For almost half a century, scientists have struggled with plutonium contamination spreading further in groundwater than expected, increasing the risk of sickness in humans and animals.

The Iranian file on the plutonium issue has been concluded and is closed, the International Atomic Energy Agency said in a document posted on its official Web site Tuesday.

A Japanese newspaper said Tuesday North Korea may have processed all its 16,000 uranium fuel rods to obtain 25 kilograms of weapons-grade plutonium, enough to produce four-five nuclear bombs.

Here’s a pollution-control tip from nature: Deep inside a flooded mine in Wisconsin, scientists from several institutions including the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have discovered a world in which bacteria emit proteins that sweep up metal nanoparticles into immobile clumps. Their finding may lead to innovative ways to remediate subsurface metal toxins.

Researchers have a better understanding of how the crystal structure of some metals becomes stable through magnetism.

Researchers at Rutgers, The State University of New Jersey, have unlocked some of the physical and chemical secrets of plutonium, an element known for its use in atomic weapons and power plant fuel. While the complex nuclear characteristics of plutonium are well-known, it has properties as a metal or a chemical compound that have often left scientists scratching their heads.