Perchlorate behavior in a municipal lake following fireworks displays.

Perchlorate salts of potassium and ammonium are the primary oxidants in pyrotechnic mixtures, yet insufficient information is available regarding the relationship between fireworks displays and the environmental occurrence of perchlorate. Here we document changes in perchlorate concentrations in surface water adjacent to a site of fireworks displays from 2004 to 2006. Preceding fireworks displays, perchlorate concentrations in surface water ranged from 0.005 to 0.081 μg/L, with a mean value of 0.043 μg/L. Within 14 h after the fireworks, perchlorate concentrations spiked to values ranging from 24 to 1028× the mean baseline value. A maximum perchlorate concentration of 44.2 μg/L was determined following the July 4th event in 2006. After the fireworks displays, perchlorate concentrations decreased toward the background level within 20 to 80 days, with the rate of attenuation correlating to surface water temperature. Adsorption tests indicate that sediments underlying the water column have limited (<100 nmol...