Figure 4: Population decay rates (for 14 years) among the heterotrophic (black symbols; YEPG plate counts) and tetracycline resistant (white symbols; YEPSS plate counts) microbiota within the PAH contaminated (circles) and non-PAH contaminated (inverted triangles) lysimeters, represented in (A) as days in log scale and in (B) as years in linear scale. The dotted line indicates the approximate culturable detection limit of 10 cfu/g soil.