Presentation on theme: "Concentartion of metals in the rivers of south part of Primorie, Russia. V. M. Shulkin, N. N. Bogdanova Pacific Geographical Institute RAS, Vladivostok."— Presentation transcript:
Concentartion of metals in the rivers of south part of Primorie, Russia. V. M. Shulkin, N. N. Bogdanova Pacific Geographical Institute RAS, Vladivostok 690041,Russia . Improvement of sampling and analysis technique leads to revision of the metal concentration in many rivers especially in moderately contaminated and pristine ones. But other consequences of these research is the increase in contrast of distribution of the metals at the significant anthropogenic influence and enhance of the opportunities to use metals as indicator of biogeochemical processes and/or anthropogenic loading Aim of presentation is to show new data on the content of dissolved Fe, Mn, Zn, Cu, Pb, Cd and their concentration in suspended solids in Razdolnaya River - one of the main rivers of the south of Primorski Krai. The second aim is to characterize of metal concentration in the downstream of Tumen River – the biggest river of Japan/East Sea basin.
Materials and Methods Two sampling along Razdolnaya River were carried out at low water in June and in September 2003 from headwaters to the downstream, and additional sampling at the high water in July, 2002 and July 2004. Water discharge of Razdolnaya River in June 2003 г changed from 34,5 m3 /s at headwaters up to 42 m3 /s at downstream. In September 2003 г the water discharge was even lower: 10 m3/s and 22,5 m3/s, accordingly. In July 2004 water discharge was 160 m3/s, and in late summer 2002 so high as 349 m3/s. The down stream of Tumen River had been sampled several times from 1998 till 2004, including high water in July 2002. Sampling were carried out in preliminary washed polyethylene bottles with use of pump MasterFlex ™ and capsule filter AquaPrep ™ with the effective pore size 0,45 microns to obtain filtrate with dissolved forms of metals directly on a place of sampling. Simultaneously 5-8 litres of water were sampled for subsequent segregation and analysis of suspended solids. The concentration of the dissolved forms of metals determined by atomic- absorption spectrophotometry (ААS) on device Shimadzu-6800F/G in flame and in graphite furnace after concentration of metals by extraction with dietilditiocarbaminat-Na in CHCl3. Concentration of metals in suspended solids was determined by the same AAS after full decomposition of filters with solids by acid mixture HF-HClO 4.
The most obvious feature is the peak of concentration of dissolved forms Mn, Zn and Fe in river waters near Ussuriisk city. In September at the lowered water discharge this maximum is expressed much more brightly, than in June though the general level of concentration of dissolved metals along Razdolnaya River in June, 2003 was higher, than in September.
Sewages from Ussuriisk do not conduct to significant increase of concentration dissolved Cu, Cd, and Pb in adjoining part of Razdolnaya Some increase in concentration of dissolved Cd and Pb is observed at all middle stream of Razdolnaya River due to non-point drainage from middle part of watershed Unusual feature of spatial distribution of dissolved Pb is a significantly increase in headwaters
For the transport of metals in the rivers the significant role of the suspended forms in the general balance is typical. The rivers of the south of Primorski Krai are not exception. Even at low water mode more than 70 % Zn, 90 % Fe and 95 % Pb are transported into suspended solids. The share of suspended forms in Cu and Cd balance makes about 50 %. In a high water sharp dominance of the suspended forms is observed for all metals due to increase in the contents of a suspended solids at the order and more. From the point of view of seasonal variability, the main factor controlling contents and a role of suspended forms of metals is a quantity of a suspended solids which itself defined by a hydrological mode, first of all. But for the characteristic of geochemical features of a river drain and for the assessment of anthropogenic influence concentration of metals in a suspended solids (on a mass unit) is more informative than content of suspended metal forms (on a volume of water unit).
Table. Concentration of metals in suspended solids of the Razdolnaya River, Tumen River RiverFe,%Mn,ppmZn,ppmCu,ppmPb,ppmCd,ppm Razdolnaya, upstream, low water* 4.083172125361021.31 Razdolnaya, down stream, low water* 5.27395913443940.43 Razdolnaya down stream, high water** 3.563026522380.08 Tumen, mouth, low water 1 5.27250321566 0.66 Tumen, mouth, high water** 5.9398215341510.04 Average on Rivers of the World 2 4,791043250100461,23
Spatial variability of metal concentration in suspended solids along Razdolnaya River is more indicative The main feature is the peak of concentration of all metals in a suspended matter near Ussuriisk. For almost all metals this maximum is especially strongly expressed in September Further downstream concentration of metals falls in most cases up to a level close or smaller, than in a suspension of head waters of Razdolnaya River.
Only for Fe concentration in suspended solids of the down stream is higher, than in head waters due to more fine grained material. The significant increase of dissolved Cd and Pb noted in upstream of Razdolnaya River was confirmed by elevated concentration of these metals in suspended matter of this part of river (Fig.3). A level achievable here (150 µg / g Pb and 2 µg /g Cd) at 5-10 time exceeds a regional background for unpolluted river suspension
Conclusions I Concentrations of dissolved Mn, Zn, and Cu in headwaters of Razdolnaya River are 20-30; 0,3-0,7; 1,2-1,3 µg /l, accordingly, that is close to the level of unpolluted rivers. However, the concentration of dissolved Pb and Cd is 3-10 time higher than background, due to additional input from Chinese People's Republic, or due to unknown sources at the Russian territory. Concentration Fe, Zn, Cu in suspended solids of headwaters is equal to background, but on Pb and Cd in suspended solids is observed 2-10 time increase upon background level as well as for the dissolved forms. Change of concentration of metals in solution and in suspended matter along Razdolnaya River allows to characterize confidently a degree and character of anthropogenic influence, and to assess existing self-cleaning ability of the river. Anthropogenic influence on the concentration of metals in Razdolnaya River could be registered on distance of 10-20 km downwards from Ussuriisk. At the greater water discharge anthropogenic increase of concentration of the dissolved metals is traced further downstream. However on distance of 40 km downstream off Ussuriisk concentration of the majority of the dissolved metals in June and September are compared and reduced up to a background level (0,09-0,9 µg/l Zn, 0,005-0,008 µg /l Pb, 0,004 µg /l Cd, 2-12 µg /l Mn).
Conclusions II: Despite of obvious and significant anthropogenic influence on the metal concentration in solution and suspended solids of Razdolnaya River, self-cleaning ability of the river is sufficient and in the downstream concentration of the dissolved metals is reduced close to background. The basic mechanism of self- cleaning is, probably, sorption on suspended matter. Concentration of metals in downstream of Tumen River do not show heavy anthropogenic press, but dissolved Cu and Zn, and Cu in suspended matter as well, are elevated compare with down stream of Razdolnaya River and unpolluted streams.