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||Last Updated: Nov 12th, 2006 - 20:38:00
By Jimmy Downs
Drinking water may contain more cancer-causing agents than previously thought. Canadian Researchers have detected two new nitrosamines in drinking water in a city, which can be 100-10,000-fold more carcinogenic than trihalomethanes(THMs).
THMs, a group of potentially carcinogenic drinking-water disinfection byproducts (DBPs), are the major concern of the Environmental Protection Agency (EPA). Early studies have linked THMs to an increased risk of bladder cancer.
The finding suggested that a better methodology be adopted to monitor the presence of nitrosamines. The water facilities often use GC-MS only to analyze water samples to detect nitrosamines and other compounds while the researchers used LC/MS/MS, which is far more sensitive.
For the study published in the November 8, 2006 issue of Environmental Science & Technology, Xingfang Li from The University of Alberta and colleagues tracked a Canadian treatment plant and distribution system for the presence of nitrosamines.
They detected four nitrosamines - N-nitrososodimethylamine (NDMA), N-nitrososopyrrolidine (NPyr), N-nitrosopiperidine (NPip), and N-nitrososodiphenylamine (NDPhA). The latter two are newly discovered in drinking water, at the level of 33-117 nanograms per liter (ng/L) and 0-2 ng/L respectively. NPyr and NDMA were up to 18-75 ng/L and 108 ng/L respectively, which are considered quite high, according to a news release by the American Chemical Society.
The levels of the nitrosamines increased as the water passed through the pipelines, the farther the water passed, the higher the concentrations of these nitrosamines were, the researchers reported.
It remains unknown whether these newly discovered nitrosamines are also present in other drinking water systems. The possibility is real as chloramines, which serve as precursors of nitrosamines, are commonly used to treat drinking water to reduce levels of THMs.
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