Grantee Research Project Results
2000 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, 1999 through September 30, 2000
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 byproducts (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 nonhalogenated aldehydes, ketones and acids, trihalomethanes, haloacetic acids (HAAs), 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:
The partition of HAA DBPs into carrots, green beans, pinto beans, chicken, spaghetti, and lettuce following cooking or contact with water spiked to contain HAAs was studied. HAAs that were evaluated were chloroacetic, bromoacetic, dichloroacetic, trichloroacetic, bromochloroacetic, dibromoacetic, bromodichloroacetic, chlorodibromoacetic, and tribromoacetic acids. Foods were chosen based on different cooking conditions, different chemical compositions (i.e., starch, vegetable, protein), as well as the fact that they are commonly consumed by children. Spaghetti and dried beans are prepared with large volumes of water. In the case of spaghetti, multiple contacts with tap water are possible if the spaghetti is rinsed following cooking. Dried beans are usually soaked overnight, drained, and then cooked. Lettuce was selected because it usually is rinsed with water while being prepared. All foods were prepared according to package directions with water spiked to contain HAAs. Foods processed in the same manner using clean reagent water served as controls. Cooked spaghetti was subjected to rinsing with both reagent and spiked water to determine if rinsing could cause additional HAA uptake. Beans were cooked in spiked water following soaking in either spiked or reagent water. Chicken was cooked in spiked water following a brief soaking in either reagent or spiked water. Lettuce was soaked briefly (approximately 5 minutes), and then drained prior to homogenization. Following handling or cooking, foods were homogenized and extracted. The methyl esters of the HAAs were then formed and analyzed by gas chromatography in conjunction with electron capture detection.In some cases, over 60 percent of the HAAs in the cooking water were taken up by the food during cooking. The HAAs showing the greatest extent of uptake were bromoacetic, dichloroacetic, bromochloroacetic, and dibromoacetic acids. Initial rinsing of the chicken and soaking of the pinto beans in spiked water did not result in any significant increases in HAA concentration in the foods cooked in spiked water compared to the case where the initial rinsing or soaking was performed with reagent water. In general, chlorodibromoacetic and tribromoacetic acids are not detected following cooking. This is consistent with the rapid loss of these compounds during boiling as shown in earlier studies. The soaking of lettuce also resulted in uptake of HAAs (1.8 to 7.8 percent of the total available).
The results for spaghetti indicated that as much as 11 percent of the available HAAs were adsorbed/absorbed during cooking in spiked water. Given the large volumes of water used to cook pasta, the masses absorbed could be much higher than for other types of food. In addition, the data shown for uptake following rinsing with spiked water indicate that additional HAAs?up to 10 percent?are taken up from the rinsing water. This was true whether the spaghetti was cooked in reagent water or in spiked water. It also is clear that the HAAs that typically show low recovery following cooking (bromodichloroacetic acid, chlorodibromacetic acid, and tribromoacetic acid) become available to contribute to exposure following contact of the spaghetti with fresh DBP-containing water.
Initial evaluation of a method to extract bromate from food (pasta) showed that material extracted from spaghetti interfered with measurement of the recovery of bromate. A specific and sensitive method for bromate based on ion chromatographic separation/post column reaction method developed for water was adapted for this work. Analysis of water recovered from the cooking of spaghetti showed that dilution was needed to affect detection of the bromate; whether this was due to adsorption of bromate onto suspended/dissolved solids or a suppression of the chromatographic detection was not clear. Bromate was detected in reagent water following its use to cook spaghetti, which indicated its presence in the pasta. Initial extractions of homogenized cooked spaghetti indicated fewer interferences than with the recovered water, but that method precision was not very good. Further method work will be conducted during the next year.
Future Activities:
During the third year of the program, the analytical method for bromate will be developed further. The use of accelerated solvent extraction will be investigated. The method will be used to assess the partition of bromate from water into foods. (If a direct assessment is not possible, for example, via the measurement in food, an indirect approach will be applied, such as the measurement of bromate in water before and after cooking.)Additional studies will be performed to evaluate some of the factors important in the partition of HAAs into foods, including the concentration of HAAs in water, the volume of water used, and the surface area of foods given a constant food type such as pasta. These data will be used to develop a model for predicting uptake. The models will be tested during the field portion of the study.
Given the delay in the method development work, a no-cost extension will be sought to permit the collection and analysis of field samples.
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:
http://www.rti.org/units/acs.htmlProgress 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.