Fourier-transform infrared spectroscopy and gas chromatography-mass spectrometry reveal a remarkable degree of structural damage in the DNA of wild fish exposed to toxic chemicals.

The use of gas chromatography-mass spectrometry with selected ion monitoring (GC-MS/SIM) and Fourier-transform infrared (FT-IR) spectroscopy revealed a remarkable degree of damage in the hepatic DNA of fish exposed to toxic environmental chemicals, compared with controls. The exposed fish, which were neoplasm-free, were part of a population with a high incidence of liver cancer. GC-MS/SIM showed markedly high concentrations of hydroxyl radical-induced ring-opening products (e.g., 2,6-diamino-4-hydroxy-5-formamidopyrimidine) and 8-hydroxy adducts of adenine and guanine (e.g., 8-hydroxyguanine) in the DNA. FT-IR spectroscopy revealed substantial changes in spectral areas, such as those assigned to NH vibrations of nucleotide bases and CO vibrations of deoxyribose. This diverse and extensive damage to DNA provides a perspective of premalignant changes resulting from xenobiotic exposure and a promising basis for predicting cancer risk in animals and humans.