How pure must our water be to be safe to drink? This is no simple question
for the chemists who are asked to answer it. We think of chemists as the ones
who can answer this because we rely on the chemical, chlorine, to clean water
and the introduction of chlorine into water creates new chemical byproducts.
Do those byproducts present a threat to water quality? Or more precisely, what
are the levels of chlorine byproducts that are acceptable?
Such technical, arcane matters may seem best left to scientists. Yet, ultimately,
government regulators must be involved. Government must play a role because
we would not want to permit private parties to decide on their own what microbial
pathogens are allowed in drinking water. Serious diseases can be borne by water
and, thus, water must be chemically treated before it comes out of the tap in
our homes and offices. As one EPA (Environmental Protection Agency) official
put it: "We use chlorine-in the twentieth century there's no single other
health measure that's been more effective than chlorine disinfectant at reducing
typhoid [and] cholera. Basically, what it does is kills most of the bacteria
and virus pathogens that may be in the source water."
The EPA's authority
to regulate drinking water derives from the Clean Water Act. Congress, however,
has left decisions on the hard science questions to EPA. There is a good deal
of scientific literature on chlorine byproducts. Some research shows a relationship
between chlorine byproducts and cancer or reproductive abnormalities in laboratory
animals. Other studies fail to find such a connection. The familiar question
also arises of whether we extrapolate incidence rates from mice or rats receiving
high doses of the chemicals to the low doses that humans are exposed to in
their drinking water.
There are many
lobbying groups that have a strong interest in this matter. Chlorine manufacturers
want their product protected. Municipal water authorities don't want to have
to make any unnecessary expenditures to add new equipment or purchase more
chemicals. Environmental groups want to ensure that our drinking water is
as safe as possible. A major effort to move the controversy over drinking
water forward was a negotiated regulation in 1992. A negotiated regulation
(or "reg-neg" in the jargon of Washington) is a procedure that allows
interested parties to try to formulate a regulation on a policy matter that
government is contemplating action on. Instead of the more common process
of a government agency determining through its own research what should be
done, the agency asks the most important interested parties in that policy
area if they would like to see if they can find common ground. If the negotiations
are successful, the government puts the regulation into effect. The 1992 reg-neg,
which was considered the first stage in a longer-term process, produced a
regulation that set water standard thresholds at 80 parts per billion (ppb)
for total trihalomethanes, 60 ppb for haloacetic acid, and 10 ppb for bromate.
Further specification
of standards began with stage two in 1999. Again, a reg-neg was initiated
and the same lobbies came back to the bargaining table. The goal was for EPA
to issue a proposed rule on standards sometime in 2001. It took a little longer
to accomplish but the reg-neg did propose enhanced regulatory standards in
the summer of 2003.