Toxic potential evaluation of liquids effluents discharged into nature by the university hospitals centers (UHC) and mixed wastewater treatment station (WWTS) at Ouagadougou-Burkina Faso

Abstract Introduction: In Burkina Faso, several investigations have raised suspicions that hospital liquid effluents are the source of contaminants in porbeagle-culture products and surface water in urban and peri-urban areas. This study aimed to evaluate the Hygienic quality of hospital liquid effluents discharged into nature by the UHC Bogodogo (UHC-BOG), Yalgado Ouédraogo (UHC-YO) and the WWTS of Kossodo (WWTS-KOS). Methodology: 15 samples of liquid effluents (five per site) discharged into nature were collected. Within the physicochemical parameters, the COD, BOD5, TSS, conductivity, copper, iron, hafnium, silver, mercury, lead and cadmium of these samples were determined using standards methods. Results: The mean values of conductivity were 1956.80±81.30, 812.80 ±45.22 and 956.00 ±39.96 μS/cm for WWTS-KOS, UHC-BOG and UHC-YO respectively. TSS were 338.20± 38.80, 45.00 ±5.79 and 187.80 ±27.58 mg/L respectively. COD were 274.80 ± 20.46, 35.00 ±5.52 and 139.80 ±25.53 mg/L respectively. BOD5 were 186.40 ±68.68, 26.20 ±4.82 and 81.80 ±15.63 mg/L respectively. Mercury were 1.93±0.38, 4.04±0.38 and 14.37±1.65 µg/L respectively. Lead were 434.70±202.42, 310.50±4.09 and 367.43±94.01 µg/L respectively. Cadmium 79.59±19.48, 109.94±8.43 and 80.26±7.85 µg/L respectively. Copper were 27.66±3.33, 30.84±1.65 and 28.32±2.36 mg/L respectively. Iron was detected only on the STEP-KOS with an average of 71.01±37.83 mg/L. Hafnium were 50.27±4.49 and 51.58±4.61 mg/L for WWTS-KOS and UHC-BOG respectively. Silver were 34.26±3.06 for WWTS-KOS. Conclusion: Liquid hospital effluents from Ouagadougou discharged into nature on the whole do not respect the Burkinabè normative values for the discharge of wastewater into the environment. On the three sites, the differences found where significant (p<0.05)