The environmental repercussions of the discharge of disinfected effluents are still poorly understood. This
study assessed the impact of ozonation and UV oxidative treatment processes on metal forms – particulate,
colloidal and permeable fractions – and bioavailability in disinfected wastewaters. In addition to
wastewater analyses, mussels were placed in continuous flow-through aquaria and exposed for 4 wk
to wastewater, then metals in their tissues were analysed in parallel with exposure biomarkers. Metal
size distribution was affected by oxidative processes; results showed that ozonation treatment generally
increases the permeable fraction of some metals, particularly Cd and Cu, in treated waters, whereas UV
treatment fosters the formation of permeable Zn. Ozone treatment of wastewater generally increased the
bioavailability of specific metals. Metal bioaccumulation was in most cases significantly higher in mussels
exposed to ozone-treated effluent compared to the UV treatment: 58%, 32%, 42% and 47% higher,
respectively, for Ag, Cd, Cr and Cu. Physical metal speciation in these wastewaters comparatively measured
the permeable fraction of metals to relate them to the bioaccumulation results for the exposed
mussels. The levels of lipid peroxidation were significantly increased in gills but not in the digestive
gland. The levels of metallothionein in the digestive gland were also significantly reduced suggest
decreased input of particulate metals. Results of bioaccumulation in mussels suggested that metal bioavailability
can be modified by the different oxidative processes. Despite this disadvantage, ozonation
still represents a great choice of treatment considering the overall environmental benefits
The environmental repercussions of the discharge of disinfected effluents are still poorly understood. This
study assessed the impact of ozonation and UV oxidative treatment processes on metal forms – particulate,
colloidal and permeable fractions – and bioavailability in disinfected wastewaters. In addition to
wastewater analyses, mussels were placed in continuous flow-through aquaria and exposed for 4 wk
to wastewater, then metals in their tissues were analysed in parallel with exposure biomarkers. Metal
size distribution was affected by oxidative processes; results showed that ozonation treatment generally
increases the permeable fraction of some metals, particularly Cd and Cu, in treated waters, whereas UV
treatment fosters the formation of permeable Zn. Ozone treatment of wastewater generally increased the
bioavailability of specific metals. Metal bioaccumulation was in most cases significantly higher in mussels
exposed to ozone-treated effluent compared to the UV treatment: 58%, 32%, 42% and 47% higher,
respectively, for Ag, Cd, Cr and Cu. Physical metal speciation in these wastewaters comparatively measured
the permeable fraction of metals to relate them to the bioaccumulation results for the exposed
mussels. The levels of lipid peroxidation were significantly increased in gills but not in the digestive
gland. The levels of metallothionein in the digestive gland were also significantly reduced suggest
decreased input of particulate metals. Results of bioaccumulation in mussels suggested that metal bioavailability
can be modified by the different oxidative processes. Despite this disadvantage, ozonation
still represents a great choice of treatment considering the overall environmental benefits
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