Genotoxic Potential and Physicochemical Parameters of Sinos River, Southern Brazil

Table 2

Damage frequency (the sum of cells with damage classes 1 to 4, in %) and damage index estimated by the comet assay (mean ± standard deviation) in the erythrocytes of H. luetkenii exposed to water samples from the Sinos River and to tap water (control).

Sampling site	Summer		Winter
	Damage frequency (n)	Damage index	Damage frequency (n)	Damage index
Caraá; (Upper course)	50.6±9.3 (12)^a	58.1±14.5	66.3±13.3 (11)^a	69.5±14.2^a
Parobé; (Middle course)	61.3±6.3 (12)^b	64.6±7.4	62.9±16.0 (8)^a	65.3±17.9^a
Sapucaia do Sul; (Lower course)	53.3±10.4 (12)^ab	60.8±16.0	59.6±11.5 (11)^a	62.5±15.0^a
Control	47.1±11.5 (12)^a	51.1±14.2	40.4±16.0 (8)^b	40.4±16.0^b
P	0.005	0.107	0.002	0.002

The number of fish analyzed in each sample is presented between brackets. P values referring to ANOVA between sampling sites and respective control group (^a,bvalues with different letters have significant difference in the same column).