A research group tested prehistoric fish for mercury. They noticed that test measurements on Fridays were much higher. What was causing this? Mysteries of Science
Transcript
Investigators have spent much of the 20th century looking for sources of mercury and studying effects of trace amounts in animals and humans. Despite the reduction and elimination of mercury in many products, trace amounts of mercury were showing up in everything, especially in fish.
A research group set out to determine if the source of the mercury was natural or just another byproduct of industrialization. The group convinced a large natural science museum to allow prehistoric fish to be tested for mercury.
Mercury was detected in many samples that predated the industrial revolution. During the analysis, a technician noticed that when measurements were viewed on a weekly basis, Friday results were very much higher.
What was causing the mercury levels in these prehistoric fish to increase on Fridays?
Here's the rest of the story.
School children and university groups could arrange tours of the museum, including the labs. Every Friday morning, groups would come to the lab for a 5-minute dissertation.
We all have mercury in our blood. While some mercury accumulates in the body, much is breathed out as the body tries to eliminate this toxic substance. So it had to be the visitors exhaling mercury vapor and compounds.
This was easy enough to test. The following week no tours were given in the lab area and the mercury test levels were near the normal baseline levels.