To understand the world’s changing climate, scientists often look to tree cores and ice samples. For a record of ocean pollutants, researchers are beginning to turn to whale ear wax. Since whales are unable to clean their ear canals, the wax builds up and creates numerous layers much like an old tree. Researchers from the Santa Barbara Museum of Natural History were able to extract a column nearly a foot long from a dead blue whale that washed up on a beach back in 2007. A recent study from Baylor University published in the Proceedings of the National Academy of Sciences looked at the giant deposit to determine the amount of toxins in the animal’s environment.
Each layer of wax in the column corresponds with a six month period in the whale’s life. According to Sascha Usenko, an environmental scientist involved in the Baylor study, blue whales are being exposed to a number of contaminants including flame retardants and pesticides. Usenko was shocked by the amount of DDT he found in the whale’s wax.
“It’s been 30-plus years since we’ve stopped using this compound, but to still see it showing up at such high concentrations — one of the dominant chemicals we see — was surprising.” he told NPR.
The Baylor team determined that whales are most vulnerable to pollutants when they are young and still nursing. While Usenko cannot tell solely from the wax whether the development of blue whales are being affected by chemicals, analyzing stress hormones in the fatty deposits may help shed light on their overall health. To gather more data, he is encouraging scientists to harvest and send him wax from dead whales.