Environmental Occurrence

The environmental occurrence of polycyclic aromatic hydrocarbons is mainly associated with dispersion of oil products and with various types of combustion. For these chemicals a kind of pre-industrial background exists, due to forest fires or to domestic wood burning. The sediments of the deepest strata were certainly deposited in the nineteenth century, when no significant industrial activities had been initiated. The ratio between PAH concentrations found in the sediments dated to this century, and the deepest ones, vary from 1.7 to 30, increasing from the beginning of the... 

Pijnenburg, A., Everts, J., and de Boer, J. et al. (1995). Polybrominated biphenyl and diphe-nylether flame retardants analysis, toxicity, and environmental occurrence. Reviews in Environmental Contamination and Toxicology. 141, 1-26. 

NPIP induces esophageal and nasal cavity tumors in the rat, forestomach, liver and lung tumors in the mouse, and tracheal tumors in the Syrian golden hamster (43, 44, 45). Its potent carcinogenicity is indicated by the fact that a single dose of only 22 mg/kg was sufficient to induce tumors in 20% of Syrian golden hamsters (45). The environmental occurrence of NPIP appears to be less frequent than that of NPYR, but it has been detected in food (J, 44). 

In order to accomplish with the aforementioned aim, during the first year of project, an extensive research on the different chemical additives used in six industrial sectors was conducted plastics, textiles, electronics, lubricants, leather, and paper. A list of selected chemical additives was identified for each sector and used as a study basis for the rest of the project. This is the case of the decabromo-diphenyl ether (BDE) used in electronics as a flame retardant or the triclosan used in the textile as a biocide. The results of this investigation were presented in the first volume of this book (Global Risk-Based Management of Chemical Additives I Production, Usage and Environmental Occurrence). This volume also included a section of case studies related to the selected additives in different countries (i.e., Denmark, Vietnam, Brazil, India). The main outcomes of the first part of the project are summarized below ... 

Bilitewski B, Darbra RM, Barcelo D (eds) (2012) Global risk-based management of chemical additives I Production, usage and environmental occurrence. The handbook of environmental chemistry, vol. 18. Springer, Berlin... 

Human exposure to complex mixtures of polycyclic aromatic hydrocarbons (PAH) occurs through inhalation of tobacco smoke and polluted indoor or outdoor air, through ingestion of certain foods and polluted water, and by dermal contact with soots, tars, and oils CO. Methylated PAH are always components of these mixtures and in some cases, as in tobacco smoke and in emissions from certain fuel processes, their concentrations can be in the same range as some unsubstituted PAH. The estimated emission of methylated PAH from mobile sources in the U.S. in 1979 was approximately 1700 metric tons (2). The occurrence of methylated and unsubstituted PAH has been recently reviewed (1, 2). In addition to their environmental occurrence, methylated PAH are among the most important model compounds in experimental carcinogenesis. 7,12-Dimethylbenz[a]anthracene, one of... 

Interaction effects of PCDDs with other polychlorinated compounds or mixtures are not extensively documented. For example, certain polychlorinated hexachlorobiphenyls (PCBs) have a low toxic potency to induce cleft palate deformities in mice (Bimbaum et al. 1985). However, mixtures of 2,3,7,8-TCDD and 2,3,4,5,3, 4 -hexachlorobiphenyl resulted in a tenfold increase in incidence of cleft palate in mice. Thus, the toxicity of compounds such as 2,3,7,8-TCDD may be enhanced by compounds of relatively low acute toxicity, such as selected PCBs. Bimbaum etal. (1985) concluded that the widespread environmental occurrence of such combinations suggests a need for further evaluation of the mechanism of this interaction. 

Table 2 Summarized table with the more important compounds included in the surfactants, polyhalogenated compounds, and other industrial residues. Their generic chemical structure and the use or origin are shown. Some reported data regarding their environmental occurrence and the more probably environmental fate are also given... 

Substance Chemical Structure Uses/Origin Environmental Occurrence Environmental Fate... 

Contrary to anionic and nonionic agents, they have poor detergency and are used more in the preparation of germicides, fabric softeners, and emulsifiers. Amphoteric surfactants are produced in much smaller amounts (5xl04 metric tons, near to 2% of the total production) [125] they are biodegradable and their ecotoxicological importance can be considered low. Their environmental occurrence up to know has been just occasional. 

Pijnenburg AMCM, Everts JW.de Boer J, Boon JP (1995) Polybrominated biphenyl and diphenyl ether flame retardants analysis, toxicity, and environmental occurrence. In Ware GW (ed) Reviews of environmental contamination and toxicology, vol 141. Springer, Berlin Heidelberg New York, p 2... 

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