Köchy, M. (2011)
Nano-particles are solid substances in tiny sizes (less than 1 millionth of a gram) that often have interesting, very different properties due to their large specific surface than much larger, conventional units of the same substance. The production of nano-particles is increasing at an exponential rate. Due to the increased application of nano-particles, it is assumed that 5 t/yr nano-silver are released into the environment in Switzerland and 3000 t/yr in the U.S.A. . The mobility and half-life of nano-particles can be great. Very little is known about how engineered nano-particles behave in the environment as they accumulate . They might be mobile, aggregate or interact with each other or with other organic pollutants. Past experience with, e.g., asbestos, DDT, chlorofluorocarbons, fossil fuels, teaches that substances that have been considered beneficial or unobtrusive at low concentrations or low amounts may become problematic as they accumulate. It is known that nano-particles applied to clothes can be found in the soil on fields when the particles are washed out with the laundry, accumulate in sewage plant sludge which is spread on arable land. Particles may be washed to the ocean. Other particles may be released into the air. It is not known which nano-particles might accumulate in animals, plants, or humans.
In order to detect early signs of accumulation and link these hotspots to potential observed effects, engineered nano-particles ought to be monitored in space and time. The monitoring procedures should be coordinated among the GEO countries.