NEW YORK, May 9 -- Columbia University's Lamont-Doherty Earth Observatory issued the following news: * * * All of the Biggest U.S. Cities Are Sinking From the coasts to the interior, urban areas are sinking. The main culprit: pumping of groundwater. By Kevin Krajick A new study of the 28 most populous U.S. cities finds that all are sinking to one degree or another. The cities include not just those on the coasts, where relative sea level is a concern, but many in the interior. Furthermore,   more