Variations in the physicochemical characteristics of the Buffalo River in the Eastern Cape Province of South Africa.

The physicochemical characteristics of the Buffalo River in the Eastern Cape Province of South Africa were evaluated using standard methods. The assessment was carried out with total of 72 water samples collected from six sites over a 12-month period, from August 2010 to July 2011. Water temperature ranged from 11 to 28 °C, while pH varied from 6.6 to 10.7 and turbidity from 1.7 to 133 NTU. Electrical conductivity, total dissolved solids (TDS) and salinity showed drastic variations (42.3-46,693 μS/cm, 20.3-23,350 mg/l and 0.02-33.8 PSU, respectively) and the significantly (P < 0.05) higher mean values of these parameters recorded at Parkside reflect the influence of seawater at the Buffalo River estuary. The concentrations of other parameters ranged as follows: chloride (3.7-168 mg/l), DO (6.9-11.1), BOD (0.6-9.4), COD (3.7-45.9), nitrite-nitrogen (0.02-0.21), nitrate-nitrogen (1-4.47) and orthophosphate (0.01-1.72). There was a significant positive correlation between water temperature and DO (r = 0.200; P < 0.01). Significant (P < 0.01) positive correlations also existed between TDS and salinity (r = 0.921), COD and each of salinity (r = 0.398), TDS (r = 0.375) and chloride (r = 0.330), nitrate and phosphate (r = 0.323) and BOD and turbidity (r = 0.290). Significant (p < 0.01) inverse relationships existed between DO and each of phosphate (r = -0.295) and nitrate (r = -0.168). We conclude that the Buffalo River water quality deteriorated in the plains, compared with the upper reaches. Urgent measures are needed to safeguard the river in view of the potential health concerns as many households rely solely on the untreated river water.