Synonyms for Contaminated (same or very similar meaning)
WordNet sense 1 (contaminated with infecting organisms):
dirty, pestiferous
WordNet sense 2 (containing or resulting from disease-causing organisms):
infected, septic
WordNet sense 3 (rendered unwholesome by contaminants and pollution):
polluted
WordNet sense 4 (combined with extraneous elements):
impure
From the ODE community, based on WordNet
add/edit