It was expected that plastic (LDPE) fragments will be green in fluorescence microscope but there are other materials like grass (attached image) also look green. Literature shows that for detecting plastic fragments the excitation wavelength: 450-490nm and emission wavelength : 515-565 nm. I am using Olympus BX43 fluorescence microscope where properties shows that it’s non UV excitation. Emission wavelength is 508 nm and excitation wavelength is 470 nm.

Is this due to the 508 nm emission wavelength? Or there might be other reason for this?

Appreciate your time.