Developmental effects of two different copper oxide nanomaterials in sea urchin (Lytechinus pictus) embryos

Abstract

Copper oxide nanomaterials (nano-CuOs) are widely used and can be inadvertently introduced into estuarine and marine environments. We analyzed the effects of different nano-CuOs (a synthesized and a less-pure commercial form), as well as ionic copper (CuSO 4 ) on embryo development in the white sea urchin, a well-known marine model. After 96 h of development with both nano-CuO exposures, we did not detect significant oxidative damage to proteins but did detect decreases in total antioxidant capacity. We show that the physicochemical characteristics of the two nano-CuOs play an essential role in their toxicities. Both nano-CuOs were internalized by embryos and their differential dissolution was the most important toxicological parameter. The synthesized nano-CuO showed greater toxicity (EC 50 ¼ 450 ppb of copper) and had increased dissolution (2.5% by weight over 96 h) as compared with the lesspure commercial nano-CuO (EC 50 ¼ 5395 ppb of copper, 0.73% dissolution by weight over 96 h). Copper caused specific developmental abnormalities in sea urchin embryos including disruption of the aboral-oral axis as a result in changes to the redox environment caused by dissolution of internalized nano-CuO. Abnormal skeleton formation also occurred.

Comparative environmental fate and toxicity of copper nanomaterials

“…Conversely, while nCuO did not cause changes in mitochondrial membrane potential (MMP), CuSO 4 significantly (p < 0.05) decreased MMP even at 1 mg/L. Interestingly, nCuO (≥ 500 μg/L) and CuSO 4 (≥200 μg/L) acted as a chemosensitizers and increased the developmental toxicity of vinblastine, a cell division inhibitor (Torres-Duarte et al, 2016;Wu et al, 2015).…”

“…However, stability of nCuO is strongly influenced by salinity and pH (Conway et al, 2015a;Torres-Duarte et al, 2015;Gomes et al, 2011;Buffet et al, 2013). Rapid aggregation and sedimentation of nCuO occurs at high IS (e.g.…”

“…Aggregation of Cu NPs in natural waters depends on ENM speciation, aqueous media characteristics, specifically ionic strength (IS), natural organic matter (NOM) concentration, and pH Conway et al, 2015a;Miao et al, 2015;Torres-Duarte et al, 2015;Rispoli et al, 2010;Gomes et al, 2011). Given their high density (8.96 g/cm 3 for nCu, 6.31 g/cm 3 for nCuO), Cu NPs settle out rapidly once they reach micron scale.…”

Release and detection of nanosized copper from a commercial antifouling paint

“…been shown that smaller sized Cu particles tend to dissolve faster, and exhibit a higher toxic effect to aquatic organisms (Cai et al, 2005;Torres-Duarte et al, 2015).…”

“…However, this classification of dissolved Cu lumps together dissolved ions, nanoparticles (generally defined as particles with at least one dimension between 1 and 100 nm) and some bulk particles (100e450 nm in size). For proper risk assessment, it is necessary to determine how much of these different fractions of Cu are leached from antifouling paints since their fate, bioavailability, and toxicity differ considerably (Bielmyer-Fraser et al, 2014;Shi et al, 2011;Siddiqui et al, 2015;Thit et al, 2013;Torres-Duarte et al, 2015).…”