aggregate stability, and qCO 2 were improved with the straw amendment, but only in saline soil. Soil differences showed the existence of a double effect: an osmotic and a specific ion effect.

Soil solution composition in forest soils of sierra de gata mountains, Central‐Western Spain: Relationship with soil water content

Nutrient ion concentrations in soil water were assessed in three deciduous forests in the Sierra de Cata Mountains, central‐western Spain, with annual precipitation ranging between 720 and 1,580 mm. Soil solutions were obtained at incremental depths from 15 to 110 cm with tension lysimeters and analyzed for pH, electrolytic conductivity (EC), dissolved organic carbon, soluble Si and Al components, Fe3+, Cu2+, Mn2+, Zn2+, Na+, K+, Ca2+, Mg2+, Cl−, SO4 2‐, and NO‐3. In general, ion concentrations and pH decreased with depth (from pH 6.5 to 5.5) and EC from 50 to 25 μS cm−1. At the driest forest site (Fuenteguinaldo), the highest EC values were at the profile surface, probably due to a lower degree of leaching and increased capillary action, as compared with profiles from forests with a higher annual precipitation. Soil water content was correlated with soil solution composition, showing a strong interdependence. The ionic composition of soil water in the three Cambisols, however, did not reflect the differences of annual precipitation.

An update on the electrolytic conductivity values for the primary standard KCl solutions: Conversion to the ITS-90 temperature scale

A new international temperature scale has replaced the 1968 scale. Here, we report the changes required in our previous results for primary conductivity standards for 0.01, 0.1 and 1.0 Demal KCl solutions at 0,18 and 25°C.

Model for the Soil Solution Composition of an Oasis

AbstractA static computer model based on the evaporative concentration of irrigation waters has been developed for the origin of soil solution compositions in the Al‐Hassa oasis in Saudi Arabia. The model successfully predicted the precipitation of calcite and the conversion of smectite to attapulgite when in equilibrium with atmospheric CO2 pressure. It also predicted precipitation of gypsum when irrigation water is concentrated by a factor of 3.7 and the precipitation of silica gel when water is concentrated by a factor of 7.5. Results from this study indicate that the model may be applicable to other oases in arid environments. Spring water discharges freely from the higher elevations and flows toward playas in the desert. Mineral fractionation follows the same natural slope within the oasis, as indicated by isoconcentration lines for salinity, carbonates, and gypsum in oasis soils. The calculated soil solution compositions at fixed electrolytic conductivity (EC) values were compared with the chemical analysis of 1:5 extracts having the same EC values. These comparisons showed that six primary processes are responsible for the formation of soil solutions from irrigation water under oases conditions. The processes are: (i) deaquation due to transpiration and evaporation, (ii) precipitation and dissolution of soil mineral phases, (iii) K fixation, (iv) Na and Cl retention, (v) MgSO04 formation, and (vi) biological formation of HCO3. Agricultural production of dates was absent in areas where the EC of 1:5 soil solution extracts exceeded 6 dS m−1 (i.e., in gypsum and silica gel precipitation areas).

Study of electrolytic dissociation by the Raman effect. II.—Nitrates

In the first part of these investigations by the author, the possibility of studying electrolytic dissociation by the Raman effect has been described with special reference to nitric acid. Accurate quantitative estimation has since been made of the degree of dissociation in the acid by measuring the intensities of Raman lines corresponding to the dissociated NO¯ 3 ions at various concentrations. The results thus obtained indicated that the dissociation in nitric acid is progressive between the concentrations 1-16 N and not complete as has been assumed for highly dilute solutions. A comparison of the values of the degree of dissociation obtained from this method with those calculated from conductivity measurements revealed a large discrepancy which was attributed to the uncertainty of the latter. The degree of dissociation cannot be directly evaluated from the values of electrolytic conductivity, which depend upon a number of factors such as viscosity of the solution, mobility of the ions, etc., as there is much uncertainty as to the dependence of conductivity on such factors. With Raman spectra, however, the number of molecules or ious is directly proportional to the intensity of the Raman lines corresponding to them. Hence a comparison of the number of molecules or ions at one concentration with that in another is made by simply comparing the intensities of the lines corresponding to them in the Raman spectra taken with the respective concentrations. The accuracy of the method is that attainable in the intensity measurements. Thus we have in this method a reliable means of measuring electrolytic dissociation, and another advantage is its applicability to concentrated solutions, for which at present no theory has been fully developed. In order to determine whether electrolytes are completely dissociated even in concentrated solutions, a systematic study of different electrolytes is being undertaken. The results for nitrates will be described in this communication.