Effect of Biochar, Activated Carbon and Spent Coffee Amendment on Arsenic and Chromium Uptake By Lettuce on CCA Contaminated Soils.

Leaching of arsenic (As) and chromium (Cr) from chromated copper arsenate (CCA)-treated wood may elevate soil arsenic and chromium leveles. Thus, an environmental concern arises regarding accumulation of As and Cr in vegetables grown in these soils. In this study, a greenhouse experiment was conducted to evaluate As and Cr accumulation by lettuce (Lactuca sativa L.) from the soil adjacent to the CCA-treated utility poles (64 mg kg^-1 As, 59 mg kg^-1 Cr and 91 mg kg^-1 Cu) and evaluates the effects of soil amendments on plant As and Cr accumulation. Lettuce (Lactuca sativaL.) was grown for eight weeks in the soil with and without biochar, activated carbon and spent coffee amendments. Spent coffee amendment significantly enhanced plant biomass compared to the control. The As and Cr concentration in plants roots were significantly greater than the concentration in the leaves. Addition of amendments, in general, decreased metal accumulation in the plant. Our results indicate that growing lettuce in soils near CCA-treated wood may still pose a risk of As and Cr exposure for humans. Biochar, activated carbon and spent coffee amendment can limit such a risks by reducing As and Cr accumulation by lettuce which can be an important strategy for remediating CCA-contaminated soils.