For the remediation of the contaminated soil with heavy metals, Cd, Cr, Cu, and Pb, the reaction parameters were optimized. Tartaric acid (TA) and oxalic acid(OA) as a washing agent were evaluated as a function of concentration, reaction time, mixing ratio of washing agent and recovery of metals. The optimum washing conditions of TA and OA were in the ratio of 1 : 20 between soil and acid solution during 2 hr reaction under unbuffered pH solutions. At the optimized reaction conditions, the removal efficiencies were compared with that of 0.1 M HC1 and ethylenediamine tetraacetic acid(EDTA). TA showed higher efficiency on the removal of Pb than that of EDTA, which established for the remediation of contaminated soil with Pb and Cd metals. The recovery of metal ions from washing solution was achieved by adding calcium hydroxide and sodium sulfide by forming the precipitation of metal hydroxide and metal sulfide. Optimum amounts of sodium sulfide and calcium hydroxide were Cd = 25g/ℓ, Cu = 5∼10g/ℓ and Pb = 5∼10g/ℓ for the washing solution of OA and 2∼5g/ℓ for the washing solution of TA, respectively. The amounts of Na2S and Ca(OH)2 for the tartaric acid was less than that of oxalic acid.

The toxicity values of various heavy metals were evaluated by acute immobilization and chronic reproduction impairment tests, using Daphnia magna. Acute tests were evaluated by the inhibition of their mobilization after 24hrs without food addition. The tests of reproductive impairment were investigated for 21 days by food addition and exchange of water. The effect of each concentration was assessed by Probit analysis and t-test. The results obtained from this study were as follows : 1) The change of pH and DO was not significant in the acute tests, while, in the reproductive tests, pH was increased by 0.3∼1.4 and DO also increased. 2) The EiG50 values of immobilization to Daphnia magna in artificial fresh water were 0.030㎎/ℓ(Cu), 0.054㎎/ℓ(Cd), 0.12㎎/ℓ(Cr), 0.74㎎/ℓ(Pb), 3.4㎎/ℓ(As) and the NOEiC values were 0.010㎎/ℓ(Cu), 0.018㎎/ℓ(Cd), 0.010㎎/ℓ(Cr), 0.10㎎/ℓ(Pb), and 1.8㎎/ℓ(As). 3) The EiC50 values of reproductive impairment to Daphnia magna were 13.8㎍/ℓ(Cu), 2.9㎍/ℓ(Cd), 15.5㎍/ℓ(Cr), 61.7㎍/ℓ(Pb), 759㎍/ℓ(As), and NOErC values were 0.95㎍/ℓ(Cu), 0.54㎍/ℓ(Cd), 1.2㎍/ℓ(Cd), 7.4㎍/ℓ(Pb), 110㎍/ℓ(As). The results of tests using OECD artificial culture water were more sensitive than natural water for culturing. The presented data show that an artificial culture water is suitable in the experiment of bioassay for assessing the toxicity of materials.