Impact of olive oil industry on benthic macroinvertebrates in the Kabylia region

To study the effect of olive mill wastewaters on benthic macroinvertebrates, we opted to carry out a biological and physicochimical study in three rivers in the Kabylia region . A series of water and wildlife was affected over three periods for two years ; from october 2015 to May 2017. The results relating to aquatic fauna during the olive period show a total disappearance of all taxa downstream from the point of discharge in theWadi Bougdoura. As well as a decrease in the number of taxa at the point of discharge with a high number of pollu- resistant taxa such as Diptera, at the point of discharge and down-stream in the Wadi Arkham during the olive period. We have also seen a disappearance of taxa sensitive to pollution such as Trichoptera at the point of discharge and down-stream after the olive period. In the Wadi Bousselam, thermal and industrial pollution leads to a low number of all taxa at the point of discharge and downstream throughout the study period.The physicochemical study revealed a drop in dissolved oxygen up to 3.10 mg/l downstream discharge point and important mineralization at stations at the point of discharge and downstream where discharged olive mill wastewater, during the olive period. High concentrations of sulphates (265mg/l to 1012.5mg/l), chlorides (201.1 mg/l to 6922.5 mg/l), salinity (0.72 PSU to 6.83 PSU) and electrical conductivity (1.737 ms/cm to 14.92 ms/cm). Nutritional salt (nitrate and nitrite) levels remain low in all study stations, ranging from 0.49 mg/l to 2.39 mg/l for NO3⁻, and from 0.03 mg/l to 1.66 mg/l for NO2⁻ .