The talk around Lincoln, Nebraska, is all about the fireworks. It’s the 4thof July; a brief 48-hr period in which anyone can shoot off spinners, fountains, and other displays of burning light. And, as a state, we rival any state in how much we spend on this novelty. Clearly, Nebraskans love fireworks. But, there is growing concern beyond our borders as to how all of this sound effects dogs and wildlife and the environment. As a limnologist, I immediately think about lakes. In any given town or city, firework displays are iconic over the water: lakes and rivers reflect the exploding light, increasing the brilliance of any display. But, what happens when the ash and materials fall below – into those waters?
Fireworks contain various chemicals, including heavy metals, nitrates, and phosphorus, that, when burned, give them their spectacular colors. Fireworks also often contain perchlorate, a chemical used to fuel the pyrotechnical display, but one that can also lead to thyroid issues in humans at high doses.
Should we worry about all of these chemicals ending up in lakes after firework displays? Some in Michigan, New Hampshire, and New York think so. Indeed, the few studies that have been done show discernible changes in lake chemistry, particularly perchlorate, following these independence displays. In one of the most cited studies, researchers in Oklahoma found dramatic increases – 1000x – of perchlorate in Wintersmith Lake following the firework display. Increases were temporary, returning to normal levels within a few months. A similar study in Washington found 10 – 60 x increases in the concentration of perchlorate in the study lakes after July 4th. Sampling on Lake Tahoe following firework displays found evidence for increases of both perchlorate and nitrate.*
Other institutions are taking notice. The New Hampshire Department of Environmental Services has released guidance on using fireworks near lakes. Disneyland, known for its almost daily firework show, has gone so far as to develop an alternative “air-launch tubes” to get the fireworks launched in the sky that are not so reliant on potential harmful chemicals.
The biggest firework display in Lincoln happened last night at Oak Lake. Should Nebraska be concerned about what this did to the lake? And, is everyone paying enough attention to the diversity of chemicals that may be released in the lakes following a fireworks display? More and broader studies, like the ones mentioned above, could help answer these questions.
*The situation in Lake Tahoe and fireworks has been the subject of at least one lawsuit: http://tahoequarterly.com/environment/fury-over-fourth-of-july-fireworks