As the United States of America celebrates its 250th anniversary, there are sure to be lots of fireworks lighting up the sky this Fourth of July. Americans have been celebrating their Independence Day with fireworks since the very first anniversary of independence from Great Britain in 1777. The tradition has become wildly popular over the years, with people of all ages gathering at homes, parks, beaches, or popular venues to watch these pyrotechnics light up the sky.
Nearly 300 million pounds of fireworks are shot off every year in the United States alone. It is common for many of these fireworks to be lit off near lakes, as the water source is seen as a safety feature in case of unexpected fires. As we think about how many fireworks are being used around the Fourth of July, it raises the question: Does the aftermath of fireworks affect the water quality of our lakes?
Collecting and Preparing the Samples for Water Quality Testing
In 2018, LECO chemists set out to answer this question by collecting Lake Michigan water samples before and after fireworks displays. Their plan was to analyze both sets of samples in order to identify chemical changes between the two. If there were an increase in chemical compounds tied directly to fireworks, it would allege that pyrotechnics indeed have a direct impact on water quality during the popular holiday time.
Analyzing the Lake Water
To analyze the samples, a powerful analytical workflow was used. Solid phase microextraction (SPME) with an SPME Arrow offered an increased sorption volume for efficient sampling of volatile and semi-volatile compounds. For analysis, comprehensive two-dimensional gas chromatography (GCxGC) was utilized for enhanced separation, along with high-resolution mass spectrometry (HRMS) for accurate identification of compounds. This non-targeted approach allowed researchers to detect a wide range of compounds, including those present at trace levels.
Surprising Water Quality Results
The results of the study were unexpected. While many compounds were uncovered, it was clear that fireworks contributed little to no direct chemical contamination to the water samples. While fireworks are often assumed to introduce pollutants, this analysis did not show significant chemical signatures directly tied to pyrotechnic residue under the conditions studied.
What the data did show, however, was a staggering increase in compounds associated with personal care products and everyday human activity. From the first sample set to the second, the data showed that more sunscreen, insect repellent, skin conditioners, and fragrances had made their way into the water. It can be assumed that these substances entered the water as beachgoers swam in the lake and gathered along the shoreline during peak holiday traffic.
Notable Chemical Changes
With non-targeted GCxGC-HRMS via the Pegasus GC-HRT 4D platform, the chemists were able to pinpoint specific compounds that increased after the fireworks shows. This led to significant discoveries, like how some sunscreen-related compounds increased by an eye-opening forty times the initial documented amount, and skin conditioning and cosmetic compounds increased tenfold. There were also several fragrance-related compounds that were newly detected only after the event.
Detecting these subtle shifts requires more than conventional techniques. The combination of GCxGC and HRMS offered several key advantages:
- Improved separation of complex mixtures, revealing compounds that would overlap in traditional methods.
- Excellent mass accuracy, enabling confident molecular formulae calculation to aid in compound annotation.
- Non-targeted analysis, allowing detection of both expected and unknown contaminants.
- Clear before-and-after comparisons showing how water chemistry evolves during high-traffic events.
This level of insight is critical when analyzing environmental samples with complex and variable compositions.
Key Takeaways for Environmental Monitoring
While fireworks attract attention as potential pollutants, this experiment found that consumer products like sunscreens and insect repellents also have a measurable effect. This isn’t to say that people shouldn’t wear sunscreen and bug spray at the beach—sunscreen is especially important for protecting oneself from harmful UV rays.
For environmental scientists and regulators, it indicates that monitoring strategies should consider human activity patterns and that non-targeted analytical methods are essential for capturing transient chemical changes. Non-targeted studies have the ability to subvert chemical expectations and offer an unbiased insight into underlying environmental processes.
By combining world-class instrumentation, such as the Pegasus GC-HRT 4D, with real-world environmental questions, researchers can better understand not just what’s in our water, but why it’s there.
Learn More
For further exploration of this study, download the technical poster, “Of Fireworks and Tourism: GCxGC-HRMS Analysis of Summer Impacts on Lake Michigan Water Quality”.
For more information on environmental analysis, visit our Environmental Resource Hub.
This article was originally published in 2019 and has been refreshed with 2026 data.
