highly significantP < 0.0001
The effect of Cu on C and N uptake is highly significant with time (P < 0.0001 df = 3) and concentration (P < 0.0001 df = 2) Concentration effects of Pb were non-significant for pC (P = 0.6012 df = 3) or pN (P = 0.3579 df = 3).