Acute Toxicity of Double-Walled Carbon Nanotubes to Three Aquatic Organisms

Table 2

Lethal concentrations (LC₅₀s and 95% confidence intervals) for Daphnia pulex following 48 h exposure to pristine and oxidised DWCNTs at different ionic strengths and humic acid (HA) concentrations. LC₅₀s with common alphabetical superscript do not differ significantly ().

Exposure	Physicochemical characteristics	EC50 (mg/L)	Confidence limits (mg/L)
Pristine	0.00335 (control reconstituted water) M Na	2.801^a	1.58–3.95
	0.00585 M Na	2.710^a	1.21–7.58
	0.00835 M Na	2.835^a	0.82–5.66
	0.0139 M Na	3.163^a	2.10–6.02
Oxidised	0.00335 (control reconstituted water) M Na	4.480^a	2.09–7.49
	0.00585 M Na	3.320^a	1.88–6.04
	0.00835 M Na	3.048^a	1.71–7.05
	0.0139 M Na	3.541^a	1.52–6.35
Pristine	0.00449 M Ca	3.048^a	1.51–6.43
	0.0226 M Ca	2.81^a	1.58–3.95
	0.03395 M Ca	3.327^a	1.72–6.44
Oxidised	0.00449 M Ca	3.77^a	1.01–5.49
	0.0226 M Ca	4.48^a	2.09–7.49
	0.03395 M Ca	3.57^a	1.81–7.58
Pristine	0 (control reconstituted water) M Na	2.80^a	1.58–3.95
	0.9 mg/L HA	1.91^a	1.21–7.58
	1.81 mg/L HA	1.89^a	0.82–5.66
	3.64 mg/L HA	1.80^a	1.10–6.02
Oxidised	0 (control reconstituted water) M Na	4.48^a	2.09–7.49
	0.9 mg/L HA	4.07^a	1.88–6.75
	1.81 mg/L HA	3.25^a	1.71–7.05
	3.64 mg/L HA	3.07^a	1.52–6.87