There are many different types of materials analysis techniques under the broad heading of “spectroscopy”, utilizing a wide variety of different approaches to probing material properties, such as absorbance, reflection, emission, scattering, thermal conductivity, and refractive index. Spectroscopy expert witnesses may opine on spectroscopic analysis and absorption spectroscopy, as well as related issues. In Atomic Absorption: Feeding the Food Safety Market, Hazel Dickson writes on metallic elements in food:
Some metallic elements are essential to the health and well being of the human body as they play an important role in basic functions. Examples of these include phosphorus, which is needed for muscle and tissue growth, and calcium, which is critical for normal cell operation. Minute amounts of zinc and manganese are required for hormone production and enzyme function. The absence or excess of these elements in the diet would result in the body not functioning in a normal and healthy way. Other elements such as arsenic, mercury, and lead are toxic and offer no physiological benefit. Entry of these elements into the body is usually via ingestion of food that has been contaminated due to pollution of the environment where the food is produced. Food and beverage suppliers and manufacturers, therefore, have a responsibility to know what is in the food they are supplying to consumers.