The following definitions shall apply in the interpretation and enforcement of these standards. If a word or term used in this subchapter is not contained in the following list, its definition shall be as shown in 30 TAC §290.38 or in Title 40 Code of Federal Regulations §141.2. Other technical terms used shall have the meanings or definitions listed in the latest edition of "Glossary, Water and Wastewater Control Engineering," prepared by a joint editorial board representing the American Public Health Association, American Society of Civil Engineers, American Water Works Association, and the Water Pollution Control Federation.

1. (1) Halogen--means one of the chemical elements chlorine, bromine, or iodine.
2. (2) Total Trihalomethanes (TTHM)--means the sum of the concentration in milligrams per liter of the trihalomethane compounds (trichloromethane, i.e., chloroform; dibromochloromethane; bromodichloromethane; tribromomethane, i.e., bromoform) rounded to two significant figures.
3. (3) Trihalomethane (THM)--means one of the family of organic compounds named as derivatives of methane, wherein three of the four hydrogen atoms in methane are each substituted by a halogen atom in the molecular structure.

Source Note:The provisions of this §290.102 adopted to be effective April 15, 1994, 19 TexReg 2282; amended to be effective February 4, 1999, 24 TexReg 738.