Eco-toxicological effects of typical petroleum pollutant naphthalene on corn in loess soil

The eco-toxicological effects of typical petroleum pollutant naphthalene on corn, a major crop on loess soil in northern Shaanxi province, were studied by a soilless cultivation experiment and a pot-planting experiment. The toxic effects on the physiological and growing characteristics of corn by different concentration of naphthalene were explored to confirm that the environmental quality of the agricultural production in this region may be adversely affected by the eco-toxicological effects of the typical petroleum pollutants. The results of the soilless cultivation experiment show that the ID₅₀ (inhibitory concentration 50%) of naphthalene in sand on the corn germinating rate and the root elongation was 0.488 g/kg and 0.487 g/kg, respectively. The results of the pot-planting experiment indicate that the ID₅₀ of naphthalene in loess soil on the germinating rate, the root elongation, the fresh weight, the plant height, chlorophyll a and chlorophyll b was 4.21 g/kg, 1.53 g/kg, 3.99 g/kg, 1.82 g/kg, 3.33 g/kg and 3.29 g/kg, respectively. In addition, the growth of corn was promoted when the concentration of naphthalene was lower than 0.25 g/kg but was inhibited when the concentration was higher than 0.25 g/kg, and the inhibitory effect increased with the increase in the concentration of naphthalene.