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Gestational and lactational effects in rats of sodium, sulfate, and concentrated disinfection by-products in drinking water
Citation:
NAROTSKY, M. G., J. G. PRESSMAN, R. J. MILTNER, T. F. SPETH, L. K. TEUSCHLER, G. E. RICE, S. D. RICHARDSON, D. S. BEST, A MCDONALD, E. S. HUNTER, AND J. E. SIMMONS. Gestational and lactational effects in rats of sodium, sulfate, and concentrated disinfection by-products in drinking water . Presented at Teratology Society Meeting, Pittsburgh, PA, June 23 - 29, 2007.
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Description:
Epidemiological and animal toxicity studies have raised concerns regarding possible adverse health effects of disinfection by-products (DBPs) in drinking water (DW). Because many DBPs are unidentified, we sought to evaluate DW concentrates. In preparation for a multigenerational reproductive study, we used a developmental toxicity screen to evaluate concentrated DBP mixtures produced by 2 methods. In Method 1, chlorinated water was concentrated ~130 fold by reverse osmosis (RO); select lost volatiles were spiked back. Concentrate was provided as DW to Sprague-Dawley (SD) and F344 rats from gestation day (GD) 1 to postnatal day (PD) 6; controls received purified DW. Pups were examined on PD 1 and 6. Implantation sites were counted to determine prenatal loss. Unexpectedly, treated F344 and SD dams had increased incidences of polyuria and diarrhea. SD rats also had red perinasal staining. DW consumption of concentrate was increased compared to controls for both strains. Pup weights in both strains were reduced compared to controls. Chemical analysis of the concentrate revealed high sodium (6.6 g/L) and sulfate (10.4 g/L) levels. To confirm that these chemicals caused polyuria and osmotic diarrhea, respectively, purified DW was provided to SD rats (GD 6 to PD 6 or 21) with Na2SO4 (0, 5, 10, 15, or 20 g/L) or NaCl (16.5 g/L); the NaCl and 20 g Na2SO4/L groups had equal Na concentrations. DW consumption was increased at 5- and 10-g Na2SO4/L and with NaCl. Pup weights were reduced at 20 g Na2SO4/L. Dose-related increases in frequency and severity of polyuria and diarrhea occurred in Na2SO4-treated rats; red perinasal staining was seen at 20 g/L. NaCl also caused polyuria and perinasal staining, but not diarrhea. Thus, a study was done in SD rats (GD 6 to PD 21) with concentrate produced by Method 2: raw water was concentrated by RO, treated with Ba(OH)2, and then chlorinated. This yielded lower Na (≤1.5 g/L) and SO4 (≤2.1 g/L) levels, and DBP proportions reflective of tap water. Treated dams had increased DW consumption, but pup weight and survival were unaffected. There were no treatment-related clinical findings, indicating that DBP mixtures produced by Method 2 are suitable for multigenerational testing.