Ecotoxicological impacts of exposure to copper oxide nanoparticles on the gill of the Swan mussel, Anodonta cygnea (Linnaeus, 1758)

Assessment of molluscicidal and larvicidal activities of CuO nanoparticles on Biomphalaria alexandrina snails

Background

Schistosomiasis is a major, but generally overlooked, tropical disease carried by snails of the genus Biomphalaria, which have a large distribution in Egypt. Control of the intermediate host snail is critical in limiting schistosomiasis spread. On the topic of snails’ management, nanotechnology has gained more interest.

Results

Copper oxide nanoparticles, characterised by transmission electron microscopy and X-ray diffraction, showed a single crystal structure with an average crystallite size around 40 nm by X-ray diffraction and typical transmission electron microscopy (TEM) image. Also, the UV–VIS spectrophotometer displayed a sharp absorption band of CuO NPs. Molluscicidal activity of copper oxide nanoparticles against B. alexandrina snails was observed. Following exposure to CuO NPs (LC50 and LC90 was 40 and 64.3 mg/l, respectively), there was a reduction in the growth and reproductive rates of treated B. alexandrina at the sub-lethal concentrations, as well as, a drop in egg viability. Moreover, CuO NPs exhibited a toxic effect on miracidiae and cercariae of S. mansoni. Scanning electron microscopy (SEM) investigations of the head-foot and mantle of control and treated snails to the sub-lethal concentrations of CuO NPs (LC10 15.6 mg\l–LC25 27.18 mg\l) indicated morphological alterations in the ultrastructure.

Conclusions

CuO NPs caused a significant effect against the intermediate hosts of S. mansoni and provide a considerable scope in exploiting local indigenous resources as snail molluscicidal agents.

Emerging investigator series: metal nanoparticles in freshwater: transformation, bioavailability and effects on invertebrates

MNPs may undergo different environmental transformations in aquatic systems, consequently changing their mobility, bioavailability and toxicity to freshwater invertebrates.

A sub-individual multilevel approach for an integrative assessment of CuO nanoparticle effects on Corbicula fluminea

Because they are widely used, copper oxide nanoparticles (CuO NPs) are likely to enter the aquatic environment and then reach the sediment. We have examined the effect of CuO NPs in the freshwater endobenthic bivalve Corbicula fluminea. Some previous studies have investigated effects at biochemical and physiological levels, but molecular endpoints are still poorly studied despite they are sensitive in early detection of NPs effect. In the present study, we have investigated short-term effects (96 h) of CuO NP (12, 30 nm; 0, 20 and 100 μg/L) using molecular endpoints as well as more conventional biochemical and physiological markers. The expression of antioxidant (CuZnSOD, MnSOD, Cat, Se-GPx, Trxr) and antitoxic (GST-Pi, HSP70, MT, Pgp, MRP1) related genes was measured at the mRNA level while antioxidant (SOD, TAC) and antitoxic (GST, ACP) defenses, energetic reserves and metabolism (ETS, Tri, LDH), and cellular damages (LPO) were assessed using a biochemical approach. The filtration rate measured at 96 h provided information at the physiological scale. Gene expression and filtration rate were responsive to CuO NPs but the effects differed according to the NP size. The results suggest that defense mechanisms may have been set up following 30 nm-NP exposure. The response to 12 nm-NP was lower but still showed that exposure to 12 nm-NP led to activation of cellular elimination mechanisms. The lowering of the filtration rate may have protected the organisms from the contamination. However, this raised the question of further repercussions on organism biology. Together, the results (i) indicate that CuO NP may exert effects at different levels even after a short-term exposure and (ii) point out the precocity of molecular response.

Copper Bioaccumulation Kinetics in Swan Mussel, Anodonta cygnea (Linnaeus, 1758) During Waterborne Exposure to CuO Nanoparticles

This study was conducted to investigate bioaccumulation of copper in two internal organs (mantle and foot) of swan mussel, Anodonta cygnea (Linnaeus, 1758) in exposure to copper oxide nanoparticles (CuO NPs). Basal concentration of Cu in the mantle (3.15 ± 1.09 µg g^-1 DW) was significantly (p < 0.05) lower than the foot (5.43 ± 1.54 µg g^-1 DW). At the end of the exposure period, the highest concentration of Cu in both organs belonged to the highest exposure concentration. Calculated bioconcentration factor (BCF) values showed significant (p < 0.05) higher values for the mantle in each day and each exposure concentration (except the lowest exposure concentration) than the foot. For both organs, the highest and lowest BCFs occurred at the lowest and highest exposure concentrations, respectively. Cu concentration in both organs was significantly (p < 0.05) decreased after day 4. Based on the results, it was obvious that exposure to sub-lethal concentrations of CuO NPs would lead to the significant accumulation of copper in mantle and foot that may have adverse effects on this organism.