(Story contributed by Jim H. Smith) Senior thesis research conducted last spring by Audrey Haynes '12 at Costa Rica’s National University, under the tutorship of Johan “Joop” Varekamp, has shown that many residents of the Central American nation have levels of mercury in their hair that far exceed those recommended by the U.S. Environmental Protection Agency. Varekamp, whose student made the discovery as part of a broad evaluation of environmental mercury in Costa Rica, says the elevated mercury levels are probably a consequence of over-consumption of large ocean fish, not exposure to mercury in the air emitted by volcanoes, as…