Perfluorinated chemicals toxicity

Environmental Defence recently released Toxic Nation A Report on Pollution in Canadians (Environmental Defence 2005). Samples were collected from 11 people for the presence of 88 chemicals, including heavy metals, PBDEs, PCBs, perfluorinated chemicals, organochlorine pesticides, organophosphorus-insecticide metabolites, and VOCs. The study objectives included determining whether pollutants were present at measurable concentrations in Canadians, identifying chemicals of concern, and creating public awareness of methods for avoiding exposure. 

U.S. Environmental Protection Agency (2006) Meeting with Registrant on Perfluorinated Chemical (Masurf-FS-780, Fluowet PL 80-B, and Fluowet PL-80) Use as Inerts. Letter from the Office of Pollution Prevention and Toxics to the Office of Pesticide Programs. U.S. EPA Public Docket AR226-3804... 

Apart from of investigating the concentration of priority pollutants to assess the temporal and geographic trends as it has been done in the Ebro river basin until nowadays, the SCARCE project pretends to evaluate the consequences of the climate change in the water quality as well as predicting new environmental risks derived from water scarcity. This will be done by determining the presence of new priority (i.e. perfluorinated compounds) and emerging toxicants in Mediterranean river ecosystems in the Iberian Peninsula. In a subsequent step, the effects of chemical and environmental stressors on the biota will be assessed by combining field and experimental studies. The effects of multiple stressors will be addressed from a multi-biomarker perspective [27]. 

The acute and/or chronic nature of the toxicity of a chemical should be part of any decision-making process about its use or subsequent release. The focus cannot be solely on reduction of acute hazards, which tends to be easily achievable. The majority of cases in which chemicals have been released into the environment, only to cause serious ecological impacts over large spatial scales, were usually identified after many years, and at chronic low-dose exposures, with low acute toxicity to nontarget organisms. The classic examples of DDT and other chlorinated pesticides such as dieldrin and toxaphene, along with PCBs, exemplify the flaws in an approach that focuses on acute hazards, with more recent examples being the perfluorinated... 

Approximately 180 vapor materials have been screened in the laboratory as candidate microencapsulated vapor taggants. In addition, several hundred other materials were rejected after a thorough analytical review. Five candidate perfluorinated cycloalkane compounds have been extensively tested, and have successfully completed barrier penetration, mutagen, toxicity, and atmospheric impact testing. The five candidate vapor taggants and their chemical properties are shown in table 16 ... 

The unique properties of highly fluorinated and perfluorinated ( fluorous ) solvents and reagents open several routes to a solution of these problems and to a sustainable green chemistry [1-5]. These properties include their very temperature-dependent miscibility with typical hydrocarbons, their non-toxicity, and their extreme chemical inertness. 

In a previous paper (2), the author described a method to dissolve the sulfonyl fluoride precursor form of a perfluorinated sulfonate ionomer. Commercially available forms of Nafion are supplied as activated membranes (i.e., saponified from the precursor to the ionic form), and near-quantitative reconstitution of the precursor functionality (such as RSOjF) must first be performed using a chemical reagent such as SF. f4) before dissolution in perhalogenated solvents is possible. Besides adding to the cost of membrane manufacture, SF. is extremely toxic and corrosive and must be handled in nickel alloy pressure equipment. Therefore, a method for dissolving perfluorinated ionomers directly would be more desirable. 

The most effective fluorous solvents are perfluorinated alkanes, perfluorinated dialkyl ethers, and perfluorinated trialkyl amines. Their remarkable chemical inertness, thermal stability, and nonflammability coupled with their unusual physical properties make them particularly attractive for catalyst immobilization. Furthermore, these materials are practically nontoxic by oral ingestion, inhalation, or intraperito-neal injection [7]. Although their thermal degradation can produce toxic decomposition products, such decomposition generally begins only at very high temperatures well above the thermal stability limits of most organometallic compounds. 

There is a pending rulemaking to require certain classes of polymers with perfluorinated units—polymers in which fluorine atoms are substituted for the hydrogen atoms that are present in many polymers—to go through the PMN process. The proposed rule would make the polymer exemption unavailable for these polymers because, as the EPA explained in its proposed rule, the EPA could not assume that all such polymers are risk-free. The EPA cited liver, developmental, and reproductive toxicity at very low exposure levels as well as data that indicates that some perfluorinated polymers maybe carcinogens. These generalizations have been criticized by the chemical industry. ... 

Perfluorinated solvents. The strength of the C—F bond confers them both thermal and chemical stability (non-flammable, inert and non-toxic), which permits them to be used in a variety of temperatures and conditions. Nevertheless, their high prize and the fact that they persist in the environment are very important drawbacks. 

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