Combined Effects of Polycyclic Aromatic Hydrocarbons and Sunlight

摘要

The authors have shown that Chinese hamster V79 cells are made photosensitive by dimethylbenzanthracene (DMBA) if the cells are treated with this PAH before, and not after, light exposure. The effective wavelengths are from approx. 290 to 400 nm. These wavelengths are present in natural sunlight reaching the earth's surface suggesting that PAH's generated by coal combustion processes may interact with sunlight to produce materials in the environment of a potentially toxic nature. In this regard we have also tested samples generated from a bench-scale pressurized fluidized bed coal combustion unit. These samples were either the fine particulates (fly ash) or the volatile organics which condense out at the end of the effluent stream. Both of these samples sensitized the mammalian cells to sunlight-simulating light as determined from cell survival measurements,, although to a lesser extent than the DMBA. In addition, the photosensitization was shown to be a true photodynamic effect. Since all three factors (i.e., PAH's, sunlight, and oxygen) necessary for the production of the phototoxic agent(s) would be expected to interact in the environment, the results may be of particular concern to human health. Both PAH's and sunlight are known carcinogens and their interaction may result in a potentiation of their carcinogenic activities. In addition the cytotoxicity produced could conceivably have a tumor promoting effect due to the resultant cellular repopulation. Our results have dealt with cell killing initially because it is the simplest and easiest endpoint of interest to measure. Additional studies ae in progress to studythe potential mutagenic and/or carcinogenic activities of combined PAH and sunlight exposure. (ERA citation 04:045433)