Table 3.

Inhibition of bioluminescence (I%) of A. fischeri after 15 and 30′ of exposure to 90% of maximum concentration samples (100 mg/L). The assay was performed at 15° ± 1 °C. Marine protocol EC50 Zn²⁺  = 10.26 mg/L (C.L. 95% = 9.22–11.43); Freshwater protocol EC50 Zn²⁺  = 1.04 mg/L (C.L. 95% = 0.80–1.36)

Samples	Bioluminescence inhibition at max concentration
	Marine protocol				Freshwater protocol
	Mean I% (15′)	S.D	Mean I% (30′)	S.D	Mean I% (15′)	S.D	Mean I% (30′)	S.D
betaine:ethylene glycol	6.16	0.32	4.80	0.62	− 22.24	0.13	− 15.72	1.56
betaine:citric acid	7.08	1.69	7.79	2.54	− 8.59	0.85	− 14.01	0.91
betaine:glycerol	3.79	0.92	4.33	0.17	− 10.19	3.97	− 13.95	0.09
betaine:levulinic acid	4.68	1.91	3.82	1.20	− 12.82	1.80	− 14.93	0.21
betaine:L-lactic acid	0.03	1.11	0.51	0.53	− 13.84	3.82	− 19.12	6.02
proline:glycerol	2.76	1.91	2.89	2.17	− 11.57	4.68	− 16.76	7.08
proline:lactic acid	− 0.26	0.89	− 1.09	0.51	− 14.53	1.65	− 17.38	0.62
proline:levulinic acid	3.78	2.42	3.43	0.02	− 7.97	2.80	− 14.58	2.00
proline:malic acid	11.15	1.26	23.45	0.84	− 5.28	2.97	− 6.82	2.18
cholinium bitartrate:citric acid	6.41	1.81	10.51	0.71	− 14.71	2.84	− 17.17	4.84
choline acetate:imidazole	4.21	1.43	5.51	0.09	− 13.25	0.52	− 14.26	1.56
choline acetate:levulinic acid	6.89	0.17	9.79	0.83	− 10.42	0.40	− 13.87	0.08
choline acetate:glycolic acid	1.20	2.25	4.65	0.95	− 10.87	1.04	− 15.25	1.31
choline acetate:diglycolic acid	2.80	0.52	3.38	0.32	− 15.43	1.56	− 17.94	1.47
choline acetate:citric acid	5.95	2.44	11.77	0.43	− 11.03	0.54	− 14.61	0.33