Persistence, environmental

Produced by fungi which can contaminate crops. Some, such as zearalenone, are oestrogenic DDT, lindane and beta-HCH are common, persistent environmental pollutants Widespread, persistent environmental pollutants... 

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. 

Characteristics (physical appearance/odor, stability, persistency, environmental fate)... 

Acid drainage is a persistent environmental problem in many mineralized areas. The problem is especially pronounced in areas that host or have hosted mining activity (e.g., Lind and Hem, 1993), but it also occurs naturally in unmined areas. The acid drainage results from weathering of sulfide minerals that oxidize to produce hydrogen ions and contribute dissolved metals to solution (e.g., Blowes et al., 2005). 

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)... 

Move the elemental composition of technology closer to biocliemistry to eliminate persistent environmentally mobile pollutants... 

Bumpus J. A., M. Tien, D. Wright, and S.D. Aust (1985). Oxidation of persistent environmental pollutants by a white rot fungus. Science 228 1434-1436. 

Heptachlor [76-44-8] or l,4,5,6,7,8,8-heptachloro-3, 4,7,7 -tetrahydro-4,7-methano-lff-indene (33) (mp 95°C, vp 0.04 Pa at 25°C), is soluble in water to 56 //g/L. It is about 3—5 times more active than chlordane as an insecticide. The rat LD5Qs are 100, 162 (oral) and 195,250 (dermal) mg/kg. Heptachlor is oxidized readily to heptachlor epoxide [1024-57-3] (mp 159°C), rat oral LD5Q 47 mg/kg, which is an important and highly persistent environmental pollutant. Hydrogenation of heptachlor produces p-dihydroheptachlor [14168-01-5] (mp 135°C), which retains high insecticidal activity with very low mammalian toxicity, rat oral LD50 >5000 mg/kg. 

The regular use of sodium pentachlorophenate has proved successful in many instances, but it is a persistent environmental hazard and cannot be recommended. However, o -benzy 1-p -chlorophenol can often produce goods results, with low bacteria counts and clean systems. But the timing of biocide applications needs to be matched carefully with the production cycles (and process leakage periods) for optimum product effectiveness. 

Brouwer, A., Morse, D.C., Lans, M.C., Schuur, A.G., Murk, A.J., Klasson-Wehler, E., Bergman, A., Visser, T.J., 1998. Interactions of persistent environmental organohalogens with the thyroid hormone system Mechanisms and possible consequences for animal and human health. Toxicol. Health. 14, 59-84. 

Another notable class of persistent organohalide compounds is the polychlorinated biphenyl (PCB) class, discussed in Section 16.4. Widely used in industrial applications, these compounds have become widespread and persistent environmental pollutants. The compound 2,3,7,8-tetrachlo-rodibenzo-p-dioxin (TCDD), commonly known as dioxin, discussed in Section 16.6, is an extremely persistent manufacturing by-product that has caused significant environmental problems. 

The exposure pathway and physicochemical characteristics of a particular environmental chemical can provide useful information on the likelihood of childhood exposure (chapter 5). Age-specific exposure pathways of particular relevance include those during the prenatal and early developmental years postnatally (e.g. placental transfer, breast milk, toys, soil, indoor air/dust, child-care centres). Exposures to persistent environmental chemicals are of special concern, since the internal exposure may continue and result in a level sufficient to cause effects during critical developmental stages, even after the external exposure has ceased or been removed. 

Green N., Bergman A. (2005) Chemical reactivity as a tool for estimating persistance. Environmental Science and Technology 39 480A-486A. 

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