Heavy metals in river sediments decreasing, improving water quality.
The study looked at levels of copper, lead, zinc, and cadmium in sediment from the Ou Jiang River estuary. They found that the area was not heavily polluted by these metals, except for a slight contamination of copper. Copper was the main contaminant, and sediment quality improved compared to 2011, except for lead. Sediments were less contaminated further offshore.