Widespread Distribution

All of the types of non-emergency environmental reports that must be submitted to the EPA under TSCA 8(e) involve the discovery of adverse effects associated with chemicals that are known to be in the environment, or the discovery that chemicals known to have adverse effects are present in the environment. 

The discovery that chemicals that are known to have adverse effects are widespread in environmental media is reportable under 8(e). There must be more to a study than simply finding a substance associated with a substantial risk in the environment before the study becomes reportable. The distribution in the environment must have been not only imknown but also unsuspected and previously considered unlikely, and there must also be a 

At this point the differences between the 2003 Reporting Guidance and the 1978 Statement of Interpretation with respect to environmental effects are only of academic interest. 

The EPA has said that companies should consider a range of factors in determining if distribution is widespread, including the amount of contamination, as well as the extent and the pattern of contamination.  

If a company establishes internal levels of concern for a substance that are lower than any levels set by an agency, it should report studies as if the internal level were the appHcable ones.  

---

In 1986, David Weininger created the SMILES Simplified Molecular Input Line Entry System) notation at the US Environmental Research Laboratory, USEPA, Duluth, MN, for chemical data processing. The chemical structure information is highly compressed and simplified in this notation. The flexible, easy to learn language describes chemical structures as a line notation [20, 21]. The SMILES language has found widespread distribution as a universal chemical nomenclature... 

Serotonin. Seiotonin [50-67-9] (5-HT), (287) is a hydioxyethylaminoindole with widespread distribution. 5-HT is synthesized from... 

There are very limited data on the kinetics and metabolism of organotins in laboratory mammals. A widespread distribution of organotins throughout body tissues has been observed. Transplacental transfer seems to occur, whereas transfer across the blood-brain barrier is limited, since brain levels are usually low. The only compound for which data are available on metabolites is dibutyltin, which has butyl(3-hydroxybutyl)tin as its major metabolite. Limited information suggests quite rapid metabolism and elimination, with half-lives of several days. Much of an oral dose of dioctyltin was eliminated in the faeces, with the remainder in urine. 

It is generally felt that a substance is more likely to be a NT if it is unevenly distributed in the CNS although if it is widely used it will be widely distributed. Certainly the high concentration (5-10 pmol/g) of dopamine, compared with that of any other monoamine in the striatum or with dopamine in other brain areas, was indicative of its subsequently established role as a NT in that part of the CNS. This does not mean it cannot have an important function in other areas such as the mesolimbic system and parts of the cerebral cortex where it is present in much lower concentrations. In fact the concentration of the monoamines outside the striatum is very much lower than that of the amino acids but since the amino acids may have important biochemical functions that necessitate their widespread distribution, the NT component of any given level of amino acid is difficult to establish. 

Raccoon Adult Hair Widespread distribution and easily studied prey for endangered species (Florida panther)... 

Lake Common loon Adult Blood, egg Widespread distribution and easily studied large existing database sensitivity to Hg existing database for continental Hg exposure and lab and field effects... 

Riverine Mink Adult Fur Widespread distribution and easily studied existing database on exposure and effects sensitivity to Hg... 

Marine nearshore Harbor porpoise Adult Muscle Widespread distribution some existing data concern about immunological effects... 

Marine offshore Leach s storm-petrel Adult, juvenile Blood Widespread distribution, common, easily sampled at nest site, potential connection with global Hg signal... 

Comparison Belted Adult, Blood, Widespread distribution across habitat... 

A study with a dog exposed to an occluded dermal dose of TOCP labeled with radioactive phosphorus provides limited evidence that organophosphate esters in hydraulic fluids may be widely distributed after dermal absorption (Hodge and Sterner 1943). Similar widespread distribution of radioactivity among tissues was observed in male cats after dermal exposure to [uniformly labeled 14C-phenyl]TOCP (Nomeir and Abou-Donia 1986). Tissues and fluids with the highest concentrations of radioactivity in these studies included the bile, gall bladder, urinary bladder, liver, kidney, and fat, thus suggesting that TOCP and metabolites are somewhat preferentially distributed to these tissues. 

We have already mentioned the polymorphism that exists for Si02. The widespread distribution and unusual environmental conditions under which Si02 has interacted with other materials (particularly oxides) has resulted in there being a large number of naturally occurring silicates. The acidic nature of Si02 causes it to undergo reactions that can be represented as... 

As zebra mussel, red swamp crayfish can be used to monitor the aquatic environment for Hg pollution owing to its capacity to accumulate metals in its tissues [54]. Other features, namely abundant populations, long life cycle, widespread distribution, and relatively sedentary lifestyle, also contribute to use this crayfish as bio-indicator of monitoring environmental quality [55]. 

Primarily nonneuronal, multiple forms, widespread distribution Widespread distribution, enriched at MTOC, severs MT Widespread distribution, destabilizes MT... 

FIGURE 17-8 Distribution of A and A2A receptors in rat brain. (A) Autoradiograph of the binding of the Arselective radioligand [3H]cyclohexyladenosine to a slice of rat brain. (Courtesy of Dr Kevin Lee, University of Virginia.) Note the widespread distribution of A receptors and the particularly high density of receptors in the hippocampus. (B) Immunohistochemistry of A2A adenosine in the mouse brain. Note the restricted striatal distribution. 

AC7 is found in several tissues, with highest levels in lung and spleen, moderate levels in heart, and low levels in brain, kidney and skeletal muscle [13, 14]. In brain, the highest levels are found in cerebellar granule cells, while lower levels are seen in hippocampus, neocortex and striatum. AC9 is expressed in brain and skeletal muscle but also displays widespread distribution in other tissues. The soluble isoform sAC is enriched in testes but is also found in other tissues. 

---