Exposure time (hr)   12   Treatment (μg.L-1) 0 0.1 0.2 0.63 2 6.3 20 63 200 Mean value in % 2.22 12.22 32.22 46.66 61.11 72.22 78.88 92.22 98.88 SE 0.211 0.279 0.279 0.183 0.211 0.279 0.279 0.105 0.105 P Value   <0.0001   Exposure time (hr)   24   Treatment (μg.L-1) 0 0.1 0.2 0.63 2 6.3 20 63 200 Mean value in % 16.66 24.44 97.77 100 100 100 100 100 100 SE 0.183 0.105 0.105 0 0 0 0 0 0 P value   0.0368

Table 1: Mortality (%) of copepods during exposure to a range concentration of cadmium after 12 and 24 hours of exposure: mean value, standard error and p value.