Lab Employees Receive Safety Awards

District staff working within the Philip L. Anthony Water Quality Laboratory have been recognized by the Association of California Water Agencies/Joint Powers Insurance Authority (ACWA/JPIA) through its H.R. LaBounty Safety Awards program.

The award specifically recognizes staff’s successful transition to a safer organic extraction procedure for the analysis of nitrosamine compounds in water samples.

The ACWA/JPIA H.R. LaBounty Safety Awards are issued twice a year and are designed to promote safe workplace behavior and operations practices and reward those employees who demonstrate safe behavior, take part in recognizable proactive activities, or participate in risk-reducing actions that can also be used by other agencies. The following District laboratory staff worked collaboratively on the nitrosamine extraction technique transition procedures and received Fall 2018 award letters, certificates, and individual award checks of $20 each:

  • Alexander Adams, Chemist
  • Pedro Alvaro, Laboratory Technician
  • Quan Kha, Senior Chemist
  • Elizabeth Mosher, Senior Chemist
  • Elder Turcios, Senior Laboratory Technician

Background of the analysis of nitrosamine compounds in water samples

The District’s Philip L. Anthony Water Quality Laboratory regularly analyzes groundwater, surface water, and recycled water samples for nitrosamines, a family of disinfection byproducts that are known human carcinogens. The analytical method for low-level nitrosamines analysis requires an organic extraction or pre-concentration step ahead of quantification via a gas chromatography/mass spectrometry (GS/MS) instrument.

For the last 20 years, the laboratory’s standard pre-concentration step involved liquid-liquid extraction using a glass separatory funnel (Figure 1) and 100-200 milliliters (ml) of methylene chloride solvent per sample; this would generate approximately 40 liters of solvent waste per month requiring hazardous waste disposal of a known carcinogen. Furthermore, the manual shaking of the separatory funnel would expose multiple laboratory staff to the risks of vapor exposure, solvent leakage, and cuts from broken glass.

To reduce these risks and increase efficiency, laboratory staff has transitioned to an automated solid-phase extraction (SPE) technique using carbon cartridges to concentrate nitrosamines (Figure 2).

The SPE procedure uses only 15 ml of methylene chloride per sample, reducing solvent waste by up to 93 percent, while also limiting solvent exposure and eliminating glass breakage risk. Furthermore, the automated system can process 24 samples in two hours using a consistent and reproducible process to improve throughput and overall quality control.