Trace elements in water

Methods. As discussed in the previous chapter, a number of approaches have been used to assess the presence of potentially toxic trace elements in water. The approaches used in this assessment include comparative media evaluation, a human health and aquatic life guidelines assessment, a mass balance evaluation, probability plots, and toxicity bioassays. Concentrations of trace elements were determined by atomic absorption spectrometry according to standard methods (21,22) by the Oregon State Department of Environmental Quality and the U.S. Geological Survey. 

In addition to soil solution, speciation of trace elements in water of the Nahr-Ibrahim river valley of Lebanon was studied with the AQUACHEM model. The results indicate that a high percentage of Pb and Zn is present as carbonate species, but in low percentages in free hydrated ion species. Cadmium exhibits as a high percentage of a free hydrated Cd2+. 

Figure 1.1 Results from an international intercomparison, IMEP 9, wl expanded uncertainty and ue the combined standard uncertainty [1] (see Chapter 6, Section 6.3). Reproduced by permission of EC-JRC-IRMM (Philip Taylor) from IMEP 9, Trace elements in water III, Cd, certified range 81.0-85.4nmoll-1 .

IMEP 9, Trace Elements in Water III, Cd, Certified Range 81.0-85.4 nmol l-1 , European Commission, Joint Research Centre, Institute for Reference Materials and Measurements (EC-JRC-IRMM), Geel, Belgium (1998). [www.irmm.jrc.be/html/interlaboratory comparisons/imep/ index.htm] (accessed 30 November, 2006). 

Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma-Atomic... 

Martin TD, Brockhoff CA, Creed JT, et al. 1992. Determination of metals and trace elements in water and wastes by inductively coupled plasma-atomic emission spectrometry. In Smoley KC, ed. Methods for the determination of metals in environmental samples. Boca Raton, FL CRC Press, 33-78. 

Papadakis, I, Aregbe, Y, Harper, C, Norgaard, J, Smeyers, P, De Smet, M, et al. (2002), IMEP-12 Trace elements in water, report to participants (Geel European Commission - Joint Research Centre, Institute for Reference Materials and Measurements). 

Kopp JF. 1969. The occurrence of trace elements in water. Proc Univ MO Annu Conf Trace Subst Environ Health. 3 59-73. 

Azcue, J.M., Mudroch, A., Rosa, F. et al. (1995) Trace elements in water, sediments, porewater, and biota polluted by tailings from an abandoned gold mine in British Columbia, Canada. Journal of Geochemical Exploration, 52(1-2), 25-34. 

Ikem, A., Egiebor, N.O. and Nyavor, K. (2003) Trace elements in water, fish and sediment from Tuskegee Lake, southeastern USA. Water Air and Soil Pollution, 149(1 1), 51-75. 

Multi-element determination of dissolved metals at ultratrace level may be performed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). U.S. EPA s Methods 200.8 and 1638 present a methodology for measuring trace elements in waters and wastes by the above technique. Sample is acid digested and the solution is introduced by pneumatic nebulization into a radio-frequency plasma. The elements in the compounds are atomized and ionized. The ions are extracted from the plasma through a differentially pumped vacuum interface and separated by a quadrupole mass spectrometer by their mass to charge ratios. The mass spectrometer must have a resolution capability of 1 amu peak width at 5% peak height. 

Elwood PC, Aberwethy M, Morton M. 1974. Mortality in adults and trace elements in water. Lancet 2 1470-1472. 

Florence, T.M. (1982) The speciation of trace elements in waters. Talanta, 29, 345-364. 

IMEP- 6 Trace elements in water synthetic water (sample " 1") Certified range (= i2uc) 1.55 1.77 pmol kg 1... 

Tl, V, and Zn are present in the aquatic environment as a result of the weathering of rocks and soils (surface and ground waters) and of industrial waste water discharges and mining activities. The toxicity of trace elements in water depends on their concentration and oxidation state (Cr or As). 

Morton MS, Elwood PC, Abernethy M. 1976. Trace elements in water and congenital malformations of the central nervous system in South Wales. Brit J Prev Soc Med 30 36-39. 

Unesco, Trace Elements in Water and Public Health, http //www.iah.org/briefings/ Trace/trace.htm (Accessed October 2004). 

Another example is IMEP-12 Trace Elements in Water. Samples form the IMEP-12 water batch were also offered to EUROMET [49]. In Figure 7.20 the results of the European NMIs are on the top. In the middle there are the results from the laboratories nominated via the WMO and the GAW programme. Finally, the Feld laboratories participating in IMEP-12 will be able to compare their results with the results of laboratories that represent their country at EUROMET level and vice versa. 

I. Papadakis, Y. Aregbe, J. N(,rgaard, L. Van Nevel, P. D. P. Taylor, IMEP-12, Trace Elements in Water, Certification Report, EUR 19924 EN. http //www.irmm.jrc.be/ html/interlaboratory comparisons/imep/imep-12/IMEP12 certiEcationreport.pdf. 

Y. Aregbe, P. Robouch, T. Colemean, P. D. P. Taylor, WMO/IMEP-15 Trace Elements in Water Laboratory Intercomparison, World Meteorological Organization Global Watch WMO TD No. 1195, 1D21. 

Liquid sampies are inserted into the two commerciai USNs through the inlet tubing by pumping with, for exampie, a peristaitic pump. For this reason, these nebulizers are frequently said to operate in the continuous mode [23]. The inlet tube also allows the USN to be used as an interface between a flow system, where other steps of the analytical process can be developed, and the detector. CETAC USNs have been used in official methods of analysis such as US-EPA Method 200.15 for the determination of metals and trace elements in water by USN-ICP-AES [24]. 

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