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.
The time required to train for a marathon really depends on your current fitness level, your running experience, and your goals for the race. For experienced runners who have already run marathons, they may be able to get race-ready in 12 weeks. If they're hoping to beat a personal record, they may need a few more weeks. Beginners should slowly build their distances and should plan to take anywhere from 18 to 22 weeks, depending on their starting point.