They are resistant organic chemical compounds by themselves having a long latency period and a lasting impacts or consequences

Organic chemical compound:
is a compound molecule that contains mostly molecules that re found in the earth, such as glucose,(C6 H12O6)because of the fact that Hydrogen, Carbon, and Oxygen exist within the earth's atmosphere. Also, an Inorganic Chemical Compound is a chemical compound that requires materials to be made before it is a compound. http://en.wikipedia.org/wiki/Organic_chemical_compound

Nnaturally-occurring (animal or plant-produced or synthetic) substances containing mainly carbon, hydrogen, nitrogen, and oxygen.
http://www.dscrt.com/glossary.asp

Resistant:
incapable to be absorbed or decomposed or biodegradable by itself;