AWWA WQTC60785

Residence times in distribution systems can be days as opposed to minutes inside plants, and this may allowsufficient time for the atrazine to be transformed by chlorination into unknown species with unknown toxicities.Hence, there is a need to more completely study atrazine chlorination for residence times typical of distributionsystems. This study aims to address three important issues in this regard. First, the chemical conditions underwhich atrazine transforms need to be determined. Second, any potential transformation products need to beidentified. Third, the mechanistic pathways for these transformation products will have to be elucidated.This study investigated the chlorination of atrazine in laboratory water buffered to pH values ranging from 5.5 to9.5 using reaction times typical of residence times in distribution systems. Reactions occurred at roomtemperature in tightly sealed, head space free, amber bottles. Multiple sample bottles were prepared whichcontained the reaction mixture of buffer, chlorine, and atrazine. Multiple bottles containing a control mixture ofatrazine and buffer and a blank mixture of chlorine and buffer were also prepared. After a selected reaction time,which ranged from a few minutes to 28 days, one of each of the sample, control, and blank bottles was analyzed.First, the free and total chlorine were measured using the DPD method. Next, the contents of the bottles weredivided, and each aliquot was separately quenched by excess ammonium chloride or sodium sulfite. Thesamples were directly analyzed by high pressure liquid chromatography with UV and MS detection (HPLC-UVand HPLC/MS). Also, the samples were extracted with MTBE, and the extracts analyzed with gaschromatography/mass spectrometry. Includes 8 references.

Product Details

Edition:

Vol. - No.

Published:

11/15/2004

Number of Pages:

3

File Size:

1 file , 230 KB