Hatched larvae fixed in 2% glutaraldehyde and 2% paraformaldehyde
in cacodylate buffer (modified Karnowsky fixation) were
embedded in Technovit after general dehydration procedures
before being sectioned both longitudinally (for overview) and
transversely (selected areas: eye/brain, buccal/gill area, oesophagus
area, yolk sac area, liver/pancreas area, urinary bladder area).
Sections (2–3 m) from at least 5 larvae from each exposure level
and the control were cut on a rotation microtome, stained with
toluidine blue and mounted on glass slides before being studied and
photographed in the microscope (Leitz Aristoplan with Olympus
Camedia digital camera).