The Iowa Geological Survey is helping take some 500 soil samples in the state as part of a nationwide effort to determine the concentration of various metals in soils. Bob Libra of the Iowa Geological Survey is helping with the Iowa effort.He says they lay out a grid of blocks across the country and randomly select a an to collect a soil sample and analyze it for 30 or 40 different kinds of metals. Libra says it’s a kind of nationwide inventory. In some places he says they’re looking for places to mine for minerals, while in other places they’re trying to determine if industrialization left behind contamination. Libra says Iowa has a variety of naturally occurring minerals. He says we have different kinds of soil from various glacial deposits and he says this mapping should help tell us something about the differences in soil. Libra says most of Iowa land is privately owned, and that creates a lot of work to get the samples. He says they’re trying to contact people via phone to get permission to take samples, and if they can’t get them on the phone, they have to go door-to-door. Libra says Iowa’s samples will join those from other states.He says it’ll all go to a Geological Survey lab in Denver to be catalogued and stored. The soil sampling is starting this month and most of the state will be sampled by the end of summer.