Scientists have created a green-glowing zebrafish to monitor ecological damage caused by pollution in real time. The flourescent fish makes it easier than ever before to see where in the body environmental chemicals act and how they affect health, particularly chemicals having a bearing on reproductive problems. Numerous studies have linked ‘endocrine-disrupting’ chemicals, used in a wide range of industrial products and contraceptive pharmaceuticals, to reproductive problems in wildlife and humans, the journal Environmental Health Perspectives reports. Previous research by the University of Exeter identified the potential for a major group of these chemicals to cause male fish to change gender, according to an Exeter statement. A team led by Tetsuhiro Kudoh and Charles Tyler, professor at Exeter, created the transgenic zebrafish by placing a genetic system into its body that amplifies the response to estrogens producing the fluorescent green signal. They tested its sensitivity to different chemicals known to affect estrogen hormone signalling, including ethinyloestradiol, used in contraceptive pill and hormone replacement therapy treatments, nonylphenol, used in paints and industrial detergents, and Bisphenol A, which is found in many plastics. Human exposure to these chemicals, which can alter hormone signalling in the body, has been tied with decreases in sperm count and other health problems, including breast and testicular cancer.