Hazardous wastes polycyclic aromatic hydrocarbons

A considerable number of reports regarding the formation of compounds that may represent a health hazard are related to the formation of polycyclic aromatic hydrocarbons (PAHs) during industrial pyrolysis processes (recycling of waste, incineration, etc.). This interest is particularly geared toward the study of polyolefins pyrolysis and synthetic and natural rubber pyrolysis. The formation of PAHs during polyethylene pyrolysis has been reported frequently in literature [6, 12] and is further discussed in Section 6.1. The formation of PAHs during tire pyrolysis is also of considerable concern. The concentrations of some components in the oils generated from the pyrolysis of used tires as a function of temperature are indicated in Table 5.3 1 [13]. 

There are currently thousands of sites in the U.S.A. containing soil contaminated with volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides, mercury, and mixed waste (radioactive and hazardous waste). One method used frequently to remediate these sites is thermal desorption. 

This statement was prepared to give you information about polycyclic aromatic hydrocarbons (PAHs) and to emphasize the human health effects that may result from exposure to them. The Environmental Protection Agency (EPA) has identified 1,408 hazardous waste sites as the most serious in the nation. These sites make up the National Priorities List (NPL) and are the sites targeted for long-term federal clean-up activities. PAHs have been found in at least 600 of the sites on the NPL. However, the number of NPL sites evaluated for PAHs is not known. As EPA evaluates more sites, the number of sites at which PAHs are found may increase. This information is important because exposure to PAHs may cause harmful health effects and because these sites are potential or actual sources of human exposure to PAHs. 

The major chemicals in coal tar creosote, coal tar, and coal tar pitch that can cause harmful health effects are polycyclic aromatic hydrocarbons (PAHs), phenol, and cresols. Coal tar pitch volatiles vary depending on the makeup of the coal tar product that is being heated. About 300 chemicals have been identified in coal tar creosote, but as many as 10,000 other chemicals may be in this mixture. Because coal tar creosote is the major type found in the environment and at hazardous waste sites in the United States, we will emphasize its effects on human health in this profile. The health effects of coal tar and coal tar pitch will also be described. 

In a recently reported study [56], Mutatox was used to measure genotoxic activity in soils contaminated with polycyclic aromatic hydrocarbons (PAHs). Water extracts fiom clean soil spiked with a mixture of PAHs and soil excavated from a hazardous waste site known to be contaminated with PAHs were tested with Mutatox. One of the major trends revealed by the test data was that removal of the original contaminants (as determined by... 

Ts aMs M, Stephanou EG (2005) Occurrence of gaseous and particulate polycyclic aromatic hydrocarbons in the urban atmosphere study of sources and ambient temperature effect on the gas/particle concentration and distribution. Environ Pollut 133 147—156 USEPA (2009a) Organics questions, http //www.epa.gov/waste/hazard/testinethods/faq/faqs org.htm. Accessed 16 July 2009... 

Waste oil generated from lubricants and hydraulic fluids is one of the more commonly recycled materials. A significant fraction of the approximately 4 billion liters of waste oil produced annually in the United States is burned as fuel, much is recycled, and lesser quantities are disposed of as waste. The collection, recycling, treatment, and disposal of waste oil are all complicated by the fact that it comes from diverse, widely dispersed sources and contains several classes of potentially hazardous contaminants. These are divided between organic constituents (polycyclic aromatic hydrocarbons, chlorinated hydrocarbons) and inorganic constituents (aluminum, chromium, and iron from wear of metal parts barium and zinc from oil additives and formerly lead from leaded gasoline). 

Immunoassay techniques have been approved for the determination of numerous analytes commonly found in hazardous wastes. Where the EPA method numbers are given in parentheses in the following list, these include pentachlorophenol (4010) 2,4-dichlorophenoxyacetic add (4015) polychlorinated biphenyls (4020) petroleum hydrocarbons (4030) polycyclic aromatic hydrocarbons (4035) toxaphene (4040) chlordane (4041) dichlorodiphenyltrichloroethane (DDT) (4042) trinitrotoluene (TNT) explosives in soil (4050) and hexahydro-l,3,5-trinitro-l,3,5-triazine (RDX) in soil (4051). ELISAs have been reported for monitoring pentachlorophenol and BTEX (benzene toluene ethylbenzene and o-, m-, and p-xylene) in industrial effluents. 

Yi-Chi Chien, Ching-Ping Liang, Pai-Haung Shih. Emission of polycyclic aromatic hydrocarbons from the pyrolysis of hquid crystal wastes. Journal of Hazardous Materials, 170(2-3) 910-914, 2009. 

---