Nuclear Photodisintegration at High Redshifts by Gamma-Ray Blazars

We analyse the photodisintegration of nuclei near the center of blazars, in particular PKS 0528+134. We show that this process could explain the recent observation of a high Al/Si ratio in a cloud on the line of sight of a distant quasar and we calculate the effect of this gamma irradiation on the abundance of deuterium, an isotope of the highest cosmological interest since it is sensitive to the baryon density of the universe. The process has interesting consequences and deserves to be inserted in a consistent scenario of the early evolution of the universe.