As I sit on a flight from Tucson to Dallas, I am making use of the onboard WI-FI service and, believe it or not, thinking about rapid micro methods. If you have ever used the lavatory during flight, or asked for a coffee from the flight attendant, I am certain that many of you (especially the microbiologists reading this post) have wondered how contaminated the airplane water really is.
In the United States, drinking water safety on airlines is jointly regulated by the EPA, the Food and Drug Administration (FDA), and the Federal Aviation Administration (FAA). EPA regulates water quality in public water systems in accordance with the Safe Drinking Water Act (SDWA). EPA regulates the public water systems that supply water to the airports and the drinking water once it is onboard the aircraft. The regulatory structure for all public water systems, including aircraft, relies upon self-monitoring and reporting of results to the primacy (primary enforcement) agency. The primacy agency for aircraft public water systems is EPA.
In 2004, EPA found all aircraft PWSs to be out of compliance with the national primary drinking water regulations (NPDWRs). According to the air carriers, it is not feasible for them to comply with all of the monitoring that is required in the existing regulations. The existing NPDWRs were designed for traditional, stationary public water systems, not mobile aircraft water systems that are operationally very different.
For example, aircraft must maintain rigorous operating schedules. They fly to multiple destinations throughout the course of any given day and may board drinking water from sources at any of these destinations. Aircraft board water from airport watering points via temporary connections.
Aircraft drinking water safety depends on a number of factors including the quality of the water that is boarded from these multiple sources, the care used to board the water, and the operation and maintenance of the onboard water system and the water transfer equipment (such as water cabinets, trucks, carts, and hoses).
These unique operational characteristics present different challenges, which EPA addressed in the Aircraft Drinking Water Rule (ADWR), which went into effect in 2009.
The primary purpose of the ADWR is to ensure that safe and reliable drinking water is provided to aircraft passengers and crew. This entails providing air carriers with a feasible way to comply with the SDWA and the NPDWRs. The existing regulations were designed primarily with traditional, stationary public water systems in mind. Some of these requirements have proven difficult to implement when applied to aircraft water systems, which are operationally very different. Therefore, using a collaborative rule making process, EPA developed the ADWR that is tailored to aircraft public water systems. The final rule combines coliform sampling, best management practices, corrective action, public notification, operator training, and reporting and record keeping to improve public health protection.
In reading the rule, the frequency of coliform monitoring is tied to the frequency of disinfection and flushing of the aircraft water system. For example, if an aircraft is disinfected and flushed on a quarterly basis, the minimum frequency of routine sampling is only one time within a 12-month period. If the disinfection and flushing schedule is only one time per year or less, then the frequency of monitoring is increased to 12 times per year (monthly).
Two coliform samples are taken per monitoring period: One sample must be taken from a lavatory and one sample from a galley. Any total coliform-positive sample must be further analyzed for the presence of E. coli. If any routine sample is E. coli-positive, public access to the water system is restricted no later than 24 hours after being notified by the testing lab of the E. coli-positive result, and all public access restrictions must remain in-place until the aircraft water system has been disinfected and flushed and a complete set of follow-up samples is total coliform-negative.
Here's the big question: if the samples are sent to a lab, how long does it take for positive results to get back to the airline in order to implement these restrictions and perform follow-up testing after the system has been disinfected and flushed? Wouldn't this be a great place to implement rapid testing methods for the airline industry? There are a number of presence/absence tests for E. coli and other potential water-borne pathogens that could be used today.
Just something to think about the next time you get on an airplane. I am thinking about it right now!