PREDICTION OF THE DEVELOPMENTAL TOXICITY HAZARD POTENTIAL OF HALOGENATED DRINKING-WATER DISINFECTION BY-PRODUCTS TESTED BY THE INVITRO HYDRA ASSAY

A series of seven randomly selected potential halogenated water disinfection by-products were evaluated in vitro by the hydra assay to determine their developmental toxicity hazard potential. For six of the chemicals tested by this assay (dibromoacetonitrile; trichloroacetonitrile; 2-chlorophenol; 2,4,6-trichlorophenol; trichloroacetic acid; dichloroacetone) it was predicted that they would be generally equally toxic to both adult and embryonic mammals when studied by means of standard developmental toxicity "teratology" tests. However, the potential water disinfection by-product chloroacetic acid (CA) was determined to be over eight times more toxic to the "embryonic" developmental portion of the assay than it was to the adults. Because of this potential selectivity, CA is a high-priority item for developmental toxicity tests in pregnant mammals to confirm or refute its apparent unique developmental hazard potential and/or to establish a NOAEL by the route of most likely human exposure. © 1990.