At the 2018 ASMS meeting, Professor Susan D. Richardson of the Department of Chemistry and Biochemistry at the University of South Carolina lectured on the development of environmental metrology, with a special emphasis on mass spectrometry. By coincidence, the start of the timeline (around 1967) mirrors that of American Laboratory and my career as a professional chemist. After the meeting, I had an opportunity to compare notes with Professor Richardson.
I recall that the concern about environmental chemistry and analysis began with air pollution, particularly in the Los Angeles basin in California, where I lived. Almost daily, afternoon smog hid the majestic mountains surrounding the cites in the SoCal basin. A few alarmists hypothesized a relationship to the Great Smog of 1952 that was implicated in the deaths of 12,000 people in London.
In the mid-1960s the word “environment” started to appear as a buzzword for surroundings. The chemistry part became “Environmental Chemistry.” Rachel Carson’s book Silent Spring was published in 1962. She blamed widespread use of DDT for thinning the eggshells of birds. Birds are near the top of the food chain, so pesticides bioaccumulate as the food passes up the chain.
Around the same time, a drilling platform in the Santa Barbara Channel spilled three million gallons of heavy petroleum into the ocean. Then-President Richard Nixon, a Californian, visited a beach in Santa Barbara, CA, where he saw the oil-soaked corpses of seagulls and pelicans that had washed ashore. He returned to Washington and prodded Congress to pass the National Environmental Policy Act of 1969, which Nixon signed on January 1, 1970. This led to the creation of the U.S. Environmental Protection Agency (U.S. EPA) on December 2, 1970. One of the actions of the new agency was to ban the manufacture and use of DDT in 1972.
Congress was on board and passed regulations in the Federal Resister. For example, U.S. EPA Method 300 focused on the assay of anions in drinking water by ion chromatography. This protocol helped Dionex build its business, since Dow Chemical patented the suppressor technology and licensed it exclusively to Dionex.
The strength of the EPA methods promulgated in the Federal Register was an “Act of Congress.” Timelines for updates involving Congress are usually measured in decades, but with inevitable advances in technology, the methods quickly became obsolete. Methods were slow to change, but they did change. Now, one can validate and use a new method involving new technology.
The 1960s were a golden age for science. It was post-Sputnik, and scientists were just beginning to develop fast, sensitive, and reliable tools for analytical chemistry, such as chromatographs and infrared spectrometers. This coincided timewise with general acceptance that humans could alter the environment as an unintended consequence of industrial and consumer activity.
According to Professor Richardson, mass spectrometry was the key enabling technology of early environmental chemistry. She offered three reasons:
- MS has low detection limits for most analytes. Currently this is nanograms/liter in water and sometimes lower.
- MS can handle complex environmental mixtures, being compatible with GC, LC, ion chromatography, and capillary electrophoresis.
- Other spectroscopic techniques such as NMR and IR are great but can’t come close to this.
However, in the early 1970s the selection of MS was not simple. Element-specific detectors for GC such as flame photometric detection (FPD) and electron capture for halogens were popular, had useful detection limits, and were much less expensive. For GC/MS, most mass analyzers were magnetic sector instruments, which were large, expensive, and maintenance-intensive.
Finnigan Instruments had just introduced the quadrupole mass analyzer, which was faster, lower in cost, and easier to maintain. However, quadrupole mass analyzers were new and hence unproven. In spite of these considerations, Dr. Bill Budde of the EPA decided to go with the new quadrupole MS. At the time, Finnigan was the sole source of quadrupole mass analyzers. The EPA ordered eight, which proved to be a very good choice. Now, chromatography (GC and LC) with MS and MS/MS technology using quadrupoles is the workhorse of environmental science in 2018 and probably beyond.
Mass spectrometry, complemented by other analytical technologies such as ion chromatography, gave analysts tools for quantitative analysis of many analytes. Environmental meetings were filled with reports from environmental advocates. While these reports often overstated the risk, society became much more aware and often frightened of the chemical threat to our environment.
1968 to 2018
Let’s look at some of the benefits that environmental science has delivered.
- Air quality in the developed world is generally much better than 60 years ago.
- Lead has been removed from gasoline.
- Petroleum refineries and oil fields are much less foul-smelling than when I was a roustabout in a petroleum processing facility 60 years ago. Perimeter regulations are working.
- Drinking water is safer, with monitoring for radon, bromate, and disinfection by-products.
- Groundwater in the developed world is much cleaner.
- Rules and regulations have improved safety and attractiveness of our rivers, roads, and cities.
Just look at the sky in the North America and Europe: the sky is blue much more often. So, environmental remediation programs are working.
Concerns in 2018
Perhaps the top concern in 2018 is not the technology, but public skepticism and even rejection of environmental metrology and associated remediation programs. Scientists globally are continuing to develop new technology that enables more definitive assays. Portable instruments, including portable GC/MS and LC/MS and surface-activated Raman spectroscopy (SARS), provide sensitive at-site measurements that are actionable. But these will not be effective without public support.
For example, global warming including climate change is a global concern. The causality is very well-documented. In time, I expect the predictions will be confirmed. However, general acceptance is another matter, especially in the U.S.A. Global warming has been politicized, with various stakeholders adopting positions of denial. The potential cost (destructive impact + remediation) is huge. Delaying remediation programs will certainly increase the risk and cost. Most likely, the cost will be borne by future generations. The procrastination scenario is not new. It will have to play out, but the delay will be costly.
Ocean pollution by plastics is another concern. Oceanic gyres are accumulating huge quantities of plastics ranging in size from nanoplastics, up to boats and miles of fishnets and lines.
Methane is a contributor to global warming. Natural sources include seeps, cow emissions, and sewage digestion. Arctic tundra sequesters a large amount of methane that is expected to be released as the region warms. Methane’s half-life in the atmosphere is about seven years.
The EPA has developed a metric called the Global Warming Potential (GWP) to compare the 100-year impact of gases such as methane and nitrous oxide. Carbon dioxide is assigned a reference value of 1.00. Methane has a GWP of 21. Nitrous oxide at 300 is much worse, but fortunately less common.
I asked Professor Richardson for her views on the status of environmental analysis in 2018. She responded, “Looking around our environment, I see many, some potentially risky, chemicals being used in a variety of settings. My lab is focused on disinfection by-products (DBPs) in water. While disinfectants are important for killing microorganisms to make water safe to drink, the disinfectants—such as Cl2, NH2Cl, O3, and ClO2—also react with organic matter in the water to produce DBPs, many of which are mutagenic or otherwise toxic.
“In one study, we traced and sampled water from the stream source to drinking water plants to swimming pools and hot tubs. We have identified hundreds of compounds with high-resolution mass spectrometry.”
High-resolution mass spectrometry is an important tool for identifying unknown chemicals because it allows the determination of the molecular formula, which is one step closer to determining the chemical structure. For quantification, MS/MS can help to eliminate the background and improve signal-to-noise and give lower detection limits.
2019 and the next five years
Mass spectrometry is clearly the key enabling technology for environmental analysis in 2018. Since Professor Richardson was recently elected vice president for Programs and will be in charge of the program for the 2019 ASMS meeting, I asked her about the future. Some anticipated environmental topics include:
- New unknown contaminants
- Per- and polyfluoroalkyl substances (PFASs)
- Pharmaceuticals and illicit drugs
- Flame retardants
- Algal toxins
- Disinfection by-products (DBPs).
Looking further ahead, refinements in MS will empower new applications. The combination with separations (chromatography, electrophoresis) will be even more powerful in research, monitoring, and enforcement.
Longer-term view
Predicting the future in science is seldom 20/20, even over the near term. Some forward-looking research programs can point out correlations, causations, and anticipate potential risks. But historically environmental chemistry is often driven by an unexpected crisis. Just look at the record in Table 1.
Each event has precipitated public concern about the root cause and remediation. For DDT, Carson’s book quickly led to global banning of the insecticide a decade later. Nuclear accidents have also reduced the promise of low-cost electricity from nuclear power stations. Many reactors have been shut down, and new construction is infrequent. Petroleum spills are rare but have a devastating impact when they occur. Their large scale makes effective remediation very difficult. Each spill has led to site-specific, science-based remediation, research programs, and regulations to decrease the risk of future events.
Human factors
Putting technology aside, let’s focus on the human factors. What are the personal qualities of scientists that have motivated development of environmental chemistry?
Professor Richardson responded, “I would say a sense of curiosity and also a passion for helping to solve important problems in the environment. We have had some brilliant and driven scientists who have greatly improved our environment and human health. While environmental issues still exist, we have come a long way from the major problems of the 1960s and 1970s. It is due to these forward-thinking environmental scientists, including Rachel Carson, who was a pioneer.”
Robert L. Stevenson, Ph.D., is Editor Emeritus, American Laboratory/Labcompare; e-mail: [email protected]