Speciation environment

Ferguson, E.A. and C. Hogstrand. 1998. Acute silver toxicity to seawater-acclimated rainbow trout influence of salinity on toxicity and silver speciation. Environ. Toxicol. Chem. 17 589-593. 

Petersen, R., 1982. Influence of copper and zinc on the growth of a freshwater alga, Scenedesmus quadricauda the significance of chemical speciation. Environ. Sci. Technol., 16 443-447. 

Kotas, J. and Z. Stasicka. 2000. Chromium occurrence in the environment and methods of its speciation. Environ. Pollut. 107 263-283. 

Gasser, U.G. et al., Lead release from smelter and mine waste impacted materials under simulated gastric conditions and relation to speciation, Environ. Sci. Technol., 30, 761, 1996. 

Ross HB. 1990. Biogeochemical cycling of atmospheric selenium. Met Speciation Environ NATO ASI Ser., Ser G Vol 23 523-543. 

Preventive Measures. The intake uptake biokinetic model (lUBK) projects the impact of lead in the environment on blood lead. This model assumes conservatively high levels of intake and cannot account for chemical speciation, thus over-predictions of blood lead levels often occur. Nonetheless, because of the allegations of the impact of blood lead and neurobehavioral development, blood lead levels in children are being reduced adrninistratively to below 10 //g/dL. In order to do so, soil leads are being reduced to a level of between 500—1000 ppm where remediation is required. 

The advantages of controlled-potential techniques include high sensitivity, selectivity towards electroactive species, a wide linear range, portable and low-cost instrumentation, speciation capability, and a wide range of electrodes that allow assays of unusual environments. Several properties of these techniques are summarized in Table 1-1. Extremely low (nanomolar) detection limits can be achieved with very small sample volumes (5-20 pi), thus allowing the determination of analyte amounts of 10 13 to 10 15 mol on a routine basis. Improved selectivity may be achieved via the coupling of controlled-potential schemes with chromatographic or optical procedures. 

Techniques for Identifying Transuranic Speciation in Aqueous Environments" International Atomic Energy Agency Vienna, 1981. 

Since the pond is easily accessible and shallow, scientists at ORNL performed several manipulative experiments with caissons to determine the effects of aerobic and anaerobic environments upon the speciation of actinide elements(9). 

Fukai, R. Yamato, A. Thein, M. and Bilinski, H., "Techniques for Identifying Transuranic Speciation in Aquatic Environments" STI/PUB/613, International Atomic Energy Agency, Vienna, 1981, pp. 37-41. 

Fig. 15-11 Effects of strong complexation on metal ion toxicity, (a) Increasing concentration of NTA, a strong multi-dentate complexing agent, decreases the toxicity of Cd to grass shrimp. All systems have equal concentrations of total Cd. (b) When the results are replotted showing survival as a function of Cd concentration, the data for all concentrations of NTA collapse to a single curve. (Reprinted with permission from W. G. Sunda et al. (1978). Effect of chemical speciation on toxicity of cadmium to grass shrimp, Palaemonetes pugio importance of free cadmium ions. Environ. Sci. Technol. 12,409-413, American Chemical Society.)...

The full appreciation of the overriding importance of metal speciation in evaluating the transport and effects of metals in an environment is a relatively recent event. As more information is gathered on the forms in which metals exist and are transported through various environmental compartments, it will become possible to predict more accurately the response of the biological communities exposed to the metals and hopefully avert or mitigate the adverse effects. 

Meylan S, Behra R, Sigg L (2003) Accumulation of Cu and Zn in periphyton in response to dynamic variations of metal speciation in freshwater. Environ Sci Technol 37 5204... 

Ressler T, J Wong, J Roos, IL Smith (2000) Quantitative speciation of Mn-bearing particulates emitted from autos burning (methylcyclopentadienyl)manganese tricarbonyl-added gasolines using XANES spectroscopy. Environ Sci Technol 34 950-958. 

Lindberg SE, Stratton WJ. 1998. Atmospheric mercury speciation concentrations and behavior of reactive gaseous mercury in ambient air. Environ Sci Technol 32 49-57. 

Sprovieri F, Pirrone N, Gardfeldt K, Sommar J. 2003. Atmospheric mercury speciation in the marine boundary layer along 6000 km cruise path over the Mediterranean Sea. Atmos Environ 37(S1) 63-72. 

Stratton WJ, Lindberg SE, Perry C J. 2001. Atmospheric mercury speciation critical evaluation of a mist chamber method for measuring reactive gaseous mercury. Environ Sci Technol 35 170-177. 

Bloom NS, Gill GA, Cappellino S, Dobbs C, McShea L, Driscoll C, Mason R, Rudd JWM. 1999. Speciation and cycling of mercury in Lavaca Bay, Texas, sediments. Environ Sci Technol 33 7-13. 

Ganguli PM, Mason RP, Abu-Saba KE, Anderson RS, Flegal AR. 2000. Mercury speciation in drainage from the New Idria mercury mine, California. Environ Sci Technol 34 4773 779. 

Gill GA, Bmland KW. 1990. Mercury speciation in surface freshwater systems in California and other areas. Environ Sci Technol 24 1392-1400. 

Gray JE, Theodorakos PM, Bailey EA, Turner RR. 2000. Distribution, speciation, and transport of mercury in stream-sediment, stream-water, and fish collected near abandoned mercury mines in southwestern Alaska, USA. Sci Total Environ 260 21-33. 

Today it has become clear that the effect of trace elements in living systems, in food, and in the environment depends on the chemical form in which the element enters the system and the final form in which it is present. The form, or species, clearly governs its biochemical and geochemical behaviour. lUPAC (the International Union for Pure and Applied Chemistry) has recently set guidelines for terms related to chemical speciation of trace elements (Templeton et al. 2000). Speciation, or the analytical activity of measuring the chemical species, is a relatively new scientific field. The procedures usually consist of two consecutive steps (i) the separation of the species, and (2) their measurement An evident handicap in speciation analysis is that the concentration of the individual species is far lower than the total elemental concentration so that an enrichment step is indispensable in many cases. Such a proliferation of steps in analytical procedure not only increases the danger of losses due to incomplete recovery, chemical instability of the species and adsorption to laboratory ware, but may also enhance the risk of contamination from reagents and equipment. 

Ra. Exceptions to this are environments where Rn is lost from the system by degassing (e.g., see Condomines et al. 2003), or aqueous systems where the insoluble nature of °Pb leads to its preferential removal. The speciation of Pb in natural waters is rather complex and heavily depends on the availability of organic complexing agents for which Pb has the highest affinity. In the oceans, Pb has a very short residence (30-150 yrs) and is rapidly scavenged by particles. 

Bulman RA, Johnson TE, Ham GJ, et al. 1993. Speciation of plutonium in potato and the gastrointestinal transfer of plutonium and americium from potato. Sci Total Environ 129 267-289. 

Lujaniene G, Lujanas V, Jankunaite D, et al. 1999. Speciation of radionuclides of the Chernobyl origin in aerosol and soil samples. J Environ Radioact 49 107-114. 

Principles and Characteristics The fastest growing area in elemental analysis is in the use of hyphenated techniques for speciation measurement. Elemental spe-ciation analysis, defined as the qualitative identification and quantitative determination of the individual chemical forms that comprise the total concentration of an element in a sample, has become an important field of research in analytical chemistry. Speciation or the process yielding evidence of the molecular form of an analyte, has relevance in the fields of food, the environment, and occupational health analysis, and involves analytical chemists as well as legislators. The environmental and toxicological effects of a metal often depend on its forms. The determination of the total metal content... 

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