Radical concerns over drinking water.

Animal studies have suggested that chlorine ingestion alters the body's handling of cholesterol and fats. For example, an Environmental Protection Agency study showed that drinking highly chlorinated water "subtly but noticeably shifted" a mouse's transport of cholesterol from high-density lipoproteins (the "good" lipoproteins) in the blood to the "bad" low-density lipoproteins, which foster atherosclerosis (SN: 6/3/89, p.342). J. Peter Bercz, who headed that study, now reports that hypochlorite -- a very reactive by-product of standard water chlorination -- can also destroy polyunsaturated fatty acids (PUFAs), including those essential to health.

"It's certainly possible," he says, that the new finding might play a role in the altered lipoprotein metabolism seen in animals drinking chlorinated water.

Hypochlorite (OCl-), a powerful bleaching agent and disinfectant, develops in water treated with pure (free) chlorine. Bercz put each of seven biologically essential PUFAs into hypochlorite-laced water. The ensuing chemical reactions effectively cleaved these PUFAs into fragments of varying lengths. The complex series of processes responsible for the PUFAs' destruction involved both the stripping of electrons (oxidation) and the incorporation, at least temporarily, of chlorine, he reports in the May/June CHEMICAL RESEARCH IN TOXICOLOGY. Indeed, he notes, oxidant-spawned free radicals "really destroy these sensitive PUFAs," producing changes similar to those responsible for rancid flavors in aging fatty foods. In animals, such oxidized PUFAs have also been associated with liver and immune-system toxicity and with pre-atherosclerotic changes.

Unsaturated fatty acids contain one or more carbon double bonds, or "valence bonds," capable of accepting an electron. The new data show that the hypochlorite-initiated fragmentation of PUFAs begins at these double bonds. However -- and paradoxically, Bercz admits -- the more such double bonds a PUFA possesses, the less susceptible it proves to oxidation.

A 1979 change in the Safe Drinking Water Act has encouraged many municipalities to switch their disinfectant from free chlorine to monochloramine. This increasingly popular oxidant kills bacteria without generating high levels of potentially toxic chlorinated organics. The new study now also shows that these "monochloramines are totally inert," says Bercz.

Chronic ingestion of hypochlorite or foods treated with chlorine bleach -- from white flour to butchered meats -- "should bioavailability of essential PUFAs [from foods], but also as a factor in generating reactive . . . toxicants," including those capable of altering DNA, Bercz concludes.