The study looked at heavy metal pollution in the Pearl River Estuary. They used a method to assess the ecological risk of these metals. Results showed that some metals decrease from northwest to southeast, while others have no clear pattern. Mercury was found to be the most enriched metal. Most metals pose a low ecological risk, except for mercury which has a moderate risk. The order of pollution levels in the estuary is mercury, cadmium, lead, copper, arsenic, chromium, and zinc.