According to recent research, toxins that were prohibited decades ago are still endangering critically endangered California condors.
Because they devour deceased marine animals around the California coast, condors may be more vulnerable to reproductive problems.
High DDT and PCB contamination risk to California coastal condors
JENS SCHLUETER/AFP via Getty Images
Scientists from the San Diego State University (SDSU) and the San Diego Zoo Wildlife Alliance (SDZWA) discovered that marine mammals stranded on the California coast have relatively high levels of halogenated organic contaminants, in collaboration with the Centro de Investigación Cientifica y de Educación Superior de Ensenada and the National Oceanographic and Atmospheric Administration (HOCs).
More than 400 pollutants were found in samples obtained from stranded marine creatures that California condors may feed on.
The marine animals on the California coast were found to have seven times more DDT and 3.5 times more PCBs than their equivalents in Baja California, Mexico.
Other unstudied chemicals were also discovered.
One set of these chemicals was found to be 148 times more common in California marine animals than in other states.
This research, which was published on May 17 in the journal Environmental Science & Technology, also found that coastal condors have more pollutants in their blood than inland condors, which do not eat marine mammals.
According to corresponding author Nathan Dodder, Ph.D., analytical chemist and research scientist in the School of Public Health at SDSU and the SDSU Research Foundation, such kind of broad survey of pollutants showed that the condors and sea animals have a plethora of pollutants that have never really been examined before, especially in detail.
The non-targeted contaminant assessment the researchers utilized not only found recognized historical pollutants but also identified new contaminants, as well as recognized but much fewer contaminants that are not frequently tested.
Last May 4, the endangered California condor returned to the sky over the state's far northern coast redwood forests for the first time in almost a century.
Two captive-bred birds were released from a prison in Redwood National Park, roughly an hour's drive south of the Oregon border, as part of a mission to return gigantic vultures to their traditional Pacific Northwest habitat, as per CBS News.
In the late morning, the two male condors were transferred into a staging area, and a remotely controlled fence was opened.
After a few minutes of nervously studying the entrance, the birds stepped through it one by one, stretched their massive wings, and flew away.
Condors were last seen in the park region about 1892, according to officials. With a wingspan of about 10 feet, the California condor is the biggest native North American bird.
The scavenger was previously common but had nearly vanished by the 1970s because of hunting, lead poisoning from eating animals shot by hunters, and habitat degradation.
Because the birds may live for 60 years and travel long miles in pursuit of carrion, their range could include multiple states.
The Yurok tribe, which has historically considered the California condor to be a holy animal and has been working for a long time to restore the species to the tribe's original region, is leading the restoration initiative.
California condors were practically extinct a few decades ago, but because of massive breeding and reintroduction efforts, their number has been slowly rebounding.
Lead poisoning, caused by swallowing shards from land animals shot with lead bullets, is still the leading cause of mortality for inland California condors.
Because of the availability of marine animal corpses for condors to eat, coastal environments are believed to provide a lower risk of lead exposure, making coastal places attractive for condor reintroduction.
However, previous chemicals discovered in the remains of marine mammals may represent a new hazard to the uncommon birds.
