Sealed parking lot with wear marks from snowplow

Once applied, sealcoat can be abraded by snowplows, as evidence here, or the abrasive action of car tires. Runoff carrying high-PAH sealcoat particles flows into storm drains, where it can be transported to streams and lakes. Runoff from coal-tar-sealcoated pavement contains extremely high concentrations of polycyclic aromatic hydrocarbons (PAHs), and is toxic to aquatic life.  Read more here.