Dose-Response of Nitrate and Other Methemoglobin Inducers on Methemoglobin Levels of InfantsEPA Grant Number: R829781
Title: Dose-Response of Nitrate and Other Methemoglobin Inducers on Methemoglobin Levels of Infants
Investigators: VanDerslice, Jim
Institution: Washington State Department of Health
EPA Project Officer: Page, Angela
Project Period: September 2, 2002 through September 1, 2005 (Extended to September 1, 2007)
Project Amount: $594,934
RFA: Health Effects of Chemical Contaminants in Drinking Water (2001) RFA Text | Recipients Lists
Research Category: Drinking Water , Health Effects , Water
The long-term goal of this research is to improve our understanding of the exposures to chemicals which may form methemoglobin, and the relationships of those exposures to measured levels of methemoglobin among infants in an area with high nitrate waters. The specific objectives of this study are 1) to estimate the intake of common methemoglobin inducers (i.e. nitrate, copper, chlorination products) from the ingestion of water, foods and medications in a random sample of infants living in an area with nitrate-contaminated groundwater; 2) to generate age-specific baseline distributions of methemoglobin levels for healthy infants apparently unexposed to methemoglobin inducers; 3) to estimate the dose-response relationship between the intake of exogenous methemoglobin inducers (nitrate, copper, chlorination products) and the level of peripheral blood methemoglobin in infants; and 4) to estimate the effect of potential endogenous production of nitrite (i.e. symptoms of infection and GI distress) on the level of methemoglobin in infants.
Infants will be recruited from a rural area of Washington state using birth certificate follow-back. Home interviews will be conducted to gather information on recent food intake and illness symptoms. Methemoglobin levels will be determined in the home on a sample of blood obtained by heel stick using a portable co-oximeter. Samples of the infants' drinking water and the household tap water will be analyzed for nitrate, residual chlorine, microbiologic indicator organisms and other chemical contaminants. The relationship between exposure to nitrate and methemoglobin levels will be assessed using multivariate models.
It is expected that this study will provide a population-based distribution of exposure to methemoglobin inducers and a baseline of methemoglobin levels in infants. In addition, we expect to clarify the relationships and interactions between nitrate and other chemical exposures, gastro-intestinal illness, and levels of methemoglobin in infants.