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The combined pollution is a common phenomenon in today 's soil pollution , combined pollution of the soil of persistent organic pollutants ( such as polycyclic aromatic hydrocarbons , PAHs ) and heavy metals ( HM ) have been reported . In this thesis, by pot experiment to study the effect of alfalfa, red clover Cu composites contaminated soil phytoremediation of phenanthrene , pyrene and heavy metals . The same time, the use of orthogonal experiment in laboratory culture conditions , available nutrients in the soil C / N ratio and C / P ratio and soil moisture content and incubation time factor strengthening of phenanthrene and pyrene contaminated soil microbial repair . The main results are as follows : the soil planted red clover (1) , phenanthrene and pyrene removal rates were 87.8% to 95.4% and from 65% to 82.5% ; alfalfa soil , phenanthrene and pyrene removal rates were 90.4% ~ 98% and 74 % to 91.8% . Soil phenanthrene and pyrene , the higher the concentration , the higher the content of the plants , phenanthrene and pyrene . Red clover and alfalfa underground part of phenanthrene and pyrene bioconcentration factor is greater than its aerial parts . Phoebe pyrene easier to transfer in plants , the transmission coefficient of phenanthrene and pyrene in the red clover average of 0.8 and 0.36 , the transmission coefficient alfalfa average values ??were 1.2 and 0.73 . Cu inhibits the absorption of alfalfa soil phenanthrene and pyrene , and red clover has no effect . Red clover and alfalfa underground part of the Cu content is higher than its aerial parts . ( 2) When the available nutrients in the soil C / N ratio to 20:1 , C / P ratio of 100:1 , and soil moisture was 25% of field capacity , training time for 60 days , soil phenanthrene the highest removal rate was 99.5 % ; when available nutrients in the soil C : N to 10:1 C : P ratio is 100:0.5 , and the soil moisture content of 60 % of the field capacity , incubation time at 60d pyrene in soil highest removal efficiency of 94.6% . According to the poor size of the value of each factor orthogonal test can determine the main factors affecting biodegradation of PAHs in soil is the soil moisture content , followed by incubation time .
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