Â
An analysis of several dolphins found dead on Brazilian beaches reveals that the animals had traces of insecticidespyrethroids, frequently used in homes and agricultural crops. The highest concentrations have been found in the offspring, less prepared to metabolize these compounds. The study is published in the journalEnvironmental International.
Scientists from the Institute for Environmental Diagnosis and Water Studies, belonging to the CSIC, found concentrations of pyrethroids in adult dolphins of 7.04 nanograms per gram of fat in adults and 68.4 nanograms per gram of fat in pups. The latter would have received the pollutants bymaternal transmissionthrough milk.
“In general, pyrethroids are metabolized and degraded, but now it is clear that they are not completely eliminated, so a part that accumulates in the body”, explains Ethel Eljarrat, one of the authors. “The constant use of pyrethroids in agriculture and in homes, and their dispersion in the environment, means that concentrations in the sea, however minimal, end up reaching fish and dolphins.”
Pyrethroids are chemical compounds that are used as insecticides in devicesanti-mosquito and anti-lice, as well as in agriculture. They generally degrade on contact with light and accumulate in plants. However, until now, tests on mammals indicated that pyrethroids degrade rapidly. The new analysis seems to indicate the opposite: “We believe that dolphins are not prepared to metabolize these compounds when they are young, but that their body begins to degrade and expel them when they become adult specimens,” Eljarrat has indicated.
Â
Â
