From Longman Business Dictionary
contaminatecon·tam·i·nate /kənˈtæməneɪt/ verb [transitiveT]1to make something dirty and dangerous, for example with chemicals or poisonA large number of eggs were contaminated with salmonella.
2INSURANCE to spoil goods carried by a ship, especially by sea water getting into them —contamination noun [uncountableU]The pollution could cause serious contamination of agricultural land.