We Need Biomarkers

As desirable as the idea sounds, we might have to finally admit to ourselves that reducing human exposure to toxic substances by curtailing their use isn’t working. There are a lot of good initiatives out there in green chemistry, and there’s REACH, but these are years in the future before they start having any effects on really reducing human exposure. The time factor bites here; there’s a progression from research initiative and legislation to regulatory programs and enforcement, pilot testing, redesign and startup of new production plants, and distribution of the new toxic-free products through the supply chain – a process that requires many years. Existing products, such as polycarbonate plastic baby bottles or computer cases with polybrominated diphenyl ether (PBDE) fire retardants, may remain in use for many years even after production and sale of them ceases, providing a continuing source of exposure. Once exposure ceases, additional time passes before human body burdens decline; the amount of time depends on the persistence of the substance in the environment and in the human body.

Bisphenol-A is metabolized rapidly in humans, and body burdens should decline quickly, once we get around to removing it from food and beverage containers. However, even with nearly a decade of intensive scientific study, we still haven’t been able to come to a decision of whether or not bisphenol-A poses a threat to human health that warrants its replacement in plastics. PBDEs will be with us for generations, even if we eliminated all of them from all products today, because of their persistence in soil, water and the foodchain. A concerted effort has been made over the past 15 years to reduce dioxin exposures, which has resulted in decreases in body burdens. The question remains as to whether that effort has been sufficient – we still don’t have an accepted assessment of dioxin health risks.

Note this doesn’t mean “giving up” on clean production. Elimination of high-toxicity substances and substitution with lower toxicity materials is always the first choice in reducing human exposures (next in the hierarchy are engineering controls, personal protective equipment and lastly, administrative controls). Adhering to good design philosophy, and attempting to use smaller quantities of lower toxicity materials along with lower amounts of energy, should remain an objective for all types of manufacturing. But at the same time, we shouldn’t kid ourselves that clean production is going to have a measurable effect on human exposure to toxic substances anytime in the near future. It would be helpful if we had a robust set of biomarkers of toxicity in humans.

Regardless of where you fall on the “yes they do”/”no they don’t” continuum about environmental chemicals causing cancer, you have to admit that the National Academy of Sciences nailed the problem when it said last year:

Many cancer patients are diagnosed at a stage in which the cancer is too far advanced to be cured, and most cancer treatments are effective in only a minority of patients undergoing therapy. Thus, there is tremendous opportunity to improve the outcome for people with cancer by enhancing detection and treatment approaches. Biomarkers will be instrumental in making that transition.

Even further, the NAS’s report on cancer biomarkers says, “. . .recharacterization of disease in pathophysiological terms via the use of biomarkers is the key to the future of medicine.” Wow. If true, biomarkers taking off could really move the “war on cancer” out of the slash and burn (i.e. surgery and chemo/rad) mentality to something more sublime, less painful and scary and probably more effective in protecting health and improving quality of life.

Postscript: A companion post is in preparation that talks more about what are biomarkers and what we can do with them, beyond saying they are early indicators of processes or events in the body that might in the future lead to disease.