presence of such species may be deleterious, if the cells do not activate compensatory scavenging mechanisms. In this case, such conditions result in cellular and
tissue damage [63], a process also known to occur in some species of annelids [64],
which seems to be counteracted when animals are exposed to antioxidant
compounds [65].
1.5 Toxic Effects of Paracetamol on Crustaceans
Crustaceans seem also to share most mechanisms described so far that are prone to
be activated by paracetamol. The study conducted by Daniel et al. [26] evidenced
that even short-term periods of exposure of the crustacean Daphnia magna to
paracetamol could elicit significant defensive mechanisms, such as the increase of
the phase II metabolic enzymes of conjugation, glutathione-S-transferases, closely
followed by the augment of catalase activity, suggesting the onset of an antioxidant
response. This oxidative effect culminated also in the decrease of cholinesterasic
activity, establishing a link between oxidative effects and other physiological levels.
Despite the occurrence of such effects, no behavioral traits were significantly
compromised. This same study also showed that chronic responses to the presence
of paracetamol did not result in any significant response in terms of the same
parameters, evidencing the transient nature of the toxic effects and the responsiveness of the adopted species. These results seem to be somewhat validated by the
results obtained by Masteling et al. [66], after exposing individuals of D. magna to
paracetamol for a sub-chronic period (8 days of exposure). The obtained data
evidenced once again the responsiveness of this species, since the activities of
both catalase and glutathione-S-transferases were significantly increased for generically all tested concentrations. The assumptions about the occurrence of oxidative
alterations were reinforced considering the establishment of peroxidative damage in
exposed individuals. The toxicity of paracetamol toward crustacean species is not
limited to exposed organisms, since transgenerational effects seem also to be
possible, according to the study by Castro et al. [67]. The authors observed that
prolonged paracetamol exposures not only caused deleterious effects in the reproductive performance of exposed D. magna but were responsible for a general
decrease in the fitness of nonexposed, daughter (first-generation neonates) organisms. These data are clear about the putative ecotoxicological effects of paracetamol
toward freshwater organisms, since toxic effects are likely to occur after short-,
middle-, and long-term exposures but can also surpass generations and compromise
the health condition of offspring born from exposed parental organisms.
138
B. Nunes
tissue damage [63], a process also known to occur in some species of annelids [64],
which seems to be counteracted when animals are exposed to antioxidant
compounds [65].
1.5 Toxic Effects of Paracetamol on Crustaceans
Crustaceans seem also to share most mechanisms described so far that are prone to
be activated by paracetamol. The study conducted by Daniel et al. [26] evidenced
that even short-term periods of exposure of the crustacean Daphnia magna to
paracetamol could elicit significant defensive mechanisms, such as the increase of
the phase II metabolic enzymes of conjugation, glutathione-S-transferases, closely
followed by the augment of catalase activity, suggesting the onset of an antioxidant
response. This oxidative effect culminated also in the decrease of cholinesterasic
activity, establishing a link between oxidative effects and other physiological levels.
Despite the occurrence of such effects, no behavioral traits were significantly
compromised. This same study also showed that chronic responses to the presence
of paracetamol did not result in any significant response in terms of the same
parameters, evidencing the transient nature of the toxic effects and the responsiveness of the adopted species. These results seem to be somewhat validated by the
results obtained by Masteling et al. [66], after exposing individuals of D. magna to
paracetamol for a sub-chronic period (8 days of exposure). The obtained data
evidenced once again the responsiveness of this species, since the activities of
both catalase and glutathione-S-transferases were significantly increased for generically all tested concentrations. The assumptions about the occurrence of oxidative
alterations were reinforced considering the establishment of peroxidative damage in
exposed individuals. The toxicity of paracetamol toward crustacean species is not
limited to exposed organisms, since transgenerational effects seem also to be
possible, according to the study by Castro et al. [67]. The authors observed that
prolonged paracetamol exposures not only caused deleterious effects in the reproductive performance of exposed D. magna but were responsible for a general
decrease in the fitness of nonexposed, daughter (first-generation neonates) organisms. These data are clear about the putative ecotoxicological effects of paracetamol
toward freshwater organisms, since toxic effects are likely to occur after short-,
middle-, and long-term exposures but can also surpass generations and compromise
the health condition of offspring born from exposed parental organisms.
138
B. Nunes