March 26, 2016
The biotech industry once told the world that Bt insecticidal crops were only harmful to insects and were harmless to pets and people. But a new study of the ecotoxicological risks of widespread commercial Bt spraying found otherwise. Introban®, a Bt-containing product, caused 100% lethality in amphibians.
Dr. Eva Sirinathsinghii tested the effects of Introban®, a commercial formulation of a Bacillus thuringiensis (Bt) subtype, Bacillus thuringiensis subsp. israelensis (Bti). She discovered that Introban® is toxic to tadpoles of an Argentinian species of frog at environmentally relevant concentrations. The Bti subtype is meant for mosquitoes, in order to prevent the spread of infectious disease.
After being exposed for only 48 hours to sub-lethal concentrations of Introban®, tadpoles of a common South American frog developed serious health problems that led to their death.
Genotoxic effects occurred in days, not weeks or months. Intestinal enzymes that would normally protect the tadpoles from oxidative stress were affected, and the results were 100% lethal. The tadpoles’ immune systems were rendered useless.
Although data have been presented suggesting that Bti products are safe for use, Dr. Lajmanovic at the National Council for Scientific and Technical Research Argentina and her colleagues found that the Bti products used widely in urban and suburban areas have dire effects for the aquatic ecosystem and environment.