In the future, Earth's population reaches over 70 billion individuals, all living under an authoritarian government. Culture, tech level and wealth are pretty monolithic and everywhere is basically the same.
The government, for unknown reasons, administers unknown chemicals into the water supply. Pollution is widespread. Most worrisome of all, however, radioactive contamination is commonplace.
These toxins have resulted in disturbing and sometimes bizarre changes in human bodies. For example, hair falling out, and changes in skin and eye color.
Can any of these changes occurring in an individual create mutations in the DNA and be passed on to a person's offspring?
Are there mutations caused by exposure that may not be present in the individual but would later show up in children that person has?
Are these “temporary mutations” (changes in DNA methylation for instance) or permanent ones (changes to the underlying DNA)?
I am mostly looking for an explanation for permanent changes to genetics such that these mutations get passed down to future generations.