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 average runner aged 20-29 finished over a minute later, with a time of 3 hours, 44 minutes and 47 seconds, The Telegraph reports. The overall average finish time for the event was 4 hours 6 minutes and 8 seconds.Read more: 1  London Marathon 2015: middle-aged runners faster than their younger counterparts-Telegraph.OU'LL SHRINK. The average marathon runner will be about 1cm shorter at the end of the race than when they began. This is because over time, the discs in the vertebrae compress, researchers at Swansea University found. However the height decrease is naturally reversed in about one dayâs time.