Fourth of July fireworks displays leave behind smoke and memories, not to mention debris from the metals and salts that give the explosions their colors. The environmental effect of single shows may be minimal, but the impact years and years worth of shows is having on the environment is not yet understood. Fireworks shot over already polluted bodies of water are of researchers' greatest concern.
The smoke from fireworks displays increases the tiny bits of dust and other materials suspended in the air. On a hot night, the concentration of particulate matter may increase.
The Vancouver National Historic Reserve Trust manages an annual fireworks display--the largest west of the Mississippi--over the Columbia River. Elson Strahan, president and chief executive officer of the Vancouver Trust, does not think there is cause for alarm over the explosions' debris.
"The fireworks are encased in a series of cardboard encasements, and not all of them will burn up so some pieces of cardboard will go into the river but, by and large, these are designed to be self-consuming," said Strahan.
The Environmental Protection Agency (EPA), though, lists perchlorate, a common fireworks ingredient, as a "contaminant of concern." Perchlorate remains in water for a long time, has been found at high levels in U.S. ground water and can affect thyroid functioning in fish.
Duane Linnertz runs the testing laboratory for the Bureau of Environmental Services in Portland, Ore. He says that the although the bureau has never tested local surface water for perchlorate, he is curious about fireworks' environmental effects.
"We've never really looked at it," Linnertz said. "I have often wondered for myself, on our cul-de-sac, after the Fourth of July Fireworks. I can see the leftovers, and then the first good rain, it goes into the storm system... this is not a well-studied issue."
While Oregon has yet to address fireworks-related pollution issues, officials in Massachusetts closed wells and began measuring perchlorate levels when the compound started showing up in drinking water. In 2005, the Massachusettes Department of Environmental Protection released a study that linked areas that had hosted annual fireworks displays to percholate-contaminated public wells. The state now has guidelines that suggest fireworks concessions and distributors use perchlorate-free fireworks, set them off away from water wells and clean up debris.
Earlier this year, a scientist at the EPA's National Risk Management Research Laboratory in Oklahoma published a paper examining the relationship between annual fireworks and a nearby lake's perchlorate levels. The researcher spent years testing the lake before and after fireworks displays. The paper suggests that while perchlorate levels increased after an over-lake display, they eventually dissipated, perhaps as a result of microbial organisms consuming the compound.
Source: The Portland Tribune
