The effect of used engine oil on carbohydrate, mineral content and nitrate reductase activity of leafy vegetable (Amaranthus hybridus L.)

The effects of used engine oil on carbohydrate, mineral elements and nitrate reductase activity of Amaranthus hybridus were investigated. Seedlings were grown for 8 weeks in soil containing 0-5 % v/w used engine oil. There was a significant (p=0.05) low level of mineral elements in plants grown in oil treated soils. The carbohydrate content of the control plants was significantly higher than the values observed for plants grown in oil treated soils. The control plants had a mean value of 48.3 ± 0.5 μg g^-1 dry wt, while 42.0 ± 1.0 and 30.9 ± 0.4 μg g^-1 dry wt were observed for plants treated with 1 and 5 % oil. There was significant inhibitory effect on nitrate reductase activity in plants that were exposed to engine oil. Therefore, the potential risk of used engine oil as potent environmental pollutant has been established from the results of this study.