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.
What is an average time for a half marathon?   The time of the person in the middle of a half-marathon run in 2003 for men whereby 1409 runners competed is around 2 hours 30 mins.The fastest runner finished with a t â¦ ime of 1hr 12 mins 0 sec. The last runner finished in about 3 hrs 58 mins. The time of the person in the middle of a half-marathon run in 2003 for men whereby 1409 runners competed is around 2 hours 30 mins.