In contrast, the mixture of
biochar and iron reduced both Cu and As leaching,
increased phenanthrene degradation, and enabled sunflower
growth, suggesting this as a useful approach
for treating co-contaminated mining sites (Sneath et
al., 2013). Biochar was more effective than greenwaste
compost at reducing bioavailable fractions of phytotoxic
Cd and Zn as well as the heavier, more toxicologically
relevant PAHs (Beesley et al., 2010). Biochar
could promote bioremediation of PAHs contaminated
soil as microbial carriers of immobilized-microorganism
technique. However, it is vital to select an appropriate
biochar as an immobilized carrier to stimulate
biodegradation (Chen et al., 2012). The removal efficiencies
of two- to four-ring PAHs were higher than
those of five- and six-ring PAHs in contaminated soil
amended with biochar (Liu et al., 2015). Biochar addition
to soil could stimulate PAH-metabolizing bacterial
activity by enhancing the number of gene copies related
to PAH degradation and changing the structure of
soil microbial community.