Rice is a staple food in many regions of the world, however it sometimes contains levels of arsenic that are hazardous to our health. An interdisciplinary team of researchers has now discovered that there are arsenic compounds which have a toxic effect on plants and yet had not previously been considered in connection with chemical analyses of rice and the estimated health risks for humans. The research concerns thioarsenates, compounds made up of arsenic and sulphur, which may be present in rice fields more often than previously assumed.