CHAPTER 14 . Chemistry of Organic Toxicants in Marine Environments
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Another important class of POPs are polychlorinated benzenes (X) and biphenyls
(PCBs, XI) (Fig. 14.5), which are widely used as the liquid dielectrics, lubricants, high
temperature heat transferrals and hydraulic liquids. Some of the PCBs are toxic (for
example, for 2,3',4,4',5-Cls biphenyl, the toxicity equivalent according to the WHO's
international system is 0.0001), but most of them are dangerous for the environment,
mainly as the precursors for the relevant dioxins and furans.
Organochlorine pesticides like DDT (XII) (plus its metabolite DDE, XIII) and lindane (HCH, XIV) (Fig. 14.6) are mostly dangerous for the environment mainly as precursors for the relevant dioxins and furans.
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Cl "
Cl n
Cln
(X)
(XI)
Fig. 14.5. Polychlorinated benzenes (X) and biphenyls (XI)
CCI 3
CCl 2
I
II
ffI~
CI
CI
ffC~
CI
CI
(XII)
(XIII)
CI
CI
CI
CI
CI
CI
(XIV)
Fig. 14.6. DDT (XII), its metabolite DDE (XIII) and lindane (XIV)