<Li> Bioremediation, involving microbial digestion of certain organic chemicals . Techniques used in bioremediation include landfarming, biostimulation and bioaugmentating soil biota with commercially available microflora . </Li> <Li> Extraction of groundwater or soil vapor with an active electromechanical system, with subsequent stripping of the contaminants from the extract . </Li> <Li> Containment of the soil contaminants (such as by capping or paving over in place). </Li> <Li> Phytoremediation, or using plants (such as willow) to extract heavy metals . </Li>

Write 3 causes and 3 effects of soil pollution