AJC: Twenty years ago, in the heady days between the fall of the Berlin Wall and the collapse of the Soviet Union, aid officials from the United States got their first, long look at a regionwide environmental mess behind the Iron Curtain. Throughout Central and Eastern Europe, visiting aid delegations found groundwater poisoned by diesel fuel and pesticides, air fouled by sooty smokestacks and agricultural soils doubling as dumps for industrial and military wastes. The recent …