title: Residual damage to hematopoietic system in mice exposed to a mixture of groundwater contaminants.
abstract: To assess the potential health effects of chemically contaminated groundwater, we initiated a toxicological program on a mixture of 25 frequently-detected groundwater contaminants derived from hazardous waste disposal sites. As part of this program, myelotoxicity studies were conducted. Bone marrow parameters were examined in mice exposed to 0, 1, 5 or 10% of a simulated chemical mixture stock solution of groundwater contaminants in drinking water for 108 days. Mice treated with 5 or 10% of chemical mixture stock solution for 108 days showed suppressed marrow granulocyte macrophage progenitors (CFU-GM); however, this suppression disappeared in 10 weeks following the cessation of treatment. The possible toxicological interaction of groundwater contaminants and radiation on hematopoiesis was investigated by using the number of bone marrow CFU-GM as an index. When mice were exposed to 200 rads whole body irradiation at 2 and 9 weeks during this 10-week recovery period, the combined treatment (i.e., chemical mixture followed by irradiation) group showed a significantly slower recovery of bone marrow progenitors as compared with the control group (i.e., radiation but without prior chemical mixture treatment). This study showed that even 10 weeks after the cessation of chemical mixture treatment when all hematological parameters were normal, a residual effect of the chemical mixture may still be demonstrated as lower progenitor cell numbers following irradiation. Thus, residual damage of hematopoiesis in mice exposed to groundwater contaminants for 108 days renders the mice more sensitive to subsequent irradiation-induced injury.
authors.affiliation: National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
authors.forename: H L
authors.initials: HL
authors.lastname: Hong
authors.forename: R S
authors.initials: RS
authors.lastname: Yang
authors.forename: G A
authors.initials: GA
authors.lastname: Boorman
mesh_terms: D000818:Animals; D001772:Blood Cell Count; D001835:Body Weight / Q000187:drug effects; D005260:Female; D005618:Fresh Water / Q000737:chemistry*; D006256:Hazardous Waste; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D006413:Hematopoietic System / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D009929:Organ Size / Q000187:drug effects; D012037:Refuse Disposal; D014873:Water Pollutants / Q000032:analysis / Q000633:toxicity*; D014916:Whole-Body Irradiation
chemical_list: D006256:Hazardous Waste; D014873:Water Pollutants