Dental amalgam controversy of mercury received by sewage treatment plants. The mercury contaminates the treatment plant sludge, which is typically disposed of by land application, landfilling or incineration. Several states, including New Jersey, New York, and Michigan, have required the installation of dental amalgam separators prior to 2017. EPA promulgated an effluent guidelines regulation in 2017 which prohibits most dental practices from disposing amalgam waste down the drain. Most dental offices nationwide are now required to use amalgam separators. The WHO reported in 2005 that in the United Kingdom mercury from amalgam accounted for 5% of total mercury emissions. In Canada, dental amalgam
Women in chemistry the only woman to be award two Nobel prizes). Her prize in chemistry was for her "discovery of the elements radium and polonium, by the isolation of radium and the study of the nature and compounds of this remarkable element." Irene Joliot-Curie, Marie's daughter, became the second woman to be awarded this prize in 1935 for her discovery of artificial radioactivity. Dorothy Hodgkin won the prize in 1964 for the development of protein crystallography. Among her significant discoveries are the structures of penicillin and vitamin B12. Forty five years later, Ada Yonath shared the prize with Venkatraman Ramakrishnan and Thomas