We systematically investigated the toxicity of graphene oxide (GO) to freshwater algae (Chlorella pyrenoidosa) in the presence of natural organic matter (NOM), mineral particles and light irradiation. GO could inhibit algal growth (EC50, 37.3 mg/L). Shading effect, membrane damage and nutrient depletion were the main mechanisms for the GO-induced toxicity. However, the toxicity was mitigated by NOM because the surface coating by NOM prevented the direct contact of GO with algal cells. Minerals such as Al2O3 particles also mitigated GO toxicity. Due to GO-Al2O3 heteroaggregation, GO-algae physical contact and algal membrane damage were both reduced, which were the two main mechanisms for Al2O3-induced toxicity reduction. NOM further decreased GO-Al2O3 toxicity due to enhanced steric hindrance with algal cells. In addition, GO could be transformed under sunlight irradiation, which enhanced the toxicity of GO to algae. This information will be useful for understanding environmental risk of graphene materials in natural waters.

Toxicity of graphene materials to freshwater algae as affected by environmental factors

2019 Spring National Meeting

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