Table 6. Alteration in the abundance of Proteobacteria, Actinobacteria, and Bacteroidetes in PAH polluted soil as reported in earlier studies.

Sample type and location	Proteobacteria	Bacteroidetes	Actinobacteria	Remarks, subphyla or other altered phyla
Wood impregnation site, Finland [38]	+	NS	-	-TM7, Planctomycetes
Soil artificially contaminated with pyrene during composting, China [39]	+	NS	+
contaminated soil from former manufactured-gas plant site, USA [12]	+	-(Not significant)	NS	+ Sphingomonas
Soil from constructed wetland from road run-off spiked with PAH, France [40]	+	NS	NS	+ Betaproteobacteria
Soil from timber preservation facility spiked with PAHs, Ireland [41]	+	-	+ or -	Actinobacteria decreased in phenanthrene contaminated and increased in fluoranthene contaminated soils + Gammaproteobacteria
Industrial creosote contaminated soil, Portugal [42]	+	-	-	+ Beta and Gammaproteobacteria, decrease in Bacteroidetes and Actinobacteria attributed to added non-ionic surfactant
Effect of sunflower rhizosphere in creosote polluted clay and agricultural soil, Spain [43]	+	-	NC
Windrow treatment of soil contaminated by 2,3,4-ring PAHs, France [1]	+	NS	-	+ Gamma, Betaproteobacteria appeared at the end of treatment

NS represents not studied, + implies increased abundance,–denotes decreased abundance, and NC denotes no change.