Toxic shock

POISONS in the environment may eventually lead to backwards evolution of the human brain, according the author of a new study into global environmental change. Christopher Williams, lecturer in international education at the University of London's Institute of Education, says toxins such as lead and radiation are affecting the intelligence of more people than earlier estimates show. He says earlier studies have not taken into account the different effects of poisons on people from poorer countries suffering from bad nutrition. Other studies have left out politicallysensitive data.

(See research papers .)