Table 2.

Effect of chronic exposure to prometryne on superoxide dismutase (SOD, nmol NBT min⁻¹ mg⁻¹ protein) activity in red swamp crayfish tissues.

Indices	Exposure time (days)	Test groups
		Control	Prometryne 0.51 μg L−1	Prometryne 0.144 mg L−1	Prometryne 1.44 mg L−1
Hepatopancreas	11	0.216 ± 0.01	0.111 ± 0.05*	0.126 ± 0.02*	0.132 ± 0.04*
	25	0.164 ± 0.04	0.155 ± 0.04	0.086 ± 0.02*	0.076 ± 0.02*
Muscle	11	0.075 ± 0.04	0.057 ± 0.03	0.093 ± 0.06	0.098 ± 0.17
	25	0.330 ± 0.01	0.043 ± 0.02	0.008 ± 0.00*	0.010 ± 0.00*

Data are means ± SD, n = 6. Significant differences compared with control value, *<0.01.