Theo Colborn (1927-2014) changed the way we think about the damage coming from chemical contamination. Her legacy is not only proving this shift in thinking for chemicals, but in providing a road map for how we should assess radiation damage, especially during child development. She continued her work until she past away on Sunday, December 14.
Her ground-breaking investigations on chemical contamination recognized that looking only at the cancers that resulted from exposure was masking a large part of the problem because, in the case of toxic chemicals, cancers were often the result of higher exposures. Once she started to include non-cancer disease, a pattern formed and she found, to her surprise, that low doses given over a longer time were responsible for more subtle, non-fatal, but still very damaging health impacts. These non-cancer effects included reproductive and neurological abnormalities, low-birth weight and premature birth.
Dr. Colborn recognized that damage also depended on when these tiny doses were delivered, overturning the concept that the dose always makes the poison. The question of timing has particular significance for in-utero cycle since the embryo starts as only a few cells that then divide and grow rapidly into a whole functioning human being. A chemical exposure delivered at any sensitive time during this process can have negative impacts on the developing child. Often chemical doses at this level were allowed by federal agencies and considered safe. This is changing in large part due to work by Dr. Colborn and her colleagues and the term “endocrine disrupting chemical” is now widely known.
Colborn’s realization that low doses of endocrine disrupters, delivered at just the wrong time, can cause non-fatal, non-cancer disease, mirrors an uncomfortable truth in radiation protection: there is a lack of focus on the impact of small, long-term doses on the developing child and other sensitive populations. Studies that have been conducted showing disruption of the birth gender ratio, thyroid abnormalities, and cardiovascular disease, have been minimized or ignored and remain unincorporated fully into protection regulations. This remains true even for some types of cancers like childhood leukemia. Dr. Colborn has expanded the way science and society examines the impact of endocrine disrupting chemicals, and public health will be better for it. In demonstrating that fresh methods were needed to assess chemical damage, she has shown us that, likewise, different methods of assessment for radiation damage are needed for much the same reasons. This is just one of the many gifts she has left us. And we are eternally grateful.
Special thanks to Rachel Carson and her Sisters: Extraordinary Women Who Have Shaped America’s Environment by Robert Musil, which explores the lives of American women activists who are linked to Rachel Carson’s work protecting humans, animals and the environment. He provides a chapter on the work of Dr. Colborn from which some of the information above was extracted.
Our Stolen Future, a chemical contamination detective story written by Dr. Theo Colborn, “brought world-wide attention to scientific discoveries about endocrine disruption and the fact that common contaminants can interfere with the natural signals controlling development of the fetus.”