How temperature can alter the combined effects of carbon nanotubes and caffeine in the clam Ruditapes decussatus

ABSTRACT Nowadays, functionalized multi-walled carbon nanotubes (f-MWCNTs) are considered to be emerging contaminants and their impact in ecosystem has rose recent concerns, while other contaminants, such as caffeine, have more coverage in literature. Despite this, the effects of a combination of the two has yet to be evaluated, especially considering predicted temperature rise. In the present study a typical bioindicator species for marine environment, the clam Ruditapes decussatus, and classical tools, such as biomarkers and histopathological indices, were used to shed light on species’ response to these contaminants, under actual and predicted warming scenarios. The results obtained showed that both contaminants have a harmful effect at tissue level, as shown by the higher histopathological index, especially in digestive tubules. Temperatures seemed to induce greater biochemical impacts than caffeine and f-MWCNTs when acting alone, namely in terms of antioxidant defences and energy reserves content, which were exacerbated when both contaminants were acting in combination (MIX treatment). Overall, the present findings highlight the complex response of clams to both pollutants, evidencing the role of temperature on clams’ sensitivity, especially to mixture of pollutants.