Transplant Quality and Metal Concentrations in Vegetable Transplants Grown in Media Containing Sewage Sludge Compost1

Tomato ( Lycopericon esculentum Mill.) and cabbage ( Brassica oleracea L. Capitata group) transplants were grown in peat-vermiculite (P-V) or in media containing sewage sludge compost from either a residential, low metal (LM) or industrially contaminated, high metal (HM) source. The transplant quality (stem diameter, fresh, and dry weight) of plants grown in P-V and LM were similar. Transplants grown in HM media were small, less-developed, and exhibited symptoms of heavy metal phytotoxicity. The concentrations of Zn, Fe, Mn, Cu, Pb, Cd, and Ni in tomato and of Zn, Cu, Cd, and Ni in cabbage plants grown in HM media were significantly higher than those in transplants grown in LM media. The addition of peatmoss to LM media had little influence on media pH or the heavy metal concentrations in transplants. However, peatmoss lowered the pH of HM media and thus the concentrations of Zn, Mn, Cu, and Ni in tomato and Zn and Mn in cabbage transplants increased. Concentrations of Zn and Cu in tomatoes and Zn in cabbage were above phytotoxic levels.