4.7.1. Water physico-chemical variables

Table 2 shows the mean, standard deviation and range of physico-chemical variables measured during the study period. With the exception of pH and temperature, the measured variables were statistically significantly different between the sampling sites (p < 0.05). The lowest value of DO and highest turbidity and BOD5 values were recorded at Site 3. The Tukey's HSD post hoc test revealed that the mean DO concentration was significantly lower at Site 3 than at Sites 1 and 2. Although pH and temperature were not statistically significantly different between the sampling sites, the highest mean pH and temperature values were at Sites 2 and 3, respectively, and the lowest at Sites 1 and 2, respectively. The Tukey's HSD post hoc test showed that the mean EC concentration was significantly lower at Site 1 than at the rest of the sampling sites and turbidity significantly higher at Site 3. The mean BOD5 concentrations were significantly higher at Sites 3 and 4 than at Site 1 (Table 2).


Table 2. Mean ± standard deviation and range (in parenthesis) of the physico-chemical variables (n = 8) in the Swartkops River during the study period (August 2009–September 2012). p and F values are indicated by ANOVA. Different superscript letters per variable across sites indicate significant differences (p < 0.05) revealed by Tukey's HSD post hoc test. The same superscript letter between sites per variable indicates no significant differences (p > 0.05).
