Enjoy the Fourth of July fireworks. And please take time to carefully sweep firework launch and debris landing areas and properly dispose of the debris afterwards.
Perchlorate, a compound used as an oxidizing agent in fireworks (i.e., fuel to make the firework burn), persists in soil and water.
How persistent? Well, Mt. Rushmore National Memorial’s firework shows stopped in 2009. In a 2016 US Geological Survey high levels of perchlorate were still reported in the park – 38 micrograms in a groundwater sample and 54 micrograms/liter in a stream, both in excess of the EPA’s 15 micrograms per liter, and 274 times higher than samples taken outside the memorial park’s borders.