Abstract:
Objective The aims were to explore the impact of the traditional waste plastics recycling industry on the soil environment.
Method The contents of five heavy metals in the waste plastics recycling base and surrounding farmland in Shahe Town, Laizhou City was detected and analyzed. The assessment method of Nemerow composite pollution index, potential ecological risk index and health risk assessment were used to analyze the potential risk of heavy metals in the farmland soil.
Result The average contents of Cd, Cr, Cu, Pb and Zn in farmland soil were 0.26 mg kg−1, 97.63 mg kg−1, 48.90 mg kg−1, 52.41 mg kg−1 and 107.24 mg kg−1 , respectively, which exceeded the soil element's background value in Yantai. According to the Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land (Trial), the over standard rates on Cd, Cu and Pb were 10%, 40% and 5%, respectively. In terms of spatial distribution, there was no significant difference between the contents of Cd, Cr, Cu and Zn in the soil of the base and the surrounding farmland. But the content of Pb in the soil of the farmland inside the site was significantly higher than that in the soil 4 km away from the site (P < 0.05). The Nemerow composite pollution index evaluation showed that 15% of sampling points at the site were at the light pollution level. The potential ecological risk assessment showed that the ecological risk of single-factor pollution of the Cd was medium ecological risk, and the comprehensive potential ecological risk was at the level of slight risk. The health risk assessment showed that only Cd had potential carcinogenic risk to children, and the other heavy metals had an acceptable level of carcinogenic and non-carcinogenic risk in both adults and children.
Conclusion The pollution of Cd, Cr, Cu, Pb and Zn in the farmland soil of the base was relatively light. The accumulation of Pb in farmland soil may be related to the production and operation activities of the original waste plastic recycling enterprise of the base. The potential ecological risks caused by heavy metals in the soil of the base farmland were generally low. However, it needs to be concerned that Cd has certain ecological risks and a potential cancer risk for children.