• soil
  • The low mobility and high persistence means that they can stay in the soil for decades, and even at sites with contaminations dating at least 50 years back, 4- or 5-ringed PAHs are found near the soil surface. (eugris.info)
  • found
  • PAHs are abundant in the universe, and have recently been found to have formed possibly as early as the first couple of billion years after the Big Bang, in association with formation of new stars and exoplanets. (wikipedia.org)
  • PAHs have been found in at least 600 of the sites on the NPL. (cdc.gov)
  • As EPA evaluates more sites, the number of sites at which PAHs are found may increase. (cdc.gov)
  • rings
  • PAHs with five or six-membered rings are most common. (wikipedia.org)
  • citation needed] In contrast, in anthracene the resonance structures have one sextet, which can be at any of the three rings, and the aromaticity spreads out more evenly across the whole molecule. (wikipedia.org)