Iowans are junking their old computers by the thousands, causing concern over landfill space. The Department of Natural Resources is launching a study to determine how many computers are being dumped in Iowa and to identify alternative options to landfills, like recycling. The D-N-R’s Bob Castelline defines e-waste as anything with a cord, including computers, microwave ovens, stereo systems and even palm pilots. He says the study will last 13 weeks and should provide a wealth of data on e-waste.Castelline says about one-point-five million computers are tossed out nationwide every year and the number may rise to 315-million by 2004.Castelline says one goal is to get electronics manufacturers to design the products to last longer or to help the consumer find other uses for their obsolete gadgets. One company hollows out old computer monitors and outfits them as fish tanks, calling them MACquariums.