While the issues of safety, fire, noise, air pollution and trauma (both physical and mental) from fireworks are well documented, the water pollution impact from private fireworks use has gone largely unnoticed and unaddressed.
Fireworks are known to have high sulfur content, contributing to acidic, low-pH runoff. Fireworks contain heavy metals such as aluminum, barium, cobalt, copper, magnesium, potassium, strontium and zinc, to name a few, that are employed to produce the brilliant colors and flash associated with pyrotechnic displays that can result in discharges of heavy metals to our air, soil and bodies of water.
Perchlorate salts used in fireworks are of particular concern. Perchlorate is a manmade chemical, but also occurs naturally. It is commonly used as a propellant in aerial pyrotechnics and in aerial fireworks that are illegal for private use under state law. Perchlorate salts are highly soluble in water and not easily degraded, posing a threat to ecological systems.
All of the foregoing pollutants are washed off county streets and sidewalks into streams and water bodies during the next rains, when these streams are in a low-flow condition and most susceptible to these types of concentrated pollution.
A 2009 study done by Snohomish County Surface Water Management Division showed perchlorate salts increases of up to 60-times background immediately following the Fourth of July. This same study recommend that individuals refrain from discharging fireworks from or into public sidewalks and roadways which may contain storm drainage systems. This 2009 water quality study on fireworks was either suppressed or certainly buried.
Under its Clean Water Act permit, Snohomish County must implement a Stormwater Management Plan to control pollution sources in stormwater. Nowhere in the county’s plan is there any mention of source controls for fireworks on the county’s paved streets and sidewalks draining to its storm drain system, that were recommend in its own study.
In order to be in compliance with its permit, Snohomish County must ban the use of fireworks in all public right-of-ways under its jurisdiction.