Comparative toxicity of single-wall and multi-wall carbon nanotubes to brine shrimp Artemia salina

Effects of single-wall (SWCNT) and multi-wall carbon nanotubes (MWCNT) on Nauplii and adults of Artemia salina were investigated in this study. Organization for Economic Co-operation and Development guideline for acute toxicity test was used to evaluate the LC50 of SWCNT and MWCNT on nauplii and adult of Artemia salina. The standard hatching method was first performed on the cysts of Artemia, and then Nauplii and adults of Artemia were exposed to concentrations of SWCNT and MWCNT for a 48-h exposure period. LC50 experiment was conducted on 24 and 48 h exposure time and for each toxicity test, a control group (without any nanomaterials) was considered. Probit software was then used to analyze the mortality and LC50 concentrations. Results showed that the LC50 of Nauplii in 24 and 48 h after exposure to SWCNT were 509.25 ± 49.04 and 241.03±19.69 mg/L, respectively. For adults, LC50 values showed 556.74 ± 29.84 and 416.57 ± 31.93 mg/L during a 24- and 48-h exposure time, respectively. In addition, the LC50 of MWCNT for Nauplii was 3750.51 ± 145.59 and 3319.73 ± 563.7 mg/L in 24 h and 48 h, respectively. For adults, LC50 values were calculated at 5619.67 ± 44.41 and 4062.81 ± 782.32 mg/L after 24- and 48- h, respectively. The toxicity of SWCNT and MWCNT to Artemia showed a time- and concentration-dependent manner in the exposure test. Taken together, as the marine environments are being faced with an ever-increasing emergence and presence of SWCNTs and MWCNTs, valuable marine food species such as Artemia salina are significantly vulnerable to carbon-based nanomaterials, and more efforts should be made to reduce the environmental concentrations ofcarbon nanotubes in the marine environments.