Response to Oct 2, 2020 New York Times Article "After Wildfires Stop Burning, a Danger in the Drinking Water"
The Oct. 2 edition of New York Times features SLVWD in an article on post-fire hazards resulting from burning of plastic pipelines. Researchers who did the work on contamination after the Tubbs and Camp Fires question whether water districts are doing sufficient testing. The article is accurate, but I believe is a bit alarmist and overly gloomy by leaving out two important points relevant to the SLVWD situation: (1) VOC contamination in SLVWD is much less than was found in Santa Rosa and Paradise. (2) The article doesn’t distinguish between the two different phases in the recovery of a water system like ours damaged by fire: the immediate months-long aftermath in which the District is sprinting to restore water service while making sure there are no contamination “hot spots” that could cause acute injury; and the ensuing years-long marathon replacing facilities and monitoring water quality to make sure no contaminants are present at low levels that could cause harm with long-term exposure. SLVWD is reaching the end of the sprint and entering the marathon. This slower and more systematic water sampling could include analyses of VOCs and semi-volatile organic compounds that arise from burning of plastics, as well as compounds known to contaminate surface waters following heavy rainfall in burned areas: polycyclic aromatic hydrocarbons formed on burning of wood, and metals leached from burned areas that reach levels above drinking water standards or aquatic-life criteria (aluminum, iron, antimony, arsenic, cadmium, lead, selenium, and zinc).
Read on if you want more details
In an article on Oct. 2, 2020, the New York Times reports on the post-fire hazards resulting from burning of plastic pipelines. Our own Rick Rogers is quoted in the discussion of the situation in San Lorenzo Valley. The article emphasizes academic researchers questioning whether water districts are doing sufficient testing. The researchers doing this published the definitive paper (Proctor et al., 2020) on contamination after the Tubbs (Santa Rosa 2017) and Camp (Paradise 2018) Fires. In particular, they say it isn’t sufficient to test solely for volatile organic compounds, as SLVWD has been instructed to do by the State Water Resources Control Board, Division of Drinking Water, as contamination by semi-volatile organic compounds, some of which are toxic, were also found after the Tubbs and Camp Fires.
Contamination by VOCs in SLVWD less than in areas affected by Tubbs and Camp Fires
The article is accurate, but in my view is alarmist and overly gloomy about the prospect for SLVWD by leaving out two important points relevant to the SLVWD situation. One is that the extent and levels of VOC contamination in SLVWD are much less than was found in Santa Rosa and Paradise. Knowing what happened in those fires, our District staff moved rapidly to isolate various parts of the system to prevent widespread contamination. In addition, they kept the central part of the line in San Lorenzo Valley pressurized in order to provide water for firefighters. Rick Rogers, the District Manager, was hopeful that this would prevent VOC contamination in the main part of the system, and restrict it to outlying areas. This turned out to be the case. The only area where VOCs were found above California drinking water limits was in the western part of Riverside Grove north of Boulder Creek. The highest concentration found of benzene (a bellwether for VOC contamination) was 40 ppb. In contrast, at Santa Rosa and Paradise the highest values found were in excess of 2,000 ppb, locally in excess of the federal OSHA exposure limit of 1,000 ppb for an 8-hour workday or 5,000 ppb for short-term exposure of 15 minutes. Since those initial analyses, the District has been flushing the system in Riverside Grove, and replacing service lines. In successive sampling, the benzene levels have dropped, so that in some areas of Riverside Grove benzene is no longer detectable.
Different approaches to water sampling in the immediate aftermath of fire and during subsequent 2-3 years
The second point is that the article doesn’t distinguish clearly between the two different phases in the recovery of a water system like ours damaged by fire. The first is the immediate aftermath in which staff are sprinting to restore water service to ratepayers while at the same time making sure that there are not contamination levels so high that they could cause acute injury. Benzene is a good proxy for whether you have serious contamination with organic compounds in the immediate aftermath. At this stage you don’t need to analyze for every possible contaminant; you just want to know where the “hot spots” are.
Once things settle down, and the most contaminated areas have had the service and distribution lines replaced, the marathon begins: replacing temporary fixes with more permanent, resilient facilities, deciding how to replace destroyed surface water sources, and monitoring water quality to make sure that there are no contaminants that are present at a low level that could cause harm with long-term exposure. This slower and more systematic water sampling could include VOCs and semi-volatile organic compounds that arise from burning of plastics. In this case one is looking for the lower concentrations consistent with standards for long-term chronic exposure. For benzene, the Federal drinking water limit is 5 ppb; California at 1 ppb is even stricter. (For comparison, the World Health Organization sets a guideline of 10 ppb, which they translate to an excess lifetime cancer risk of one person in 100,000). One would also want to analyze for compounds found to contaminate surface waters during heavy rainfall in areas burned by wildfires: polycyclic aromatic hydrocarbons (PAHs), which form on burning of wood, and metals leached from burned areas that reach levels above drinking water standards or aquatic-life criteria (aluminum, iron, antimony, arsenic, cadmium, lead, selenium, and zinc).
SLVWD nearing end of sprint phase of recovery; settle in for a marathon while the watershed recovers
My reading of the water analyses available through 9/30/20, which the District made available on its website, is that we are nearing the end of the sprint phase of recovery. Get ready to settle in for the marathon phase, which is likely to take two to three years as the watershed recovers.