This is the 15071st most frequent Polish word.
rtęci
"Rtęci" is the genitive form of "rtęć," meaning "mercury" (the chemical element).
Rtęci refers to the chemical element mercury, whose levels are being tested in the context of the water sample.
W laboratorium sprawdzano poziom rtęci w próbce wody.
In the laboratory, they were checking the mercury level in the water sample.
Rtęci is used again in the context of mercury as the substance found in thermometers for measuring temperature.
Termometr zawierał słup rtęci, który unosił się, wskazując temperaturę.
The thermometer contained a column of mercury, which rose indicating the temperature.
Here, rtęci is used in the context of the chemical substance which can cause health issues upon exposure.