As and Hg were not measured in these studies, hence
there are no values reported (‘‘–’’), but our Hg concentration results,
if compared with the permissible limits set by the RoHS
Directive, are far below. Regarding Cr, Zn and Pb, our results were
above the ones presented in Table 5, in most of our LCD samples.
There is no much literature concerning heavy metal concentrations
in LCDs and that is one of the reasons for duplicating these particular
experiments. The results showed fairly good repeatability and
the concentrations for all elements presented in Table 4 are the
mean values from both experiments, with each concentration of
each metal measured in triplicate. Finally, Ni showed similar
behavior with concentration values reported in literature data in
most our samples and only in one of them (PCBs sample 2002–
2006, 3.01 wt.%) was found in values a little higher compared to
the ones reported in other studies (see Table 5).