Effects of sand extraction from the Karasu river (Van) on water quality and tarek (Alburnus tarichi, Guldenstaedt 1814) population

In this study, the effects of the sand extraction from the Karasu Stream and the sandy quarries on water quality and tarek populations were investigated. Water temperature, pH, dissolved oxygen, oxygen saturation, electrical conductivity, salinity, turbidity and flow measurements were determined at five locations in the study. Water samples taken from these points were brought to the laboratory and various chemical and microbial analyzes were carried out. In addition to water quality analyzes, TSS - turbidity experiments were tested in the laboratory and it was determined how much the eggs and larvae were affected by the experiments to determine the impact of sandy quarries and sand extraction activities on tarek. Sampling stations have been started from the highest station where there is no sandy quarries, and continue to cover the stations where the sandy quarries are located and the stations after sandy quarries. Monthly samples were carried out for two years between June 2016 and May 2014 at these stations.The average annual water quality was determined that temperature as 12.6±0.7 (2.0 - 25.5) ºC, pH 8.36±0.02 (7.72 - 8.87), dissolved oxygen 9.7±0.19 mg/L (6.53 - 16.50), oxygen saturation % 102.7±1.6 (67.2 - 156.2), electrical conductivity 518.0±7.2 (338 – 670) μS/cm, salinity ‰ 0.31±0.03 (0.22 - 0.36), turbidity 180.0±18.28 (2.6 - 689.3) NTU and flow rate 2.02±0.10 (0.96 - 5.48) m3/sn. In other water analyzes, the average chlorine was 23.3±0.4 mg/L, calcium 110.9±3.2 mg/L, magnesium 77.8±0.8 mg/L, carbonate 0.0±0.0 mg/L, bicarbonate 457.9±62.1 mg/L, total hardness 583.8±5.4 mg/L, total alkalinity 478.8±4.2 mg/L, nitrite 23.9±1.0 µg/L, nitrite nitrogen 9.3±0.6 mg/L, nitrate 3.4±0.1 mg/L, nitrate nitrogen 9.3±0.6, ammonium 0.49±0.05 mg/L, ammonia 0.52±0.05 mg/L, ammoniac nitrogen 0.44±0.05 mg/L, sulfate 21.3±0.5 mg/L, orthophosphate 0.23±0.01 mg/L, phosphorus 0.11±0.01 mg/L, aluminum 7.2±1.0 μg/L, total iron 0.12±0.01 mg/L, the chromium 21.2±0.9 μg/L, the zinc 15.6±1.0 μg/L, the copper 0.2±0.0 μg/L, the fluoride 0.11±0.01 mg/L, the manganese 1.3±0.1 mg/L 1.9±0.1 mg/L, cyanide 8.51±0.71 μg/L, cobalt 27.8±1.3 μg/L, nickel, 18.1±1.0 μg/L, silicon 12.9±0.68 mg/L, silicon dioxide 27.3±1.46 mg/L, TSS 212.5±18.7 mg/L, BOD 7.1±0.34 mg/L, COD 10.4±0.51 mg/L and fecal coliform 538.3±69.7 colonies/100 ml.Five different experiment groups (0, 10, 50, 100 and 600 mg/L TSS; control, G1, G2, G3 and G4 respectively) were planned in the TSS - turbidity experiments. In the study of three different eggs, live larvae, dead larvae, unopened eggs counts and percentages were determined. Numbers of live larvae were also found high in experiment groups with the highest number of eggs and percentages. The number of larvae from the egg was low in experiment groups with high levels of TSS. As the amount of TSS increased in the egg experiments, the sediment thickness accumulated on the eggs also increased. In the larvae experiments, there were equal number of larvae at the beginning of the experiment and second (G2, 50 mg/L TSS), third (G3, 100 mg/L TSS) and fourth groups (G4, 600 mg/L TSS) in which the highest number of dead larvae was highest in groups at the end of the experiment. In the larval experiment, the best survival rate was found in the control (0 mg/L TSS) and first groups (G1, 10 mg/L TSS) with a low amount of TSS. The final live weight, specific growth rate and proportional growth values were obtained with the highest control (0 mg/L TSS) and the first group (G1, 10 mg/L TSS) and these values were lower in the second group (G2, 50 mg/L TSS), third (G3, 100 mg/L TSS) and in the fourth group (G4, 600 mg/L TSS).As a result of the water quality analyzes and AKM - turbidity experiments, Karasu River is adversely affected by environmental pollution, sand extraction - sand quarries activities and pollution from F type prison and the quality of the water of reiver and the tarek were found to be damaged.