Persistent environmental contaminants

Nacci, D.E., Coiro, L., and Champlin, D. et al. (1999). Adaptations of wild populations of the estuarine fish Fundulus heteroclitus to persistent environmental contaminants. Marine Biology 134, 9-17. 

Name persistent environmental contaminants (have various names depending on agency - i.e. US EPA persistent bioaccumulative and toxic (PBT) or United Nations persistent organic pollutant (POP)... 

DDT and the cyclodiene pesticides are only a few components of a large soup of persistent environmental contaminants consisting of halogenated organics - that is, molecules with a carbon skeleton (usually aromatic) deriving some or all of their toxicological activity through the insertion of chlorine. 

Chlorinated naphthalenes (CN) are persistent environmental contaminants, which accumulate and biomagnify in human and wildlife food-chains. Many of the CN congeners show relatively high dioxin-like activity and have been identified as common food contaminants, especially in fish. 

Chlorinated naphthalenes are persistent environmental contaminants, which accumulate and biomagnify in human and wildlife food-chains. 

Polychorinated biphenyl (PCB) mixtures were used extensively in the past as coolant fluids in power transformers and capacitors. PCBs were widely used because of their higher stability, but are persistent environmental contaminants due to careless disposal practices, leakage, or accidents. Similar to PAHs, PCBs are neutral, highly hydrophobic, and present a large number of congeners, thus demanding EKC methodologies. 

Environmental Not expected to be a persistent environmental contaminant, due to rapid transfomiatnn hydrolyzes rapidly in moist soils readily biodeg. 

Typical contaminants of concern are PCBs and polychlorinated dibenzo-p-dioxins (dioxins), which are highly persistent environmental contaminants arising from industrial processes, detergents, and disinfectants (especially in milk) that are used in cleaning processes, process contaminants such as PAHs and acrylamide, and food packaging monomers and residual solvents from extraction processes or printed packaging material. 

Even though polychlorinated biphenyls (PCBs) are no longer imported into Canada or manufactured in many parts of the globe, large quantities are stiU being used in transformers or kept in storage facilities for future disposal. First developed and synthesized in 1881 and introduced commercially in 1929, PCBs were manufaetured in response to the North American electrical industry s urgent need for a more stable and effeetive transformer and eapacitor fluid. Unfortunately, their chemical and physical stability have also led to widespread and persistent environmental contamination. As a result, the further import and use of PCBs were banned in Canada in 1977. 

Some pharmaceuticals, such as antibiotics, should be recognized as ubiquitous persistent environmental contaminants. 

Given the relatively well-known history of production and release of many persistent environmental contaminants, the contaminants themselves often ean serve as a useful historical marker. Figure 10.9 shows arecord ofU.S. polychlorinated biphenyl (PCB) sales and a corresponding dated profile of PCB in Lake Ontario sediments (Schwarzenbach et al., 1993). Similar to the radioisotope methods deseribed above, the similarity of the PCB manufacturing history and depositional profiles provides evidence of a long-term, stable deposition of solids-associated PCB with minimal mixing of surficial sediments. 

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