The effects of sole, mixture heavy metals and soil samples was assessed based on the seed (Lactuca sativa L.) germination. In general, tested sole metals were showed considerable sensitivity on the germination, showing following EC50s: As(III) 1.02 mg/L, Cr(VI) 1.33 mg/L, Cu 2.26 mg/L, Cd 2.61 mg/L, As(V) 3.00 mg/L. Though obvious patterns were not observed on the effects by binary mixture metal, generally more synergistic mode was observed rather than antagonistic or additive. No significant correlation between toxicity and total metal contents was observed, but two groups classified according to contaminated arsenic concentration, showed considerable differences. Interactive effects of metals may vary depending on the bioassays used as well as on the mixture metals and their respective concentrations. Therefore, more detailed evaluation, such as with battery of assays, sample grouping and various mixtures, may comprise a useful tool for the assessment of the environmental samples with mixture contaminants.