Evaluation of the Cytotoxic Effects of Humid Lightweight
Coal Ash derived from the Disposal of Waste on Normal
Human Keratinocyte and Endothelial Cell Lines in 2-D and
3-D Culture
The presence of waste in the environment has frequently been indicated as a significant risk
to human health. Therefore, landfill sites and the disposal of urban solid and non-hazardous waste by incineration
are subject to much environmental monitoring, in addition to the regulations already in place.
However, little action has been taken, and consequently no specific legislation exists, in relation to the
assessment of the real biological risk of various substances, including chemical mixtures and ashes, derived
from the incineration processes. This study assessed the cytotoxic potential of humid lightweight coal ash
(LA) derived from incineration processes and waste management, on two cell lines: NCTC 2544 normal
human keratinocytes and HECV endothelial cells. To reach this goal and to assess more-realistic methods
for animal replacement, we employed different in vitro experimental approaches: acute and longer exposure
to LA, by direct and indirect contact (0\u20132mg/ml and 16mg, respectively), both in 2-D and 3-D cultures.
In 2-D HECV cultures, we observed a decrease in the viability index, but only during direct contact with LA
doses higher than 0.1mg/ml. Moreover, some striking differences in cytotoxicity were observed between
the 2-D and 3-D models. Taken together, these observations indicate that, for studying pollutant toxicity
during longer exposure times, 3-D cultures in direct contact with the pollutant seem to offer a more suitable
approach \u2014 they mimic the in vivo behaviour of cells more realistically and under strictly controlled
conditions. Thus, in readiness for possible forthcoming European regulations, we believe that the proposed
study, even in its preliminary phase, can provide new advice on the assessment of the toxic and biological
potential of particular chemical compounds derived from waste management processes
