Which of the following most
correctly describes what is meant by contamination? (A) The mixing of a substance with
other substances. (B) Chemical changes in a
substance. (C) Changes to the nuclei of atoms
in a substance.
To understand contamination, we
need to know that more than one substance must be involved. If we have some substance — say, a
cloud of gas — nothing that happens in this cloud by itself can contaminate the
gas. Contamination requires that some
other substance — say, another gas cloud — moves in and mixes with this one. That is, it’s only by mixing
substances that contamination can happen. We choose answer option (A). Note, by the way, that this
contamination may be radioactive contamination or not. Here, we’re speaking generally
about contamination and what it means. It’s the mixing of a substance with
one or more other substances.