Fluorosurfactant

Perfluorinated surfactants ( PFT ), organic surface-active compounds in which the hydrogen atoms have been replaced in its entirety on the carbon skeleton by fluorine atoms. Perfluorinated surfactants have no natural source. Due to their special physico-chemical properties they are produced industrially and used in a variety of products. They accumulate in the environment and in human and animal tissue. PFT are to be suspected carcinogens.

Chemical Properties

Perfluorinated surfactants have a high thermal and chemical stability. The carbon chain of the compound is hydrophobic, while the head group has a hydrophilic property. For this amphiphilic character due to the use as a surfactant.

In contrast to the conventional surfactants, the perfluorinated carbon chain also has a lipophobic character. So you has in addition to water from well as oil, grease and other non-polar compounds and dirt particles.

The perfluorinated surfactants can be divided into the following groups of substances:

• The perfluorinated alkyl sulfonates ( PFAS ) with the best-known representatives perfluorooctane sulfonate ( PFOS)
• The perfluorinated carboxylic acids ( PFCAs ) with the best-known representatives of perfluorooctanoic acid ( PFOA)

Some authors also include the Fluortelomeralkohole ( FTOH ) thereto, but it is polyfluorinated surfactants.

Production

For the production of perfluorinated surfactants are the method of electrochemical fluorination ( ECF) Simons (1941), or are applied in the industrial Fluortelomerisierung synthesizing most. Several thousand tonnes are produced annually PFT, the country with the largest production volume is the USA.

Use

The compounds are mainly used in the textile industry for the production of breathable jackets and in the paper industry for the production of dirt, grease and water repellent papers. Other applications include the photographic industry, the production of fire extinguishing agents, aviation, and Galvanic industry. They may also be part of lubricating and impregnants. In the preparation of fluoropolymers, PTFE ( polytetrafluoroethylene, "Teflon" ) and PVDF (polyvinylidene fluoride), PFOA is used as an emulsifier. In this application, PFOA occurs as a process and as a contaminant emission into final products.

Environmental and health aspects

PFT are not degradable in nature. They are therefore classified as persistent organic pollutants. Meanwhile, the chemicals in this group are spread throughout the world; they were about already detected in liver samples from polar bears.

The Demminer Health and Food Control Office warned in February 2008 against the consumption of local wild boar liver: The liver of examined animals that were killed in the district of Demmin, increased values ​​found of perfluorinated surfactants. The Federal Institute for Risk Assessment estimates an amount of 0.1 micrograms per kilogram of body weight than " tolerable daily intake " one. In the studied wild boar organs, an average of 122 micrograms per kilogram of liver was found, which "means that the consumption of 65 grams so loaded liver the daily tolerable amount of 8 micrograms has already been reached, " calculated the head of Demminer veterinary and public health department. The report notes a PFT is deposited in blood and liver of animals and is only slowly degraded.

Perfluorinated surfactants are toxic to humans and animals and are suspected to cause cancer. In the body, perfluorinated surfactants accumulate in the blood and organ tissue and are only slowly excreted (with humans in 4.4 years by about half in PFOA, PFOS in at about 8.7 years ). The first evidence in the blood of chemical workers were paid in the 1960s. It was only in 2001, sensitive measuring methods have been published according to which also allowed the detection of PFT strains in the general population. In 2006, PFT was detected in Lower Saxony in elevated concentrations in breast milk.

PFT in German waters

North Rhine -Westphalia

In March 2006, a study by the Institute for Hygiene and Public Health ( IHÖG ) at the University of Bonn were subsequently detected on the occurrence of PFT increased in various surface waters in Germany concentrations in the Ruhr and in the Möhne in the frame. Reason for this investigation was a test series with respect to high PFT values ​​in the aquatic environment in the U.S., the German researchers wanted to study German soils also after the carcinogen to check the quality of drinking water. In Arnsberg- Neheim district a concentration of 0.56 ug / L was found in drinking water, the Drinking Water Commission of the Federal Environment Agency seeks a value of 0.1 ug / L to. It turned out that the burden of industrial waste produced from fertilizer stemmed, which was spread on lying in the catchment area of the rivers fields. Some areas have been redeveloped as a result. Depending on the degree of contamination of the subsurface geology and opted for a drainage followed by activated carbon treatment of the leachate or for the removal and disposal of the topsoil (see pictures).

In November 2006, studies have shown at the sewage treatment plant in roadstead that in the inlet of the treatment plant, high levels of PFT in the waste water are available. Significantly elevated concentrations were also measured in the effluent of the WWTP yet. These studies suggest that PFT accumulate in sewage sludge.

Due to the wide application Perfluorinated surfactants via municipal sewage treatment plants in the environment and are trackable especially below settlement focus on comparatively weak outflow outfalls. An example of this is the Itter below Solingen, in which up to 0.7 g / l PFT were detected.

Harald Friedrich, at the time of the responsible department in the Ministry of Environment suggested due to the possible bias of the Ruhr water, basically to improve the treatment of drinking water gained in the waterworks at the Ruhr by other measures.

The PFT cargo der Ruhr in Essen were determined only 0.044 microgram per liter for the sum of PFOA and PFOS in the annual average for 2009. Compared to 2007, the average daily load decreased at the Ruhr estuary by a total of 59 percent.

Bavaria

Abnormal PFT values ​​were also measured in 2006 in South East Upper Bavaria beneath the water law approved initiation of the Gendorf industrial estate in the Alz (sum PFT about 8 g / L, of which PFOA 7.5 ug / L). According to still further dilution concentrations of 0.1 and 0.05 ug / L for PFOA were measured downstream of the Inn and the Danube.

For the construction of the Nord connection of the Nuremberg airport to the A3 motorway (main road 4f) with tunneling of the start and runway has made to support the government of Middle Franconia in their planning approval dated 15 February 2012 that the construction will not affect the found in the airport area PFT residues has. The proposed tunnel construction lowering of the ground water level by 22 meters requires extensive water diversion measures. In order for a shipment of PFT in the soil residues can not be excluded. This resulted from infiltration of fighting foam at fire drills on the airport grounds. First, since the methods of disposal of the PFT must be found and tested in the soil, the construction may be delayed by many years.

2012 Stoiber mill were also in the lake north of the airport and Munich detected in Lindacher lake north of the air base Ingolstadt / Manching elevated levels of PFT.

Saarland

An increased PFT - load of an extinguishing agent was also found in a fish pond and outfall that have been observed in Saarland after a " normal" fire fighting operation.

Clarification PFT - contaminated waters

PFT is not degraded in normal sewage treatment plants. These are based primarily on biological degradation by microorganisms, but can not metabolize the PFT. The PFT gets so unabated in the receiving water and the sludge. The only way to completely remove water from the PFT is, the waste water through activated charcoal filter. Polluter investigating the origin of the PFTs present in the wastewater are difficult. One with very good success so far employed passive sampler method is by Günther et al. (2009) described.

PFT in breast milk and food

A 2006 Greenpeace commissioned and carried out by the Fraunhofer IME study of French fries in several German cities showed a broad public the presence of PFT in food. Previously, the Institute had demonstrated in a pilot study PFT in breast milk. International studies show that food based on fish have comparatively high levels of PFOS, PFHxS and perfluorocarboxylic.

Uptake via food appears due to the long half-life in the human body to explain the PFT blood levels of the general population in the lower ppb range. However, the mathematical models underlying the studies have high uncertainties and can not rule out that other sources contribute significantly to human exposure.

Contact by military use

There are theories that perfluorinated surfactants are part of the universal fuel used by NATO JP -8, where they serve as a carrier for additives. There is suspicion is expressed that this fuel is associated with multiple chemical sensitivity.

Prohibitions

On a proposal from the European Commission, the Environment Committee of the European Parliament adopted an extension of the ban of perfluorinated surfactants on 13 July 2006. The European Commission had initially proposed a limit of 0.1 percent.

Which entered into force on 26 October 2007 amending Regulation 11 chemical law regulations pursuant to Directive 2006/122/EC of the European Parliament and of the Council of 12 December 2006 may from June 27, 2008 Perfluoroktansulfonate (PFOS; Perfluoroktansulfonsäure, metal salts, halides, amides and other derivatives including polymers) and preparations not be used more with a few exceptions with a mass content of 0.005% or PFOS.