CO2-induced pH reduction increases physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus

Abstract

The increasing usage of nanoparticles has caused their considerable release into the aquatic environment. Meanwhile, anthropogenic CO2 emissions have caused a reduction of seawater pH. However, their combined effects on marine species have not been experimentally evaluated. This study estimated the physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus under high pCO2 (2500–2600 μatm). We found that respiration rate (RR), food absorption efficiency (AE), clearance rate (CR), scope for growth (SFG) and O:N ratio were significantly reduced by nano-TiO2, whereas faecal organic weight rate and ammonia excretion rate (ER) were increased under nano-TiO2 conditions. High pCO2 exerted lower effects on CR, RR, ER and O:N ratio than nano-TiO2. Despite this, significant interactions of CO2-induced pH change and nano-TiO2 were found in RR, ER and O:N ratio. PCA showed close relationships among most test parameters, i.e., RR, CR, AE, SFG and O:N ratio. The normal physiological responses were strongly correlated to a positive SFG with normal pH and no/low nano-TiO2 conditions. Our results indicate that physiological functions of M. coruscus are more severely impaired by the combination of nano-TiO2 and high pCO2.

Rethinking Nano‐TiO2 Safety: Overview of Toxic Effects in Humans and Aquatic Animals

“…Thus, exposures to high levels of waterborne nano-TiO 2 (2.5 and 10 mg L −1 ) suppressed the filtration activity, food absorption efficiency and aerobic scope for growth in the mussel M. coruscus. [127] The specific dynamic action (reflecting the energy demand for food digestion and absorption) and activity of the digestive enzymes decreased in nano-TiO 2 exposed mussels, which reflected suppressed feeding. [93,128] Similarly, exposure to 50 and 100 µg L −1 nano-TiO 2 decreased filtration activity of the Mediterranean clam R. decussatus.…”

Synergistic Effects of Nano-ZnO and Low pH of Sea Water on the Physiological Energetics of the Thick Shell Mussel Mytilus coruscus

“…In addition, high concentration of nano-ZnO significantly reduced the SFG, showing that nano-ZnO obviously damage the growth of M. coruscus. There was a similar study made by Hu et al (2017) who pointed out that the NPs could significantly reduce SFG of M. coruscus. Acidification also resulted in a decreased SFG of the thick shell mussel at days 7 and 14 when nano-ZnO was 2.5 and 10 mg L -1 .…”

“…However, low pH made the CR of the pearl oyster Pinctada martensi increased while the filtration activities of the mussel M. galloprovincialis were not affected by the pH reduction ( Fernández-Reiriz et al, 2012 ). For NPs effects, nano-TiO 2 exposure reduced CR of M. coruscus ( Hu et al, 2017 ). CR of M. galloprovincialis increased with nano-CeO 2 concentration but decreased over time in groups exposed to nano-CeO 2 ( Conway et al, 2014 ).…”

“…If the oyster Pinctada mazatlanica was exposed to high temperature, the majority of feces is amino acid catabolism products ( Saucedo et al, 2004 ), indicating an amino acid catabolism under stress conditions. It was found that higher ER values under low pH were observed when NPs were present ( Hu et al, 2017 ). In this study, the increase in ER may indicate a sharp increase in amino acid catabolism of the mussels exposed to high nano-ZnO and low pH.…”

Antagonistic Interactions between Benzo[a]pyrene and C₆₀ in Toxicological Response of Marine Mussels

“…This high filtration rate has been shown to be associated with the high potential accumulation of different chemicals in their tissues. A variety of mussel species have been used to elucidate both physiological and molecular mechanisms of action to nanoparticles [29,30] making them an ideal model to investigate how organisms respond to environmental stressors such as chemical mixtures [27]. This Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 15 May 2019 doi:10.20944/preprints201905.0180.v1…”