FAQ: Additional Information About Test Results for Swimming Pool Water at Edison High School
October 24, 2019
The City of Huntington Beach contracted with Sierra Analytical—an environmental laboratory certified by the Department of Health Services—to test the swimming pool water at Edison High School in June 2019. Those testing results can be found at https://www.hbuhsd.edu/apps/pages/ascon-landfill
Based on the Ascon project’s review of the City of Huntington Beach’s testing results, we’re responding to questions from community members. We provided a response to an earlier question on October 9 (scroll to that date on Project Updates). Below are additional questions we’ve received.
Where does southeast Huntington Beach drinking water come from?
The City of Huntington Beach provides drinking water to residents from both municipal groundwater wells and from imported water provided by the Metropolitan Water District. This is the water used in the Edison High School swimming pool. There are no drinking water wells in southeast Huntington Beach due to seawater intrusion into groundwater aquifers.
I noticed other chemicals listed on the Edison High School swimming pool test results. What do the results for hexavalent chromium mean?
The amount of hexavalent chromium reported in June 2019 was 0.96 micrograms per liter (ug/L), which is less than 1 part per billion (ppb). This amount is below the California Drinking Water Standard for total chromium of 50 parts per billion and also is below the federal Environmental Protection Agency (EPA) standard of 100 parts per billion for total chromium.
Total chromium includes all forms of chromium, including chromium-6 (hexavalent chromium). You can read more about this from EPA at https://www.epa.gov/dwstandardsregulations/chromium-drinking-water
What about the other chemicals detected in the pool water?
Three other chemicals—chloroform, bromodichloromethane and dibromochloromethane—were reported as detected in the pool water at levels below the California Safe Drinking Water Standard or Maximum Contaminant Level (MCL). These are three of the four regulated trihalomethanes (THMs) typically found in drinking water as a result of adding chlorine or some type of disinfection. The fourth regulated trihalomethane is bromoform, which was not found in the pool water.
Trihalomethanes are “disinfection byproducts” resulting from the addition of chlorine or other disinfectants to drinking water and also to swimming pools. The Safe Drinking Water Standard or California Maximum Contaminant Level (MCL) for total trihalomethanes is 80 micrograms per liter (ug/L) or parts per billion (ppb). Trihalomethanes are required to be reported as the combined total concentration of the four regulated chemicals.
- The chloroform concentration was 13.2 micrograms per liter (ug/L or ppb)
- The bromodichloromethane concentration was 4.56 micrograms per liter (ug/L or ppb)
- The dibromochloromethane concentration was 1.40 micrograms per liter (ug/L or ppb)
- Bromoform was not detected in the pool
The combined total concentration of the four regulated trihalomethanes reported in June 2019—including bromoform, the chemical that was not found—was 19.16 micrograms per liter (ug/L ) or parts per billion (ppb). This is well below the California MCL of 80 micrograms per liter (ug/L) or parts per billion (ppb).
More about chlorination:
Almost all community water systems in California—including Huntington Beach—use some type of chlorine-based disinfection method to prevent microbial waterborne disease epidemics, such as typhoid and cholera. Disinfection of community water systems also prevents growth of slime bacteria, molds and algae. Community water systems are required by federal law to ensure adequate disinfection so that a residual of the disinfectant is present throughout a water distribution system to protect public health.
The City of Huntington Beach provides more information about disinfectants and disinfection byproducts on page four of their annual Drinking Water Quality Report for 2019 at https://www.huntingtonbeachca.gov/2019dwqr/2019-water-quality-report.pdf