Three of the five Great Lakes --Huron, Superior and Erie--are awash in plastic. But it's not the work of a Christo-like landscape artist covering the waterfront. Rather, small plastic beads, known as micro plastic, are the offenders, according to survey results to be published this summer in Marine Pollution Bulletin . "The highest counts were in the micro plastic category, less than a millimeter in diameter," explained chemist Sherri "Sam" Mason of the State University of New York at Fredonia, who led the Great Lakes plastic pollution survey last July. "Under the scanning electron microscope, many of the particles we found were perfectly spherical plastic balls."