Contents and Enrichment Coefficients of Heavy Metals in Sediment and Lotus Grown in Ponds at Downtown Wuyishan City

Samples of sediment as well as seeds and leaves of the lotus grown in the pond at Wufu, downtown of Wuyishan city, were collected for this study. Contents of 7 heavy metals, including Cu, Zn, Pb, Cr, Cd, As and Hg, were determined. The ecological risk by the metals was evaluated based on the single pollution index, the comprehensive pollution index, and the enrichment coefficient of the lotus parts. The results showed that the Cd and Hg contents in the sediment exceeded the national standard limits set forth by the Environmental Conditions for Non-Pollution Agricultural Products Production Area. The heavy metals in the lotus seeds and leaves were within the Maximum Allowable Levels of Pollutants in Food, Green Food-Tea, and the Maximum Allowable Levels of Cr, Cd, Hg, As, and F in Tea.Significant differences existed in the enrichment coefficients on the two metals, especially Hg, in the lotus leaves. The average comprehensive pollution indices of the sediment, lotus seeds and leaves from ponds of different types exhibited a similar trend, that is, in an increasing order of:natural growing pond < managed pond < tourism-oriented pond. Thus, reinforced pollutant monitoring and control on pond sediment to mitigate the potential harms to the environment and consumer health by Cd and Hg at the locations was strongly recommended.