Hormonal Fireworks?

Remember the old TV commercial: It's not nice to fool Mother Nature? Well that's what environmental hormones do--fool our bodies, or those of the critters around us, into taking biochemical directions from pollutants. Perchlorate is one such pollutant with a relatively recently recognized hormonal alter ego. A new report finds aquatic animals may encounter dramatic spikes in exposure to perchlorate following pyrotechnic displays.

Perchlorate is an ingredient of many rocket fuels, which is why Air Force bases can become perchlorate-rich environments. The compound also appears to help boost ceremonial rockets--firecrackers--into the sky. Unfortunately, our bodies mistake perchlorate for thyroid hormones. Ands because thyroid hormones play important roles in growth and neural development, exposure to this pollutant has the potential to do some pretty dastardly things.

For instance, I wrote a story for Science News, last August, that showed perchlorate masculinized certain female fish. So dramatic were the impacts that scientists initially mistook affected females for males. Several of these macho moms even displayed male-courtship behavior and produced sperm. Clearly, that was not something Mother Nature had intended. At a minimum, it could jeopardize reproduction in affected populations.

In the new study, researchers measured perchlorate concentrations in an Oklahoma lake over which fireworks were displayed. The scientists sampled the water before and for weeks after July 4 fireworks rained the rocket ingredient into the water. What they found is that concentrations peaked within a day of the pyrotechnic display, then disappeared. However, it could take almost 3 months for the pollutant to vanish.

To understand how it vanished, the scientists took some lake water back to the lab and added perchlorate to it. As long as the water housed its normal complement of aquatic microbes, the pollutant disappeared. It seems these bugs chow down on it--and how quickly they eliminate the perchlorate can depend on water temperature. However, when the researchers sterilized the water--killing its microbes--the perchlorate showed no signs of disappearing. The findings will appear in an upcoming issue of Environmental Science & Technology. Subscribers can see the article early online.

Although most concentrations in the new study were well below a part per billion, in one instance the peak maxxed out at 44 ppb. For perspective, the latter is within the range that perturbed the reproductive development of fish in the story I wrote last year.

I guess we'll just have to hope that our pyrotechnic displays don't coincide with pivotal developmental periods of nearby fish. Oops...aren't there places--like Disney World, for instance--where fireworks occur year-round?