Final answer:
The bleach contaminating the lettuce on the vegetable prep table would be considered a chemical contaminant due to its non-natural, harmful nature when present in food.
Step-by-step explanation:
If a bottle of bleach has been left on the vegetable prep table and has leaked onto some chopped lettuce, the type of contaminant in this scenario would be chemical. Bleach is a substance used for cleaning and disinfection which, if it comes into contact with food, represents a chemical contaminant. This is because it is a non-natural substance that can cause harm if ingested, and is not related to the physical makeup of the food (a physical contaminant), a pathogenic organism (a biological contaminant), or radiation (a radiological contaminant).