The key environmental problem we face as a result of landfills is groundwater pollution from leachates (the liquid that drains or 'leaches' from a landfill). Although they intended to protect human beings from toxins, due to natural deterioration the protective barriers only delay the inevitable.andfills create a clear and obvious threat to human health as well as a threat to our environment from the hazardous contaminated air emissions emitted from the landfill biodegradation.