Substances and Categorization

Hazard Class A series of nine descriptive terms that have been established by the UN Committee of Experts to categorize the hazardous nature of chemical, physical, and biological materials. These categories are flammable liquids, flammable solids, explosives, gases, oxidizers, radioactive materials, corrosives, poisonous and infectious substances, and dangerous substances. 

In the case of reproductive toxicity, substances are categorized and labelled according to Appendix VI to the Guideline 93/21/ EEG (10). Within this complex, two different endpoints are considered separately, namely substances which impair fertility and substances which cause developmental toxicity (see Chapter 34). 

Vitamins are exogenous chemical substance required by the body in very small amount for the various metabolic functions of the body and categorized as essential nutrients. They do not yield energy but enable the body to use other nutrients and are primarily used in the prevention and treatment of certain deficiency diseases. 

The amendment states that any new drug that is substantially similar to a controlled substance currently listed under the Code of Federal Regulations (CFR), Schedule I or II, and has either pharmacological properties similar to a Schedule I or II substance or is represented as having those properties, will be considered a controlled substance and duly categorized as Schedule I. 

It is useful to categorize the factors that influence toxicity within the following three classifications (1) the toxic substance and its matrix, (2) circumstances of exposure, and (3) the subject and its environment (see Figure 6.1). These are considered in the following sections. 

For all those chemical substances so categorized as needing further attention, a screening risk assessment is required. There can be three results at this stage no further action is required, the chemical substance is determined to be toxic and measures may be needed for control, or it is placed on the Priority Substances List (PSL) and subjected to an in-depth assessment. 

Fragrance creation is not necessarily confined to natural aroma substances and many rely heavily on artificial compounds. Therefore, classical perfumes categorized into fundamental types along with the representative natural products are covered here (Table 13). 

More information on different chemical substances, as well as the categorization, kinds of uses, and possible health effects, is available in other chapters of this book and in other published literature. To protect themselves and the living environment, students and workers must be well aware of potential toxicity and the implications of negligence and improper use. The different chapters of this book discuss specihc chemical substances and their uses, toxicity, health effects on animals and humans, and the importance of taking precautions during use. 

A number of substances and preparations are available for the treatment of liver diseases. They can be categorized as follows (s. tab. 40.3) ... 

The factors and processes affecting the deposition of airborne substances in all regions of the respiratory tract can be broadly categorized as those related to the (1) structure of the respiratory system, (2) chemical and physical properties of the airborne substance, and (3) ventilatory functions including route of breathing (nasal, oral, and oronasal). 

Van der Waals forces represent important intermolecular interactions between nonelectrolyte substances, and can be categorized into dipole-dipole, dipole-induced-dipole, and induced-dipole-induced-dipole forces. Polar molecules, by definition, will have a permanent dipole moment, and will interact with the oppositely charged portions or other molecules having permanent dipole moments. The dipole-dipole interaction is known as the orientation effect, or as the Keesom force. 

Solid form selection involves the preparation and property evaluation of many derivatives of an active molecule. Drug substance properties of importance in the drug development process may be categorized as shown in Table 1. These properties depend on the nature of the drug substance and the final formulation. Many bioactive organic molecules contain ionizable groups such as carboxylic... 

Given the name or chemical formula for a substance, (1) categorize the substance as a metallic element, carbon in the diamond form, another nonmetallic element, an ionic compound, a polar molecular compound with hydrogen bonds, a polar molecular compound without hydrogen bonds, or a nonpolar molecular compound (2) identify the type of particle that forms its fundamental structure and (3) identify the type of attraction holding its particles in the solid and liquid form. 

One way of categorizing exposure is set out in Figure 2.1. This illustrates that there are a great number of exposure scenarios. While some may be irrelevant to particular substances and processes, normally several will be applicable. 

The Directive defines a system for the classification and categorization of substances according to their hazard potential. Risk assessment, evaluating hazard in the context of quantitative exposure information, is not carried out [3]. Generally, the classification and categorization procedure is conducted by a committee of National Experts who represent Member States. If necessary, a committee of Specialized Experts in a particul field may be convened to review the scientific evidence and attempt to reach a consensus. 

According to mineralization (total amount of dissolved solid substances) and content of gas, the groundwaters are categorized into normal and mineral waters. 

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