Westudyamodelforthelong-termbehaviorofasingle-speciespopulationwithsomedegreeofpollutiontoleranceinapollutedenvironment.Themodelconsistsofthreeordinarydifferentialequations:oneforthepopulationdensity,onefortheamountoftoxicantinsidethelivingorganisms,andonefortheamountoftoxicantintheenvironment.Wederivesufficientconditionsforthepersistenceandtheextinctionofthepopulationdependingontheexogenousinputrateofthetoxicantintotheenvironmentandthelevelofpollutiontoleranceoftheorganisms.Numericalsimulationsarecarriedouttoillustrateourmainresults.
