Mutagenicity in Emissions from Coal- and Oil-Fired Boilers

Abstract

The mutagenicity of emission samples from three oil-fired and four coal-fired boilers have been compared by using the Salmonella/microsome assay. Very little or no mutagenic activity was observed in samples from five of these boilers. The sample from one oil-fired boiler showed mutagenic activity of about 500 revertants/MJ, and the sample from a coal-fired fluidized bed combustor had an activity of 58.000 revertants/MJ measured with strain TA 98 in the absence of metabolic activation. All samples contained substances that were cytotoxic to the test bacteria, thus making it difficult to obtain linear dose-response curves. Mutagenic activity at low levels may remain undetected due to this toxicity of the samples. Samples with mutagenic activity below the detection limit in the Salmonella test have also been tested for forward mutations at the HGPRT locus in V79 hamster cells. Weak mutagenic effects were detected in two of the samples, whereas the sample from one oil-fired boiler remained negative. In this test, as well as in the Salmonella test, a strong cytotoxic effect could be observed with all samples.

Consensus Report: Mutagenicity and Carcinogenicity of Car Exhausts and Coal Combustion Emissions

“…Generally the solventextractable organic composition of coal fly ash from modern pulverized coal plants is quite low. Similarily, gaseous emissions of organic compounds include ethylene, benzene, toluene, and a variety of alkanes (11). Large power plants fired with pulverized coal generally have efficient combustion and emit very small amounts of organic compounds whereas smaller boilers are often less efficient and produce greater concentrations or organic effluents (50).…”

“…Mutagenicity not detected with the Ames Salmonella assay with several samples has however been reported as positive in the mammalian V79 hamster cells assay (11,53). Technical difficulties have prevented measurement of the mutagenicity of the gas phase of coal-fired power plant emissions.…”

Characterization of microbial mutagens in complex samples—methodology and application

“…review by Chrisp and Fisher). 28 Mutagens from residential oil burning have been reported by Lewtas 174 and from coal-and oil-fired power plants and industrial boilers by M0ller and Alfheim 87 and Alfheim et al 18 Furthermore, mutagens have been found in emission samples from wood and peat combustion, 17>7M73 -' 74 cereal straw combustion,' 75 ' 176 and from fluidized bed coal combustors. 18 -177182 However, only a few of these studies have aimed at further characterization of the mutagens present.…”

“…This discrepancy can easily be understood since later studies have shown a great variation in the mutagenic activity of fly ash from one plant to another. 18 Fisher et al 184 found that most mutagens were associated with the finest size fraction of the fly ash as found for particles from ambient air. Furthermore, they observed a variation of the mutagenic activity depending on the sampling temperature.…”

“…Even when it has not been possible to separate the mutagenic and the bacteriostatic compounds, a fractionation may distribute and dilute the toxic compounds in several fractions allowing the mutagenic activity to be expressed in an ordinary plate incorporation test. 18 On the other hand, the biological activity of complex mixtures may not be reliably predicted from the known effects of its separate components or from the test results of separate fractions, since the components need not act additively in a complex mixture. The literature includes examples of compounds exhibiting antagonistic effects 22 -23 when tested for mutagenicity as well as compounds showing synergism.…”