Macrophytes of the Grlište reservoir (Serbia): Fifteen years after its establishment

A large number of macrophytes, often in dense populations, have developed on the Grlište Reservoir, Serbia over a period of 15 years. Fast development of vegetation is a consequence of anthropogenic impact in lake management. The methodology used in this research covered 100% of the water body, including all areas with or without aquatic plants. The results indicate that plant communities are still in the early phase of development. This leaves space for future development of competitor macrophyte species (Najas marina, Eleocharis palustris, Typha latifolia, Typha angustifolia, Phragmites australis, etc.) capable of endangering stability of the lake, which will tend toward eutrophication

Dugoročne promene u trofičkom statusu i ekološkim parametrima akumulacije Grlište, Srbija

In the purpose of monitoring the change of trophic status and water quality in the reservoir Grlište, in the period of 20 years, once a month sampling of water was conducted at two places. The obtained results were used in the purpose of finding a cause of cyanobacteria bloom which appeared in the dry years in the time of critically low water level in the reservoir. On the basis of the obtained results of analyzed parameters, the trophic state indexes of Carlson (TSIChl-a, TSITP and TSISD) were calculated and difference between TSIChl-a and TSITP showed that phosphorus was not a limiting factor of algal production. Content of nitrogen in tributaries of the reservoir was in creased in the examined period, but research results indicated that limiting factor of algal production was light, not nitrogen and phosphorus. On the basis of the concentrations of dissolved oxygen, total phosphorus and chlorophyll a in the surface and in the bottom, it was concluded that the reservoir went through four development phases during the examined period. In the first years after the formation of the reservoir the highest trophicity was detected (hypereutrophic status), but later the reservoir maintained eutrophic status.U cilju praćenja promene trofičkog statusa i kvaliteta vode u akumulaciji Grlište, u periodu od 20 godina, jednom mesečno je vršeno uzorkovanje vode i to na dva mesta. Dobijeni rezultati su korišćeni u svrhu pronalaženja uzroka cijanobakterijskog cvetanja, koje se javljalo u sušnim godinama u vreme kritično niskog nivoa vode u akumulaciji. Sadržaj azota u pritokama akumulacije je bio u trendu porasta u ispitivanom periodu, ali rezultati istraživanja su ukazali da je limitirajući faktor algalne produkcije bila svetlost a ne azot i fosfor. Na osnovu dobijenih rezultata analiziranih parametara, izračunati su Carlson-ovi indeksi trofičnosti (TSIChl-a,TSITP i TSISD-a) a razlika TSIChl-a i TSITP je ukazala da fosfor nije bio ograničavajući faktor algalne produkcije. Na osnovu koncentracija rastvorenog kiseonika, ukupnog fosfora i hlorofila a na površini i na dnu, zapaženo je da je akumulacija tokom ispitivanog perioda prošla kroz četiri razvojne faze. Uočeno je da je u prvim godinama nakon formiranja akumulacije trofičnost bila najizraženija (hipereutrofan status), da bi u daljem periodu zadržala uglavnom eutrofan status

Dugoročne promene u trofičkom statusu i ekološkim parametrima akumulacije Grlište, Srbija

In the purpose of monitoring the change of trophic status and water quality in the reservoir Grlište, in the period of 20 years, once a month sampling of water was conducted at two places. The obtained results were used in the purpose of finding a cause of cyanobacteria bloom which appeared in the dry years in the time of critically low water level in the reservoir. On the basis of the obtained results of analyzed parameters, the trophic state indexes of Carlson (TSIChl-a, TSITP and TSISD) were calculated and difference between TSIChl-a and TSITP showed that phosphorus was not a limiting factor of algal production. Content of nitrogen in tributaries of the reservoir was in creased in the examined period, but research results indicated that limiting factor of algal production was light, not nitrogen and phosphorus. On the basis of the concentrations of dissolved oxygen, total phosphorus and chlorophyll a in the surface and in the bottom, it was concluded that the reservoir went through four development phases during the examined period. In the first years after the formation of the reservoir the highest trophicity was detected (hypereutrophic status), but later the reservoir maintained eutrophic status.U cilju praćenja promene trofičkog statusa i kvaliteta vode u akumulaciji Grlište, u periodu od 20 godina, jednom mesečno je vršeno uzorkovanje vode i to na dva mesta. Dobijeni rezultati su korišćeni u svrhu pronalaženja uzroka cijanobakterijskog cvetanja, koje se javljalo u sušnim godinama u vreme kritično niskog nivoa vode u akumulaciji. Sadržaj azota u pritokama akumulacije je bio u trendu porasta u ispitivanom periodu, ali rezultati istraživanja su ukazali da je limitirajući faktor algalne produkcije bila svetlost a ne azot i fosfor. Na osnovu dobijenih rezultata analiziranih parametara, izračunati su Carlson-ovi indeksi trofičnosti (TSIChl-a,TSITP i TSISD-a) a razlika TSIChl-a i TSITP je ukazala da fosfor nije bio ograničavajući faktor algalne produkcije. Na osnovu koncentracija rastvorenog kiseonika, ukupnog fosfora i hlorofila a na površini i na dnu, zapaženo je da je akumulacija tokom ispitivanog perioda prošla kroz četiri razvojne faze. Uočeno je da je u prvim godinama nakon formiranja akumulacije trofičnost bila najizraženija (hipereutrofan status), da bi u daljem periodu zadržala uglavnom eutrofan status

Assessment of the Trophic Status by Monitoring of Reservoir’s Water Quality

Continuous long-term monitoring of aquatic systems is important for understanding their complete evolution in order to monitor changes in the trophic status and water quality. The continuous monitoring during a period of 20 years, by sampling once a month at two locations, the water quality of reservoir “Grlište”, which is used for the water supplying town Zaječar (Eastern Serbia), is observed and developmental stages in the life of the reservoir were determinated. It should be noted that the obtained results were used also in the purpose of finding a cause of cyanobacteria bloom, as a consequence of algal production. Limiting factors of algal production usually were nitrogen and phosphorus, however, in this study, obtained results of subtraction between trophic state index, calculated through total chlorophyll a (TSIChl-a) and trophic state index, calculated through total phosphorus (TSITP), indicated that limiting factor of algal production was light. On the basis of the concentrations of dissolved oxygen (DO), total phosphorus (TP) and chlorophyll a (Chl-a) in the surface and in the bottom, it was concluded that the reservoir passed through four development phases during the examined period. Results of long-term monitoring showed that in the first years after the formation of the reservoir, the highest trophicity was detected (hypereutrophic status), but later the reservoir mostly maintained eutrophic status

Određivanje neorganskih jona u rastvoru biljnih čajeva jonskom hromatografijom

The ionic content was examined in nine aqueous tea extracts in which time of boiling, acidification of the medium using lemon juice and way of preparation were observed as factors. Ion chromatography was used for determination of inorganic anion content, and data were processed using CANOCO program for multivariate analysis. The variations in ionic content were observed among different tea samples. The highest concentrations of chloride, nitrate, phosphate, and sulphate ions were found in nettle, while the highest concentrations of fluorides were detected in elderflower tea infusion. The effect of boiling time (5, 10, and 20 min), acidification of the medium and different preparation procedure (boiling and cooling at room temperature) were statistically presented using principal component analysis. The examined factors did not have a significant effect on the ionic concentration in tea infusions.Јонски садржај испитиван је код девет водених раствора чаја, при чему је на екстракцију јона посматран утицај дужине кувања, киселости средине (која је постигнута додатком лимуновог сока) и начинa припреме. Јонска хроматографија коришћена је за одређивање садржаја неорганских анјона, а пoдаци су обрађени помоћу Canoco програма за мултиваријациону анализу. Јонски садржај варира код различитих узорака чаја. Највеће концентрације хлоридних, нитратних, фосфатних и сулфатних јона одређене су у коприви, док су највеће концентрације флуорида одређене у инфузији кантариона. Утицај времена кључања (5, 10 и 20 мин.), киселост медијума и различити начини припреме (кључање и хлађење на собној температури) статистички су приказани помоћу анализе главних компоненти. Испитивани фактори нису имали значајан утицај на јонску концентрацију у чајним инфузијама

Značaj, priprema i kondicioniranje vode u prehrambenoj industriji

Nedostatak vode na globalnom nivou ima direktan uticaj na razvoj poljoprivrede i prehrambene industrije, što se direktno odražava na povećanje proizvodnje hrane. Činjenica da je voda limitirajući faktor u proizvodnji hrane i saznanja da veliki broj ljudi umire od gladi, ukazuju na značaj vode u prehrambenoj industriji. Osim prehrambene i farmaceutska industrija je u direktnoj vezi sa zdravljem ljudi. Obe ove industrije ne samo da troše velike količine vode nego imaju i specifične zahteve u pogledu stepena kvaliteta i kondicioniranja vode. Zbog visokog stepena kvaliteta, ove vode su pod posebnim zakonskim nadzorom, po kojem se hemikalije bez atesta FDA (Food and Drug Administration) ne smeju dodavati vodi, bilo da se radi o pripremi vode ili njenom kondicioniranju. Zahtevi ove vrste često prave probleme i ograničavaju razvoj prehrambene i farmaceutske industrije

Freshwater cyanobacterial blooms and primary liver cancer epidemiological studies in Serbia

A large part of Central Serbia experiences continual shortage of sufficient ground water resources. For that reason, more than 20 reservoirs serve as drinking water suppliers. Significant and persistent cyanobacterial "blooms" have been recognized in nine of them. Samples for cyanotoxin analyses were taken during and after "blooms" in Celije Reservoir and from Krusevac town-supplied tap water from that reservoir two days later. Concentration of microcystin-LR was 650 μgL-1 in the reservoir, while the tap water contained 2.5 μgL-1. In the two investigated periods, the high primary liver cancer (PLC) mortality of 11.6 from 1980-1990 and extremely high PLC incidence of 34.7 from 2000-2002 were observed in the regions affected by heavy cyanobacterial "blooms." In contrast, PLC mortality and incidence rates were substantially lower in the regions not affected by cyanobacterial blooms: in 1980-1990 the rate of PLC mortality amounted to 2.7 in Kosovo, 7.6 in Vojvodina, and 8.3 in the non-affected regions of Central Serbia; while in 2000-2002 PLC incidence amounted to 4.1 in Kosovo, 5.2 in Vojvodina, and 13.6 in the non- or less-affected regions of Central Serbia. Keeping in mind that the most affected PLC regions in Central Serbia (Toplicki, Niski, and Sumadijski regions) have the water supply systems based on six reservoirs found regularly in bloom during summer months and that some of the regions are also connected with two boundary "blooming" reservoirs, representing a total of eight of nine blooming reservoirs, it is easy to presume that the PLC incidence could be related to drinking water quality. The uneven geographic distribution of liver cancer in Serbia is conspicuous and hot spots could be related to drinking water supply. It is very clear that the high-risk regions for PLC occurrence correspond with drinking water reservoirs continually found with cyanobacterial blooms, and the low risk regions correspond with water supplies not affected by cyanobacteria. Copyrigh

Occurrence of hyperalkaline spring water in the Brezanska river, Central Serbia

Hyperalkaline (pH>10.5) springs are extremely rare. There are only about ten in the entire world. This type of water has been identified in an ultramafic massif in central Serbia, on Mt. Studena, during the course of investigations conducted in 2017. The investigations included prospecting, terrain mapping and sampling, followed by assessment of data collected in situ and from laboratory analyses. The hyperalkaline spring is of the ascending type, its yield is very low (~0.05 L/s), and the water emerges in a diffuse fashion along fractures. The spring water is of the Ca-OH type, the pH level is 11.6 and the water temperature 11.2°C. The drainage area of the spring, like the entire Mt. Studena, is built up of Paleozoic ultramafic rocks, which geotectonically belong to the External Vardar Subzone. The spring is situated in the floodplain of the Brezanska River, whose channel is the local base level of erosion. The primary point of groundwater emergence is in solid ultramafic rocks, within a zone of fractures up to 0.5 mm wide, over a land area of ~1.5 m2. The paper describes a conceptual model of the formation of hyperalkaline water for the ascending spring in the ultramafic valley of the Brezanska River, on the northern slopes of Mt. Studena. The pH level of the groundwater is indicative of contemporary serpentinization, deep groundwater circulation and a prolonged contact between groundwater and ultramafic rocks along secondary fracture systems

Hydrogeochemical investigation of the influence of natural radionuclides on the environment, NW Backa, Serbia

In the research phase of nuclear materials from the Backa area (NW of Serbia), hydrogeochemical prospecting was applied, which covers an area of about 500 km2. Samples were collected from surface water, from sources and wells, and bores. Combined hydrogeochemical methods included the examination of U, Ra, Pb, Zn, Cu, Mo, Li, Sr; anions HCO3-, SO42-, Cl-; cations Ca2+, Mg2+, Na+, K+, as well as the determination of SiO2, Eh, Ep and pH values. Additional testing determined the water content: NO3, F, Br, J, P. Value content of uranium (U) varied in the range of 0.1 - 125 ppb; Ra 0.026 - 0.33 Bq/l; Rn 1.45 - 32.63 Bq/l. At selected locations the uranium content in the A - horizon (15 - 20 cm) were determined. According to the geological and structural characteristics of the research area, results are shown on the maps in scale of 1:50000 and on appropriate diagrams and tables. The aim of this study was the application of geochemical prospecting method for the identification of geopathogenic zones of the influence of natural radionuclides in the rural settlements environment