When referring to certain types of damage to the environment (daños medioambientales), these terms are often cognates, as in contaminación medioambiental (“environmental contamination”) or contaminación radioactiva (“radioactive contamination”).
But in this same context contaminación is just as often rendered as “pollution” rather than “contamination.” “Environmental pollution” and “radioactive pollution” are quite common, as are similar expressions such as contaminación atmosférica (“air pollution”), contaminación de las aguas (“water pollution”), contaminación acústica (“noise pollution”) and contaminación lumínica (“light pollution”). Likewise, in this context contaminantes may be rendered as “contaminants” or “pollutants.”
In other respects, “contamination” is used in criminal forensics in expressions such as “contamination of evidence” or “contamination of DNA samples.” These may be rendered respectively as contaminación de pruebas and contaminación de muestras de ADN.
And, as a final example, lately in the Spanish press, journalists who disagree with judicial decisions often use the term jueces contaminados. In English the expression “contaminated judges” generally denotes judges who have a conflict of interest or who have already been involved or ruled on a related case. In contrast, in Spain jueces contaminados appears to be a term intended to accuse judges of a lack of impartiality when adjudicating politically sensitive matters.