I’ve recently noticed a lot of articles and scientific studies about micro- and nanomaterials in the environment. So what are these? They are very, very small particles. The definitions are not hard and fast, but microparticles range from 0.1 and 100 µm (1 µm = 1 millionth of a meter). Nanoparticles are much smaller, on the order of 1 – 100 nm (1 nm = 1 billionth of a meter). There are both natural and engineered micro- and nanomaterials in our world. Ocean spray, smoke, and milk all contain natural nanomaterials. In recent years, engineered materials have been designed and produced with many useful applications. Some of the most commonly used nanomaterials are platinum, which is used in catalytic converters, and titanium dioxide, used is self-cleaning paint. Lithium-ion batteries often contain nickel magnesium cobalt oxide (NMC).
As with just about every new compound we introduce into our lives, there can be environmental consequences. The problem of microplastics in marine environments has been known for some years now. Microplastics come from a variety of sources, including vehicle tire wear, household dust, and deterioration of plastic surfaces and materials, such as bottles, artificial turf, and polymeric paint. Recent studies reported that agricultural soil may be a large sink for microplastics, primarily due to the application of sewage sludge. [Nizetto et al. Environ. Sci. Tech. 2016 50, 10777−10779]
The environmental effects of nanomaterials are much less well known, but studies are beginning to be done. A recent paper reported that some nanomaterials can negatively impact beneficial soil bacteria. Silver nanomaterials have been reported to affect the growth of fish embryos. [Levard et al. Environ. Sci. Tech. 2012, 46 (13):6900–6914] But research on these issues is still in its infancy, and there is much we need to learn.
