According to a new study, canine sperm quality could be rapidly declining because of environmental contaminants, The New York Times reports. The study, published today in Scientific Reports, spanned 26 years and five different dog breeds. Researchers found that the dogs’ sperm motility—how well a sperm can swim—dropped by 30%, and their testicular tissue and sperm contained chemicals common in electrical transformers, paint, and plastics. The chemicals were also found in an unspecified dog food sold all over the world, the source of which could be from packaging or water that was in contact with the ingredients. Although it’s unclear whether food is the sole contributor of chemicals, the researchers say it is likely a major one.