Drinking water can also be a source of immune system problems. High rates of leukemia and recurrent infections were reported in children exposed to drinking water contaminated with industrial solvents. Immunology studies found increases of autoantibodies (autoantibodies are antibodies which mistakenly attack healthy tissue), recurrent rashes, infections and altered ratios of T-cell subpopulations. This study was reported at the Sixth Annual Allergy Conference sponsored by the National Institute of Health, Research Triangle Park, North Carolina. Several other major points were brought out in this conference including:

Groundwater contaminated with low levels of the pesticide aldicarb (temik) caused alterations in the number of T-cells including decreased helper-T/suppresser-T ratios

A large number of therapeutic and abused drugs have been reported to inadvertently alter immune functions in humans

Since many of the cellular events involved in the immune system are also involved in the developing unborn child, several immune weakening chemicals are also capable of causing birth defects

The components of the immune system that generally appear to be a primary target for synthetic chemicals includes the thymus, hematopoitic stem cells (immune system making cells in the bone marrow), antigen stimulated B lymphocytes, monocytes and helper T-cells.

Exposure to immunotoxic chemicals may represent additional risk to individuals with already fragile immune systems (such as infants, the elderly and malnourished).

Other problems with drinking water come from a chemical known as DCP (2,4 dichlorophenol). DCP is formed from the chlorinating of municipal water and from the breakdown of the widely used weed killer 2,4-D. In a study conducted at the University of Idaho, laboratory rats were exposed to DCP in their drinking water. Rats whose drinking water contained DCP at levels of 300 parts per million showed depression of the part of the immune system regulating cell mediated immunity, thereby affecting helper T-cell communication.