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Sediments organoleads

At least one of the organolead compounds has been shown to be a normal constituent of the aqueous environment. Tetramethyl lead has been found as a product of anaerobic bacterial metabolism in lake sediments [23]. It should perhaps be sought in the air over coastal mud flats. [Pg.460]

Reisinger et al. [21] used the gas chromatographic-atomic absorption spectrometric technique to demonstrate that biomethylation of inorganic lead does not account for the presence of organolead compounds in sediments. Sulphide induced chemical conversion of organic lead(IV) salts into alkyl lead compounds is, however, possible. [Pg.394]

The concentration factors for organolead compounds range from very low values, i.e. no concentration in sediments, to 100, i.e. some adsorption. [Pg.460]

Determination of organotin and organolead pollutants in environmental sediments after LLE with 91 solution and derivatization. ... [Pg.303]

There is very little information about the stabilities of lead species in aqueous solution containing less than lOngdm-3 lead. No changes in concentrations of ionic organolead species in water occurred over a period of 3 months when samples were stored at 4°C in the dark (Van Cleuvenbergen et al., 1992). Freezing is probably the best means of preserving soils and sediments. [Pg.421]

Investigations of lead speciation in various environmental samples have relied upon gas and liquid chromatographic separations coupled to mass spectrometric and atomic absorption spectrometric detectors. The combination of atomic absorption spectrometry with gas chromatography (GC-AAS) has proved to be the most widely applied technique. Sample types have included air, surface water, air particulates, sediments, grass, and clinical materials such as blood. A review of speciation analyses of organolead compounds by GC-AAS, with emphasis on environmental materials, was published (Lobinski et al., 1994). [Pg.422]

Methylmercury species in sediment samples were speciated in a study by Hintelman et al. [89]. Detection limits were 1 pg (as Hg) in dry sediment samples. Organomercury compounds, along with organotin and organolead compounds, were also separated in another study by Prange and Jantzen [90]. Detection limits were three orders of magnitude lower than those reported previously in the literature. A quartz transfer line was used in this study. [Pg.397]

Lead enters surface water from atmospheric fallout, run-off, or wastewater. Little lead is transferred from natural minerals or leached from soil. Pb ", the stable ionic species of lead, forms complexes of low solubility with major anions in the natural environment such as the hydroxide, carbonate, sulfide, and sulfate ions, which limit solubility. Organolead complexes are formed with humic materials, which maintain lead in a bound form even at low pH. Lead is effectively removed from the water column to the sediment by adsorption to organic matter and clay minerals, precipitation as insoluble salt (the carbonate, sulfate, or sulfide) and reaction with hydrous iron, aluminum, and manganese oxides. Lead does not appear to bioconcentrate significantly in fish but does in some shellfish such as mussels. When released to the atmosphere, lead will generally occur as particulate matter and will be subject to gravitational settling. Transformation to oxides and carbonates may also occur. [Pg.883]

MIP-AED GC GG-heated transfer line-AED pg element P e.g., 2pgkg butyltin in sediment 0.01-0.03 pgkg organolead compounds in peat Commercial systems detector based on atomic emission non-volatile compounds require derivatization 417,421... [Pg.623]

Work in the 1980s established concentration levels to be expected in atmospheres remote from the source when TALs were routinely used in gasoline. Typically, these would be at the ngm level. Ionic lead would also be at similar levels. Ionic leads in waters are also very low (at about the ng L level), with TALs being very low. There is little information about organolead species in sediments and soil. The analytical methodologies are discussed in Section 12.13.5. A recent tabular summary of organolead species detected in the various environmental compartments at the levels noted above is given in Ref 149. [Pg.630]

Rosenberg et al. [72] used reversed-phase HPLC with atmospheric pressure chemical ionization MS to separate and measure several organotin species that had been extracted from sediments. These species were used as a fuel additive when organolead compounds were replaced. They are environmentally important because of their bioaccumulation and toxicities. [Pg.1006]

The concentrations of organolead compounds found in the different environmental compartments are often in the pgm, ngl , and ng per g levels for air, water, and sediment and biological tissues, respectively. However, inorganic lead forms can simultaneously be present in the same samples at a 1000-fold higher level. For this reason, the instrumentation necessary to carry out lead speciation analysis in real samples requires the isolation, separation, and sensitive detection of the individual organolead species in the presence of thousands of... [Pg.2467]

Levels of tetra-, tri-, and dialkyllead were measured in street dust samples collected in 1976 in Lancaster (UK), and the concentrations ranged between 0.4 and 7.4pgPbg. With regards to the study carried out in Sibenik (Croatia), in contrast to the total lead (19.8 +17ng per g), organolead compovmds were not found to be accumulated in sediments (0.2 +0.2 ng per g). [Pg.2469]

The use of a helium MIP as a detector for compounds separated by GC has been mentioned and will be discussed in Chapter 12, but has been used for the determination of thiophene in benzene at ppb levels F, C, N, and S in gasoline organolead and organomanganese compounds in gasoline and elements in sediment and coal. The website at www.jas.de provides a number of application notes. [Pg.564]

Organolead compounds are pollutants in air, water, soil, and sediments. The toxicity of organolead species depends on the organic groups bound to the Pb atom. Lead has four stable isotopes ( Pb, Pb, Pb, and Pb) and isotopic analysis of Pb can be used for geological dating and to track environmental processes and sources of Pb species. [Pg.511]

Other experiments indicated that conversion of lead(ll) compounds to Pb(CH3)4 was inconsistent and time-independent [130]. Lead contained in mine tailings is not mobilized in detectable amounts by biomethylation [125, 130]. A volatile organolead compound, presumably the methyllead derivative, was observed upon aerobic, not upon anaerobic, incubation of marine sediment with lead(ll) acetate [131]. Marine sediments inoculated with (CH3)3PbOOCCH3 produced Pb(CH3)4 in experiments employing flow-through conditions both under anaerobic and aerobic conditions. Production under anaerobic conditions was approximately threefold greater [130]. [Pg.185]

Release of Pb(C2H5)4 by sediment samples possibly due to biological activity was observed [134], but no indication of a large-scale natural source for tetraalkyllead compounds was found [79, 80, 82, 89]. See also Organolead Compounds 1, 1987, pp.184/6. A biogeochemical cycle for organolead compounds was proposed [78, 85, 86, 97, 115, 141,152]. [Pg.265]


See other pages where Sediments organoleads is mentioned: [Pg.80]    [Pg.406]    [Pg.437]    [Pg.442]    [Pg.852]    [Pg.899]    [Pg.240]    [Pg.252]    [Pg.288]    [Pg.323]    [Pg.394]    [Pg.240]    [Pg.252]    [Pg.288]    [Pg.323]    [Pg.31]    [Pg.175]    [Pg.375]    [Pg.390]    [Pg.406]    [Pg.1064]    [Pg.2469]    [Pg.216]    [Pg.75]    [Pg.185]    [Pg.264]    [Pg.299]   
See also in sourсe #XX -- [ Pg.900 , Pg.901 ]




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