Common Plant Chemical Pyrogallol Linked to Organ Damage in Aquatic Animals, Review Finds

A review published in the journal New Contaminants examined existing research on pyrogallol, a compound produced naturally when plant tannins break down and also used in dyes, photography, personal care products, pharmaceuticals, metal processing and oxygen removal. These uses give it multiple routes into freshwater systems, including wastewater, industrial activity and the decomposition of organic material.

Laboratory studies reviewed by the authors found pyrogallol exposure in fish was associated with changes in blood chemistry, immune responses, antioxidant defenses, reproductive hormones, neural activity and tissue structure, along with damage involving the liver, kidney, intestine, spleen, brain, heart and reproductive tissues. Studies in freshwater invertebrates similarly found effects on immune, neurological, reproductive and tissue-level processes.

The review points to oxidative stress as a major mechanism: pyrogallol can oxidize to generate reactive oxygen species, chemically reactive molecules that, in excess, can overwhelm the body's antioxidant defenses and damage lipids, proteins, mitochondria and DNA. "Pyrogallol is a good example of why naturally occurring chemicals should not automatically be assumed to be environmentally harmless," said corresponding author Mohamed Hamed.

Previous studies cited in the review have detected pyrogallol in tap water, rivers, domestic wastewater, industrial areas and sewage, but the authors note that direct measurements from aquatic environments remain limited, leaving actual exposure levels for wildlife largely unmeasured.