City Begins Investigating Source of Benzene Intrusion
During a recent annual water quality test, results showed detection of benzene, a chemical widely used in many industries, at the City’s single groundwater production well, Well No. 5. Immediately following a confirmation of test results, the City took Well 5 offline and transitioned to imported water. The City is now temporarily relying on water from Metropolitan Water District (MWD), the City’s approved alternate source, to supply all households until the source of the contamination can be identified and the issue has been resolved.
The City continues to adhere to all water quality guidelines in its response to confirming detection of benzene and has partnered with State regulators to investigate and mitigate the source. Benzene is a known carcinogen that, in high levels over a long period of exposure, can increase cancer risk. The City does not believe water users are at risk at this time, but–as a measure of precaution–has transitioned to the backup imported water source while it conducts its investigations.
In California, the maximum contaminant level (MCL) for benzene in public drinking water supply is 1 part per billion (ppb) or 0.001 milligrams per liter. On May 9th, the City received a result for a single annual water quality test sample collected on April 30 that showed benzene detection over the MCL at 3.2 ppb in the water supply at Well No. 5 at the Cypress Water Production Facility (CWPF). Lomita Water operators conducted additional confirmation sampling at Well No. 5 and sampling throughout the City’s distribution system to verify the results. Benzene was detected at 3.6 ppb and 3.7 ppb at Well No.5, and from Not Detected (ND) to 1.4 ppb in the distribution system.
The City’s only domestic production well, Well No. 5, was immediately taken offline after the City’s receipt of laboratory confirmation results. The City has temporarily switched to securing all water from MWD and enlisted the assistance of State regulators to identify the source of the benzene contamination. The State has been assisting the City in identifying the source of contamination, further testing, and evaluation of mitigation measures and treatment options and to bring Well No. 5 back into operations with treatment to mitigate the present situation.
“The public’s safety is our top priority, which is why we moved immediately to remove Well No. 5 from our water supply once the benzene results were confirmed. The City’s commitment to open, transparent and high-quality water service is unwavering and we will continue to strictly follow water quality protocols to protect the public’s health. The transition is an operational shift to ensure the safety of our residents and we will continue to exceed State requirements by being transparent with our findings and operational decisions. We want our Lomita community to know the steps we are taking to ensure their water supply is safe and protected. We appreciate the assistance of our partners at the State level and we are working with them to: (1) identify and hold responsible the source of the contamination, and (2) return Well No. 5 to its routine operation.” – Lomita City Manager Ryan Smoot
Benzene is a chemical that is a colorless or light yellow liquid at room temperature. It has a sweet odor and is highly flammable. The Department of Health and Human Services (DHHS) has determined that long-term exposure to high levels of benzene causes cancer in humans. Per the Centers for Disease Control and Prevention (CDC), “long-term exposure” is continued exposure of a year or more. The seriousness of poisoning caused by benzene depends on the amount, route, and length of time of exposure, as well as the age and pre-existing medical condition of the exposed person.
The City is working closely with the State Water Resources Control Board, Division of Drinking Water, the Los Angeles Regional Water Quality Control Board, and other agencies to identify the potential source of benzene contamination through extensive testing. This testing may include identification and investigation of potential sources both inside and outside the City, extensive sampling, boring and monitoring of likely sources in the area, and ongoing monitoring of soil and water levels. It may take some time to identify the source, but with the help of the State’s regulatory agencies, the City will continue to take appropriate action to protect its residents. Throughout the identification and mitigation processes, the City will share progress through LomitaWater.com and other City communication channels.
If you have questions about this notice, please contact the City’s Public Works Director, Carla Dillon at (310) 325-7110 x124, or reach us directly through the City’s dedicated water quality website, www.LomitaWater.com. If you have any other concerns about your water quality, please send us a detailed report.
Timeline of City’s Response
- April 2018 – Last year’s test confirmed benzene levels at only 0.54 ppb
- April 30, 2019 – First sample collected showing benzene above MCL at 3.2 ppb
- May 9, 2019 – First confirmation test
- May 10-22, 2019 – Additional confirmation samples taken at Well No. 5 and throughout distribution system, and analyzed
- May 15, 2019 – Confirmation of benzene intrusion from samples
- May 15, 2019 – Switched to MWD water supply
- May 29, 2019 – Notification of temporary water supply switch through LomitaWater.com
- June 10, 2019 – Expect to publish next Water Quality Report
- Late June/early July – Expect to send next Water Bill to ratepayers
- July 2019 – Next Consumer Confidence Report (CCR) goes out, which will include data from 2018
Frequently Asked Questions about benzene, the April 30 test results and follow-up confirmation testing, what the City is doing to investigate the benzene intrusion, and future plans to ensure a clean water supply:
The Cypress Water Production Facility provides blended water to Zone 1 (generally the area of town to the North of PCH). Elevated levels of benzene in the City’s pre-blended raw water was initially detected on April 30th and, once confirmed, the City immediately transitioned to 100% imported water. This pressure zone typically receives a blend of water purchased from Metropolitan Water District (MWD) and treated water from Well No. 5 in the Cypress Water Production Facility (CWPF). Per the sampling throughout the City’s distribution system, benzene was detected from ‘Not Detected’ (ND) to 1.4 parts per billion (ppb) in the distribution system. As of May 15, Zone 1 is receiving water entirely from MWD.
In California, the maximum contaminant level (MCL) of benzene in public drinking water supply is 1 part per billion (ppb), or 0.001 milligrams per liter. Federal regulations set that same MCL at 5 ppb.
On May 9, 2019, the City received a result for a single annual water quality test sample collected on April 30, 2019 that showed benzene detection over the maximum contaminant level (MCL) at 3.2 parts per billion (ppb) in the water supply at Well No. 5. Lomita Water operators conducted additional confirmation sampling at Well No. 5 and sampling throughout the City’s distribution system to verify the results. Benzene was detected at 3.6 ppb and 3.7 ppb at Well No.5, and from Not Detected (ND) to 1.4 ppb in the distribution system.
Where and when did the City test the water supply and find elevated levels of benzene in May 2019?
Benzene was first detected at the groundwater well (Well No. 5) located at the Cypress Water Production Facility (CWPF) at 26112 Cypress Street. On May 9, 2019, the City received a result for a single annual water quality test sample collected on April 30, 2019 that showed benzene detection over the maximum contaminant level (MCL) at 3.2 parts per billion (ppb) in the water supply at Well No. 5. Between May 9 and May 15, 2019, the City then tested at multiple points throughout the City’s treatment and distribution systems. Test results confirmed benzene was detected at 3.6 ppb and 3.7 ppb at Well No.5, and from Not Detected (ND) to 1.4 ppb in the distribution system.
What is the City doing to identify the May 2019 source of benzene contamination and how will I know when it’s been fixed?
While there is no immediate threat to health or safety, the City is working closely with the California State Division of Drinking Water, the L.A. Regional Water Quality Control Board, and other agencies to identify the potential source of benzene contamination through extensive testing. This testing may include identification and investigation of potential sources both inside and outside the City, extensive sampling, boring and monitoring of likely sources in the area, and ongoing monitoring of soil and water levels. It may take some time to find evidence of where the problem is. The City will then receive guidance from our State partners on how to address the issue. Throughout the process, the City will let the public know of progress through LomitaWater.com and other City communication channels.
When did the City learn about the May 2019 benzene contamination and how quickly did the City switch to a different water supply?
On May 9, 2019, the City received results from a single annual water quality test sampled on April 30, 2019 that showed higher-than-usual levels of benzene. In compliance with state water quality procedures, a second confirmation test was arranged to confirm the finding. After the additional testing from an independent laboratory analysis and confirmation of the results, the City transitioned its water supply to the approved back-up supply through Metropolitan Water District (MWD) on May 15, 2019.
Why didn’t the City notify the public as soon as the April 30, 2019 test showed elevated levels of benzene?
The City first learned about possible elevated traces of benzene in Well No. 5’s water supply on May 9, 2019 when it received preliminary results from a regular water quality sample collected on April 30, 2019. Per State procedures, the City immediately conducted a confirmation sample and expedited the testing to confirm. The City and supporting agencies worked as quickly as possible to complete testing within seven days of obtaining the initial results. Per the Centers for Disease Control and Prevention (CDC), the adverse impacts of benzene exposure typically require continued exposure over a year or more at levels higher than what was recorded during the water quality tests. Given the relatively short time period between the first test and final confirmation of test results, as well as the relatively low levels (below the federal maximum contaminant level), the City does not believe there is any danger to the health or safety of the public.
As an immediate response, the provision of water from the approved back-up source will mitigate any further exposure. Also, the City has recently completed the design of a Granular Activated Carbon (GAC) filtration system for the Cypress Water Production Facility to improve aesthetic qualities of the City’s water system, and has budgeted for construction of the project in the coming fiscal year. Although the City could not have foreseen the benzene contamination, GAC filtration is also widely recognized as the best-practice method of addressing and removing benzene, and the City has already begun the process of increasing the design scope of the project to accommodate for benzene removal. The City will also continue to work with our partners at the State level to identify the source of the benzene and mitigate any continued contamination. Once complete, the GAC project will allow the City to return to normal operation of Well No. 5 and continue to provide a safe, clean, and reliable source of local water supply.
- Facts about Benzene from the Centers for Disease Control and Prevention (CDC)
- Benzene health risks from the National Institute of Health (NIH)
- Previous Lomita Water Quality Reports and Consumer Confidence Reports
- 2015 City of Lomita Water Master Plan
Laboratory Reports for Benzene
- April 30, 2019 – Annual Volatile Organic Compound (VOC) testing at the Well
- May 10, 2019 – Benzene Resample
- May 13, 2019 – Benzene Sampling across the CWPF (View the Sample Locations)
- May 22, 2019 – Benzene Sampling in Distribution System
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