If you read my previous blog post on heavy metal contamination event in Colorado’s Animas River, you have heard how a single mistake can lead to the contamination of a natural resource as along with economic consequences and public health concerns. Just two weeks ago, on October 12, it was discovered that Peterson Air Force Base was responsible for dumping 150,000 gallons of wastewater containing toxic perfluorinated chemicals into the Colorado Springs sewer systems without notifying the municipality and environmental regulators. The chemicals were discharged without any treatment and allowed to flow downstream into Fountain Creek.
Perfluorinated Chemicals and Regulations
Perfluorinated chemicals (PFCs), categorized as persistent organic pollutants (POPS), are toxic chemicals that slowly degrade both in the environment and in human and animal tissues. These compounds are suspected endocrine disruptors and carcinogens that are known to damage liver and kidney function. There are many different PFC compounds but the two major types of PFCs, Perfluorooctanoic Acid (PFOA) & Perfluorooctane Sulfonate (PFOS), have been actively monitored by environmental analysts and are found to be widely distributed in the environment (water, soil and air), food (milk), and human body (blood). Their abundant presence is primarily due to the high frequency of the use of these compounds in industrial and commercial applications such as fire-fighting, metal plating, paper and packaging, and many others within the last 50 years.
Although these chemicals were forced to phase out due to their persistence and toxicity, it is estimated that more than 6.5 million Americans in 27 States have been exposed to PFCs through migration of these compounds into their drinking water. The U.S. EPA monitored 6 PFCs through the unregulated contaminant monitoring rule 3 (UCMR 3) during 2013 and 2015 to gather nationwide occurrence data and as a result recently issued health advisory on PFCs in May 2016. Although no enforceable regulatory determination has been made, the EPA’s health advisory sets the combined levels of PFOA and PFOS at 70 part per trillion, which are significantly lower than the health advisory issued in 2009 with 400 ppt for PFOA and 200 ppt for PFOS. Other states have set even lower levels of contamination limits for PFOA.
Analysis of Perfluorinated Chemicals and Challenges
PFOA and PFOS can be identified and quantified using reversed-phase HPLC with suppressed conductivity or LC-MS, or more recently using online SPE coupled with LC-MS/MS. The latter method provides low LODs ranging from 0.2 to 5 ppt and LOQs from 1 to 20 ppt for PFOA, PFOS, and many other PFCs. The technique has been accepted widely for the determination of perfluoroalkyl acids in Italian surface and ground waters. Additionally a study of PFOS/PFOA as well as other PFAA compounds conducted by the IDAEA in Barcelona Spain using this method detected these compounds in drinking water, source waters and wastewaters. During the UCMR 3 monitoring, EPA Method 537 was designated as the testing method for PFCs. Currently, LC-MS/MS method is widely used in different testing service companies. More recently, Orbitrap-based LC-MS/MS technique has also been used for comparison with EPA Method 537. The technique provides better sensitivity compared to the traditional LC-MS/MS technique used in EPA Method 537.
Because of their chemical properties and widespread presence there are many difficulties experienced in developing methods for PFCs. Recently the EPA provided a technical advisory for addressing some of the known issues and other important points of emphasis in PFC analysis. Blank contamination is a critical concern. Minimizing the contamination of lab glassware, extraction apparatus and instrumentation can aid in lowering their minimum reporting levels (MRLs) and increase the confidence in lab data. The presence of isomeric compounds also makes analysis difficult. As a result a greater importance has been placed on identifying and expanding the panel of PFCs to linear and branched isomeric forms. Detection and separation of isomeric compounds could be potentially troublesome when using triple quadrupole mass spectrometric detectors. The use of Orbitrap technology for collecting high resolution accurate mass data could prove beneficial in future analysis of these compounds and many other emerging environmental contaminants.
As is the case with many emerging contaminants and POPs, wastewater and drinking water treatment facilities are not equipped to remove PFCs using traditional methods. The number of technologies or methods for removal of PFCs that are known to be effective is limited. Without a proper method for removal from wastewater, PFCs will continue to be a source of contamination to our natural water resources. The oversight of these compounds and permitted release represents a direct contradiction to the goals of the Clean Water Act (CWA), calling to question the effectiveness of current regulatory standards that are responsible for protecting our environment.
Should we be alarmed? After reading this blog, what are your thoughts?
Dwain Cardona coauthored this post. Dwain Cardona is currently the Vertical Market Manager for the Environmental and Industrial markets specializing in GC and GC-MS technology for Thermo Fisher Scientific Inc.