Multigenerational effects of gold nanoparticles in Caenorhabditis elegans: Continuous versus intermittent exposures

•Nanomaterials are exposed to ecosystems with various unpredictable patterns.•Permanent reproduction defects occur following continuous nanomaterial exposure.•Immediate recovery occurred after a single generation of intermittent exposure.•The strongest defects were found at F3, after gaps in AuNP exposure in F1 and F2.•The effects of exposure could be an important factor in evaluating nano-toxicity.

Nanomaterials can become disseminated directly or indirectly into the soil ecosystem through various exposure routes. Thus, it is important to study various deposition routes of nanomaterials into the soil, as well as their toxicities. Here, we investigated the multigenerational effects of gold nanoparticles (AuNPs) on C. elegans after continuous or intermittent food intake. Following continuous exposure, significant differences were observed in the reproduction rate of C. elegans in the F2-F4 generations, which were associated with reproductive system abnormalities. However, following intermittent AuNP exposure in P0 and F3, reproductive system abnormalities and inhibited reproduction rates were observed in F2 and F3. While continuous AuNP exposure impaired reproduction from F2 to F4, intermittent exposure caused more pronounced effects on F3 worms, which may have resulted from damage during the convalescence period up through F2. These data showed the occurrence of multigenerational effects following different exposure patterns, exposure levels, and recovery periods. To our knowledge, this is the first study to demonstrate that multigenerational nano-toxicity is caused by different exposure patterns and provides insights into the unpredictable exposure scenarios of AuNPs and their adverse effects.

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