Does a single fiber really matter amid all the sediment and detritus that amphipods regularly swallow? Jamieson thinks so. For a start, PCBs and other toxins can stick to plastic, turning fibers into sinks for other contaminants. Also, many of the pieces that his team found were relatively huge. "The worst example I saw was a purple fiber, a few millimeters long, tied in a figure-of-eight in an animal no longer than a centimeter," Jamieson says. "Imagine if you swallowed a meter of polypropylene rope."