Earth/Environment

Early puberty linked to flame retardants
Researchers report one possible explanation for the falling age of puberty in U.S. girls: certain widely used flame retardants commercially introduced during the 1970s. In animals (and in the genitals of male babies), some polybrominated diphenyl ether flame retardants, or PBDEs, have been shown to have feminizing effects. Now University of Cincinnati College of Medicine scientists have compared when a girl’s first period occurred with blood levels of PBDEs. Blood data came from a nationally representative cross-section of U.S. girls. The higher the concentrations of some PBDEs, the more likely that a girl’s first period occurred early — before 12. The findings appear online June 12 in Environmental Research. —Janet Raloff

Lakes bring toxins to dinner
Fish and drinking water pulled from lakes can host unacceptably high concentrations of bacterial poisons known as microcystins, a new study finds. Cyanobacteria, often called blue-green algae, release these toxins into nutrient-rich (often greenish) waters. A U.S.-Canadian research team measured microcystin levels in 10 tropical lakes in Uganda and two U.S. Great Lakes, Erie and Ontario. Water in nine lakes, including Erie, exceeded World Health Organization drinking-water limits for microcystins and almost all sampled fish — especially predators and sport fish — in each lake hosted high concentrations of microcystins, the scientists report online June 14 in Environmental Science & Technology. —Janet Raloff

Platypus seems headed for dodo-dom
By 2070, the continued warming and drying forecast for Down Under could perilously shrink the dwindling habitat of the platypus, report scientists at Monash University in Clayton, Australia. The team pored over nearly 10,000 records of the animals’ range going back 200 years. Since the 1960s, rainfall gave way to heat as the predominant limiting factor for the egg-laying mammal’s range, the scientists report online June 6 in Global Change Biology.  With cool streams — which are drying up — the animals’ only remaining sanctuary, the researchers recommend planting stream banks with shade species to create refuges. —Janet Raloff