A federal study released explains for the first time the link between global mercury emissions and the contamination of tuna and other marine life in the North Pacific Ocean. The U.S. Geological Survey study documents the formation in the North Pacific of methylmercury, a highly toxic form of mercury that rapidly accumulates in the food chain to levels that can cause serious health concerns for people who consume seafood.
Source: http://www.scientificamerican.com/article.cfm?id=air-pollution-poisoned-seafood
Also See:
http://www.usgs.gov/themes/factsheet/146-00/
http://www.sciencedaily.com/releases/2009/05/090501195628.htm
http://articles.mercola.com/sites/articles/archive/2009/09/29/WARNING-New-Evidence-Shows-that-Mercury-Present-in-Nearly-ALL-Fish.aspx
Adventist Apology Site 