Organolead compounds environmental

Grandjean P, Nielsen T. 1979. Organolead compounds Environmental health aspects. Res Rev 72 98-148. 

Cassells DAK, Dodds EC Tetra-ethyl lead poisoning. BM] 2 681-685,1946 Grandjean P, Nielsen T Organolead compounds environmental health aspects. Residue Reviews 72 97-148, 1979... 

Grandjean, P. and Nielsen, T. (1979), Organolead Compounds Environmental Health Aspects, Residue Rev., 72, 97-148. 

The main concern regarding tetraalkyl lead has been about human health hazards, a concern that has resulted in the progressive replacement of leaded petrol by unleaded petrol in most countries (Environmental Health Criteria 85). There has been particular concern about possible brain damage to children in polluted urban areas. Little work has been done on the effects of organolead compounds on wildlife or ecosystems, so the following account will be brief. 

The vast majority of measurements of organolead compounds in the environment do not constitute evidence for biomethylation of lead. Most environmental organic lead comes from incomplete combustion or spillage of methyl- or ethyl-lead gasoline additives (viz tetraalkylleads or TALs). A literature search will produce several hundred TAL or ionic alkyllead results, but few of them are evidence for methylation in or by the environment. 

The major organolead compounds found in the environment are the tetraalkyllead compounds and their di- and trialkyl decomposition products. Elevated levels of tetraalkyl-leads have two possible sources either (i) anthropogenic leaded petroleum inputs or (ii) environmental methylation of natural lead compounds. While the former is well established, the latter is the subject of some controversy in the literature. Interest in the environmental methylation process derives from the increased toxicity of methyllead compounds compared to their inorganic analogs. 

Heisterkamp, M., DeSmaele, T., Candelone, J.E, Moens, L., Dams, R. and Adam, F.C. (1997) Inductively coupled plasma mass spectrometry hyphenated to capillary gas chromatography as a detection system for the speciation of organolead compounds in environmental waters./. Anal. At. Spectrom., 12, 1077-1081. 

Lobinski, R., Dirkx, W.M.R., Szpunar-Lobinska, J. and Adams, F.C. (1996) Speciation analysis of organolead compounds. Status and future projects. In Quality Assurance for Environmental Analysis (eds Quevauviller, Ph., Maier, E.A. and Griepink, B.), Vol. 14. Elsevier, Amsterdam, 320 pp. 

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). 

Lobiriski, R. 1995. Organolead compounds in archives of environmental pollution. Analyst 120 615-621. 

In what sense are the toxicities and environmental effects of organolead compounds particularly noteworthy ... 

Casas, J., Sordo, J. (2006). Lead Chemistry, Analytical Aspects, Environmental Impact, and Health Effects. Amsterdam Elsevier Science. Chapter 1 deals with the history, occurrence, properties, and uses of lead compounds. Chapters 2 and 3 cover the chemistry of coordination and organolead compounds. 

In this overview, we have limited our discussion to the speciation of four important organometals, each presenting specific analytical features, in environmental samples organomer-cury, organoarsenical, organotin, and organolead compounds. Their uses, presence in the environment, toxicity and threat to human health are also briefly discussed. 

ICP-AES. These detectors are element specific, avoiding most chemical and spectral interferences, and also sufficiently sensitive to quantify the organolead compounds in most environmental samples. The LODs obtained on trimethyllead after ethylation with CGC-MIP-... 

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. 

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... 

Atomic absorption spectrometry (AAS) was established as the most popular gas chromatography (GC) detection technique for lead speciation analysis in the first years of speciation studies. The increase of the residence time of the species in the flame using a ceramic tube inside the flame and, later, the use of electrically heated tubes, made out of graphite or quartz where electrothermal atomization was achieved, provided lower detection limits but still not sufficiently low. Later, the boom of plasma detectors, mainly microwave induced plasma atomic emission (MIP-AES) and, above all, inductively coupled plasma atomic emission and mass spectrometry (ICP-AES and ICP-MS, respectively) allowed the sensitivity requirements for reliable organolead speciation analysis in environmental and biological samples (typically subfemtogram levels) to be achieved. These sensitivity requirements makes speciation analysis of organolead compounds by molecular detection techniques such as electrospray mass spectrometry (ES-MS) a very difficult task and, therefore, the number of applications in the literature is very limited. 

Prior to their separation by GC, organolead compounds need to be extracted from the sample matrix and, if necessary, derivatized into a volatile and thermally stable form. Volatile nonpolar tetraalkyl compounds can be extracted from environmental samples with nonpolar solvents such as benzene or hexane and injected directly onto the gas chromatograph. The case of nonvolatile, ionic alkyl compounds (R2Pb and RsPb ) is more complex. They should first be extracted and preconcentrated in the presence of NaCl and sodium diethyldithiocarbamate and then derivatized into a volatile form. The most widespread derivatization methods are of two distinct types those based on the use of tetraalkylborates that can be directly performed in the aqueous solution (ethylation and propylation) and those applying... 

It is estimated that 1% of organolead in gasoHne is emitted from vehicles in the form of TAL and ionic alkyllead. The presence of alkyllead compovmds was confirmed in different types of environmental samples, such as air and rainwatei which contained organolead compounds in appreciable concentrations. The presence of organolead compovmds in aquatic ecosystems, and especially in the marine environment, has not been studied extensively. 

While some of the scientific literature has addressed organolead compounds as environmental contaminants and hazards, the predominant concern is with the inorganic, divalent form and that is the form covered in this book. 

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. 

Chau et al pointed out that as the authenticity of the compounds to be analyzed must be preserved, any of the digestion methods with acids or alkalis are not suitable, and that extraction seemed to be the method of choice for removing these compounds from samples. For this traction, they adopted benzene as recommended by Sirota and Uthe for the quantitative extraction of tetramethyllead and tetraethyllead from fish homogenates suspended in aqueous EDTA solution. Although ionic forms of lead such as Pb(II), diethyllead dichloride, and trimethyllead acetate do not extract in the benzene phase, any lead compounds that distribute into the benzene phase as tetraalkyllead will be determined. Chau et al421 found that environmental samples can contain other forms of organolead compounds that are extractable into benzene but which are not volatile enough to be analyzed by the GC-AAS technique, hence the need for a speciation specific analytical system. 

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