The sum of the concentration in milligrams per liter of the trihalomethane compounds (trichloromethane [chloroform], dibromochloromethane, bromodichloromethane and tribromomethane [bromoform]), rounded to two significant figures.
TOTAL TRIHALOMETHANES (TTHM)
Meaning of TOTAL TRIHALOMETHANES (TTHM) in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012