Association of Nitrate Ion with Metal Cations in Aqueous Solution: a UV-Vis Spectrometric and Factor-Analytical Study

Ion association in aqueous solutions of varied concentrations of LiNO3, NaNO3, Ca(NO3)2, Sr(NO3)2, Ba(NO3)2, Mn(NO3)2, Co(NO3)2, Ni(NO3)2, Cu(NO3)2, Zn(NO3)2, and Cd(NO3)2 was studied by means of UV spectrometry. In all cases, except for Zn(NO3)2(aq) the principal-components (PCA) and evolving-factor (EFA) analyses of the spectra indicated formation of associated ion pairs [MNO3]z-1 (Mz denotes the cation) at higher salt concentrations. The (dis)similarities of the [MNO3]z-1 (Mz spectral profiles (computed by EFA) were examined by means of cluster analysis. The influence of transition-metal ions on the nitrate UV spectrum was found to be remarkably different compared to that of non-transition cations. That could be a consequence of different types of cation-anion interactions. The ion pairs containing non-transition metal ions could be regarded as classical electrostatic ones, whereas a weak coordination interaction was presumably present in the ion pairs formed by the nitrate and the cations of transition metals

Promjene u kvaliteti vode rijeke Drave prije i poslije Domovinskog rata

The goal of this study was to analyse 13 physico-chemical and microbiological parameters of the Drava River water at three sampling sites in the lower Drava region (eastern Croatia) over two distinct periods: the pre-war period between 1985 and 1992 and the post-war period between 1993 and 2008. Over both periods, most parameters kept within the tolerable water quality limits, while NO3-N, NH4-N and BOD5 were higher. The lower Drava showed slight organic pollution with high concentrations of dissolved oxygen. High levels of total coliforms and heterotrophic bacteria in the post-war period were only found downstream of the town of Osijek. Upstream of Osijek, the river showed a tendency for improvement.prostornih i vremenskih promjena tijekom perioda od 24 godine. Analizirali smo 13 fi zikalno-kemijskih i mikrobioloških parametara vode rijeke Drave na tri mjerne postaje smještene na području donjeg toka Drave (istočna Hrvatska) tijekom dvaju različitih razdoblja: 1985.-1992. (period prije rata) i 1993.-2008. (period poslije rata). Iako su vrijednosti većine podataka prikupljenih tijekom dvaju promatranih razdoblja oscilirale, vrijednosti su im se još uvijek nalazile u granicama za I. i II. vrstu voda. Vrijednosti nekih fi zikalno-kemijskih varijabla, kao što su NO3-N, NH4-N i BPK5 još su uvijek iznad granice za II. vrstu. Rezultati ovog istraživanja pokazali su blago organsko onečišćenje vode rijeke Drave s visokim koncentracijama otopljenog kisika. Povećanje broja ukupnih koliformnih i heterotrofnih bakterija u poslijeratnom razdoblju veliki je problem u području nizvodno od Osijeka pri čemu njihov broj katkad dostiže i vrijednosti za V. skupinu površinskih voda. Rezultati analize kvalitete vode rijeke Drave u dva različita razdoblja na dva mjerna mjesta uzvodno od Osijeka upućuju na tendenciju poboljšanja, iako neki od promatranih parametara pokazuju vrijednosti više od onih za II. skupinu riječnih voda. Različitosti, odnosno sličnosti među mjernim postajama istražene su metodom klasterske analize

Assessment of Variations of O3 Concentrations in Kopački Rit Nature Park, Eastern Croatia

Result of the first ozone monitoring in ambient air Nature Park of Kopački Rit (Eastern Croatia) are reported for the growth season in 2008. The measured hourly concentrations of ozone in the air do not exceed the limit value of 110 μg m–3 statutory regulation by Croatian legalization for the protection of human health. There were only 13 days exceeding of the target value of 120 μg m–3 (8-h averages) as established in the European Union guidelines on ozone pollution in ambient air. In contrast to the measured AOT40 whose value does not exceed the critical level of 18 000 (μg m–3) ·h for vegetation injury, an estimated AOT40 value was somewhat higher. The relationships between O3 and meteorological variables were investigated by a principal component analysis (PCA). Fourier analysis methods applied to ozone concentrations data showed that the most important variations in the O3 data are represented by usual daily cycles. (doi: 10.5562/cca2147

An Analysis of the Pollution Problem in Slavonski Brod (Eastern Croatia)

H2S, PM2.5, O3, NO2, SO2 and meteorological parameters such as temperature, relative humidity, precipitation, wind speed and wind direction were measured simultaneously in an eastern Croatian town called Slavonski Brod during the season winter/spring 2010. Emissions from the nearby cross-border (Bosnia and Herzegovina) oil refinery were identified as sources of temporary elevated concentrations of H2S. The maximum daily averages of PM2.5 concentrations during the winter period were as high as 240 mg m–3 which is a value 10 times greater than the threshold prescribed by the World Health Organization. It is considered that the heating season, dense traffic, intense industrial activities and temperature inversion during stable weather conditions are prevailing contributors to higher winter concentrations of PM2.5. The results of the principal component analysis technique (PCA) have shown that lower air temperature, lower wind speed and higher relative humidity play a significant role in the winter pollution episodes. From a public health point of view, implementation of measures aimed at reducing the levels of H2S and PM2.5 should be considered

Trace Metals in the Environment and Population as Possible Long Term Consequence of War in Osijek-Baranja County, Croatia

War in Croatia resulted with a significant release of contaminants into the environment as a result of the use of combat assets, mainly conventional, mostly aimed at civilian targets. The aim of the study was to investigate the concentration of metals and metalloids in the soils, water, plants (Taraxacum officinale), serum, urine and hair of the inhabitants in eastern Croatia. Overall results show minor abnormalities in presence of some trace metals in soil (As, Hg, Pb, Sb), water (As, Fe) and dandelion leaves (As) in some locations. Compared with soil samples from areas exposed to low intensity combat activity soil samples from areas exposed to heavy fighting had higher concentrations of As, Hg and Pb than allowed by national legislation for ecologic farming. Drinking water with the exceptions of the concentrations of Fe, As and Mn was in accordance with national legislation. Examinees from Dalj had mean hair Sb level 10-19x higher then examinees from any other location. However, when these data are correlated through methods of Principal Component Analysis, presence of trace metals in some war affected areas can be followed from soil, through plants up to population proving that intense combat activities over small area leave metal presence that can be followed even 15 years after the war

Application of Spectrophotometric Fingerprint in Cluster Analysis for Starch Origin Determination

Botaničko podrijetlo škroba je od velike važnosti za primjenu u industriji i proizvodnji hrane jer može bitno utjecati na svojstva krajnjeg proizvoda. Trenutno dostupne mikroskopske metode za određivanje podrijetla škroba su dugotrajne. Škrob se sastoji od amiloze i amilopektina, čiji omjer ovisi o njegovom botaničkom podrijetlu. Trijodidni ioni se obično vežu za amilozu i amilopektin, a njihovo vezivanje ovisi o podrijetlu škroba. U ovom je istraživanju mjeren apsorpcijski spektar kompleksa škrob-trijodid različitih vrsta, kao što su pšenica, krumpir, kukuruz, raž, ječam, riža, tapioka i škrob nepoznatog podrijetla, te različitih sorata iste vrste. Svaki je uzorak škroba imao specifične parametre: maksimalnu valnu duljinu pika za kompleks škrob-trijodid (λmax/nm), maksimalnu promjenu apsorbancije pri λmax (ΔA) i pomak λmax prema uzorku škroba nepoznatog botaničkog podrijetla. Vidljivi je dio apsorpcijskog spektra (500-800 nm) za svaki uzorak škroba dao jedinstveni otisak, koji je zatim obrađen klaster analizom. Tom su analizom podaci razdvojeni u dva klastera, jedan klaster žitarica i drugi klaster krumpira, tapioke i riže. Unutar klastera škrobova žitarica u podklastere su se izrazito razdvojili škrobovi pšenice, ječma i raži od kukuruznih škrobova. Podaci o sortama dobro su se grupirali unutar istog podklastera. Predložena metoda, koja kombinira klaster analizu i podatke dobivene mjerenjem apsorbancije vidljivog dijela spektra kompleksa škrob-trijodid, uspješno je razvrstala škrobove na osnovi njihove pripadnosti vrstama te sortama unutar iste vrste. Metoda je jednostavnija i praktičnija za uporabu od standardnih dugotrajnih metoda.The botanical origin of starch is of importance in industrial applications and food processing because it may influence the properties of the final product. Current microscopic methods are time-consuming. Starch consists of an origin-dependent amylose/amylopectin ratio. Triiodide ions bind characteristically to the amylose and amylopectin depending on the botanical origin of the starch. The absorbance of the starch-triiodide complex was measured for wheat, potato, corn, rye, barley, rice, tapioca and unknown origin starch, and within the different cultivars. Each starch sample had specific parameters: starch-triiodide complex peak wavelength maximum (λmax/nm), maximum absorbance change at λmax (ΔA) and λmax shift towards the unknown origin starch sample values. The visible absorption spectra (500-800 nm) for each starch sample were used as a unique fingerprint, and then elaborated by cluster analysis. The cluster analysis managed to distinguish data of two clusters, a cereal type cluster and a potato/tapioca/rice starch cluster. The cereal subclusters extensively distinguished wheat/barley/rye starches from corn starches. Data for cultivars were mostly in good agreement within the same subclaster. The proposed method that combines cluster analysis and visible absorbance data for starch-triiodide complex was able to distinguish starch of different botanical origins and cultivars within the same species. This method is simpler and more convenient than standard time-consuming methods