1 A highly toxic form (methylmercury) builds up in fish, shellfish and animals that eat fish. 2  Fish and shellfish are the main sources of methylmercury exposure to humans.3  Mercury exposure at high levels can harm the brain, heart, kidneys, lungs, and immune system. A highly toxic form (methylmercury) builds up in fish, shellfish and animals that eat fish. 2  Fish and shellfish are the main sources of methylmercury exposure to humans.
The 2016 Boston Marathon will begin on Monday, April 18. Here is some of the basic information you should know about the historic event. Length: According to Olympic standards, marathons are 26 miles and 385 yards, or roughly 26.2 miles long. Route: The Boston Marathon starts on Main Street in Hopkinton, Mass.
Marathon runners can average 8.8mph for 26.2 miles. Best I can tell and would have to agree is the average human jogs at about 8mph, of course distance is the great variable. There is a range in between walking speed 4-5kmh/h and 100m record sprinting 37.58km/h (Usain Bolt 2009). Generally for longer distances average speeds are half those of professionals, so for a marathon 2 hours becomes 4 hours or 10.5km/h.