John Leal was all of these, except:

Heavy metals found in water usually arise from:

Which of these is NOT a likely source of contamination for ocean water and beaches? 

When tuna decomposes before consumption, it produces large quantities of histamine, resulting in this disease in those who eat it.

Which of these is NOT a surrogate measure used to determine the efficiency of waste water treatment methods?

The most common cause of hand, foot, and mouth disease (HFMD) in the US is

Attendance at the Olympic games in Brazil was not affected by the Zika outbreak.

What do Shigella dysenteriae and EHEC have in common?

Pasteur used heat to destroy microorganisms causing spoilage based on the experiments of Nicolas Appert, who developed canning.

The multiple tube fermentation technique is being replaced in most labs by the membrane filter method.