Dolphins in the English Channel carry a toxic cocktail of chemicals, including substances that have been banned since the 1970s, according to a new study.
Belgian and French researchers tested for mercury in the blubber and skin of 82 dolphins living off the coast of France and found levels of the chemical were among the highest concentrations observed in the species.
Some of the toxins found in the marine mammals, particularly those containing chlorine from industrial fluids and pesticides, have been banned from most developed countries since the 1970s and 1980s.
The levels of mercury in the skin samples studied by researchers were similar to concentrations detected in bottlenose dolphins in the Mediterranean Sea and Florida Everglades, two sites already known for their high mercury contamination levels, the study published in the journal Scientific Reports said.
The toxins are passed through the food chain, including by lactating mothers to their calves.
Report author Krishna Das said newborn survival rates of bottlenose dolphins in the Normanno-Breton Gulf may be affected by the chemicals and suggested it should become a special area of conservation to protect one of the largest coastal populations of bottlenose dolphins in Europe.