On March 14 and 15, the PBS NewsHours science correspondent Miles OBrien presented a two-part report about hexavalent chromium in drinking water with the intent to show that the current Environmental Protection Agency safety standards for the chemical are not restrictive enough. His presentation provided several examples of sensationalistic rather than factually balanced reporting, which is worrisome in that it might portend a new NewsHour type of coverage.
OBrien, a historian by education, started the series by revisiting Hinkley, Calif.s groundwater contamination brought to popular attention in 1993 by Erin Brockovich, a legal assistant portrayed by Julia Roberts in a movie. Brockovich discovered that Pacific Gas & Electrics nearby plant leached hexavalent chromium also called chromium six or chromium (VI) into the Hinkley water supply at levels significantly above EPA standards. That part of her investigation was correct and forced PG&E to start cleanup measures. But the court case she won involved 650 plaintiffs with symptoms as varied as breast and prostate cancer, Hodgkins disease, miscarriages and spinal deterioration, which she claimed were caused from drinking the water. Brockovich won by convincing the jury that the chemical was toxic no matter how it entered the body and was responsible for the 650 ailments. In 1996, PG&E settled for $333 million.
Scientists challenged the evidence but only after the case was settled, explaining that chromium (VI) is carcinogenic when inhaled from dust during a manufacturing process but not when ingested orally as was true of the Hinkley population. Its nontoxicity when taken orally is most likely because it is converted in the stomach into chromium (III), an essential nutrient for humans. Furthermore, physiologists said that no one chemical could possibly have cause the variety of the ailments presented in the 650 cases.
OBriens revisiting the issue ignored the critics challenges and described Brockovich the way Hollywood did, as a persistent seeker after truth. Epidemiologists have described her as a statistically naïve individual who believed she had found a cause-and-effect relationship between a chemical and a plethora of medical symptoms, and convinced a jury of that belief, even though there was no empirical evidence that such a relationship existed.
With that, OBrien went on to try to find scientists that could show that chromium (VI) is carcinogenic when ingested orally. No scientist he interviewed would confirm his insistence that if it is toxic to breathe it, must also be toxic to drink.
With no cooperation from the scientists, OBriens approach shifted to accusing the EPA of using only compromised scientists in their deliberation about chromium (VI). He pointed out that most of those the EPA consulted were beholden to chemical companies through such benefits as research grants. That could well be true but irrelevant. Science can judge the validity of research irrespective of funding sources through the methodology used, peer review and independent replication.
Research conducted at universities is commonly funded by outside sources. The accusation is a ploy used by special-interest groups when the evidence provided by research does not support their cause.
As a final tactic, OBrien pleaded with one of those interviewed, that even though there has been no harmful evidence found to date, the EPA should be on the safe side and stiffen its safety standards for chromium (VI) in drinking water. That plea represents what is known as the precautionary principle, which states that for technologies or products that some believe might cause harm to peoples health, action should be taken to prevent such harm even though there is no current evidence of such effects.
While seemingly innocuous, the principle is scientifically absurd. Editorials in journals such as Nature and Science have warned that because benefits are not included as a part of the principle, a minor risk could deprive society of a technology or product that would confer much greater net benefits.
Chromium (VI) is used in a large number of products and a raise in safety standards with no evidence that such a change is warranted, would simply increase costs for producers and consumers alike. Furthermore, attempts to resurrect the issue without new justification takes attention away from more pressing water problems. The precautionary principle issue is not trivial because it has been adapted by some European countries and has been lobbied by environmental groups to be incorporated into California law.
I was not surprised that a sensationalized report like OBriens was aired on television. What did surprise me is that the PBS NewsHour (the former revered Lehrer NewsHour) was the source. Where is Jim Lehrer when we need him?
Garth Buchanan holds a doctorate in applied science and has 35 years of experience in operations research. Reach him at firstname.lastname@example.org.