Plastic pollution has become a global problem with the proliferation many plastic goods. This study thus hypothesized that accumulated plastic waste will have adverse effect on mangrove growth. The study was carried out at a sand-filled and deforested mangrove forest at Eagle Island. Ten soils samples each (n =20) were collected underneath accumulated plastic waste vertically and horizontally. The soils were put in polythene bags and sent to the laboratory for analysis of total hydrocarbon content (THC), and heavy metals i.e., Zinc (Zn), Lead (Pb) and Cadmium (Cd) using the HACH DR 890 colorimeter (wavelength 420 nm) and microwave accelerated reaction system (MARS Xpress, North Carolina) respectively. In addition, mangrove (Rhizophora species) seedlings were also collected with soils from the plastic waste and non-plastic waste sites (control). The result shows that there is no significant difference in heavy metal concentration along the profile i.e., surface, and sub-surface soils (F1, 30 = 1.83, P = 0.186), and soil gradients (F3, 28 = 0.60, P = 0.619) of the soil. In contrast, there is significant difference in seedling growth between the control and plastic soils (F4, 200 , 65.24, P<0.001). Furthermore, microbial population showed significant difference horizontally (F3, 11 = 3.86, P = 0.04) but not vertically (F1, 11 = 4.60, P = 0.055) in plastic soil. This result implies that plastic pollutants can migrate horizontally to contaminate nearby mangroves. Thus, plastic waste should be managed to prevent pollutants from entering the food chain to contaminate humans.