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PECULARITIES OF DYNAMICS OF PHOSPHORUS FORMS IN WATER,PARTICULATE MATERIALS AND BOTTOM SEDIMENTS OF RIVER DNIESTERV. Rusu, L.Postolachi, T. LupascuInstitute of Chemistry of Academy of Sciences of Moldova, Lab of Ecological Chemistry, Academiei 3 str, MD-2028 Chisinau, Moldova, E-mail:larisapostolachi@rambler.ruSeasonal and spatial dynamics of phosphorus forms in water, particulate materials and bottom sediments of river Dniester was elucidated. Thescheme for determination of phosphorus forms in water and particulate materials according to World Health Organization classification was completedand tested for estimation of phosphorus forms in bottom sediments. Dynamics recorded during 2009 agree well with ones established during 2004.IntroductionPhosphorus compounds constitute nutrients whichstimulate growth of hydrobionts population in water bodies.In large quantities phosphorus compounds have fertilizingeffect, affecting both water quality and entirely ecosystem.Thus, monitoring of phosphorus content in natural watersrepresents essential issue for protection and rational utilizationof aquatic resources. Monitoring of phosphorus contentin the aquatic environment is very important, consequentlyphosphorus compounds are introduced in list of dangeroussubstances discharged into the aquatic environmentof the European Community. Thus, according to Directive2006/11/EC [1], the organic-phosphorus compounds areintroduced in Annex I, List I, and inorganic compounds ofphosphorus – in List II of this directive.According to World Health Organization (WHO), phosphoruscompounds occurred in natural waters are classifiedinto 12 phosphorus forms, by chemical type – (i) orthophosphates,(ii) acid hydrolysable phosphates, (iii) organic-phosphorus,(iv) total content, and by physical state – (i) dissolved(filterable), (ii) particulate, (iii) total content [2].Additionally, this scheme was tested for estimation ofphosphorus content in bottom sediments being determined(i) inorganic phosphorus (orthophosphate plus condensedforms – polyphosphates and pyrophosphates), (ii) organic-phosphorus and (iii) the total amount of phosphorus [3].Thus, the supplemented scheme allows the analysis of thephosphorus forms for the entirely system “water – particulatematerials – bottom sediments”, considerably extendingpossibilities for interpretation of phosphorus dynamics innatural waters. This scheme was applied for evaluationof phosphorus dynamics for lakes from Chisinau [4], forresearch of seasonal and spatial dynamics of phosphorusfor river Dniester during 2004 [5, 6], and for river Prut [3].Case studySamples of water, particulate materials and bottom sedimentswere collected during 2009 along river Dniester (sitesOxentia, Malovata and Vadul-lui-Voda). Contents of phosphorusforms in water and particulate materials were determinedusing methods according to World Health Organization classification[2]. To determinate total phosphorus (form P13 infig. 1) in bottom sediments, fresh (wet) samples were used,and oxidative hydrolyze in acid medium in presence of ammoniumperoxodisulfate was realized. Inorganic phosphorus(form P14 in fig. 1) in bottom sediments was determinateusing hydrolyze in acid medium in severity-moderate condition.The amount of organic phosphorus (form P15 in fig. 1)is obtained by subtracting inorganic phosphorus (P14) fromthe amount of total phosphorus (P13).Fig. 1. Phosphorus forms in natural waters for the entirely system “water-particulate materials-bottom sediments”.Supplemented scheme for analysis of the phosphorus forms in water and particulate materials accordingto World Health Organization classification (forms 1-12) and in sediments (forms 13-15).— 192 —