Table 5. Mean number of micronuclei (MCN) in the erythrocytes of Astyanax altiparanae exposed to water samples collected from P1, P2, and P3 (surface water) in the Água Boa stream (Dourados, MS) and P4 (groundwater) during December 2012 and February, April, July, September and October 2013.

Average number of micronuclei at collection points
Collection points	December	February	April	July	September	October
P1	2.80 ± 2.58 a bB	3.20 ± 2.48 ab B	14.60 ± 11.56 a A	#	8.20 ± 4.08 a AB	10.60 ± 2.79 a AB
P2	5.40 ± 1.94 a CD	3.00 ± 2.82 ab D	14.80 ± 5.97 a AB	15.40 ± 2.70 a A	8.20 ± 4.43 a BCD	10.40 ± 1.81 a ABC
P3	4.20 ± 3.03 ab B	4.20 ± 1.78 a B	8.80 ± 3.03 a B	16.60 ± 2.88 a A	9.20 ± 2.16 a B	9.20 ± 3.19 a B
P4	0.20 ± 0.44 b B	0.80 ± 0.83 b B	4.60 ± 4.82 a AB	3.40 ± 2.19 b AB	6.80 ± 3.49 a A	3.20 ± 1.48 b AB

Average number of MCN followed by the same bold lowercase letter in a given column or capital letters in a given row did not differ significantly by Tukey's test (P ≤ 0.05).

Columns indicate statistical differences between collection points, while rows indicate statistical differences between the sampling months.

^#Sample not collected