Testing the Link Between Wildfires and Benzene Contamination

In the weeks following the Santa Rosa, CA wildfires last October, city officials found elevated levels of benzene in water system samples taken from the nearly totally-razed Fountaingrove neighborhood. The first round of samples returned 4 results of over 500 parts per billion, with one of these at 918 parts per billion (MCL for benzene in drinking water is 1 part per billion). A second round of testing produced similar numbers over the MCL, without the higher spikes. A total of 145 samples have now shown elevated levels.

According to this article in The Press Democrat, city officials, who for months have stressed that the contamination appeared isolated to the advisory area, were taken by surprise that six of those results were from outside the existing advisory area.

With the help of a forensic chemist, who helped eliminate the possibility of petroleum leaks, the city now suspects that the most likely cause of contamination is heat damage to high-density polyethylene service lines or other plastic components (such as PVC) in the water or wastewater system. The city is enacting more extensive testing to find out if plastic laterals are responsible. Once the exact cause is identified, the city will consider solutions. Replacing the water system could cost over $20 million.

Interested in finding out more about benzene contamination in drinking water supplies, including sampling methods, treatment strategies, and private well concerns? Check out this EPA website or this Oregon Health Authority factsheet. Another useful resource is this template (from North Carolina) to be used when high levels of Benzene need to be reported to the public.