Grantee Research Project Results
1999 Progress Report: Assessment of Human Dietary Ingestion Exposures to Water Disinfection Byproducts via Food
EPA Grant Number: R826836Title: Assessment of Human Dietary Ingestion Exposures to Water Disinfection Byproducts via Food
Investigators: Raymer, James H. , Clayton, C. Andrew , Pellizzari, Edo D. , Akland, Gerald G. , Smith, D. J.
Current Investigators: Raymer, James H. , Hu, Ye A. , Pellizzari, Edo D. , Akland, Gerald G. , Michael, Lisa J. , Weinberg, Howard S. , Marrero, Thomas , Unnam, Vasu
Institution: Desert Research Institute
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1998 through September 30, 2003
Project Period Covered by this Report: October 1, 1998 through September 30, 1999
Project Amount: $446,468
RFA: Drinking Water (1998) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
Objective:
The overall objective of this research is to estimate the magnitude of exposure to disinfection by-products (DBPs) in drinking water via their ingestion after uptake into food during cooking. It has been shown in our laboratory that foods can become contaminated with chemicals in the water used in the home during food preparation (e.g., cooking). The magnitude of this contamination process has not been studied. This research will specifically address the uptake of compounds known to arise from the process of water disinfection (ozonation in conjunction with a secondary process such as chloramination) including non-halogenated aldehydes, ketones and acids, trihalomethanes, haloacetic acids, bromate, chloropicrin, and haloacetonitriles. The main hypotheses to be tested are: (1) foods prepared using contaminated water become contaminated; (2) food is a significant source of DBP exposure; (3) DBP concentrations in food can be predicted with knowledge of DBP concentrations in tap water and foods consumed; and (4) dietary exposures of children are higher than for an adult living in the same household.Progress Summary:
An analytical method for the determination of non-halogenated water disinfection by-products (DBPs) in foods and beverages was investigated. As a starting point, Standard Method 6252 (Disinfection By-products: Aldehydes) for aldehydes in tap water was modified. The method, which relies on the derivatization of carbonyl compounds with o-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine to form the corresponding oxime with subsequent determination using gas chromatography with electron capture detection, was optimized with regard to reduced reagent volumes and derivatization time and temperature. The modified method was applied to the determination of formaldehyde, acetaldehyde, propanal, butanal, pentanal, hexanal, heptanal, octanal, benzaldehyde, nonanal, glyoxal, and methyl glyoxal in homogenize medium-fat food composite (1 ppm each) and composite beverage (200 ppb each). The results suggested that non-halogenated aldehydes can be derivatized and extracted, but that some of the analytes are retained by the matrix or cannot be detected because of substantial interferences. A clean-up step consisted of the extraction of the hexane extract containing the derivatized carbonyl compounds with aqueous bicarbonate to remove potentially interfering acidic compounds; this resulted in a minimal improvement. Mass spectrometric analysis of the recovered analytes is underway to determine whether or not substantial interferences exist.
The stability of an aqueous solution of the target haloacetic acids (HAAs)?chloroacetic, bromoacetic, dichloroacetic, trichloroacetic, bromochloroacetic, dibromoacetic, bromodichloroacetic, chlorodibromoacetic, and tribromoacetic acids?to boiling showed that bromodichloroacetic, chlorodibromoacetic, and tribromoacetic acids were not recovered, but the other analytes survived and could contribute to human exposure via ingestion. When the target HAAs were spiked into oatmeal, bromoacetic, dichloroacetic, and bromochloroacetic acids were recovered within the target 70-130 percent range indicating that some HAAs can contribute to human exposure via food. Preliminary studies in which pasta was cooked in water spiked to contain the target HAAs (10 to 100 ppb in water) showed that a small amount of each of the HAAs, except for chlorodibromoacetic and tribromoacetic acids, which decompose during cooking, were retained by the pasta. In addition, additional HAAs were retained by pasta as a result of rising the cooked pasta in water containing HAAs. This process will add to exposure to HAAs via food.
Stability studies showed that HAAs in composite beverage are stable for 7 days of refrigerator storage, and that HAAs in composite food are generally stable for 7 days with refrigerator storage and are stable for at least 14 days with freezer storage. This will influence sample collection in the field study. As designed, the studies did not test the stability of HAAs in non-composited food.
Future Activities:
Additional studies will be performed to evaluate the partition of DBPs, especially haloacetic acids, into foods during the cooking process. The model to be used to predict DBP exposure via food will be developed and the required input parameters will be used to define the partition experiments that will be performed. The impact of cooking on trihalomethane (THM) concentrations in food also will be evaluated. It is anticipated that THMs will be volatilized/lost in the same manner as the haloacetonitriles, but this must be verified. For those analytes lost during cooking, the importance of food contact with water during non-heat processes on the uptake of DBPs might be important and will be investigated.
An important aspect of the application of methods for DBPs in food and beverage to samples collected during the field sampling aspect of this study will be an understanding of the stability of the target analytes in the collected samples during the time of storage prior to sample processing. Storage stability studies will be undertaken during the second year of the program. The field studies will be deferred until the methods are complete. However, studies at both proposed locations should be possible during the third project period.
Journal Articles:
No journal articles submitted with this report: View all 8 publications for this projectSupplemental Keywords:
drinking water, exposure, children, organics, measurement methods., RFA, Health, Scientific Discipline, Toxics, Water, National Recommended Water Quality, Health Risk Assessment, Chemistry, Risk Assessments, Susceptibility/Sensitive Population/Genetic Susceptibility, Disease & Cumulative Effects, Children's Health, genetic susceptability, Drinking Water, trihalomethane, risk assessment, dissinfection biproducts, disinfection biproducts, sensitive populations, disinfection byproducts, haloacetonitriles, aldehydes, biomarkers, detection, human health effects, trihalomethanes, exposure and effects, THM, chemical byproducts, disinfection byproducts (DPBs), exposure, DBPs , children, human exposure, analytical chemistry, bromate formation, brominated DPBs, haloacetic acids, food, treatment, chloramines, cooking, diet, water quality, DBPs, dietary ingestion exposures, drinking water contaminants, ketones, dietary exposure, DBP exposure, drinking water system, ozonation, environmental hazard exposuresRelevant Websites:
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.