The experiment was conducted to evaluate the effect of cow manure compost (CMC) application on
leaching toxicity of leachate polluted soils by using Tetrahymena pyriformis (TP). Soils treated with various
levels of leachate (0, 12.5 ml, 25 ml, 37.5 ml, and 50 ml leachate per 300 g soil) were amended with 0, 25 g
and 50 g CMC, respectively. The results showed CMC application resulted in 7–18% lower leaching toxicity
while excessive CMC has no significant benefit for decreasing leaching toxicity further. The alleviating
effect of CMC on biotoxicity of soil extract was mainly attributed to either pH increase, high content of P
and organic matter, or promotion on soil microbial metabolism and especially pH played an important
role in alleviating effect. And the observations indicated that death rate (DR) of TP was more sensitive to
leachate level respect to other biological parameters above and TP was effective as the test organism for
leaching toxicity. Further studies are needed to unambiguously determine in-deep mechanism of toxicity
impacts on TP posed by leachate pollutants.