Science Briefing

Weed killer, used by many, in doubt

The widely used weed killer atrazine affects the sexual development of frogs, raising questions about the effects of its use in the environment, the University of Ottawa says.

A study by researchers at the university found that at low levels comparable to those measured in the environment, fewer tadpoles reached the froglet stage and the ratio of females to males increased.

Atrazine “is so widely used that it can be detected in many rivers, streams and in some water supplies,” the university said in a statement.

The U.S. Environmental Protection Agency said in October that it was reviewing the health effects of the herbicide. Some studies have tied it to birth defects, low birth weight and premature babies.

NASA analyzing parachute failure

NASA still isn’t sure why two parachutes failed during a test flight of its prototype moon rocket Oct. 28.

The two-minute flight of the Ares I-X rocket went well, but only one of the three main parachutes on the first-stage booster opened properly. That caused the booster to slam harder than intended into the Atlantic Ocean, badly denting it.

An engineering manager, Marshall Smith, said Thursday that one parachute may have inflated too quickly, putting too much load on the system. The flapping parachute lines may have damaged the second parachute, which opened only partially, he said.

Several more months of analysis are needed.

The rocket is supposed to replace the space shuttles and eventually fly astronauts to the moon, although the White House may scrap that plan.

-- from times staff and wire reports