Veterinary antibiotics used in animal agriculture as NDMA precursors.
The formation of carcinogenic N-nitrosodimethylamine (NDMA) during chloramination at drinking water treatment plants has raised concerns as more plants have switched from chlorine to chloramine disinfection. In this study, a source of NDMA precursors that has yet to be investigated was examined. Veterinary antibiotics are used in large quantities at animal agricultural operations. They may contaminate drinking water sources and may not be removed during wastewater and drinking water treatment. Ten antibiotics used in animal agriculture were shown to produce NDMA or N-nitrosodiethylamine (NDEA) during chloramination. Molar conversions ranged from 0.04 to 4.9 percent, with antibiotics containing more than one dimethylamine (DMA) functional group forming significantly more NDMA. The highest formation for most of the compounds was seen near pH 8.4, in a range of pH 6 to 11 that was investigated. The effect of chlorine-to-ammonia ratio (Cl2/NH3), temperature, and hold time varied for each chemical, suggesting that the effects of these parameters were compound-specific.
Environmental Science and Engineering Program, Institute for the Environment and Sustainability, University of California, Los Angeles, La Kretz Hall, Suite 300, Box 951496, Los Angeles, CA 90095-1496, USA; Metropolitan Water District of Southern California, 700 Moreno Avenue, La Verne, CA 91750, USA. Electronic address: shannon.roback@gmail.com.
Shannon L
SL
Leavey-Roback
Metropolitan Water District of Southern California, 700 Moreno Avenue, La Verne, CA 91750, USA.
Stuart W
SW
Krasner
Environmental Science and Engineering Program, Institute for the Environment and Sustainability, University of California, Los Angeles, La Kretz Hall, Suite 300, Box 951496, Los Angeles, CA 90095-1496, USA.
Irwin Mel H
IM
Suffet
D000641:Ammonia / Q000032:analysis; D000822:Animal Husbandry; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000737:chemistry; D002700:Chloramines / Q000737:chemistry; D002713:Chlorine / Q000032:analysis; D004123:Dimethylamines / Q000737:chemistry; D004128:Dimethylnitrosamine / Q000032:analysis* / Q000737:chemistry; D004203:Disinfection; D060766:Drinking Water / Q000032:analysis; D019155:Veterinary Drugs / Q000032:analysis* / Q000737:chemistry; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
D000641:Ammonia; D000900:Anti-Bacterial Agents; D002700:Chloramines; D002713:Chlorine; D004123:Dimethylamines; D004128:Dimethylnitrosamine; D060766:Drinking Water; D019155:Veterinary Drugs; D062065:Wastewater; D014874:Water Pollutants, Chemical; C034516:dimethylamine; C030816:chloramine
Agricultural run-off; Antibiotics; Disinfection byproduct; N-nitrosamine; N-nitrosodimethylamine (NDMA)