Notice of RetractionPotential Risks of Heavy Metal Pollution in Greenhouse Soils Cultivated for Different Periods

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

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Assessing the concentration of potentially harmful heavy metals in the soil of greenhouses is important in order to evaluate the potential risks to humans. These risks may be higher in soils to which fertilizers have been applied over many years. To investigate this risk, the concentrations of copper (Cu), chromium (Cr), cadmium (Cd), lead (Pb) and zinc (Zn) were measured by a flame atomic absorption spectrophotometer in greenhouse soils collected in Shenyang, Liaoning Province, China, a region well-known for greenhouse cultivation. The environmental quality of greenhouse soil was assessed using the single pollution index method and the Nemerow comprehensive index method based on the environmental standard for greenhouse vegetable production in China (HJ333-2006). The results indicated that the heavy metals accumulated to greater levels in the greenhouse topsoils with increasing cultivation periods. The highest concentration of Cu was observed in greenhouse topsoils planted for 15 years. The distribution of heavy metals in soil profiles (0~20cm, 20~40cm, 40~60cm, 60~80cm, 80~100cm) displayed a wide range of variation. Cr, Pb, and Zn tended to accumulate in the greenhouse topsoil (0~20cm). The maximum value of Cu and Cd were observed at a depth of 80~100cm and 40~60cm in the greenhouse cultivated for 20 years, respectively. As the cultivation periods prolonged, Cu was subject to downward movement to the lower soil horizons and Cd began to accumulate below the topsoil due to the strong migration ability. Using the - he single pollution index and the Nemerow comprehensive index of heavy metals, the soil quality in greenhouse topsoils were generally found to be polluted by Cd. This suggests that care should be taken with fertilizers in greenhouse cultivation. This study shows that heavy metals may accumulate in the greenhouse soils with prolonged cultivation periods.