Distribution and Effects of Chemicals in Communities and Ecosystems - Organic Pollutants: An Ecotoxicological Perspective - page 77

BOX 4.1 peRSIStent ORGanIC pOllutantS (pOpS)
A list of hazardous environmental chemicals, sometimes referred to as
the “dirty dozen,” has been drawn up by the United Nations Environment
Programme (UNEP). These are:

PoP year of Introduction classification

Aldrin 1949 Insecticide

Chlordane 1945 Insecticide

DDT 1942 Insecticide

Dieldrin 1948 Insecticide

Endrin 1951 Insecticide and rodenticide

Heptachlor 1948 Insecticide

Hexachlorobenzene 1945 Fungicide

Mirex 1959 Insecticide

Toxaphene 1948 Insecticide and acaricide

PCBs 1929 Various industrial uses

Dioxins 1920s By-products of combustion, for example,

of plastics, PCBs

Furans 1920s By-products of PCB manufacture

The selection of these compounds was made on the grounds of their tox-
icity, environmental stability, and tendency to undergo biomagnification; the
intention was to move toward their removal from the natural environment. In
the REACH proposals of the European Commission (EC; published in 2003),
a similar list of 12 POPs was drawn up, the only differences being the inclusion
of hexachlorobiphenyl and chlordecone, and the exclusion of the by-products,
dioxins, and furans. The objective of the EC directive is to ban the manufac-
ture or marketing of these substances. It is interesting that no fewer than eight
of these compounds, which are featured on both lists, are insecticides.

taBLe 4.1
Principal mechanisms of uptake and Loss for Lipophilic compounds

mechanisms of uptake mechanisms of Loss

Habitat/type of
organism

from
Ingested water

diffusion from food diffusion metabolism

aquatic
Mollusks ++++ + ++++

Fish ++++ + → +++ ++++ + → +++

terrestrial
Vertebrates ++++ < ++ ++++