However, there is evidence that three of the polymers (HDPE, LDPE, and PP) consistently soaked up POPs at concentrations an order of magnitude higher than did the remaining two (PVC and PET). After 12 months of exposure, for example, there was a 34-fold difference in average total POPs amassed on LDPE compared to PET at one location. At another site, average total POPs adhered to HDPE was nearly 30 times that of PVC. The researchers think that differences in the size and shape of the polymer molecules can explain why some accumulate more pollutants than others.The fungus Aspergillus fumigatus effectively degrades plasticized PVC. Phanerochaete chrysosporium was grown on PVC in a mineral salt agar. Phanerochaete chrysosporium, Lentinus tigrinus, Aspergillus niger, and Aspergillus sydowii can effectively degrade PVC.