PBTs have a high environmental mobility relative to other contaminants mainly due to their resistance to degradation (persistence). This allows PBTs to travel far and wide in both the atmosphere and in aqueous environments.nother factor that makes PBTs especially dangerous are the degradation products which are often relatively as toxic as the parent compound. These factors have resulted in global contamination most notable in remote areas such as the arctic and high elevation areas which are far from any source of PBTs.
They have been claimed as the oldest free-standing structures on Earth, although the largely buried GÃ¶bekli Tepe complex is far older. Archaeologists believe that these megalithic complexes are the result of local innovations in a process of cultural evolution.
The Oldest Tree in the World: Old Tjikko (9,550 Years Old) The oldest individual clonal tree in the world is believed to be 9,550 years old (carbon-dated)! This Norway Spruce is located on the FulufjÃ¤llet Mountain of Dalarna province in Sweden and was discovered by a professor of Physical Geography, Leif Kullman. The tree has been nicknamed Old Tjikko after his dog.