Immunotoxicological profile of chloramine in female B₆C₃F₁ mice when administered in the drinking water for 28 days

Abstract

Monochloramine has been used to provide a disinfecting residual in water distribution systems where it is difficult to maintain an adequate free-chlorine residual or where disinfection by-product formation is of concern. The goal of this study was to characterize the immunotoxic effects of chloramine in female B₆C₃F₁ mice when administered via the drinking water. Mice were exposed to chloramine-containing deionized tap water at 2, 10, 20, 100, or 200 ppm for 28 days. No statistically significant differences in drinking water consumption, body weight, body weight gain, organ weights, or hematological parameters between the exposed and control animals were noted during the experimental period. There were no changes in the percentages and numbers of total B-lymphocytes, T-lymphocytes, CD4⁺ and CD8⁺ T-lymphocytes, natural killer (NK) cells, and macrophages in the spleen. Exposure to chloramine did not affect the IgM antibody-forming cell response to sheep red blood cells (SRBC) or anti-SRBC IgM antibody production. Minimal effects, judged to be biologically insignificant, were observed in the mixed-leukocyte response and NK activity. In conclusion, chloramine produced no toxicological and immunotoxic effects in female B₆C₃F₁ mice when administered for 28 days in the drinking water at concentrations ranging from 2–200 ppm.

Keywords::

• Chloramine
• monochloramine
• immunotoxicity
• drinking water disinfection

Acknowledgment

This work was supported in part by EPA Interagency Agreement DW75937992 and the Division of Intramural Research at the NIEHS through Contract ES55538. The authors thank D. L. Musgrove and R. D. Brown for their technical assistance, and Dr Michelle Hooth and Dr Marsha Ward for their comments and review of the manuscript.

Declaration of interest

Dr Kimber L. White, Jr. is the owner of a company, ImmunoTox^®, Inc., that conducts immunotoxicological studies under Good Laboratory Practices (GLP). This work was supported by the National Institute of Environmental Health Sciences [ES55538]. This article may be the work product of an employee or group of employees of the National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), however, the statements, opinions, or conclusions contained therein do not necessarily represent the statements, opinions, or conclusions of NIEHS, NIH, or the US government. This report has been reviewed by the Environmental Protection Agency’s Office of Research and Development and approved for publication. Approval does not signify that the contents necessarily reflect the views of the Agency nor does mention of trade names or commercial products constitute endorsement or recommendation for use.