The effects of some forms of chemical poisoning acquired from the environment, such as endocrine disruptors, can be passed down up to three generations. At least in fish.
Small fish that are exposed to even low levels of synthetic endocrine disrupting chemicals that have become common in many freshwater sources may end up transmitting the genetic impacts of these chemicals to their offspring who were never directly exposed to the same chemicals. say researchers from Oregon State University in the United States.
This phenomenon can affect three generations of fish, which is equivalent to having grandparents who come into contact with pollutants in their environment and transmit the effects to their grandchildren, scientists explain in a study published in the journalFrontiers in Marine Science .
Endocrine disruptors mimic hormones in the body and can cause adverse biological effects in aquatic and other animals by triggering changes in their development, behavior, and fertility rates.
These chemicals are used in a wide variety of household and industrial products, including flame retardants, foods, toys, cosmetics, and pesticides. They often seep into water sources where they later accumulate. Even small amounts can have a marked impact.
It has previously been shown that when fish are exposed to these chemicals in their environment, their populations can end up suffering from altered sex ratios, lower fertility rates, and various deformities.
In their own research, Oregon scientists examined how chemicals affected generations of inland silversides (Menidia beryllina ), a small fish native to estuaries in eastern North America and the Gulf of Mexico, where they feed primarily on zooplankton. These small fish are an important source of food for birds and predatory fish.
In one experiment, scientists exposed indoor silversides to the equivalent of a few drops of endocrine disruptors in an Olympic-size swimming pool, which is a relatively low concentration. They then began studying three generations of fish over 21 months to see if the effects of the chemical were passed from generation to generation.
To their surprise, they found marked changes in three generations, despite the fact that only the first generation was exposed to endocrine disruptors for a few weeks in early life. The growth and development of subsequent generations were also affected. Needless to say, it is a puzzling find.
"It is really important to understand how animals can deal with stress in the environment, particularly when we are introducing new stressors on a daily basis," emphasizes Susanne Brander, assistant professor and aquatic toxicologist in the university's Department of Fish and Wildlife.
“Our research helps show what animals do to respond to these changes and how quickly they can respond to them. That will help us understand our long-term impact on the environment, "he adds.