Researchers expect that nanocatalysts and magnetic nanoparticles will enable the use of heavily polluted water for drinking, sanitation, and irrigation. Use of catalytic particles could chemically degrade pollutants instead of simply moving them somewhere else, including pollutants for which existing technologies are inefficient or cost prohibitive. Magnetic nanoparticles, when coated with different compounds that have a selective affinity for diverse contaminating substances, could be used to remove pollutants, including arsenic, from water. Companies are commercializing these technologies and researchers are frequently publishing new discoveries in this area. Researchers are developing new sensor technologies that combine micro- and nanofabrication technology to create small, portable, and highly accurate sensors to detect chemical and biochemical parameters in water. Several research consortia are field testing devices that incorporate nanosensor technology to detect pollutants in water.